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Subject[PATCH] LTT for 2.5.38 2/9: Trace driver

This is the LTT trace driver itself.

Here are the file modifications:
drivers/Makefile | 1
drivers/trace/Config.help | 48
drivers/trace/Config.in | 8
drivers/trace/Makefile | 17
drivers/trace/tracer.c | 2398 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/trace/tracer.h | 233 ++++
6 files changed, 2705 insertions
diff -urpN linux-2.5.38/drivers/Makefile linux-2.5.38-ltt/drivers/Makefile
--- linux-2.5.38/drivers/Makefile Sun Sep 22 00:25:17 2002
+++ linux-2.5.38-ltt/drivers/Makefile Sun Sep 22 00:51:51 2002
@@ -41,5 +41,6 @@ obj-$(CONFIG_MD) += md/
obj-$(CONFIG_BLUEZ) += bluetooth/
obj-$(CONFIG_HOTPLUG_PCI) += hotplug/
obj-$(CONFIG_ISDN_BOOL) += isdn/
+obj-$(CONFIG_TRACE) += trace/

include $(TOPDIR)/Rules.make
diff -urpN linux-2.5.38/drivers/trace/Config.help linux-2.5.38-ltt/drivers/trace/Config.help
--- linux-2.5.38/drivers/trace/Config.help Wed Dec 31 19:00:00 1969
+++ linux-2.5.38-ltt/drivers/trace/Config.help Sun Sep 22 00:51:51 2002
@@ -0,0 +1,48 @@
+Kernel events tracing support
+CONFIG_TRACE
+ It is possible for the kernel to log important events to a tracing
+ driver. Doing so, enables the use of the generated traces in order
+ to reconstruct the dynamic behavior of the kernel, and hence the
+ whole system.
+
+ The tracing process contains 4 parts :
+ 1) The logging of events by key parts of the kernel.
+ 2) The trace driver that keeps the events in a data buffer.
+ 3) A trace daemon that opens the trace driver and is notified
+ every time there is a certain quantity of data to read
+ from the trace driver (using SIG_IO).
+ 4) A trace event data decoder that reads the accumulated data
+ and formats it in a human-readable format.
+
+ If you say Y or M here, the first part of the tracing process will
+ always take place. That is, critical parts of the kernel will call
+ upon the kernel tracing function. The data generated doesn't go
+ any further until a trace driver registers himself as such with the
+ kernel. Therefore, if you answer Y, then the driver will be part of
+ the kernel and the events will always proceed onto the driver and
+ if you say M, then the events will only proceed onto the driver when
+ it's module is loaded. Note that event's aren't logged in the driver
+ until the profiling daemon opens the device, configures it and
+ issues the "start" command through ioctl().
+
+ The impact of a fully functionnal system (kernel event logging +
+ driver event copying + active trace daemon) is of 2.5% for core events.
+ This means that for a task that took 100 seconds on a normal system, it
+ will take 102.5 seconds on a traced system. This is very low compared
+ to other profiling or tracing methods.
+
+ For more information on kernel tracing, the trace daemon or the event
+ decoder, please check the following address :
+ http://www.opersys.com/LTT
+
+CONFIG_LOCKLESS_TRACE
+ There are normally two tracing schemes available and selectable at
+ run-time via the trace daemon - locking and lockless. In some cases
+ e.g. embedded real-time systems, it may be desirable to exclude the
+ lockless code from the driver in the interest of making it smaller.
+ Even in such a case, the advantages provided by the lockless code
+ outweigh the slight increase in size (about 4KB). Unless you're
+ really out of space, keep this to Y. Setting this to N is probably
+ a sign that you probably have size problems elsewhere ...
+
+ If unsure, say Y.
diff -urpN linux-2.5.38/drivers/trace/Config.in linux-2.5.38-ltt/drivers/trace/Config.in
--- linux-2.5.38/drivers/trace/Config.in Wed Dec 31 19:00:00 1969
+++ linux-2.5.38-ltt/drivers/trace/Config.in Sun Sep 22 00:51:51 2002
@@ -0,0 +1,8 @@
+mainmenu_option next_comment
+comment 'Kernel tracing'
+tristate 'Kernel events tracing support' CONFIG_TRACE
+if [ "$CONFIG_TRACE" != "n" ]; then
+ dep_mbool ' Lock-free tracing support' CONFIG_LOCKLESS_TRACE $CONFIG_TRACE
+fi
+
+endmenu
diff -urpN linux-2.5.38/drivers/trace/Makefile linux-2.5.38-ltt/drivers/trace/Makefile
--- linux-2.5.38/drivers/trace/Makefile Wed Dec 31 19:00:00 1969
+++ linux-2.5.38-ltt/drivers/trace/Makefile Sun Sep 22 00:51:51 2002
@@ -0,0 +1,17 @@
+#
+# Makefile for the kernel tracing drivers.
+#
+# Note! Dependencies are done automagically by 'make dep', which also
+# removes any old dependencies. DON'T put your own dependencies here
+# unless it's something special (ie not a .c file).
+#
+# Note 2! The CFLAGS definitions are now inherited from the
+# parent makes..
+#
+
+O_TARGET := built-in.o
+
+# Is it loaded as a module or as part of the kernel
+obj-$(CONFIG_TRACE) = tracer.o
+
+include $(TOPDIR)/Rules.make
diff -urpN linux-2.5.38/drivers/trace/tracer.c linux-2.5.38-ltt/drivers/trace/tracer.c
--- linux-2.5.38/drivers/trace/tracer.c Wed Dec 31 19:00:00 1969
+++ linux-2.5.38-ltt/drivers/trace/tracer.c Sun Sep 22 00:51:51 2002
@@ -0,0 +1,2398 @@
+/*
+ * linux/drivers/trace/tracer.c
+ *
+ * (C) Copyright, 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
+ *
+ * Contains the code for the kernel tracing driver (tracer for short).
+ *
+ * Author:
+ * Karim Yaghmour (karim@opersys.com)
+ *
+ * Changelog:
+ * 16/02/02, Added Tom Zanussi's implementation of K42's lockless logging.
+ * K42 tracing guru Robert Wisniewski participated in the
+ * discussions surrounding this implementation. A big thanks to
+ * the IBM folks.
+ * 03/12/01, Added user event support.
+ * 05/01/01, Modified PPC bit manipulation functions for x86 compatibility.
+ * (andy_lowe@mvista.com)
+ * 15/11/00, Finally fixed memory allocation and remapping method. Now using
+ * BTTV-driver-inspired code.
+ * 13/03/00, Modified tracer so that the daemon mmaps the tracer's buffers
+ * in it's address space rather than use "read".
+ * 26/01/00, Added support for standardized buffer sizes and extensibility
+ * of events.
+ * 01/10/99, Modified tracer in order to used double-buffering.
+ * 28/09/99, Adding tracer configuration support.
+ * 09/09/99, Chaging the format of an event record in order to reduce the
+ * size of the traces.
+ * 04/03/99, Initial typing.
+ *
+ * Note:
+ * The sizes of the variables used to store the details of an event are
+ * planned for a system who gets at least one clock tick every 10
+ * milli-seconds. There has to be at least one event every 2^32-1
+ * microseconds, otherwise the size of the variable holding the time doesn't
+ * work anymore.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/time.h>
+#include <linux/trace.h>
+#include <linux/wrapper.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#include <asm/io.h>
+#include <asm/current.h>
+#include <asm/uaccess.h>
+#include <asm/bitops.h>
+#include <asm/pgtable.h>
+#include <asm/trace.h>
+
+#include "tracer.h"
+
+/* Module information */
+MODULE_AUTHOR("Karim Yaghmour (karim@opersys.com)");
+MODULE_DESCRIPTION("Linux Trace Toolkit (LTT) kernel tracing driver");
+MODULE_LICENSE("GPL");
+
+/* Driver */
+static int sMajorNumber; /* Major number of the tracer */
+static int sOpenCount; /* Number of times device is open */
+/* Locking */
+static int sTracLock; /* Tracer lock used to lock primary buffer */
+static spinlock_t sSpinLock; /* Spinlock in order to lock kernel */
+/* Daemon */
+static int sSignalSent; /* A signal has been sent to the daemon */
+static struct task_struct* sDaemonTaskStruct; /* Task structure of the tracer daemon */
+/* Tracer configuration */
+static int sTracerStarted; /* Is the tracer started */
+static trace_event_mask sTracedEvents; /* Bit-field of events being traced */
+static trace_event_mask sLogEventDetailsMask; /* Log the details of the events mask */
+static int sLogCPUID; /* Log the CPUID associated with each event */
+static int sUseSyscallEIPBounds; /* Use adress bounds to fetch the EIP where call is made */
+static int sLowerEIPBoundSet; /* The lower bound EIP has been set */
+static int sUpperEIPBoundSet; /* The upper bound EIP has been set */
+static void* sLowerEIPBound; /* The lower bound EIP */
+static void* sUpperEIPBound; /* The upper bound EIP */
+static int sTracingPID; /* Tracing only the events for one pid */
+static int sTracingPGRP; /* Tracing only the events for one process group */
+static int sTracingGID; /* Tracing only the events for one gid */
+static int sTracingUID; /* Tracing only the events for one uid */
+static pid_t sTracedPID; /* PID being traced */
+static pid_t sTracedPGRP; /* Process group being traced */
+static gid_t sTracedGID; /* GID being traced */
+static uid_t sTracedUID; /* UID being traced */
+static int sSyscallEIPDepthSet; /* The call depth at which to fetch EIP has been set */
+static int sSyscallEIPDepth; /* The call depth at which to fetch the EIP */
+/* Event data buffers */
+static int sBufReadComplete; /* Number of buffers completely filled */
+static int sSizeReadIncomplete; /* Quantity of data read from incomplete buffers */
+static int sEventsLost; /* Number of events lost because of lack of buffer space */
+static u32 sBufSize; /* Buffer sizes */
+static u32 sAllocSize; /* Size of buffers allocated */
+static u32 sBufferID; /* Unique buffer ID */
+static char* sTracBuf = NULL; /* Trace buffer */
+static char* sWritBuf = NULL; /* Buffer used for writting */
+static char* sReadBuf = NULL; /* Buffer used for reading */
+static char* sWritBufEnd; /* End of write buffer */
+static char* sReadBufEnd; /* End of read buffer */
+static char* sWritPos; /* Current position for writting */
+static char* sReadLimit; /* Limit at which read should stop */
+static char* sWritLimit; /* Limit at which write should stop */
+static int sUseLocking; /* Holds command from daemon */
+static u32 sBufnoBits; /* Holds command from daemon */
+static u32 sBufOffsetBits; /* Holds command from daemon */
+static int sBuffersFull; /* All-buffers-full boolean */
+
+/* Time */
+static struct timeval sBufferStartTime; /* The time at which the buffer was started */
+
+/* Large data components allocated at load time */
+static char *sUserEventData = NULL; /* The data associated with a user event */
+
+/* The global per-buffer control data structure, shared between the tracing
+ driver and the trace daemon via ioctl. */
+static struct buffer_control sBufferControl;
+
+/* The size of the structures used to describe the events */
+static int sEventStructSize[TRACE_EV_MAX + 1] =
+{
+ sizeof(trace_start) /* TRACE_START */ ,
+ sizeof(trace_syscall_entry) /* TRACE_SYSCALL_ENTRY */ ,
+ 0 /* TRACE_SYSCALL_EXIT */ ,
+ sizeof(trace_trap_entry) /* TRACE_TRAP_ENTRY */ ,
+ 0 /* TRACE_TRAP_EXIT */ ,
+ sizeof(trace_irq_entry) /* TRACE_IRQ_ENTRY */ ,
+ 0 /* TRACE_IRQ_EXIT */ ,
+ sizeof(trace_schedchange) /* TRACE_SCHEDCHANGE */ ,
+ 0 /* TRACE_KERNEL_TIMER */ ,
+ sizeof(trace_soft_irq) /* TRACE_SOFT_IRQ */ ,
+ sizeof(trace_process) /* TRACE_PROCESS */ ,
+ sizeof(trace_file_system) /* TRACE_FILE_SYSTEM */ ,
+ sizeof(trace_timer) /* TRACE_TIMER */ ,
+ sizeof(trace_memory) /* TRACE_MEMORY */ ,
+ sizeof(trace_socket) /* TRACE_SOCKET */ ,
+ sizeof(trace_ipc) /* TRACE_IPC */ ,
+ sizeof(trace_network) /* TRACE_NETWORK */ ,
+ sizeof(trace_buffer_start) /* TRACE_BUFFER_START */ ,
+ 0 /* TRACE_BUFFER_END */ ,
+ sizeof(trace_new_event) /* TRACE_NEW_EVENT */ ,
+ sizeof(trace_custom) /* TRACE_CUSTOM */ ,
+ sizeof(trace_change_mask) /* TRACE_CHANGE_MASK */
+};
+
+/* The file operations available for the tracer */
+static struct file_operations sTracerFileOps =
+{
+ owner: THIS_MODULE,
+ ioctl: tracer_ioctl,
+ mmap: tracer_mmap,
+ open: tracer_open,
+ release: tracer_release,
+ fsync: tracer_fsync,
+};
+
+#if CONFIG_LOCKLESS_TRACE
+static u32 sLastEventIndex; /* For full-buffers state */
+static struct timeval sLastEventTimeStamp; /* For full-buffers state */
+/* Space reserved for TRACE_EV_BUFFER_START */
+static u32 sStartReserve = TRACER_FIRST_EVENT_SIZE;
+
+/* Space reserved for TRACE_EV_BUFFER_END event + sizeof lost word, which
+ though the sizeof lost word isn't necessarily contiguous with rest of
+ event (it's always at the end of the buffer) is included here for code
+ clarity. */
+static u32 sEndReserve = TRACER_LAST_EVENT_SIZE;
+#endif /* CONFIG_LOCKLESS_TRACE */
+
+/* This inspired by rtai/shmem */
+#define FIX_SIZE(x) (((x) - 1) & PAGE_MASK) + PAGE_SIZE
+
+/* \begin{Code inspired from BTTV driver} */
+
+/* Here we want the physical address of the memory.
+ * This is used when initializing the contents of the
+ * area and marking the pages as reserved.
+ */
+static inline unsigned long kvirt_to_pa(unsigned long adr)
+{
+ unsigned long kva, ret;
+
+ kva = (unsigned long) page_address(vmalloc_to_page((void *) adr));
+ kva |= adr & (PAGE_SIZE - 1); /* restore the offset */
+ ret = __pa(kva);
+ return ret;
+}
+
+static void *rvmalloc(unsigned long size)
+{
+ void *mem;
+ unsigned long adr;
+
+ mem = vmalloc_32(size);
+ if (!mem)
+ return NULL;
+
+ memset(mem, 0, size); /* Clear the ram out, no junk to the user */
+ adr = (unsigned long) mem;
+ while (size > 0) {
+ mem_map_reserve(vmalloc_to_page((void *) adr));
+ adr += PAGE_SIZE;
+ size -= PAGE_SIZE;
+ }
+
+ return mem;
+}
+
+static void rvfree(void *mem, unsigned long size)
+{
+ unsigned long adr;
+
+ if (!mem)
+ return;
+
+ adr = (unsigned long) mem;
+ while ((long) size > 0) {
+ mem_map_unreserve(vmalloc_to_page((void *) adr));
+ adr += PAGE_SIZE;
+ size -= PAGE_SIZE;
+ }
+ vfree(mem);
+}
+
+static int tracer_mmap_region(struct vm_area_struct *vma,
+ const char *adr,
+ const char *start_pos,
+ unsigned long size)
+{
+ unsigned long start = (unsigned long) adr;
+ unsigned long page, pos;
+
+ pos = (unsigned long) start_pos;
+ while (size > 0) {
+ page = kvirt_to_pa(pos);
+ if (remap_page_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
+ return -EAGAIN;
+ start += PAGE_SIZE;
+ pos += PAGE_SIZE;
+ size -= PAGE_SIZE;
+ }
+ return 0;
+}
+/* \end{Code inspired from BTTV driver} */
+
+/**
+ * tracer_write_to_buffer: - Write data to destination buffer
+ *
+ * Writes data to the destination buffer and updates the begining the
+ * buffer write position.
+ */
+#define tracer_write_to_buffer(DEST, SRC, SIZE) \
+do\
+{\
+ memcpy(DEST, SRC, SIZE);\
+ DEST += SIZE;\
+} while(0);
+
+#if CONFIG_LOCKLESS_TRACE
+/*** Lockless scheme functions ***/
+
+/**
+ * init_buffer_control: - Init buffer control struct for new tracing run.
+ * @pmBC: buffer control struct to be initialized
+ * @pmUseLockless: which tracing scheme to use, TRUE for lockless
+ * @pmBufnoBits: number of bits in index word to use for buffer number
+ * @pmOffsetBits: number of bits in index word to use for buffer offset
+ *
+ * Sanity of param values should be checked by caller. i.e. bufno_bits and
+ * offset_bits must reflect sane buffer sizes/numbers.
+ */
+static void init_buffer_control(struct buffer_control * pmBC,
+ int pmUseLockless,
+ u8 pmBufnoBits,
+ u8 pmOffsetBits)
+{
+ unsigned i;
+
+ if((pmBC->using_lockless = pmUseLockless) == TRUE) {
+ pmBC->index = sStartReserve;
+ pmBC->bufno_bits = pmBufnoBits;
+ pmBC->n_buffers = TRACE_MAX_BUFFER_NUMBER(pmBufnoBits);
+ pmBC->offset_bits = pmOffsetBits;
+ pmBC->offset_mask = TRACE_BUFFER_OFFSET_MASK(pmOffsetBits);
+ pmBC->index_mask = (1UL << (pmBufnoBits + pmOffsetBits)) - 1;
+
+ pmBC->buffers_produced = pmBC->buffers_consumed = 0;
+
+ /* When a new buffer is switched to, TRACE_BUFFER_SIZE is
+ subtracted from its fill_count in order to initialize it
+ to the empty state. The reason it's done this way is
+ because an intervening event may have already been written
+ to the buffer while we were in the process of switching and
+ thus blindly initializing to 0 would erase that event.
+ The first buffer is initialized to 0 and the others are
+ initialized to TRACE_BUFFER_SIZE because the very first
+ buffer we ever see won't be initialized in that way by
+ the switching code and since there's never been an event,
+ we know it should be 0 and that it must be explicitly
+ initialized that way before logging begins. sStartReserve
+ is is factored into the end-of-buffer processing, so isn't
+ added to the fill counts here, except for the first. */
+ atomic_set(&pmBC->fill_count[0], (int)sStartReserve);
+ for(i = 1; i < TRACER_MAX_BUFFERS; i++)
+ atomic_set(&pmBC->fill_count[i], (int)TRACE_BUFFER_SIZE(pmOffsetBits));
+
+ /* All buffers are empty at this point */
+ sBuffersFull = FALSE;
+ }
+}
+
+/* These inline atomic functions wrap the linux versions in order to
+ implement the interface we want as well as to ensure memory barriers. */
+
+/**
+ * compare_and_store_volatile: - Self-explicit
+ * @ptr: ptr to the word that will receive the new value
+ * @oval: the value we think is currently in *ptr
+ * @nval: the value *ptr will get if we were right
+ *
+ * If *ptr is still what we think it is, atomically assign nval to it and
+ * return a boolean indicating TRUE if the new value was stored, FALSE
+ * otherwise.
+ *
+ * Pseudocode for this operation:
+ *
+ * if(*ptr == oval) {
+ * *ptr = nval;
+ * return TRUE;
+ * } else {
+ * return FALSE;
+ * }
+ */
+inline int compare_and_store_volatile(volatile u32 *ptr,
+ u32 oval,
+ u32 nval)
+{
+ u32 prev;
+
+ barrier();
+ prev = cmpxchg(ptr, oval, nval);
+ barrier();
+
+ return (prev == oval);
+}
+
+/**
+ * atomic_set_volatile: - Atomically set the value in ptr to nval.
+ * @ptr: ptr to the word that will receive the new value
+ * @nval: the new value
+ *
+ * Uses memory barriers to set *ptr to nval.
+ */
+inline void atomic_set_volatile(atomic_t *ptr,
+ u32 nval)
+{
+ barrier();
+ atomic_set(ptr, (int)nval);
+ barrier();
+}
+
+/**
+ * atomic_add_volatile: - Atomically add val to the value at ptr.
+ * @ptr: ptr to the word that will receive the addition
+ * @val: the value to add to *ptr
+ *
+ * Uses memory barriers to add val to *ptr.
+ */
+inline void atomic_add_volatile(atomic_t *ptr, u32 val)
+{
+ barrier();
+ atomic_add((int)val, ptr);
+ barrier();
+}
+
+/**
+ * atomic_sub_volatile: - Atomically substract val from the value at ptr.
+ * @ptr: ptr to the word that will receive the subtraction
+ * @val: the value to subtract from *ptr
+ *
+ * Uses memory barriers to substract val from *ptr.
+ */
+inline void atomic_sub_volatile(atomic_t *ptr, s32 val)
+{
+ barrier();
+ atomic_sub((int)val, ptr);
+ barrier();
+}
+
+/**
+ * trace_commit: - Atomically commit a reserved slot in the buffer.
+ * @index: index into the trace buffer
+ * @len: the value to add to fill_count of the buffer contained in index
+ *
+ * Atomically add len to the fill_count of the buffer specified by the
+ * buffer number contained in index.
+ */
+static inline void trace_commit(u32 index, u32 len)
+{
+ u32 bufno = TRACE_BUFFER_NUMBER_GET(index, sBufferControl.offset_bits);
+ atomic_add_volatile(&sBufferControl.fill_count[bufno], len);
+}
+
+/**
+ * write_start_buffer_event: - Write start-buffer event to buffer start.
+ * @pmIndex: index into the trace buffer
+ * @pmTime: the time of the start-buffer event
+ *
+ * Writes start-buffer event at the start of the buffer specified by the
+ * buffer number contained in pmIndex.
+ */
+static inline void write_start_buffer_event(u32 pmIndex, struct timeval pmTime)
+{
+ trace_buffer_start lStartBufferEvent; /* Start of new buffer event */
+ u8 lEventID; /* Event ID of last event */
+ uint16_t lDataSize; /* Size of tracing data */
+ trace_time_delta lTimeDelta; /* The time elapsed between now and the last event */
+ char* lWritPos; /* Current position for writing */
+
+ /* Clear the offset bits of index to get the beginning of buffer */
+ lWritPos = sTracBuf + TRACE_BUFFER_OFFSET_CLEAR(pmIndex,
+ sBufferControl.offset_mask);
+
+ /* Increment buffer ID */
+ sBufferID++;
+
+ /* Write the start of buffer event */
+ lStartBufferEvent.ID = sBufferID;
+ lStartBufferEvent.Time = pmTime;
+
+ /* Write event type to tracing buffer */
+ lEventID = TRACE_EV_BUFFER_START;
+ tracer_write_to_buffer(lWritPos,
+ &lEventID,
+ sizeof(lEventID));
+
+ /* Write event time delta to tracing buffer */
+ lTimeDelta = 0;
+ tracer_write_to_buffer(lWritPos,
+ &lTimeDelta,
+ sizeof(lTimeDelta));
+
+ /* Write event structure */
+ tracer_write_to_buffer(lWritPos,
+ &lStartBufferEvent,
+ sizeof(lStartBufferEvent));
+
+ /* Compute the data size */
+ lDataSize = sizeof(lEventID)
+ + sizeof(lTimeDelta)
+ + sizeof(lStartBufferEvent)
+ + sizeof(lDataSize);
+
+ /* Write the length of the event description */
+ tracer_write_to_buffer(lWritPos,
+ &lDataSize,
+ sizeof(lDataSize));
+}
+
+/**
+ * write_end_buffer_event: - Write end-buffer event to end of buffer.
+ * @pmIndex: index into the trace buffer
+ * @pmTime: the time of the end-buffer event
+ *
+ * Writes end-buffer event at the end of the buffer specified by the
+ * buffer number contained in pmIndex, at the offset also contained in
+ * pmIndex.
+ */
+static inline void write_end_buffer_event(u32 pmIndex, struct timeval pmTime)
+{
+ u8 lEventID; /* Event ID of last event */
+ u8 lCPUID; /* CPUID of currently runing process */
+ trace_time_delta lTimeDelta; /* The time elapsed between now and the last event */
+ char* lWritPos; /* Current position for writing */
+
+ lWritPos = sTracBuf + pmIndex;
+
+ /* Write the CPUID to the tracing buffer, if required */
+ if (sLogCPUID == TRUE) {
+ lCPUID = smp_processor_id();
+ tracer_write_to_buffer(lWritPos,
+ &lCPUID,
+ sizeof(lCPUID));
+ }
+ /* Write event type to tracing buffer */
+ lEventID = TRACE_EV_BUFFER_END;
+ tracer_write_to_buffer(lWritPos,
+ &lEventID,
+ sizeof(lEventID));
+
+ /* Write event time delta to tracing buffer */
+ lTimeDelta = 0;
+ tracer_write_to_buffer(lWritPos,
+ &lTimeDelta,
+ sizeof(lTimeDelta));
+}
+
+/**
+ * write_lost_size: - Write lost size to end of buffer contained in index.
+ * @pmIndex: index into the trace buffer
+ * @pmSizeLost: number of bytes lost at the end of buffer
+ *
+ * Writes the value contained in pmSizeLost as the last word in the
+ * the buffer specified by the buffer number contained in pmIndex. The
+ * 'lost size' is the number of bytes that are left unused by the tracing
+ * scheme at the end of a buffer for a variety of reasons.
+ */
+static inline void write_lost_size(u32 pmIndex, u32 pmSizeLost)
+{
+ char* lWritBufEnd; /* End of buffer */
+
+ /* Get end of buffer by clearing offset and adding buffer size */
+ lWritBufEnd = sTracBuf
+ + TRACE_BUFFER_OFFSET_CLEAR(pmIndex, sBufferControl.offset_mask)
+ + TRACE_BUFFER_SIZE(sBufferControl.offset_bits);
+
+ /* Write size lost at the end of the buffer */
+ *((u32 *) (lWritBufEnd - sizeof(pmSizeLost))) = pmSizeLost;
+}
+
+/**
+ * finalize_buffer: - Utility function consolidating end-of-buffer tasks.
+ * @pmEndIndex: index into trace buffer to write the end-buffer event at
+ * @pmSizeLost: number of unused bytes at the end of the buffer
+ * @pmTimestamp: the time of the end-buffer event
+ *
+ * This function must be called from within a lock, because it increments
+ * buffers_produced.
+ */
+static inline void finalize_buffer(u32 pmEndIndex, u32 pmSizeLost, struct timeval *pmTimestamp)
+{
+ /* Write end buffer event as last event in old buffer. */
+ write_end_buffer_event(pmEndIndex, *pmTimestamp);
+
+ /* In any buffer switch, we need to write out the lost size,
+ which can be 0. */
+ write_lost_size(pmEndIndex, pmSizeLost);
+
+ /* Add the size lost and end event size to fill_count so that
+ the old buffer won't be seen as incomplete. */
+ trace_commit(pmEndIndex, pmSizeLost);
+
+ /* Every finalized buffer means a produced buffer */
+ sBufferControl.buffers_produced++;
+}
+
+/**
+ * finalize_lockless_trace: - finalize last buffer at end of trace
+ *
+ * Called when tracing is stopped, to finish processing last buffer.
+ */
+static inline void finalize_lockless_trace(void)
+{
+ u32 lEventsEnd; /* Index of end of last event */
+ u32 lSizeLost; /* Bytes after end of last event */
+ unsigned long int lFlags; /* CPU flags for lock */
+
+ /* Find index of end of last event */
+ lEventsEnd = TRACE_BUFFER_OFFSET_GET(sBufferControl.index, sBufferControl.offset_mask);
+
+ /* Size lost in buffer is the unused space after end of last event
+ and end of buffer. */
+ lSizeLost = TRACE_BUFFER_SIZE(sBufferControl.offset_bits) - lEventsEnd;
+
+ /* Lock the kernel */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+
+ /* Write end event etc. and increment buffers_produced. The
+ time used here is what the locking version uses as well. */
+ finalize_buffer(sBufferControl.index & sBufferControl.index_mask, lSizeLost, &sBufferStartTime);
+
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+}
+
+/**
+ * discard_check: - Determine whether an event should be discarded.
+ * @pmOldIndex: index into trace buffer where check for space should begin
+ * @pmLen: the length of the event to check
+ * @pmTimestamp: the time of the end-buffer event
+ *
+ * Checks whether an event of size pmLen will fit into the available
+ * buffer space as indicated by the value in pmOldIndex. A side effect
+ * of this function is that if the length would fill or overflow the
+ * last available buffer, that buffer will be finalized and all
+ * subsequent events will be automatically discarded until a buffer is
+ * later freed.
+ *
+ * The return value contains the result flags and is an ORed combination
+ * of the following:
+ *
+ * LTT_EVENT_DISCARD_NONE - event should not be discarded
+ * LTT_BUFFER_SWITCH - buffer switch occurred
+ * LTT_EVENT_DISCARD - event should be discarded (all buffers are full)
+ * LTT_EVENT_TOO_LONG - event won't fit into even an empty buffer
+ */
+static inline int discard_check(u32 pmOldIndex,
+ u32 pmLen,
+ struct timeval *pmTimestamp)
+{
+ u32 lBuffersReady;
+ u32 lOffsetMask = sBufferControl.offset_mask;
+ u8 lOffsetBits = sBufferControl.offset_bits;
+ u32 lIndexMask = sBufferControl.index_mask;
+ u32 lSizeLost;
+ unsigned long int lFlags; /* CPU flags for lock */
+
+ /* Check whether the event is larger than a buffer */
+ if(pmLen >= TRACE_BUFFER_SIZE(sBufferControl.offset_bits))
+ return LTT_EVENT_DISCARD | LTT_EVENT_TOO_LONG;
+
+ /* Lock the kernel */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+
+ /* We're already overrun, nothing left to do */
+ if(sBuffersFull == TRUE) {
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+
+ return LTT_EVENT_DISCARD;
+ }
+
+ lBuffersReady = sBufferControl.buffers_produced - sBufferControl.buffers_consumed;
+
+ /* If this happens, we've been pushed to the edge of the last
+ available buffer which means we need to finalize it and increment
+ buffers_produced. However, we don't want to allow
+ sBufferControl.index to be actually pushed to full or beyond,
+ otherwise we'd just be wrapping around and allowing subsequent
+ events to overwrite good buffers. It is true that there may not
+ be enough space for this event, but there could be space for
+ subsequent smaller event(s). It doesn't matter if they write
+ themselves, because here we say that anything after the old_index
+ passed in to this function is lost, even if other events have or
+ will reserve space in this last buffer. Nor can any other event
+ reserve space in buffers following this one, until at least one
+ buffer is consumed by the daemon. */
+ if(lBuffersReady == sBufferControl.n_buffers - 1) {
+ /* We set this flag so we only do this once per overrun */
+ sBuffersFull = TRUE;
+
+ /* Get the time of the event */
+ do_gettimeofday(pmTimestamp);
+
+ /* Size lost is everything after old_index */
+ lSizeLost = TRACE_BUFFER_SIZE(lOffsetBits)
+ - TRACE_BUFFER_OFFSET_GET(pmOldIndex, lOffsetMask);
+
+ /* Write end event and lost size. This increases buffer_count
+ by the lost size, which is important later when we add the
+ deferred size. */
+ finalize_buffer(pmOldIndex & lIndexMask, lSizeLost, pmTimestamp);
+
+ /* We need to add the lost size to old index, but we can't
+ do it now, or we'd roll index over and allow new events,
+ so we defer it until a buffer is free. Note however that
+ buffer_count does get incremented by lost size, which is
+ important later when start logging again. */
+ sLastEventIndex = pmOldIndex;
+ sLastEventTimeStamp = *pmTimestamp;
+
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+
+ /* We lose this event */
+ return LTT_BUFFER_SWITCH | LTT_EVENT_DISCARD;
+ }
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+
+ /* Nothing untoward happened */
+ return LTT_EVENT_DISCARD_NONE;
+}
+
+/**
+ * trace_reserve_slow: - The slow reserve path in the lockless scheme.
+ * @pmOldIndex: the value of the buffer control index when we were called
+ * @pmLen: the length of the slot to reserve
+ * @pmIndex: variable that will receive the start pos of the reserved slot
+ * @pmTimestamp: variable that will receive the time the slot was reserved
+ *
+ * Called by trace_reserve() if the length of the event being logged would
+ * most likely cause a 'buffer switch'. The value of the variable pointed
+ * to by pmIndex will contain the index actually reserved by this
+ * function. The timestamp reflecting the time the slot was reserved
+ * will be saved in *pmTimestamp. The return value indicates whether
+ * there actually was a buffer switch (not inevitable in all cases).
+ * If the return value also indicates a discarded event, the values in
+ * *pmIndex and *pmTimestamp will be indeterminate.
+ *
+ * The return value contains the result flags and is an ORed combination
+ * of the following:
+ *
+ * LTT_BUFFER_SWITCH_NONE - no buffer switch occurred
+ * LTT_EVENT_DISCARD_NONE - event should not be discarded
+ * LTT_BUFFER_SWITCH - buffer switch occurred
+ * LTT_EVENT_DISCARD - event should be discarded (all buffers are full)
+ * LTT_EVENT_TOO_LONG - event won't fit into even an empty buffer
+ */
+static inline int trace_reserve_slow(u32 pmOldIndex, /* needed for overruns */
+ u32 pmLen,
+ u32 *pmIndex,
+ struct timeval *pmTimestamp)
+{
+ u32 lNewIndex, lOffset, lNewBufno;
+ unsigned long int lFlags; /* CPU flags for lock */
+ u32 lOffsetMask = sBufferControl.offset_mask;
+ u8 lOffsetBits = sBufferControl.offset_bits;
+ u32 lIndexMask = sBufferControl.index_mask;
+ u32 lSizeLost = sEndReserve; /* size lost always includes end event */
+ int lDiscardEvent;
+ int lBufferSwitched = LTT_BUFFER_SWITCH_NONE;
+
+ /* We don't get here unless the event might cause a buffer switch */
+
+ /* First check whether conditions exist do discard the event */
+ lDiscardEvent = discard_check(pmOldIndex, pmLen, pmTimestamp);
+ if(lDiscardEvent != LTT_EVENT_DISCARD_NONE)
+ return lDiscardEvent;
+
+ /* If we're here, we still have free buffers to reserve from */
+
+ /* Do this until we reserve a spot for the event */
+ do {
+ /* Yeah, we're re-using a param variable, is that bad form? */
+ pmOldIndex = sBufferControl.index;
+
+ /* We're here because the event + ending reserve space would
+ overflow or exactly fill old buffer. Calculate new index
+ again. */
+ lNewIndex = pmOldIndex + pmLen;
+
+ /* We only care about the offset part of the new index */
+ lOffset = TRACE_BUFFER_OFFSET_GET(lNewIndex + sEndReserve, lOffsetMask);
+
+ /* If we would actually overflow and not exactly fill the old
+ buffer, we reserve the first slot (after adding a buffer
+ start event) in the new one. */
+ if((lOffset < pmLen) && (lOffset > 0)) {
+
+ /* This is an overflow, not an exact fit. The
+ reserved index is just after the space reserved for
+ the start event in the new buffer. */
+ *pmIndex = TRACE_BUFFER_OFFSET_CLEAR(lNewIndex + sEndReserve, lOffsetMask)
+ + sStartReserve;
+
+ /* Now the next free space is at the reserved index
+ plus the length of this event. */
+ lNewIndex = *pmIndex + pmLen;
+ } else if (lOffset < pmLen) {
+ /* We'll exactly fill the old buffer, so our reserved
+ index is still in the old buffer and our new index
+ is in the new one + sStartReserve */
+ *pmIndex = pmOldIndex;
+ lNewIndex = TRACE_BUFFER_OFFSET_CLEAR(lNewIndex + sEndReserve, lOffsetMask)
+ + sStartReserve;
+ } else
+ /* another event has actually pushed us into a new
+ buffer since we were called. */
+ *pmIndex = pmOldIndex;
+
+ /* Get the time of the event */
+ do_gettimeofday(pmTimestamp);
+ } while (!compare_and_store_volatile(&sBufferControl.index,
+ pmOldIndex, lNewIndex));
+
+ /* Once we're successful in saving a new_index as the authoritative
+ new global buffer control index, finish the buffer switch
+ processing. */
+
+ /* Mask off the high bits outside of our reserved index */
+ *pmIndex &= lIndexMask;
+
+ /* At this point, our indices are set in stone, so we can safely
+ write our start and end events and lost count to our buffers.
+ The first test here could fail if between the time reserve_slow
+ was called and we got a reserved slot, we slept and someone else
+ did the buffer switch already. */
+ if(lOffset < pmLen) { /* Event caused a buffer switch. */
+ if(lOffset > 0) /* We didn't exactly fill the old buffer */
+ /* Set the size lost value in the old buffer. That
+ value is len+sEndReserve-offset-sEndReserve,
+ i.e. sEndReserve cancels itself out. */
+ lSizeLost += pmLen - lOffset;
+ else /* We exactly filled the old buffer */
+ /* Since we exactly filled the old buffer, the index
+ we write the end event to is after the space
+ reserved for this event. */
+ pmOldIndex += pmLen;
+
+ /* Lock the kernel */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+
+ /* Write end event etc. and increment buffers_produced. */
+ finalize_buffer(pmOldIndex & lIndexMask, lSizeLost, pmTimestamp);
+
+ /* If we're here, we had a normal buffer switch and need to
+ update the start buffer time before writing the event.
+ The start buffer time is the same as the event time for the
+ event reserved, and lTimeDelta of 0 but that also appears
+ to be the case in the locking version as well. */
+ sBufferStartTime = *pmTimestamp;
+
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+
+ /* new_index is always valid here, since it's set correctly
+ if offset < len + sEndReserve, and we don't get here
+ unless that's true. The issue would be that if we didn't
+ actually switch buffers, new_index would be too large by
+ sEndReserve bytes. */
+ write_start_buffer_event(lNewIndex & lIndexMask, *pmTimestamp);
+
+ /* We initialize the new buffer by subtracting
+ TRACE_BUFFER_SIZE rather than directly initializing to
+ sStartReserve in case events have been already been added
+ to the new buffer under us. We subtract space for the start
+ buffer event from buffer size to leave room for the start
+ buffer event we just wrote. */
+ lNewBufno = TRACE_BUFFER_NUMBER_GET(lNewIndex & lIndexMask, lOffsetBits);
+ atomic_sub_volatile(&sBufferControl.fill_count[lNewBufno],
+ TRACE_BUFFER_SIZE(lOffsetBits) - sStartReserve);
+
+ /* We need to check whether fill_count is less than the
+ sStartReserve. If this test is true, it means that
+ subtracting the buffer size underflowed fill_count i.e.
+ fill_count represents an incomplete buffer. Any any case,
+ we're completely fubared and don't have any choice but to
+ start the new buffer out fresh. */
+ if(atomic_read(&sBufferControl.fill_count[lNewBufno]) < sStartReserve)
+ atomic_set_volatile(&sBufferControl.fill_count[lNewBufno], sStartReserve);
+
+ /* If we're here, there must have been a buffer switch */
+ lBufferSwitched = LTT_BUFFER_SWITCH;
+ }
+
+ return lBufferSwitched;
+}
+
+/**
+ * trace_reserve: - Reserve a slot in the trace buffer for an event.
+ * @pmLen: the length of the slot to reserve
+ * @pmIndex: variable that will receive the start pos of the reserved slot
+ * @pmTimestamp: variable that will receive the time the slot was reserved
+ *
+ * This is the fast path for reserving space in the trace buffer in the
+ * lockless tracing scheme. If a slot was successfully reserved, the
+ * caller can then at its leisure write data to the reserved space (at
+ * least until the space is reclaimed in an out-of-space situation).
+ *
+ * If the requested length would fill or exceed the current buffer, the
+ * slow path, trace_reserve_slow(), will be executed instead.
+ *
+ * The index reflecting the start position of the slot reserved will be
+ * saved in *pmIndex, and the timestamp reflecting the time the slot was
+ * reserved will be saved in *pmTimestamp. If the return value indicates
+ * a discarded event, the values in *pmIndex and *pmTimestamp will be
+ * indeterminate.
+ *
+ * The return value contains the result flags and is an ORed combination
+ * of the following:
+ *
+ * LTT_BUFFER_SWITCH_NONE - no buffer switch occurred
+ * LTT_EVENT_DISCARD_NONE - event should not be discarded
+ * LTT_BUFFER_SWITCH - buffer switch occurred
+ * LTT_EVENT_DISCARD - event should be discarded (all buffers are full)
+ * LTT_EVENT_TOO_LONG - event won't fit into even an empty buffer
+ */
+static inline int trace_reserve(u32 pmLen,
+ u32 *pmIndex,
+ struct timeval *pmTimestamp)
+{
+ u32 lOldIndex, lNewIndex, lOffset;
+ u32 lOffsetMask = sBufferControl.offset_mask;
+
+ /* Do this until we reserve a spot for the event */
+ do {
+ lOldIndex = sBufferControl.index;
+
+ /* If adding len + sEndReserve to the old index doesn't put us
+ into a new buffer, this is what the new index would be. */
+ lNewIndex = lOldIndex + pmLen;
+ lOffset = TRACE_BUFFER_OFFSET_GET(lNewIndex + sEndReserve, lOffsetMask);
+
+ /* If adding the length reserved for the end buffer event and
+ lost count to the new index would put us into a new buffer,
+ we need to do a buffer switch. If in between now and the
+ buffer switch another event that does fit comes in, no
+ problem because we check again in the slow version. In
+ either case, there will always be room for the end event
+ in the old buffer. The trick in this test is that adding
+ a length that would carry into the non-offset bits of the
+ index results in the offset portion being smaller than the
+ length that was added. */
+ if(lOffset < pmLen)
+ /* We would roll over into a new buffer, need to do
+ buffer switch processing. */
+ return trace_reserve_slow(lOldIndex, pmLen, pmIndex, pmTimestamp);
+
+ /* Get the time of the event */
+ do_gettimeofday(pmTimestamp);
+ } while (!compare_and_store_volatile(&sBufferControl.index,
+ lOldIndex, lNewIndex));
+
+ /* Once we're successful in saving a new_index as the authoritative
+ new global buffer control index, we can return old_index, the
+ successfully reserved index. */
+
+ /* Return the reserved index value */
+ *pmIndex = lOldIndex & sBufferControl.index_mask;
+
+ return LTT_BUFFER_SWITCH_NONE; /* No buffer switch occurred */
+}
+
+/**
+ * lockless_write_event: - Locklessly reserves space and writes an event.
+ * @pmEventID: event id
+ * @pmEventStruct: event details
+ * @pmDataSize: total event size
+ * @pmCPUID: CPU ID associated with event
+ * @pmVarDataBeg: ptr to variable-length data for the event
+ * @pmVarDataLen: length of variable-length data for the event
+ *
+ * This is the main event-writing function for the lockless scheme. It
+ * reserves space for an event if possible, writes the event and signals
+ * the daemon if it caused a buffer switch.
+ */
+int lockless_write_event(u8 pmEventID,
+ void *pmEventStruct,
+ uint16_t pmDataSize,
+ u8 pmCPUID,
+ void *pmVarDataBeg,
+ int pmVarDataLen)
+{
+ u32 lReservedIndex;
+ struct timeval lTime;
+ trace_time_delta lTimeDelta; /* The time elapsed between now and the last event */
+ struct siginfo lSigInfo; /* Signal information */
+ int lReserveRC;
+ char* lWritPos; /* Current position for writing */
+ int lRC = 0;
+
+ /* Reserve space for the event. If the space reserved is in a new
+ buffer, note that fact. */
+ lReserveRC = trace_reserve((u32)pmDataSize,
+ &lReservedIndex, &lTime);
+
+ /* Exact lost event count isn't important to anyone, so this is OK. */
+ if(lReserveRC & LTT_EVENT_DISCARD)
+ sEventsLost++;
+
+ /* We don't write the event, but we still need to signal */
+ if((lReserveRC & LTT_BUFFER_SWITCH) &&
+ (lReserveRC & LTT_EVENT_DISCARD)) {
+ lRC = -ENOMEM;
+ goto send_buffer_switch_signal;
+ }
+
+ /* no buffer space left, discard event. */
+ if((lReserveRC & LTT_EVENT_DISCARD) ||
+ (lReserveRC & LTT_EVENT_TOO_LONG))
+ /* return value for trace() */
+ return -ENOMEM;
+
+ /* The position we write to in the trace memory area is simply the
+ beginning of trace memory plus the index we just reserved. */
+ lWritPos = sTracBuf + lReservedIndex;
+ /* Compute the time delta between this event and the time at which
+ this buffer was started */
+ lTimeDelta = (lTime.tv_sec - sBufferStartTime.tv_sec) * 1000000
+ + (lTime.tv_usec - sBufferStartTime.tv_usec);
+
+ /* Write the CPUID to the tracing buffer, if required */
+ if ((sLogCPUID == TRUE) && (pmEventID != TRACE_EV_START) && (pmEventID != TRACE_EV_BUFFER_START))
+ tracer_write_to_buffer(lWritPos,
+ &pmCPUID,
+ sizeof(pmCPUID));
+
+ /* Write event type to tracing buffer */
+ tracer_write_to_buffer(lWritPos,
+ &pmEventID,
+ sizeof(pmEventID));
+
+ /* Write event time delta to tracing buffer */
+ tracer_write_to_buffer(lWritPos,
+ &lTimeDelta,
+ sizeof(lTimeDelta));
+
+ /* Do we log event details */
+ if (ltt_test_bit(pmEventID, &sLogEventDetailsMask)) {
+ /* Write event structure */
+ tracer_write_to_buffer(lWritPos,
+ pmEventStruct,
+ sEventStructSize[pmEventID]);
+
+ /* Write string if any */
+ if (pmVarDataLen)
+ tracer_write_to_buffer(lWritPos,
+ pmVarDataBeg,
+ pmVarDataLen);
+ }
+ /* Write the length of the event description */
+ tracer_write_to_buffer(lWritPos,
+ &pmDataSize,
+ sizeof(pmDataSize));
+
+ /* We've written the event - update the fill_count for the buffer. */
+ trace_commit(lReservedIndex, (u32)pmDataSize);
+
+send_buffer_switch_signal:
+
+ /* Signal the daemon if we switched buffers */
+ if(lReserveRC & LTT_BUFFER_SWITCH) {
+ /* Setup signal information */
+ lSigInfo.si_signo = SIGIO;
+ lSigInfo.si_errno = 0;
+ lSigInfo.si_code = SI_KERNEL;
+
+#if 0
+ /* DEBUG */
+ printk("<1> Sending SIGIO to %d \n", sDaemonTaskStruct->pid);
+#endif
+ /* Signal the tracing daemon */
+ send_sig_info(SIGIO, &lSigInfo, sDaemonTaskStruct);
+ }
+
+ return lRC;
+}
+
+/**
+ * continue_trace: - Continue a stopped trace.
+ *
+ * Continue a trace that's been temporarily stopped because all buffers
+ * were full.
+ */
+static inline void continue_trace(void)
+{
+ int lDiscardSize;
+ u32 lLastEventBufno;
+ u32 lLastBufferLostSize;
+ u32 lLastEventOffset;
+ u32 lNewIndex;
+
+ /* A buffer's been consumed, and as we've been waiting around at the
+ end of the last one produced, the one after that must now be free */
+ int lFreedBufno = sBufferControl.buffers_produced % sBufferControl.n_buffers;
+
+ /* Start the new buffer out at the beginning */
+ atomic_set_volatile(&sBufferControl.fill_count[lFreedBufno], sStartReserve);
+
+ /* In the all-buffers-full case, sBufferControl.index is frozen at the
+ position of the first event that would have caused a buffer switch.
+ However, the fill_count for that buffer is not frozen and reflects
+ not only the lost size calculated at that point, but also any
+ smaller events that managed to write themselves at the end of the
+ last buffer (because there's technically still space at the end,
+ though it and all those contained events will be erased here).
+ Here we try to salvage if possible that last buffer, but to do
+ that, we need to subtract those pesky smaller events that managed
+ to get in. If after all that, another small event manages to
+ sneak in in the time it takes us to do this, well, we concede and
+ the daemon will toss that buffer. It's not the end of the world
+ if that happens, since that buffer actually marked the start of a
+ bunch of lost events which continues until a buffer is freed. */
+
+ /* Get the bufno and offset of the buffer containing the last event
+ logged before we had to stop for a buffer-full condition. */
+ lLastEventOffset = TRACE_BUFFER_OFFSET_GET(sLastEventIndex, sBufferControl.offset_mask);
+ lLastEventBufno = TRACE_BUFFER_NUMBER_GET(sLastEventIndex, sBufferControl.offset_bits);
+
+ /* We also need to know the lost size we wrote to that buffer when we
+ stopped */
+ lLastBufferLostSize = TRACE_BUFFER_SIZE(sBufferControl.offset_bits) - lLastEventOffset;
+
+ /* Since the time we stopped, some smaller events probably reserved
+ space and wrote themselves in, the sizes of which would have been
+ reflected in the fill_count. The total size of these events is
+ calculated here. */
+ lDiscardSize = atomic_read(&sBufferControl.fill_count[lLastEventBufno])
+ - lLastEventOffset
+ - lLastBufferLostSize;
+
+ /* If there were events written after we stopped, subtract those from
+ the fill_count. If that doesn't fix things, the buffer either is
+ really incomplete, or another event snuck in, and we'll just stop
+ now and say we did what we could for it. */
+ if(lDiscardSize > 0)
+ atomic_sub_volatile(&sBufferControl.fill_count[lLastEventBufno], lDiscardSize);
+
+ /* Since our end buffer event probably got trounced, rewrite it in old
+ buffer. */
+ write_end_buffer_event(sLastEventIndex & sBufferControl.index_mask, sLastEventTimeStamp);
+
+ /* We also need to update the buffer start time and write the start
+ event for the next buffer, since we couldn't do it until now */
+ do_gettimeofday(&sBufferStartTime);
+
+ /* The current buffer control index is hanging around near the end of
+ the last buffer. So we add the buffer size and clear the offset to
+ get to the beginning of the newly freed buffer. */
+ lNewIndex = sBufferControl.index + TRACE_BUFFER_SIZE(sBufferControl.offset_bits);
+ lNewIndex = TRACE_BUFFER_OFFSET_CLEAR(lNewIndex, sBufferControl.offset_mask) + sStartReserve;
+ write_start_buffer_event(lNewIndex & sBufferControl.index_mask, sBufferStartTime);
+
+ /* Fixing up sBufferControl.index is simpler. Since a buffer has been
+ consumed, there's now at least one buffer free, and we can continue.
+ We start off the next buffer in a fresh state. Since nothing else
+ can be meaningfully updating the buffer control index, we can safely
+ do that here. 'Meaningfully' means that there may be cases of
+ smaller events managing to update the index in the last buffer but
+ they're essentially erased by the lost size of that buffer when
+ sBuffersFull was set. We need to restart the index at the beginning
+ of the next available buffer before turning off sBuffersFull, and
+ avoid an erroneous buffer switch. */
+ sBufferControl.index = lNewIndex;
+
+ /* Now we can continue reserving events */
+ sBuffersFull = FALSE;
+}
+
+/**
+ * tracer_set_n_buffers: - Sets the number of buffers.
+ * @pmNBuffers: number of buffers.
+ *
+ * Sets the number of buffers containing the trace data, valid only for
+ * lockless scheme, must be a power of 2.
+ *
+ * Returns:
+ *
+ * 0, Size setting went OK
+ * -EINVAL, not a power of 2
+ */
+int tracer_set_n_buffers(int pmNBuffers)
+{
+ if(hweight32(pmNBuffers) != 1) /* Invalid if # set bits in word != 1 */
+ return -EINVAL;
+
+ /* Find position of one and only set bit */
+ sBufnoBits = ffs(pmNBuffers) - 1;
+
+ return 0;
+}
+#else
+static void init_buffer_control(struct buffer_control * pmBC,
+ int pmUseLockless,
+ u8 pmBufnoBits,
+ u8 pmOffsetBits)
+{
+ pmBC->using_lockless = pmUseLockless;
+}
+static inline void write_start_buffer_event(u32 pmIndex, struct timeval pmTime)
+{
+}
+static inline void finalize_lockless_trace(void)
+{
+}
+static inline void continue_trace(void)
+{
+}
+int tracer_set_n_buffers(int pmNBuffers)
+{
+ return -EINVAL;
+}
+#endif /* CONFIG_LOCKLESS_TRACE */
+
+/**
+ * trace: - Tracing function per se.
+ * @pmEventID: ID of event as defined in linux/trace.h
+ * @pmEventStruct: struct describing the event
+ *
+ * Returns:
+ * 0, if everything went OK (event got registered)
+ * -ENODEV, no tracing daemon opened the driver.
+ * -ENOMEM, no more memory to store events.
+ * -EBUSY, tracer not started yet.
+ *
+ * Note:
+ * The kernel has to be locked here because trace() could be called from
+ * an interrupt handling routine and from process service routine.
+ */
+int trace(u8 pmEventID,
+ void *pmEventStruct)
+{
+ int lVarDataLen = 0; /* Length of variable length data to be copied, if any */
+ void *lVarDataBeg = NULL; /* Begining of variable length data to be copied */
+ int lSendSignal = FALSE; /* Should the daemon be summoned */
+ u8 lCPUID; /* CPUID of currently runing process */
+ uint16_t lDataSize; /* Size of tracing data */
+ struct siginfo lSigInfo; /* Signal information */
+ struct timeval lTime; /* Event time */
+ unsigned long int lFlags; /* CPU flags for lock */
+ trace_time_delta lTimeDelta; /* The time elapsed between now and the last event */
+ struct task_struct *pIncomingProcess = NULL; /* Pointer to incoming process */
+
+ /* Is there a tracing daemon */
+ if (sDaemonTaskStruct == NULL)
+ return -ENODEV;
+
+ /* Is this the exit of a process? */
+ if ((pmEventID == TRACE_EV_PROCESS) &&
+ (pmEventStruct != NULL) &&
+ ((((trace_process *) pmEventStruct)->event_sub_id) == TRACE_EV_PROCESS_EXIT))
+ trace_destroy_owners_events(current->pid);
+
+ /* Do we trace the event */
+ if ((sTracerStarted == TRUE) || (pmEventID == TRACE_EV_START) || (pmEventID == TRACE_EV_BUFFER_START))
+ goto TraceEvent;
+
+ return -EBUSY;
+
+TraceEvent:
+ /* Are we monitoring this event */
+ if (!ltt_test_bit(pmEventID, &sTracedEvents))
+ return 0;
+
+ /* Always let the start event pass, whatever the IDs */
+ if ((pmEventID != TRACE_EV_START) && (pmEventID != TRACE_EV_BUFFER_START)) {
+ /* Is this a scheduling change */
+ if (pmEventID == TRACE_EV_SCHEDCHANGE) {
+ /* Get pointer to incoming process */
+ pIncomingProcess = (struct task_struct *) (((trace_schedchange *) pmEventStruct)->in);
+
+ /* Set PID information in schedchange event */
+ (((trace_schedchange *) pmEventStruct)->in) = pIncomingProcess->pid;
+ }
+ /* Are we monitoring a particular process */
+ if ((sTracingPID == TRUE) && (current->pid != sTracedPID)) {
+ /* Record this event if it is the scheduling change bringing in the traced PID */
+ if (pIncomingProcess == NULL)
+ return 0;
+ else if (pIncomingProcess->pid != sTracedPID)
+ return 0;
+ }
+ /* Are we monitoring a particular process group */
+ if ((sTracingPGRP == TRUE) && (current->pgrp != sTracedPGRP)) {
+ /* Record this event if it is the scheduling change bringing in a process of the traced PGRP */
+ if (pIncomingProcess == NULL)
+ return 0;
+ else if (pIncomingProcess->pgrp != sTracedPGRP)
+ return 0;
+ }
+ /* Are we monitoring the processes of a given group of users */
+ if ((sTracingGID == TRUE) && (current->egid != sTracedGID)) {
+ /* Record this event if it is the scheduling change bringing in a process of the traced GID */
+ if (pIncomingProcess == NULL)
+ return 0;
+ else if (pIncomingProcess->egid != sTracedGID)
+ return 0;
+ }
+ /* Are we monitoring the processes of a given user */
+ if ((sTracingUID == TRUE) && (current->euid != sTracedUID)) {
+ /* Record this event if it is the scheduling change bringing in a process of the traced UID */
+ if (pIncomingProcess == NULL)
+ return 0;
+ else if (pIncomingProcess->euid != sTracedUID)
+ return 0;
+ }
+ }
+
+ /* Compute size of tracing data */
+ lDataSize = sizeof(pmEventID) + sizeof(lTimeDelta) + sizeof(lDataSize);
+
+ /* Do we log the event details */
+ if (ltt_test_bit(pmEventID, &sLogEventDetailsMask)) {
+ /* Update the size of the data entry */
+ lDataSize += sEventStructSize[pmEventID];
+
+ /* Some events have variable length */
+ switch (pmEventID) {
+ /* Is there a file name in this */
+ case TRACE_EV_FILE_SYSTEM:
+ if ((((trace_file_system *) pmEventStruct)->event_sub_id == TRACE_EV_FILE_SYSTEM_EXEC)
+ || (((trace_file_system *) pmEventStruct)->event_sub_id == TRACE_EV_FILE_SYSTEM_OPEN)) {
+ /* Remember the string's begining and update size variables */
+ lVarDataBeg = ((trace_file_system *) pmEventStruct)->file_name;
+ lVarDataLen = ((trace_file_system *) pmEventStruct)->event_data2 + 1;
+ lDataSize += (uint16_t) lVarDataLen;
+ }
+ break;
+
+ /* Logging of a custom event */
+ case TRACE_EV_CUSTOM:
+ lVarDataBeg = ((trace_custom *) pmEventStruct)->data;
+ lVarDataLen = ((trace_custom *) pmEventStruct)->data_size;
+ lDataSize += (uint16_t) lVarDataLen;
+ break;
+ }
+ }
+
+ /* Do we record the CPUID */
+ if ((sLogCPUID == TRUE) && (pmEventID != TRACE_EV_START) && (pmEventID != TRACE_EV_BUFFER_START)) {
+ /* Remember the CPUID */
+ lCPUID = smp_processor_id();
+
+ /* Update the size of the data entry */
+ lDataSize += sizeof(lCPUID);
+ }
+
+#if CONFIG_LOCKLESS_TRACE
+/* Lock-free event-writing isn't available without cmpxchg */
+#if __HAVE_ARCH_CMPXCHG
+ /* If we're using the lockless scheme, we preempt the default path
+ here - nothing after this point in this function will be executed.
+ Note that even if we do have cmpxchg, we still want to have a
+ choice between the lock-free and locking schemes at run-time, thus
+ the using_lockless check. This used to be implemented as a kernel
+ hook, and will be again when/if kernel hooks are accepted into the
+ kernel. */
+ if(sBufferControl.using_lockless)
+ return lockless_write_event(pmEventID,
+ pmEventStruct,
+ lDataSize,
+ lCPUID,
+ lVarDataBeg,
+ lVarDataLen);
+#endif /* __HAVE_ARCH_CMPXCHG */
+#endif /* CONFIG_LOCKLESS_TRACE */
+
+ /* Lock the kernel */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+
+ /* The following time calculations have to be done within the spinlock because
+ otherwise the event order could be inverted. */
+
+ /* Get the time of the event */
+ do_gettimeofday(&lTime);
+
+ /* Compute the time delta between this event and the time at which this buffer was started */
+ lTimeDelta = (lTime.tv_sec - sBufferStartTime.tv_sec) * 1000000
+ + (lTime.tv_usec - sBufferStartTime.tv_usec);
+
+ /* Is there enough space left in the write buffer */
+ if (sWritPos + lDataSize > sWritLimit) {
+ /* Have we already switched buffers and informed the daemon of it */
+ if (sSignalSent == TRUE) {
+ /* We've lost another event */
+ sEventsLost++;
+
+ /* Bye, bye, now */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+ return -ENOMEM;
+ }
+ /* We need to inform the daemon */
+ lSendSignal = TRUE;
+
+ /* Switch buffers */
+ tracer_switch_buffers(lTime);
+
+ /* Recompute the time delta since sBufferStartTime has changed because of the buffer change */
+ lTimeDelta = (lTime.tv_sec - sBufferStartTime.tv_sec) * 1000000
+ + (lTime.tv_usec - sBufferStartTime.tv_usec);
+ }
+ /* Write the CPUID to the tracing buffer, if required */
+ if ((sLogCPUID == TRUE) && (pmEventID != TRACE_EV_START) && (pmEventID != TRACE_EV_BUFFER_START))
+ tracer_write_to_buffer(sWritPos,
+ &lCPUID,
+ sizeof(lCPUID));
+
+ /* Write event type to tracing buffer */
+ tracer_write_to_buffer(sWritPos,
+ &pmEventID,
+ sizeof(pmEventID));
+
+ /* Write event time delta to tracing buffer */
+ tracer_write_to_buffer(sWritPos,
+ &lTimeDelta,
+ sizeof(lTimeDelta));
+
+ /* Do we log event details */
+ if (ltt_test_bit(pmEventID, &sLogEventDetailsMask)) {
+ /* Write event structure */
+ tracer_write_to_buffer(sWritPos,
+ pmEventStruct,
+ sEventStructSize[pmEventID]);
+
+ /* Write string if any */
+ if (lVarDataLen)
+ tracer_write_to_buffer(sWritPos,
+ lVarDataBeg,
+ lVarDataLen);
+ }
+ /* Write the length of the event description */
+ tracer_write_to_buffer(sWritPos,
+ &lDataSize,
+ sizeof(lDataSize));
+
+ /* Should the tracing daemon be notified */
+ if (lSendSignal == TRUE) {
+ /* Remember that a signal has been sent */
+ sSignalSent = TRUE;
+
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+
+ /* Setup signal information */
+ lSigInfo.si_signo = SIGIO;
+ lSigInfo.si_errno = 0;
+ lSigInfo.si_code = SI_KERNEL;
+
+ /* DEBUG */
+#if 0
+ printk("<1> Sending SIGIO to %d \n", sDaemonTaskStruct->pid);
+#endif
+
+ /* Signal the tracing daemon */
+ send_sig_info(SIGIO, &lSigInfo, sDaemonTaskStruct);
+ } else
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+
+ return 0;
+}
+
+/**
+ * tracer_switch_buffers: - Switches between read and write buffers.
+ * @pmTime: current time.
+ *
+ * Put the current write buffer to be read and reset put the old read
+ * buffer to be written to. Set the tracer variables in consequence.
+ *
+ * No return values.
+ *
+ * This should be called from within a spin_lock.
+ */
+void tracer_switch_buffers(struct timeval pmTime)
+{
+ char *lTempBuf; /* Temporary buffer pointer */
+ char *lTempBufEnd; /* Temporary buffer end pointer */
+ char *lInitWritPos; /* Initial write position */
+ u8 lEventID; /* Event ID of last event */
+ u8 lCPUID; /* CPUID of currently runing process */
+ uint16_t lDataSize; /* Size of tracing data */
+ u32 lSizeLost; /* Size delta between last event and end of buffer */
+ trace_time_delta lTimeDelta; /* The time elapsed between now and the last event */
+ trace_buffer_start lStartBufferEvent; /* Start of the new buffer event */
+
+ /* Remember initial write position */
+ lInitWritPos = sWritPos;
+
+ /* Write the end event at the write of the buffer */
+
+ /* Write the CPUID to the tracing buffer, if required */
+ if (sLogCPUID == TRUE) {
+ lCPUID = smp_processor_id();
+ tracer_write_to_buffer(sWritPos,
+ &lCPUID,
+ sizeof(lCPUID));
+ }
+ /* Write event type to tracing buffer */
+ lEventID = TRACE_EV_BUFFER_END;
+ tracer_write_to_buffer(sWritPos,
+ &lEventID,
+ sizeof(lEventID));
+
+ /* Write event time delta to tracing buffer */
+ lTimeDelta = 0;
+ tracer_write_to_buffer(sWritPos,
+ &lTimeDelta,
+ sizeof(lTimeDelta));
+
+ /* Get size lost */
+ lSizeLost = sWritBufEnd - lInitWritPos;
+
+ /* Write size lost at the end of the buffer */
+ *((u32 *) (sWritBufEnd - sizeof(lSizeLost))) = lSizeLost;
+
+ /* Switch buffers */
+ lTempBuf = sReadBuf;
+ sReadBuf = sWritBuf;
+ sWritBuf = lTempBuf;
+
+ /* Set buffer ends */
+ lTempBufEnd = sReadBufEnd;
+ sReadBufEnd = sWritBufEnd;
+ sWritBufEnd = lTempBufEnd;
+
+ /* Set read limit */
+ sReadLimit = sReadBufEnd;
+
+ /* Set write limit */
+ sWritLimit = sWritBufEnd - TRACER_LAST_EVENT_SIZE;
+
+ /* Set write position */
+ sWritPos = sWritBuf;
+
+ /* Increment buffer ID */
+ sBufferID++;
+
+ /* Set the time of begining of this buffer */
+ sBufferStartTime = pmTime;
+
+ /* Write the start of buffer event */
+ lStartBufferEvent.ID = sBufferID;
+ lStartBufferEvent.Time = pmTime;
+
+ /* Write event type to tracing buffer */
+ lEventID = TRACE_EV_BUFFER_START;
+ tracer_write_to_buffer(sWritPos,
+ &lEventID,
+ sizeof(lEventID));
+
+ /* Write event time delta to tracing buffer */
+ lTimeDelta = 0;
+ tracer_write_to_buffer(sWritPos,
+ &lTimeDelta,
+ sizeof(lTimeDelta));
+
+ /* Write event structure */
+ tracer_write_to_buffer(sWritPos,
+ &lStartBufferEvent,
+ sizeof(lStartBufferEvent));
+
+ /* Compute the data size */
+ lDataSize = sizeof(lEventID)
+ + sizeof(lTimeDelta)
+ + sizeof(lStartBufferEvent)
+ + sizeof(lDataSize);
+
+ /* Write the length of the event description */
+ tracer_write_to_buffer(sWritPos,
+ &lDataSize,
+ sizeof(lDataSize));
+}
+
+/**
+ * tracer_ioctl: - "Ioctl" file op
+ *
+ * @pmInode: the inode associated with the device
+ * @pmFile: file structure given to the acting process
+ * @pmCmd: command given by the caller
+ * @pmArg: arguments to the command
+ *
+ * Returns:
+ * >0, In case the caller requested the number of events lost.
+ * 0, Everything went OK
+ * -ENOSYS, no such command
+ * -EINVAL, tracer not properly configured
+ * -EBUSY, tracer can't be reconfigured while in operation
+ * -ENOMEM, no more memory
+ * -EFAULT, unable to access user space memory
+ *
+ * Note:
+ * In the future, this function should check to make sure that it's the
+ * server that make thes ioctl.
+ */
+int tracer_ioctl(struct inode *pmInode,
+ struct file *pmFile,
+ unsigned int pmCmd,
+ unsigned long pmArg)
+{
+ int lRetValue; /* Function return value */
+ int lDevMinor; /* Device minor number */
+ int lNewUserEventID; /* ID of newly created user event */
+ trace_start lStartEvent; /* Event marking the begining of the trace */
+ unsigned long int lFlags; /* CPU flags for lock */
+ trace_custom lUserEvent; /* The user event to be logged */
+ trace_change_mask lTraceMask; /* Event mask */
+ trace_new_event lNewUserEvent; /* The event to be created for the user */
+ trace_buffer_start lStartBufferEvent; /* Start of the new buffer event */
+
+ /* Get device's minor number */
+ lDevMinor = minor(pmInode->i_rdev) & 0x0f;
+
+ /* If the tracer is started, the daemon can't modify the configuration */
+ if ((lDevMinor == 0)
+ && (sTracerStarted == TRUE)
+ && (pmCmd != TRACER_STOP)
+ && (pmCmd != TRACER_DATA_COMITTED)
+ && (pmCmd != TRACER_GET_BUFFER_CONTROL))
+ return -EBUSY;
+
+ /* Only some operations are permitted to user processes trying to log events */
+ if ((lDevMinor == 1)
+ && (pmCmd != TRACER_CREATE_USER_EVENT)
+ && (pmCmd != TRACER_DESTROY_USER_EVENT)
+ && (pmCmd != TRACER_TRACE_USER_EVENT)
+ && (pmCmd != TRACER_SET_EVENT_MASK)
+ && (pmCmd != TRACER_GET_EVENT_MASK))
+ return -ENOSYS;
+
+ /* Depending on the command executed */
+ switch (pmCmd) {
+ /* Start the tracer */
+ case TRACER_START:
+ /* Initialize buffer control regardless of scheme in use */
+ init_buffer_control(&sBufferControl,
+ !sUseLocking, /* using_lockless */
+ sBufnoBits, /* bufno_bits, 2**n */
+ sBufOffsetBits); /* offset_bits, 2**n */
+
+ /* Check if the device has been properly set up */
+ if (((sUseSyscallEIPBounds == TRUE)
+ && (sSyscallEIPDepthSet == TRUE))
+ || ((sUseSyscallEIPBounds == TRUE)
+ && ((sLowerEIPBoundSet != TRUE)
+ || (sUpperEIPBoundSet != TRUE)))
+ || ((sTracingPID == TRUE)
+ && (sTracingPGRP == TRUE)))
+ return -EINVAL;
+
+ /* Set the kernel-side trace configuration */
+ if (trace_set_config(trace,
+ sSyscallEIPDepthSet,
+ sUseSyscallEIPBounds,
+ sSyscallEIPDepth,
+ sLowerEIPBound,
+ sUpperEIPBound) < 0)
+ return -EINVAL;
+
+ /* Always log the start event and the buffer start event */
+ ltt_set_bit(TRACE_EV_BUFFER_START, &sTracedEvents);
+ ltt_set_bit(TRACE_EV_BUFFER_START, &sLogEventDetailsMask);
+ ltt_set_bit(TRACE_EV_START, &sTracedEvents);
+ ltt_set_bit(TRACE_EV_START, &sLogEventDetailsMask);
+ ltt_set_bit(TRACE_EV_CHANGE_MASK, &sTracedEvents);
+ ltt_set_bit(TRACE_EV_CHANGE_MASK, &sLogEventDetailsMask);
+
+ /* Get the time of start */
+ do_gettimeofday(&sBufferStartTime);
+
+ /* Set the event description */
+ lStartBufferEvent.ID = sBufferID;
+ lStartBufferEvent.Time = sBufferStartTime;
+
+ /* Set the event description */
+ lStartEvent.MagicNumber = TRACER_MAGIC_NUMBER;
+ lStartEvent.ArchType = TRACE_ARCH_TYPE;
+ lStartEvent.ArchVariant = TRACE_ARCH_VARIANT;
+ lStartEvent.SystemType = TRACE_SYS_TYPE_VANILLA_LINUX;
+ lStartEvent.MajorVersion = TRACER_VERSION_MAJOR;
+ lStartEvent.MinorVersion = TRACER_VERSION_MINOR;
+ lStartEvent.BufferSize = sBufSize;
+ lStartEvent.EventMask = sTracedEvents;
+ lStartEvent.DetailsMask = sLogEventDetailsMask;
+ lStartEvent.LogCPUID = sLogCPUID;
+
+ /* Trace the buffer start event using the appropriate method depending on the locking scheme */
+ if(sBufferControl.using_lockless == TRUE)
+ write_start_buffer_event(sBufferControl.index & sBufferControl.index_mask,
+ sBufferStartTime);
+ else
+ trace(TRACE_EV_BUFFER_START, &lStartBufferEvent);
+
+ /* Trace the start event */
+ trace(TRACE_EV_START, &lStartEvent);
+
+ /* Start tapping into Linux's syscall flow */
+ syscall_entry_trace_active = ltt_test_bit(TRACE_EV_SYSCALL_ENTRY, &sTracedEvents);
+ syscall_exit_trace_active = ltt_test_bit(TRACE_EV_SYSCALL_EXIT, &sTracedEvents);
+
+ /* We can start tracing */
+ sTracerStarted = TRUE;
+
+ /* Reregister custom trace events created earlier */
+ trace_reregister_custom_events();
+ break;
+
+ /* Stop the tracer */
+ case TRACER_STOP:
+ /* Stop tracing */
+ /* We don't log new events, but old lockless ones can finish */
+ sTracerStarted = FALSE;
+
+ /* Stop interrupting the normal flow of system calls */
+ syscall_entry_trace_active = 0;
+ syscall_exit_trace_active = 0;
+
+ /* Make sure the last buffer touched is finalized */
+ if(sBufferControl.using_lockless) {
+ /* Write end buffer event as last event in old buf. */
+ finalize_lockless_trace();
+ break;
+ } /* Else locking scheme */
+
+ /* Acquire the lock to avoid SMP case of where another CPU is writing a trace
+ while buffer is being switched */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+
+ /* Switch the buffers to ensure that the end of the buffer mark is set (time isn't important) */
+ tracer_switch_buffers(sBufferStartTime);
+
+ /* Release lock */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+ break;
+
+ /* Set the tracer to the default configuration */
+ case TRACER_CONFIG_DEFAULT:
+ tracer_set_default_config();
+ break;
+
+ /* Set the memory buffers the daemon wants us to use */
+ case TRACER_CONFIG_MEMORY_BUFFERS:
+ /* Is the given size "reasonable" */
+ if (sUseLocking == TRUE) {
+ if (pmArg < TRACER_MIN_BUF_SIZE)
+ return -EINVAL;
+ } else {
+ if ((pmArg < TRACER_LOCKLESS_MIN_BUF_SIZE) ||
+ (pmArg > TRACER_LOCKLESS_MAX_BUF_SIZE))
+ return -EINVAL;
+ }
+
+ /* Set the buffer's size */
+ return tracer_set_buffer_size(pmArg);
+ break;
+
+ /* Set the number of memory buffers the daemon wants us to use */
+ case TRACER_CONFIG_N_MEMORY_BUFFERS:
+ /* Is the given size "reasonable" */
+ if ((sUseLocking == TRUE) || (pmArg < TRACER_MIN_BUFFERS) ||
+ (pmArg > TRACER_MAX_BUFFERS))
+ return -EINVAL;
+
+ /* Set the number of buffers */
+ return tracer_set_n_buffers(pmArg);
+ break;
+
+ /* Set locking scheme the daemon wants us to use */
+ case TRACER_CONFIG_USE_LOCKING:
+ /* Set the locking scheme in a global for later */
+ sUseLocking = pmArg;
+#if !(CONFIG_LOCKLESS_TRACE && __HAVE_ARCH_CMPXCHG)
+ if(sUseLocking == FALSE) /* Trying to use lock-free scheme */
+ /* Lock-free scheme not supported on this platform */
+ return -EINVAL;
+#endif
+ break;
+
+ /* Trace the given events */
+ case TRACER_CONFIG_EVENTS:
+ if (copy_from_user(&sTracedEvents, (void *) pmArg, sizeof(sTracedEvents)))
+ return -EFAULT;
+ break;
+
+ /* Record the details of the event, or not */
+ case TRACER_CONFIG_DETAILS:
+ if (copy_from_user(&sLogEventDetailsMask, (void *) pmArg, sizeof(sLogEventDetailsMask)))
+ return -EFAULT;
+ break;
+
+ /* Record the CPUID associated with the event */
+ case TRACER_CONFIG_CPUID:
+ sLogCPUID = TRUE;
+ break;
+
+ /* Trace only one process */
+ case TRACER_CONFIG_PID:
+ sTracingPID = TRUE;
+ sTracedPID = pmArg;
+ break;
+
+ /* Trace only the given process group */
+ case TRACER_CONFIG_PGRP:
+ sTracingPGRP = TRUE;
+ sTracedPGRP = pmArg;
+ break;
+
+ /* Trace the processes of a given group of users */
+ case TRACER_CONFIG_GID:
+ sTracingGID = TRUE;
+ sTracedGID = pmArg;
+ break;
+
+ /* Trace the processes of a given user */
+ case TRACER_CONFIG_UID:
+ sTracingUID = TRUE;
+ sTracedUID = pmArg;
+ break;
+
+ /* Set the call depth a which the EIP should be fetched on syscall */
+ case TRACER_CONFIG_SYSCALL_EIP_DEPTH:
+ sSyscallEIPDepthSet = TRUE;
+ sSyscallEIPDepth = pmArg;
+ break;
+
+ /* Set the lowerbound address from which EIP is recorded on syscall */
+ case TRACER_CONFIG_SYSCALL_EIP_LOWER:
+ /* We are using bounds for fetching the EIP where syscall was made */
+ sUseSyscallEIPBounds = TRUE;
+
+ /* Set the lower bound */
+ sLowerEIPBound = (void *) pmArg;
+
+ /* The lower bound has been set */
+ sLowerEIPBoundSet = TRUE;
+ break;
+
+ /* Set the upperbound address from which EIP is recorded on syscall */
+ case TRACER_CONFIG_SYSCALL_EIP_UPPER:
+ /* We are using bounds for fetching the EIP where syscall was made */
+ sUseSyscallEIPBounds = TRUE;
+
+ /* Set the upper bound */
+ sUpperEIPBound = (void *) pmArg;
+
+ /* The upper bound has been set */
+ sUpperEIPBoundSet = TRUE;
+ break;
+
+ /* The daemon has comitted the last trace */
+ case TRACER_DATA_COMITTED:
+#if 0
+ /* DEBUG */
+ printk("Tracer: Data has been committed \n");
+#endif
+
+ /* The lockless version doesn't use sSignalSent. pmArg is the
+ number of buffers the daemon has told us it just consumed.
+ Add that to the global count. */
+ if(sBufferControl.using_lockless) {
+ /* Lock the kernel */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+
+ /* We consumed some buffers, note it. */
+ sBufferControl.buffers_consumed += (u32)pmArg;
+
+ /* If we were full, we no longer are */
+ if(sBuffersFull && ((u32)pmArg > 0))
+ continue_trace();
+
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+ break;
+ } /* Else locking version below */
+
+ /* Safely set the signal sent flag to FALSE */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+ sSignalSent = FALSE;
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+ break;
+
+ /* Get the number of events lost */
+ case TRACER_GET_EVENTS_LOST:
+ return sEventsLost;
+ break;
+
+ /* Create a user event */
+ case TRACER_CREATE_USER_EVENT:
+ /* Copy the information from user space */
+ if (copy_from_user(&lNewUserEvent, (void *) pmArg, sizeof(lNewUserEvent)))
+ return -EFAULT;
+
+ /* Create the event */
+ lNewUserEventID = trace_create_owned_event(lNewUserEvent.type,
+ lNewUserEvent.desc,
+ lNewUserEvent.format_type,
+ lNewUserEvent.form,
+ current->pid);
+
+ /* Has the operation succeded */
+ if (lNewUserEventID >= 0) {
+ /* Set the event ID */
+ lNewUserEvent.id = lNewUserEventID;
+
+ /* Copy the event information back to user space */
+ if (copy_to_user((void *) pmArg, &lNewUserEvent, sizeof(lNewUserEvent))) {
+ /* Since we were unable to tell the user about the event, destroy it */
+ trace_destroy_event(lNewUserEventID);
+ return -EFAULT;
+ }
+ } else
+ /* Forward trace_create_event()'s error code */
+ return lNewUserEventID;
+ break;
+
+ /* Destroy a user event */
+ case TRACER_DESTROY_USER_EVENT:
+ /* Pass on the user's request */
+ trace_destroy_event((int) pmArg);
+ break;
+
+ /* Trace a user event */
+ case TRACER_TRACE_USER_EVENT:
+ /* Copy the information from user space */
+ if (copy_from_user(&lUserEvent, (void *) pmArg, sizeof(lUserEvent)))
+ return -EFAULT;
+
+ /* Copy the user event data */
+ if (copy_from_user(sUserEventData, lUserEvent.data, lUserEvent.data_size))
+ return -EFAULT;
+
+ /* Log the raw event */
+ lRetValue = trace_raw_event(lUserEvent.id,
+ lUserEvent.data_size,
+ sUserEventData);
+
+ /* Has the operation failed */
+ if (lRetValue < 0)
+ /* Forward trace_create_event()'s error code */
+ return lRetValue;
+ break;
+
+ /* Set event mask */
+ case TRACER_SET_EVENT_MASK:
+ /* Copy the information from user space */
+ if (copy_from_user(&(lTraceMask.mask), (void *) pmArg, sizeof(lTraceMask.mask)))
+ return -EFAULT;
+
+ /* Trace the event */
+ lRetValue = trace(TRACE_EV_CHANGE_MASK, &lTraceMask);
+
+ /* Change the event mask. (This has to be done second or else may loose the
+ information if the user decides to stop logging "change mask" events) */
+ memcpy(&sTracedEvents, &(lTraceMask.mask), sizeof(lTraceMask.mask));
+ syscall_entry_trace_active = ltt_test_bit(TRACE_EV_SYSCALL_ENTRY, &sTracedEvents);
+ syscall_exit_trace_active = ltt_test_bit(TRACE_EV_SYSCALL_EXIT, &sTracedEvents);
+
+ /* Always trace the buffer start, the trace start and the change mask */
+ ltt_set_bit(TRACE_EV_BUFFER_START, &sTracedEvents);
+ ltt_set_bit(TRACE_EV_START, &sTracedEvents);
+ ltt_set_bit(TRACE_EV_CHANGE_MASK, &sTracedEvents);
+
+ /* Forward trace()'s error code */
+ return lRetValue;
+ break;
+
+ /* Get event mask */
+ case TRACER_GET_EVENT_MASK:
+ /* Copy the information to user space */
+ if (copy_to_user((void *) pmArg, &sTracedEvents, sizeof(sTracedEvents)))
+ return -EFAULT;
+ break;
+
+ /* Get buffer control data */
+ case TRACER_GET_BUFFER_CONTROL:
+ /* We can't copy_to_user() with a lock held (accessing user
+ memory may cause a page fault), so buffers_produced may
+ actually be larger than what the daemon sees when this
+ snapshot is taken. This isn't a problem because the
+ daemon will get a chance to read the new buffer the next
+ time it's signaled. */
+ /* Copy the buffer control information to user space */
+ if(copy_to_user((void *) pmArg, &sBufferControl, sizeof(sBufferControl)))
+ return -EFAULT;
+ break;
+
+ /* Unknown command */
+ default:
+ return -ENOSYS;
+ }
+
+ return 0;
+}
+
+/**
+ * tracer_mmap: - "Mmap" file op
+ * @pmInode: the inode associated with the device
+ * @pmFile: file structure given to the acting process
+ * @pmVmArea: Virtual memory area description structure
+ *
+ * Returns:
+ * 0 if ok
+ * -EAGAIN, when remap failed
+ * -EACCESS, permission denied
+ */
+int tracer_mmap(struct file *pmFile,
+ struct vm_area_struct *pmVmArea)
+{
+ int lRetValue; /* Function's return value */
+
+ /* Only the trace daemon is allowed access to mmap */
+ if (current != sDaemonTaskStruct)
+ return -EACCES;
+
+ /* Remap trace buffer into the process's memory space */
+ lRetValue = tracer_mmap_region(pmVmArea,
+ (char *) pmVmArea->vm_start,
+ sTracBuf,
+ pmVmArea->vm_end - pmVmArea->vm_start);
+
+#if 0
+ printk("Tracer: Trace buffer virtual address => 0x%08X \n", (u32) sTracBuf);
+ printk("Tracer: Trace buffer physical address => 0x%08X \n", (u32) virt_to_phys(sTracBuf));
+ printk("Tracer: Trace buffer virtual address in daemon space => 0x%08X \n", (u32) pmVmArea->vm_start);
+ printk("Tracer: Trace buffer physical address in daemon space => 0x%08X \n", (u32) virt_to_phys((void *) pmVmArea->vm_start));
+#endif
+
+ return lRetValue;
+}
+
+/**
+ * tracer_open(): - "Open" file op
+ * @pmInode: the inode associated with the device
+ * @pmFile: file structure given to the acting process
+ *
+ * Returns:
+ * 0, everything went OK
+ * -ENODEV, no such device.
+ * -EBUSY, daemon channel (minor number 0) already in use.
+ */
+int tracer_open(struct inode *pmInode,
+ struct file *pmFile)
+{
+ int lDevMinor = minor(pmInode->i_rdev) & 0x0f; /* Device minor number */
+
+ /* Only minor number 0 and 1 are used */
+ if ((lDevMinor > 0) && (lDevMinor != 1))
+ return -ENODEV;
+
+ /* If the device has already been opened */
+ if (sOpenCount) {
+ /* Is there another process trying to open the daemon's channel (minor number 0) */
+ if (lDevMinor == 0)
+ return -EBUSY;
+ else
+ /* Only increment use, this is just another user process trying to log user events */
+ goto IncrementUse;
+ }
+ /* Fetch the task structure of the process that opened the device */
+ sDaemonTaskStruct = current;
+
+ /* Reset the default configuration since this is the daemon and he will complete the setup */
+ tracer_set_default_config();
+
+#if 0
+ /* DEBUG */
+ printk("<1>Process %d opened the tracing device \n", sDaemonTaskStruct->pid);
+#endif
+
+IncrementUse:
+ /* Lock the device */
+ sOpenCount++;
+
+#ifdef MODULE
+ /* Increment module usage */
+ MOD_INC_USE_COUNT;
+#endif
+
+ return 0;
+}
+
+/**
+ * tracer_release: - "Release" file op
+ * @pmInode: the inode associated with the device
+ * @pmFile: file structure given to the acting process
+ *
+ * Returns:
+ * 0, everything went OK
+ * -EBUSY, there are still event writes in progress so the buffer can't
+ * be released.
+ *
+ * Note:
+ * It is assumed that if the tracing daemon dies, exits or simply stops
+ * existing, the kernel or "someone" will call tracer_release. Otherwise,
+ * we're in trouble ...
+ */
+int tracer_release(struct inode *pmInode,
+ struct file *pmFile)
+{
+ int lCount;
+ int lDevMinor = minor(pmInode->i_rdev) & 0x0f; /* Device minor number */
+
+ /* Is this a simple user process exiting? */
+ if (lDevMinor != 0)
+ goto DecrementUse;
+
+ /* Did we loose any events */
+ if (sEventsLost > 0)
+ printk(KERN_ALERT "Tracer: Lost %d events \n", sEventsLost);
+
+ /* Reset the daemon PID */
+ sDaemonTaskStruct = NULL;
+
+ /* Free the current buffers, if any, but only if they're not still
+ in use */
+ if (sTracBuf != NULL) {
+ lCount = trace_get_pending_write_count();
+ if(lCount == 0)
+ rvfree(sTracBuf, sAllocSize);
+ else {
+ printk(KERN_ERR "Tracer: Couldn't release tracer - %d event writes pending \n",
+ lCount);
+ return -EBUSY;
+ }
+ }
+
+ /* Reset the read and write buffers */
+ sTracBuf = NULL;
+ sWritBuf = NULL;
+ sReadBuf = NULL;
+ sWritBufEnd = NULL;
+ sReadBufEnd = NULL;
+ sWritPos = NULL;
+ sReadLimit = NULL;
+ sWritLimit = NULL;
+ sUseLocking = TRUE;
+
+ /* Reset the tracer's configuration */
+ tracer_set_default_config();
+ sTracerStarted = FALSE;
+
+ /* Reset number of bytes recorded and number of events lost */
+ sBufReadComplete = 0;
+ sSizeReadIncomplete = 0;
+ sEventsLost = 0;
+
+ /* Reset signal sent */
+ sSignalSent = FALSE;
+
+DecrementUse:
+ /* Unlock the device */
+ sOpenCount--;
+
+#ifdef MODULE
+ /* Decrement module usage */
+ MOD_DEC_USE_COUNT;
+#endif
+
+ return 0;
+}
+
+/**
+ * tracer_fsync: - "Fsync" file op
+ * @pmFile: file structure given to the acting process
+ * @pmDEntry: dentry associated with file
+ *
+ * Returns:
+ * 0, everything went OK
+ * -EACCESS, permission denied
+ *
+ * Note:
+ * We need to look the modifications of the values because they are read
+ * and written by trace().
+ */
+int tracer_fsync(struct file *pmFile,
+ struct dentry *pmDEntry,
+ int pmDataSync)
+{
+ unsigned long int lFlags;
+
+ /* Only the trace daemon is allowed access to fsync */
+ if (current != sDaemonTaskStruct)
+ return -EACCES;
+
+ /* Lock the kernel */
+ spin_lock_irqsave(&sSpinLock, lFlags);
+
+ /* Reset the write positions */
+ sWritPos = sWritBuf;
+
+ /* Reset read limit */
+ sReadLimit = sReadBuf;
+
+ /* Reset bytes recorded */
+ sBufReadComplete = 0;
+ sSizeReadIncomplete = 0;
+ sEventsLost = 0;
+
+ /* Reset signal sent */
+ sSignalSent = FALSE;
+
+ /* Unlock the kernel */
+ spin_unlock_irqrestore(&sSpinLock, lFlags);
+
+ return 0;
+}
+
+/**
+ * tracer_set_buffer_size: - Sets the size of the buffers.
+ * @pmSize: Size of buffers
+ *
+ * Returns:
+ * 0, Size setting went OK
+ * -ENOMEM, unable to get a hold of memory for tracer
+ *
+ * sBufnoBits must have already been set before this function is called.
+ */
+int tracer_set_buffer_size(int pmSize)
+{
+ int lSizeAlloc;
+ int lNBuffers = TRACE_MAX_BUFFER_NUMBER(sBufnoBits);
+
+ if(sUseLocking == TRUE)
+ /* Set size to allocate (= pmSize * 2) and fix it's size to be on a page boundary */
+ lSizeAlloc = FIX_SIZE(pmSize << 1);
+ else {
+ /* Calculate power-of-2 buffer size */
+ if(hweight32(pmSize) != 1)
+ /* Invalid if # set bits != 1 */
+ return -EINVAL;
+
+ /* Find position of one and only set bit */
+ sBufOffsetBits = ffs(pmSize) - 1;
+
+ /* Calculate total size of buffers */
+ lSizeAlloc = pmSize * lNBuffers;
+
+ /* Sanity check */
+ if(lSizeAlloc > TRACER_LOCKLESS_MAX_TOTAL_BUF_SIZE)
+ return -EINVAL;
+ }
+
+ /* Free the current buffers, if any, but only if they're not still in use */
+ if (sTracBuf != NULL) {
+ if(trace_get_pending_write_count() == 0)
+ rvfree(sTracBuf, sAllocSize);
+ else
+ return -EBUSY;
+ }
+
+ /* Allocate space for the tracing buffers */
+ if ((sTracBuf = (char *) rvmalloc(lSizeAlloc)) == NULL)
+ return -ENOMEM;
+
+#if 0 /* DEBUG - init all of buffer with easy-to-spot default values */
+ {
+ int i;
+ for(i=0; i<lSizeAlloc; i+=4)
+ *((u32 *)(sTracBuf+i)) = 0xcafebabe;
+ }
+#endif
+
+ /* Remember the size set */
+ sBufSize = pmSize;
+ sAllocSize = lSizeAlloc;
+
+ /* Set the read and write buffers */
+ sWritBuf = sTracBuf;
+ sReadBuf = sTracBuf + sBufSize;
+
+ /* Set end of buffers */
+ sWritBufEnd = sWritBuf + sBufSize;
+ sReadBufEnd = sReadBuf + sBufSize;
+
+ /* Set write position */
+ sWritPos = sWritBuf;
+
+ /* Set read limit */
+ sReadLimit = sReadBuf;
+
+ /* Set write limit */
+ sWritLimit = sWritBufEnd - TRACER_LAST_EVENT_SIZE;
+
+ return 0;
+}
+
+/**
+ * tracer_set_default_config: - Sets the tracer in its default config
+ *
+ * Returns:
+ * 0, everything went OK
+ * -ENOMEM, unable to get a hold of memory for tracer
+ */
+int tracer_set_default_config(void)
+{
+ int i;
+ int lError = 0;
+
+ /* Initialize the event mask */
+ sTracedEvents = 0;
+
+ /* Initialize the event mask with all existing events with their details */
+ for (i = 0; i <= TRACE_EV_MAX; i++) {
+ ltt_set_bit(i, &sTracedEvents);
+ ltt_set_bit(i, &sLogEventDetailsMask);
+ }
+
+ /* Do not interfere with Linux's syscall flow until we actually start tracing */
+ syscall_entry_trace_active = 0;
+ syscall_exit_trace_active = 0;
+
+ /* Forget about the CPUID */
+ sLogCPUID = FALSE;
+
+ /* We aren't tracing any PID or GID in particular */
+ sTracingPID = FALSE;
+ sTracingPGRP = FALSE;
+ sTracingGID = FALSE;
+ sTracingUID = FALSE;
+
+ /* We aren't looking for a particular call depth */
+ sSyscallEIPDepthSet = FALSE;
+
+ /* We aren't going to place bounds on syscall EIP fetching */
+ sUseSyscallEIPBounds = FALSE;
+ sLowerEIPBoundSet = FALSE;
+ sUpperEIPBoundSet = FALSE;
+
+ /* Set the kernel trace configuration to it's basics */
+ trace_set_config(trace,
+ sSyscallEIPDepthSet,
+ sUseSyscallEIPBounds,
+ 0,
+ 0,
+ 0);
+
+ return lError;
+}
+
+/**
+ * tracer_init: - Tracer initialization function.
+ *
+ * Returns:
+ * 0, everything went OK
+ * -ENONMEM, incapable of allocating necessary memory
+ * Forwarded error code otherwise
+ */
+int __init tracer_init(void)
+{
+ int lError = 0;
+
+ /* Initialize configuration */
+ if ((lError = tracer_set_default_config()) < 0)
+ return lError;
+
+ /* Initialize open count */
+ sOpenCount = 0;
+
+ /* Initialize tracer lock */
+ sTracLock = 0;
+
+ /* Initialize signal sent */
+ sSignalSent = FALSE;
+
+ /* Initialize bytes read and events lost */
+ sBufReadComplete = 0;
+ sSizeReadIncomplete = 0;
+ sEventsLost = 0;
+
+ /* Initialize buffer ID */
+ sBufferID = 0;
+
+ /* Initialize tracing daemon task structure */
+ sDaemonTaskStruct = NULL;
+
+ /* Allocate memory for large data components */
+ if ((sUserEventData = vmalloc(CUSTOM_EVENT_MAX_SIZE)) < 0)
+ return -ENOMEM;
+
+ /* Initialize spin lock */
+ sSpinLock = SPIN_LOCK_UNLOCKED;
+
+ /* By default, use locking scheme */
+ sUseLocking = TRUE;
+
+ /* Register the tracer as a char device */
+ sMajorNumber = register_chrdev(0, TRACER_NAME, &sTracerFileOps);
+
+ /* Register the tracer with the kernel */
+ if ((lError = register_tracer(trace)) < 0) {
+ /* Tell the user about the problem */
+ printk(KERN_ALERT "Tracer: Unable to register tracer with kernel, tracer disabled \n");
+
+ /* Make sure no one can open this device */
+ sOpenCount = 1;
+ } else
+ printk(KERN_INFO "Tracer: Initialization complete \n");
+
+ return lError;
+}
+
+/* Is this loaded as a module */
+#ifdef MODULE
+/**
+ * cleanup_module: - Cleanup of the tracer.
+ *
+ * No return values.
+ *
+ * Note: The order of the unregesterings is important. First, rule out any
+ * possibility of getting more trace data. Second, rule out any
+ * possibility of being read by the tracing daemon. Last, free the tracing
+ * buffer, but only if it's not still in use - it's better to lose the
+ * memory than crash the system.
+ */
+void tracer_exit(void)
+{
+ int lCount;
+
+ /* Unregister the tracer from the kernel */
+ unregister_tracer(trace);
+
+ /* Unregister the tracer from being a char device */
+ unregister_chrdev(sMajorNumber, TRACER_NAME);
+
+ /* Free the current buffers, if any, but only if they're not still n use */
+ if (sTracBuf != NULL) {
+ lCount = trace_get_pending_write_count();
+ if(lCount == 0)
+ rvfree(sTracBuf, sAllocSize);
+ else
+ printk(KERN_ERR "Tracer: Couldn't exit tracer - %d event writes pending \n",
+ lCount);
+ }
+
+ /* Paranoia */
+ if(trace_get_pending_write_count() == 0)
+ sTracBuf = NULL;
+}
+module_exit(tracer_exit);
+#endif /* #ifdef MODULE */
+
+module_init(tracer_init);
diff -urpN linux-2.5.38/drivers/trace/tracer.h linux-2.5.38-ltt/drivers/trace/tracer.h
--- linux-2.5.38/drivers/trace/tracer.h Wed Dec 31 19:00:00 1969
+++ linux-2.5.38-ltt/drivers/trace/tracer.h Sun Sep 22 00:51:51 2002
@@ -0,0 +1,233 @@
+/*
+ * drivers/trace/tracer.h
+ *
+ * Copyright (C) 1999, 2000, 2001, 2002 Karim Yaghmour (karim@opersys.com)
+ * Portions contributed by T. Halloran: (C) Copyright 2002 IBM Poughkeepsie, IBM Corporation
+ *
+ * This contains the necessary definitions the system tracer
+ */
+
+#ifndef _TRACER_H
+#define _TRACER_H
+
+/* Logic values */
+#define FALSE 0
+#define TRUE 1
+
+/* Structure packing within the trace */
+#ifndef LTT_PACKED_STRUCT
+#if LTT_UNPACKED_STRUCTS
+#define LTT_PACKED_STRUCT
+#else /* if LTT_UNPACKED_STRUCTS */
+#define LTT_PACKED_STRUCT __attribute__ ((packed));
+#endif /* if LTT_UNPACKED_STRUCTS */
+#endif /* if LTT_PACKED_STRUCT */
+
+/* Tracer properties */
+#define TRACER_NAME "tracer" /* Name of the device as seen in /proc/devices */
+
+/* Tracer buffer information */
+#define TRACER_DEFAULT_BUF_SIZE 50000 /* Default size of tracing buffer */
+#define TRACER_MIN_BUF_SIZE 1000 /* Minimum size of tracing buffer */
+#define TRACER_MAX_BUF_SIZE 500000 /* Maximum size of tracing buffer */
+#define TRACER_MIN_BUFFERS 2 /* Minimum number of tracing buffers */
+#define TRACER_MAX_BUFFERS 256 /* Maximum number of tracing buffers */
+
+/* Local definitions */
+typedef u32 trace_time_delta; /* The type used to start the time delta between events */
+
+/* Number of bytes reserved for first event */
+#define TRACER_FIRST_EVENT_SIZE (sizeof(u8) + sizeof(trace_time_delta) + sizeof(trace_buffer_start) + sizeof(uint16_t))
+
+/* Number of bytes reserved for last event, including lost size word */
+#define TRACER_LAST_EVENT_SIZE (sizeof(u8) + sizeof(u8) + sizeof(trace_time_delta) + sizeof(u32))
+
+/* System types */
+#define TRACE_SYS_TYPE_VANILLA_LINUX 1 /* Vanilla linux kernel */
+
+/* The information logged when the tracing is started */
+#define TRACER_MAGIC_NUMBER 0x00D6B7ED /* That day marks an important historical event ... */
+#define TRACER_VERSION_MAJOR 1 /* Major version number */
+#define TRACER_VERSION_MINOR 14 /* Minor version number */
+typedef struct _trace_start {
+ u32 MagicNumber; /* Magic number to identify a trace */
+ u32 ArchType; /* Type of architecture */
+ u32 ArchVariant; /* Variant of the given type of architecture */
+ u32 SystemType; /* Operating system type */
+ u8 MajorVersion; /* Major version of trace */
+ u8 MinorVersion; /* Minor version of trace */
+
+ u32 BufferSize; /* Size of buffers */
+ trace_event_mask EventMask; /* The event mask */
+ trace_event_mask DetailsMask; /* Are the event details logged */
+ u8 LogCPUID; /* Is the CPUID logged */
+} LTT_PACKED_STRUCT trace_start;
+
+/* Start and end of trace buffer information */
+typedef struct _trace_buffer_start {
+ struct timeval Time; /* Time stamp of this buffer */
+ u32 ID; /* Unique buffer ID */
+} LTT_PACKED_STRUCT trace_buffer_start;
+
+/* The configurations possible */
+#define TRACER_START TRACER_MAGIC_NUMBER + 0 /* Start tracing events using the current configuration */
+#define TRACER_STOP TRACER_MAGIC_NUMBER + 1 /* Stop tracing */
+#define TRACER_CONFIG_DEFAULT TRACER_MAGIC_NUMBER + 2 /* Set the tracer to the default configuration */
+#define TRACER_CONFIG_MEMORY_BUFFERS TRACER_MAGIC_NUMBER + 3 /* Set the memory buffers the daemon wants us to use */
+#define TRACER_CONFIG_EVENTS TRACER_MAGIC_NUMBER + 4 /* Trace the given events */
+#define TRACER_CONFIG_DETAILS TRACER_MAGIC_NUMBER + 5 /* Record the details of the event, or not */
+#define TRACER_CONFIG_CPUID TRACER_MAGIC_NUMBER + 6 /* Record the CPUID associated with the event */
+#define TRACER_CONFIG_PID TRACER_MAGIC_NUMBER + 7 /* Trace only one process */
+#define TRACER_CONFIG_PGRP TRACER_MAGIC_NUMBER + 8 /* Trace only the given process group */
+#define TRACER_CONFIG_GID TRACER_MAGIC_NUMBER + 9 /* Trace the processes of a given group of users */
+#define TRACER_CONFIG_UID TRACER_MAGIC_NUMBER + 10 /* Trace the processes of a given user */
+#define TRACER_CONFIG_SYSCALL_EIP_DEPTH TRACER_MAGIC_NUMBER + 11 /* Set the call depth at which the EIP should be fetched on syscall */
+#define TRACER_CONFIG_SYSCALL_EIP_LOWER TRACER_MAGIC_NUMBER + 12 /* Set the lowerbound address from which EIP is recorded on syscall */
+#define TRACER_CONFIG_SYSCALL_EIP_UPPER TRACER_MAGIC_NUMBER + 13 /* Set the upperbound address from which EIP is recorded on syscall */
+#define TRACER_DATA_COMITTED TRACER_MAGIC_NUMBER + 14 /* The daemon has comitted the last trace */
+#define TRACER_GET_EVENTS_LOST TRACER_MAGIC_NUMBER + 15 /* Get the number of events lost */
+#define TRACER_CREATE_USER_EVENT TRACER_MAGIC_NUMBER + 16 /* Create a user tracable event */
+#define TRACER_DESTROY_USER_EVENT TRACER_MAGIC_NUMBER + 17 /* Destroy a user tracable event */
+#define TRACER_TRACE_USER_EVENT TRACER_MAGIC_NUMBER + 18 /* Trace a user event */
+#define TRACER_SET_EVENT_MASK TRACER_MAGIC_NUMBER + 19 /* Set the trace event mask */
+#define TRACER_GET_EVENT_MASK TRACER_MAGIC_NUMBER + 20 /* Get the trace event mask */
+#define TRACER_GET_BUFFER_CONTROL TRACER_MAGIC_NUMBER + 21 /* Get the buffer control data for the lockless schem*/
+#define TRACER_CONFIG_N_MEMORY_BUFFERS TRACER_MAGIC_NUMBER + 22 /* Set the number of memory buffers the daemon wants us to use */
+#define TRACER_CONFIG_USE_LOCKING TRACER_MAGIC_NUMBER + 23 /* Set the locking scheme to use */
+
+/* For the lockless scheme:
+
+ A trace index is composed of two parts, a buffer number and a buffer
+ offset. The actual number of buffers allocated is a run-time decision,
+ although it must be a power of two for efficient computation. We define
+ a maximum number of bits for the buffer number, because the fill_count
+ array in buffer_control must have a fixed size. offset_bits must be at
+ least as large as the maximum event size+start/end buffer event size+
+ lost size word (since a buffer must be able to hold an event of maximum
+ size). Making offset_bits larger reduces fragmentation. Making it
+ smaller increases trace responsiveness. */
+
+/* We need at least enough room for the max custom event, and we also need
+ room for the start and end event. We also need it to be a power of 2. */
+#define TRACER_LOCKLESS_MIN_BUF_SIZE CUSTOM_EVENT_MAX_SIZE + 8192 /* 16K */
+/* Because we use atomic_t as the type for fill_counts, which has only 24
+ usable bits, we have 2**24 = 16M max for each buffer. */
+#define TRACER_LOCKLESS_MAX_BUF_SIZE 0x1000000 /* 16M */
+/* Since we multiply n buffers by the buffer size, this provides a sanity
+ check, much less than the 256*16M possible. */
+#define TRACER_LOCKLESS_MAX_TOTAL_BUF_SIZE 0x8000000 /* 128M */
+
+#define TRACE_MAX_BUFFER_NUMBER(bufno_bits) (1UL << (bufno_bits))
+#define TRACE_BUFFER_SIZE(offset_bits) (1UL << (offset_bits))
+#define TRACE_BUFFER_OFFSET_MASK(offset_bits) (TRACE_BUFFER_SIZE(offset_bits) - 1)
+
+#define TRACE_BUFFER_NUMBER_GET(index, offset_bits) ((index) >> (offset_bits))
+#define TRACE_BUFFER_OFFSET_GET(index, mask) ((index) & (mask))
+#define TRACE_BUFFER_OFFSET_CLEAR(index, mask) ((index) & ~(mask))
+
+/* Flags returned by trace_reserve/trace_reserve_slow */
+#define LTT_BUFFER_SWITCH_NONE 0x00
+#define LTT_EVENT_DISCARD_NONE 0x00
+#define LTT_BUFFER_SWITCH 0x01
+#define LTT_EVENT_DISCARD 0x02
+#define LTT_EVENT_TOO_LONG 0x04
+
+/* Structure used for communicating buffer info between tracer and daemon
+ for lock-free tracing. This is a per-buffer (CPU, etc.) data structure. */
+struct buffer_control
+{
+ int using_lockless;
+ u32 index;
+ u8 bufno_bits;
+ u32 n_buffers; /* cached value */
+ u8 offset_bits;
+ u32 offset_mask; /* cached value */
+ u32 index_mask; /* cached value */
+
+ u32 buffers_produced;
+ u32 buffers_consumed;
+#if CONFIG_LOCKLESS_TRACE
+ /* atomic_t has only 24 usable bits, limiting us to 16M buffers */
+ atomic_t fill_count[TRACER_MAX_BUFFERS];
+#endif /* CONFIG_LOCKLESS_TRACE */
+};
+
+/* If cmpxchg isn't defined for the architecture, we don't want to
+ generate a link error - the locking scheme will still be available. */
+#ifndef __HAVE_ARCH_CMPXCHG
+#define cmpxchg(p,o,n) 0
+#endif
+
+extern __inline__ int ltt_set_bit(int nr, void *addr)
+{
+ unsigned char *p = addr;
+ unsigned char mask = 1 << (nr & 7);
+ unsigned char old;
+
+ p += nr >> 3;
+ old = *p;
+ *p |= mask;
+
+ return ((old & mask) != 0);
+}
+
+extern __inline__ int ltt_clear_bit(int nr, void *addr)
+{
+ unsigned char *p = addr;
+ unsigned char mask = 1 << (nr & 7);
+ unsigned char old;
+
+ p += nr >> 3;
+ old = *p;
+ *p &= ~mask;
+
+ return ((old & mask) != 0);
+}
+
+extern __inline__ int ltt_test_bit(int nr, void *addr)
+{
+ unsigned char *p = addr;
+ unsigned char mask = 1 << (nr & 7);
+
+ p += nr >> 3;
+
+ return ((*p & mask) != 0);
+}
+
+/* Function prototypes */
+int trace
+ (u8,
+ void *);
+void tracer_switch_buffers
+ (struct timeval);
+int tracer_ioctl
+ (struct inode *,
+ struct file *,
+ unsigned int,
+ unsigned long);
+int tracer_mmap
+ (struct file *,
+ struct vm_area_struct *);
+int tracer_open
+ (struct inode *,
+ struct file *);
+int tracer_release
+ (struct inode *,
+ struct file *);
+int tracer_fsync
+ (struct file *,
+ struct dentry *,
+ int);
+#ifdef MODULE
+void tracer_exit
+ (void);
+#endif /* #ifdef MODULE */
+int tracer_set_buffer_size
+ (int);
+int tracer_set_n_buffers
+ (int);
+int tracer_set_default_config
+ (void);
+int tracer_init
+ (void);
+#endif /* _TRACER_H */
-
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