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Subject[PATCH 2/2] ftrace: support for PowerPC
This patch adds full support for ftrace for PowerPC (both 64 and 32 bit).
This includes dynamic tracing and function filtering.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
arch/powerpc/Kconfig | 5
arch/powerpc/kernel/Makefile | 14 ++
arch/powerpc/kernel/entry_32.S | 130 ++++++++++++++++++++++++
arch/powerpc/kernel/entry_64.S | 62 +++++++++++
arch/powerpc/kernel/ftrace.c | 165 +++++++++++++++++++++++++++++++
arch/powerpc/kernel/io.c | 3
arch/powerpc/kernel/irq.c | 6 -
arch/powerpc/kernel/setup_32.c | 11 +-
arch/powerpc/kernel/setup_64.c | 5
arch/powerpc/platforms/powermac/Makefile | 5
kernel/trace/trace_selftest.c | 11 +-
11 files changed, 406 insertions(+), 11 deletions(-)
Index: linux-sched-devel.git/arch/powerpc/kernel/io.c
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/kernel/io.c 2008-05-14 19:30:53.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/kernel/io.c 2008-05-14 19:31:48.000000000 -0700
@@ -120,7 +120,8 @@ EXPORT_SYMBOL(_outsl_ns);

#define IO_CHECK_ALIGN(v,a) ((((unsigned long)(v)) & ((a) - 1)) == 0)

-void _memset_io(volatile void __iomem *addr, int c, unsigned long n)
+notrace void
+_memset_io(volatile void __iomem *addr, int c, unsigned long n)
{
void *p = (void __force *)addr;
u32 lc = c;
Index: linux-sched-devel.git/arch/powerpc/kernel/Makefile
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/kernel/Makefile 2008-05-14 19:30:53.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/kernel/Makefile 2008-05-14 19:31:56.000000000 -0700
@@ -12,6 +12,18 @@ CFLAGS_prom_init.o += -fPIC
CFLAGS_btext.o += -fPIC
endif

+ifdef CONFIG_FTRACE
+# Do not trace early boot code
+CFLAGS_REMOVE_cputable.o = -pg
+CFLAGS_REMOVE_prom_init.o = -pg
+
+ifdef CONFIG_DYNAMIC_FTRACE
+# dynamic ftrace setup.
+CFLAGS_REMOVE_ftrace.o = -pg
+endif
+
+endif
+
obj-y := cputable.o ptrace.o syscalls.o \
irq.o align.o signal_32.o pmc.o vdso.o \
init_task.o process.o systbl.o idle.o \
@@ -79,6 +91,8 @@ obj-$(CONFIG_KEXEC) += machine_kexec.o
obj-$(CONFIG_AUDIT) += audit.o
obj64-$(CONFIG_AUDIT) += compat_audit.o

+obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
+
obj-$(CONFIG_8XX_MINIMAL_FPEMU) += softemu8xx.o

ifneq ($(CONFIG_PPC_INDIRECT_IO),y)
Index: linux-sched-devel.git/arch/powerpc/platforms/powermac/Makefile
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/platforms/powermac/Makefile 2008-05-14 19:30:53.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/platforms/powermac/Makefile 2008-05-14 19:31:48.000000000 -0700
@@ -1,5 +1,10 @@
CFLAGS_bootx_init.o += -fPIC

+ifdef CONFIG_FTRACE
+# Do not trace early boot code
+CFLAGS_REMOVE_bootx_init.o = -pg
+endif
+
obj-y += pic.o setup.o time.o feature.o pci.o \
sleep.o low_i2c.o cache.o pfunc_core.o \
pfunc_base.o
Index: linux-sched-devel.git/arch/powerpc/Kconfig
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/Kconfig 2008-05-14 19:30:50.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/Kconfig 2008-05-14 19:31:56.000000000 -0700
@@ -106,11 +106,12 @@ config PPC
bool
default y
select HAVE_IDE
- select HAVE_OPROFILE
+ select HAVE_IMMEDIATE
+ select HAVE_FTRACE
select HAVE_KPROBES
select HAVE_KRETPROBES
select HAVE_LMB
- select HAVE_IMMEDIATE
+ select HAVE_OPROFILE

config EARLY_PRINTK
bool
Index: linux-sched-devel.git/arch/powerpc/kernel/entry_32.S
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/kernel/entry_32.S 2008-05-14 19:30:50.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/kernel/entry_32.S 2008-05-14 19:31:56.000000000 -0700
@@ -1035,3 +1035,133 @@ machine_check_in_rtas:
/* XXX load up BATs and panic */

#endif /* CONFIG_PPC_RTAS */
+
+#ifdef CONFIG_FTRACE
+#ifdef CONFIG_DYNAMIC_FTRACE
+_GLOBAL(mcount)
+_GLOBAL(_mcount)
+ stwu r1,-48(r1)
+ stw r3, 12(r1)
+ stw r4, 16(r1)
+ stw r5, 20(r1)
+ stw r6, 24(r1)
+ mflr r3
+ stw r7, 28(r1)
+ mfcr r5
+ stw r8, 32(r1)
+ stw r9, 36(r1)
+ stw r10,40(r1)
+ stw r3, 44(r1)
+ stw r5, 8(r1)
+ .globl mcount_call
+mcount_call:
+ bl ftrace_stub
+ nop
+ lwz r6, 8(r1)
+ lwz r0, 44(r1)
+ lwz r3, 12(r1)
+ mtctr r0
+ lwz r4, 16(r1)
+ mtcr r6
+ lwz r5, 20(r1)
+ lwz r6, 24(r1)
+ lwz r0, 52(r1)
+ lwz r7, 28(r1)
+ lwz r8, 32(r1)
+ mtlr r0
+ lwz r9, 36(r1)
+ lwz r10,40(r1)
+ addi r1, r1, 48
+ bctr
+
+_GLOBAL(ftrace_caller)
+ /* Based off of objdump optput from glibc */
+ stwu r1,-48(r1)
+ stw r3, 12(r1)
+ stw r4, 16(r1)
+ stw r5, 20(r1)
+ stw r6, 24(r1)
+ mflr r3
+ lwz r4, 52(r1)
+ mfcr r5
+ stw r7, 28(r1)
+ stw r8, 32(r1)
+ stw r9, 36(r1)
+ stw r10,40(r1)
+ stw r3, 44(r1)
+ stw r5, 8(r1)
+.globl ftrace_call
+ftrace_call:
+ bl ftrace_stub
+ nop
+ lwz r6, 8(r1)
+ lwz r0, 44(r1)
+ lwz r3, 12(r1)
+ mtctr r0
+ lwz r4, 16(r1)
+ mtcr r6
+ lwz r5, 20(r1)
+ lwz r6, 24(r1)
+ lwz r0, 52(r1)
+ lwz r7, 28(r1)
+ lwz r8, 32(r1)
+ mtlr r0
+ lwz r9, 36(r1)
+ lwz r10,40(r1)
+ addi r1, r1, 48
+ bctr
+#else
+_GLOBAL(mcount)
+_GLOBAL(_mcount)
+ stwu r1,-48(r1)
+ stw r3, 12(r1)
+ stw r4, 16(r1)
+ stw r5, 20(r1)
+ stw r6, 24(r1)
+ mflr r3
+ lwz r4, 52(r1)
+ mfcr r5
+ stw r7, 28(r1)
+ stw r8, 32(r1)
+ stw r9, 36(r1)
+ stw r10,40(r1)
+ stw r3, 44(r1)
+ stw r5, 8(r1)
+
+ LOAD_REG_ADDR(r5, ftrace_trace_function)
+#if 0
+ mtctr r3
+ mr r1, r5
+ bctrl
+#endif
+ lwz r5,0(r5)
+#if 1
+ mtctr r5
+ bctrl
+#else
+ bl ftrace_stub
+#endif
+ nop
+
+ lwz r6, 8(r1)
+ lwz r0, 44(r1)
+ lwz r3, 12(r1)
+ mtctr r0
+ lwz r4, 16(r1)
+ mtcr r6
+ lwz r5, 20(r1)
+ lwz r6, 24(r1)
+ lwz r0, 52(r1)
+ lwz r7, 28(r1)
+ lwz r8, 32(r1)
+ mtlr r0
+ lwz r9, 36(r1)
+ lwz r10,40(r1)
+ addi r1, r1, 48
+ bctr
+#endif
+
+_GLOBAL(ftrace_stub)
+ blr
+
+#endif /* CONFIG_MCOUNT */
Index: linux-sched-devel.git/arch/powerpc/kernel/entry_64.S
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/kernel/entry_64.S 2008-05-14 19:30:50.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/kernel/entry_64.S 2008-05-14 19:31:56.000000000 -0700
@@ -870,3 +870,65 @@ _GLOBAL(enter_prom)
ld r0,16(r1)
mtlr r0
blr
+
+#ifdef CONFIG_FTRACE
+#ifdef CONFIG_DYNAMIC_FTRACE
+_GLOBAL(mcount)
+_GLOBAL(_mcount)
+ /* Taken from output of objdump from lib64/glibc */
+ mflr r3
+ stdu r1, -112(r1)
+ std r3, 128(r1)
+ .globl mcount_call
+mcount_call:
+ bl ftrace_stub
+ nop
+ ld r0, 128(r1)
+ mtlr r0
+ addi r1, r1, 112
+ blr
+
+_GLOBAL(ftrace_caller)
+ /* Taken from output of objdump from lib64/glibc */
+ mflr r3
+ ld r11, 0(r1)
+ stdu r1, -112(r1)
+ std r3, 128(r1)
+ ld r4, 16(r11)
+.globl ftrace_call
+ftrace_call:
+ bl ftrace_stub
+ nop
+ ld r0, 128(r1)
+ mtlr r0
+ addi r1, r1, 112
+_GLOBAL(ftrace_stub)
+ blr
+#else
+_GLOBAL(mcount)
+ blr
+
+_GLOBAL(_mcount)
+ /* Taken from output of objdump from lib64/glibc */
+ mflr r3
+ ld r11, 0(r1)
+ stdu r1, -112(r1)
+ std r3, 128(r1)
+ ld r4, 16(r11)
+
+
+ LOAD_REG_ADDR(r5,ftrace_trace_function)
+ ld r5,0(r5)
+ ld r5,0(r5)
+ mtctr r5
+ bctrl
+
+ nop
+ ld r0, 128(r1)
+ mtlr r0
+ addi r1, r1, 112
+_GLOBAL(ftrace_stub)
+ blr
+
+#endif
+#endif
Index: linux-sched-devel.git/arch/powerpc/kernel/ftrace.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-sched-devel.git/arch/powerpc/kernel/ftrace.c 2008-05-14 19:31:56.000000000 -0700
@@ -0,0 +1,165 @@
+/*
+ * Code for replacing ftrace calls with jumps.
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ *
+ * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
+ *
+ */
+
+#include <linux/spinlock.h>
+#include <linux/hardirq.h>
+#include <linux/ftrace.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/list.h>
+
+#include <asm/cacheflush.h>
+
+#define CALL_BACK 4
+
+static unsigned int ftrace_nop = 0x60000000;
+
+#ifdef CONFIG_PPC32
+# define GET_ADDR(addr) addr
+#else
+/* PowerPC64's functions are data that points to the functions */
+# define GET_ADDR(addr) *(unsigned long *)addr
+#endif
+
+notrace int ftrace_ip_converted(unsigned long ip)
+{
+ unsigned int save;
+
+ ip -= CALL_BACK;
+ save = *(unsigned int *)ip;
+
+ return save == ftrace_nop;
+}
+
+static unsigned int notrace ftrace_calc_offset(long ip, long addr)
+{
+ return (int)((addr + CALL_BACK) - ip);
+}
+
+notrace unsigned char *ftrace_nop_replace(void)
+{
+ return (char *)&ftrace_nop;
+}
+
+notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+{
+ static unsigned int op;
+
+ addr = GET_ADDR(addr);
+
+ /* Set to "bl addr" */
+ op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffe);
+
+ /*
+ * No locking needed, this must be called via kstop_machine
+ * which in essence is like running on a uniprocessor machine.
+ */
+ return (unsigned char *)&op;
+}
+
+#ifdef CONFIG_PPC64
+# define _ASM_ALIGN " .align 3 "
+# define _ASM_PTR " .llong "
+#else
+# define _ASM_ALIGN " .align 2 "
+# define _ASM_PTR " .long "
+#endif
+
+notrace int
+ftrace_modify_code(unsigned long ip, unsigned char *old_code,
+ unsigned char *new_code)
+{
+ unsigned replaced;
+ unsigned old = *(unsigned *)old_code;
+ unsigned new = *(unsigned *)new_code;
+ int faulted = 0;
+
+ /* move the IP back to the start of the call */
+ ip -= CALL_BACK;
+
+ /*
+ * Note: Due to modules and __init, code can
+ * disappear and change, we need to protect against faulting
+ * as well as code changing.
+ *
+ * No real locking needed, this code is run through
+ * kstop_machine.
+ */
+ asm volatile (
+ "1: lwz %1, 0(%2)\n"
+ " cmpw %1, %5\n"
+ " bne 2f\n"
+ " stwu %3, 0(%2)\n"
+ "2:\n"
+ ".section .fixup, \"ax\"\n"
+ "3: li %0, 1\n"
+ " b 2b\n"
+ ".previous\n"
+ ".section __ex_table,\"a\"\n"
+ _ASM_ALIGN "\n"
+ _ASM_PTR "1b, 3b\n"
+ ".previous"
+ : "=r"(faulted), "=r"(replaced)
+ : "r"(ip), "r"(new),
+ "0"(faulted), "r"(old)
+ : "memory");
+
+ if (replaced != old && replaced != new)
+ faulted = 2;
+
+ if (!faulted)
+ flush_icache_range(ip, ip + 8);
+
+ return faulted;
+}
+
+notrace int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ unsigned long ip = (unsigned long)(&ftrace_call);
+ unsigned char old[4], *new;
+ int ret;
+
+ ip += CALL_BACK;
+
+ memcpy(old, &ftrace_call, 4);
+ new = ftrace_call_replace(ip, (unsigned long)func);
+ ret = ftrace_modify_code(ip, old, new);
+
+ return ret;
+}
+
+notrace int ftrace_mcount_set(unsigned long *data)
+{
+ unsigned long ip = (long)(&mcount_call);
+ unsigned long *addr = data;
+ unsigned char old[4], *new;
+
+ /* ip is at the location, but modify code will subtact this */
+ ip += CALL_BACK;
+
+ /*
+ * Replace the mcount stub with a pointer to the
+ * ip recorder function.
+ */
+ memcpy(old, &mcount_call, 4);
+ new = ftrace_call_replace(ip, *addr);
+ *addr = ftrace_modify_code(ip, old, new);
+
+ return 0;
+}
+
+int __init ftrace_dyn_arch_init(void *data)
+{
+ /* This is running in kstop_machine */
+
+ ftrace_mcount_set(data);
+
+ return 0;
+}
+
Index: linux-sched-devel.git/arch/powerpc/kernel/irq.c
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/kernel/irq.c 2008-05-14 19:30:50.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/kernel/irq.c 2008-05-14 19:31:56.000000000 -0700
@@ -98,7 +98,7 @@ EXPORT_SYMBOL(irq_desc);

int distribute_irqs = 1;

-static inline unsigned long get_hard_enabled(void)
+static inline notrace unsigned long get_hard_enabled(void)
{
unsigned long enabled;

@@ -108,13 +108,13 @@ static inline unsigned long get_hard_ena
return enabled;
}

-static inline void set_soft_enabled(unsigned long enable)
+static inline notrace void set_soft_enabled(unsigned long enable)
{
__asm__ __volatile__("stb %0,%1(13)"
: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
}

-void raw_local_irq_restore(unsigned long en)
+notrace void raw_local_irq_restore(unsigned long en)
{
/*
* get_paca()->soft_enabled = en;
Index: linux-sched-devel.git/arch/powerpc/kernel/setup_32.c
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/kernel/setup_32.c 2008-05-14 19:30:50.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/kernel/setup_32.c 2008-05-14 19:31:56.000000000 -0700
@@ -47,6 +47,11 @@
#include <asm/kgdb.h>
#endif

+#ifdef CONFIG_FTRACE
+extern void _mcount(void);
+EXPORT_SYMBOL(_mcount);
+#endif
+
extern void bootx_init(unsigned long r4, unsigned long phys);

int boot_cpuid;
@@ -81,7 +86,7 @@ int ucache_bsize;
* from the address that it was linked at, so we must use RELOC/PTRRELOC
* to access static data (including strings). -- paulus
*/
-unsigned long __init early_init(unsigned long dt_ptr)
+notrace unsigned long __init early_init(unsigned long dt_ptr)
{
unsigned long offset = reloc_offset();
struct cpu_spec *spec;
@@ -111,7 +116,7 @@ unsigned long __init early_init(unsigned
* This is called very early on the boot process, after a minimal
* MMU environment has been set up but before MMU_init is called.
*/
-void __init machine_init(unsigned long dt_ptr, unsigned long phys)
+notrace void __init machine_init(unsigned long dt_ptr, unsigned long phys)
{
/* Enable early debugging if any specified (see udbg.h) */
udbg_early_init();
@@ -133,7 +138,7 @@ void __init machine_init(unsigned long d

#ifdef CONFIG_BOOKE_WDT
/* Checks wdt=x and wdt_period=xx command-line option */
-int __init early_parse_wdt(char *p)
+notrace int __init early_parse_wdt(char *p)
{
if (p && strncmp(p, "0", 1) != 0)
booke_wdt_enabled = 1;
Index: linux-sched-devel.git/arch/powerpc/kernel/setup_64.c
===================================================================
--- linux-sched-devel.git.orig/arch/powerpc/kernel/setup_64.c 2008-05-14 19:30:50.000000000 -0700
+++ linux-sched-devel.git/arch/powerpc/kernel/setup_64.c 2008-05-14 19:31:56.000000000 -0700
@@ -85,6 +85,11 @@ struct ppc64_caches ppc64_caches = {
};
EXPORT_SYMBOL_GPL(ppc64_caches);

+#ifdef CONFIG_FTRACE
+extern void _mcount(void);
+EXPORT_SYMBOL(_mcount);
+#endif
+
/*
* These are used in binfmt_elf.c to put aux entries on the stack
* for each elf executable being started.
Index: linux-sched-devel.git/kernel/trace/trace_selftest.c
===================================================================
--- linux-sched-devel.git.orig/kernel/trace/trace_selftest.c 2008-05-14 19:30:50.000000000 -0700
+++ linux-sched-devel.git/kernel/trace/trace_selftest.c 2008-05-14 19:31:56.000000000 -0700
@@ -123,6 +123,7 @@ int trace_selftest_startup_dynamic_traci
int ret;
int save_ftrace_enabled = ftrace_enabled;
int save_tracer_enabled = tracer_enabled;
+ char *func_name;

/* The ftrace test PASSED */
printk(KERN_CONT "PASSED\n");
@@ -142,9 +143,15 @@ int trace_selftest_startup_dynamic_traci
return ret;
}

+ /*
+ * Some archs *cough*PowerPC*cough* add charachters to the
+ * start of the function names. We simply put a '*' to
+ * accomodate them.
+ */
+ func_name = "*" STR(DYN_FTRACE_TEST_NAME);
+
/* filter only on our function */
- ftrace_set_filter(STR(DYN_FTRACE_TEST_NAME),
- sizeof(STR(DYN_FTRACE_TEST_NAME)), 1);
+ ftrace_set_filter(func_name, strlen(func_name), 1);

/* enable tracing */
tr->ctrl = 1;
--


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