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Subject[PATCH v3 39/44] metag: ftrace support
Date
Add ftrace support for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
---
arch/metag/Kconfig | 5 ++
arch/metag/include/asm/Kbuild | 1 -
arch/metag/include/asm/ftrace.h | 23 +++++++
arch/metag/kernel/ftrace.c | 127 +++++++++++++++++++++++++++++++++++++++
arch/metag/kernel/ftrace_stub.S | 76 +++++++++++++++++++++++
arch/metag/kernel/metag_ksyms.c | 5 ++
scripts/recordmcount.c | 13 ++++
7 files changed, 249 insertions(+), 1 deletions(-)
create mode 100644 arch/metag/include/asm/ftrace.h
create mode 100644 arch/metag/kernel/ftrace.c
create mode 100644 arch/metag/kernel/ftrace_stub.S

diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig
index d60de2b..e2235e3 100644
--- a/arch/metag/Kconfig
+++ b/arch/metag/Kconfig
@@ -11,7 +11,12 @@ config METAG
select GENERIC_SMP_IDLE_THREAD
select HAVE_64BIT_ALIGNED_ACCESS
select HAVE_ARCH_TRACEHOOK
+ select HAVE_C_RECORDMCOUNT
select HAVE_DEBUG_KMEMLEAK
+ select HAVE_DYNAMIC_FTRACE
+ select HAVE_FTRACE_MCOUNT_RECORD
+ select HAVE_FUNCTION_TRACER
+ select HAVE_FUNCTION_TRACE_MCOUNT_TEST
select HAVE_GENERIC_HARDIRQS
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_GZIP
diff --git a/arch/metag/include/asm/Kbuild b/arch/metag/include/asm/Kbuild
index 3a13981..6ae0ccb 100644
--- a/arch/metag/include/asm/Kbuild
+++ b/arch/metag/include/asm/Kbuild
@@ -11,7 +11,6 @@ generic-y += errno.h
generic-y += exec.h
generic-y += fb.h
generic-y += fcntl.h
-generic-y += ftrace.h
generic-y += futex.h
generic-y += hardirq.h
generic-y += hw_irq.h
diff --git a/arch/metag/include/asm/ftrace.h b/arch/metag/include/asm/ftrace.h
new file mode 100644
index 0000000..2901f0f
--- /dev/null
+++ b/arch/metag/include/asm/ftrace.h
@@ -0,0 +1,23 @@
+#ifndef _ASM_METAG_FTRACE
+#define _ASM_METAG_FTRACE
+
+#ifdef CONFIG_FUNCTION_TRACER
+#define MCOUNT_INSN_SIZE 8 /* sizeof mcount call */
+
+#ifndef __ASSEMBLY__
+extern void mcount_wrapper(void);
+#define MCOUNT_ADDR ((long)(mcount_wrapper))
+
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+ return addr;
+}
+
+struct dyn_arch_ftrace {
+ /* No extra data needed on metag */
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* CONFIG_FUNCTION_TRACER */
+
+#endif /* _ASM_METAG_FTRACE */
diff --git a/arch/metag/kernel/ftrace.c b/arch/metag/kernel/ftrace.c
new file mode 100644
index 0000000..8cbeb53
--- /dev/null
+++ b/arch/metag/kernel/ftrace.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2008 Imagination Technologies Ltd.
+ * Licensed under the GPL
+ *
+ * Dynamic ftrace support.
+ */
+
+#include <linux/ftrace.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+
+#include <asm/cacheflush.h>
+
+#define D04_MOVT_TEMPLATE 0x02200005
+#define D04_CALL_TEMPLATE 0xAC200005
+#define D1RTP_MOVT_TEMPLATE 0x03200005
+#define D1RTP_CALL_TEMPLATE 0xAC200006
+
+static const unsigned long NOP[2] = {0xa0fffffe, 0xa0fffffe};
+static unsigned long movt_and_call_insn[2];
+
+static unsigned char *ftrace_nop_replace(void)
+{
+ return (char *)&NOP[0];
+}
+
+static unsigned char *ftrace_call_replace(unsigned long pc, unsigned long addr)
+{
+ unsigned long hi16, low16;
+
+ hi16 = (addr & 0xffff0000) >> 13;
+ low16 = (addr & 0x0000ffff) << 3;
+
+ /*
+ * The compiler makes the call to mcount_wrapper()
+ * (Meta's wrapper around mcount()) through the register
+ * D0.4. So whenever we're patching one of those compiler-generated
+ * calls we also need to go through D0.4. Otherwise use D1RtP.
+ */
+ if (pc == (unsigned long)&ftrace_call) {
+ writel(D1RTP_MOVT_TEMPLATE | hi16, &movt_and_call_insn[0]);
+ writel(D1RTP_CALL_TEMPLATE | low16, &movt_and_call_insn[1]);
+ } else {
+ writel(D04_MOVT_TEMPLATE | hi16, &movt_and_call_insn[0]);
+ writel(D04_CALL_TEMPLATE | low16, &movt_and_call_insn[1]);
+ }
+
+ return (unsigned char *)&movt_and_call_insn[0];
+}
+
+static int ftrace_modify_code(unsigned long pc, unsigned char *old_code,
+ unsigned char *new_code)
+{
+ unsigned char replaced[MCOUNT_INSN_SIZE];
+
+ /*
+ * 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.
+ */
+
+ /* read the text we want to modify */
+ if (probe_kernel_read(replaced, (void *)pc, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* Make sure it is what we expect it to be */
+ if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
+ return -EINVAL;
+
+ /* replace the text with the new text */
+ if (probe_kernel_write((void *)pc, new_code, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
+
+ return 0;
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ int ret;
+ unsigned long pc;
+ unsigned char old[MCOUNT_INSN_SIZE], *new;
+
+ pc = (unsigned long)&ftrace_call;
+ memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
+ new = ftrace_call_replace(pc, (unsigned long)func);
+ ret = ftrace_modify_code(pc, old, new);
+
+ return ret;
+}
+
+int ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned char *new, *old;
+ unsigned long ip = rec->ip;
+
+ old = ftrace_call_replace(ip, addr);
+ new = ftrace_nop_replace();
+
+ return ftrace_modify_code(ip, old, new);
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned char *new, *old;
+ unsigned long ip = rec->ip;
+
+ old = ftrace_nop_replace();
+ new = ftrace_call_replace(ip, addr);
+
+ return ftrace_modify_code(ip, old, new);
+}
+
+/* run from kstop_machine */
+int __init ftrace_dyn_arch_init(void *data)
+{
+ /* The return code is returned via data */
+ writel(0, data);
+
+ return 0;
+}
diff --git a/arch/metag/kernel/ftrace_stub.S b/arch/metag/kernel/ftrace_stub.S
new file mode 100644
index 0000000..e70bff7
--- /dev/null
+++ b/arch/metag/kernel/ftrace_stub.S
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2008 Imagination Technologies Ltd.
+ * Licensed under the GPL
+ *
+ */
+
+#include <asm/ftrace.h>
+
+ .text
+#ifdef CONFIG_DYNAMIC_FTRACE
+ .global _mcount_wrapper
+ .type _mcount_wrapper,function
+_mcount_wrapper:
+ MOV PC,D0.4
+
+ .global _ftrace_caller
+ .type _ftrace_caller,function
+_ftrace_caller:
+ MOVT D0Re0,#HI(_function_trace_stop)
+ ADD D0Re0,D0Re0,#LO(_function_trace_stop)
+ GETD D0Re0,[D0Re0]
+ CMP D0Re0,#0
+ BEQ $Lcall_stub
+ MOV PC,D0.4
+$Lcall_stub:
+ MSETL [A0StP], D0Ar6, D0Ar4, D0Ar2, D0.4
+ MOV D1Ar1, D0.4
+ MOV D0Ar2, D1RtP
+ SUB D1Ar1,D1Ar1,#MCOUNT_INSN_SIZE
+
+ .global _ftrace_call
+_ftrace_call:
+ MOVT D1RtP,#HI(_ftrace_stub)
+ CALL D1RtP,#LO(_ftrace_stub)
+ GETL D0.4, D1RtP, [A0StP++#(-8)]
+ GETL D0Ar2, D1Ar1, [A0StP++#(-8)]
+ GETL D0Ar4, D1Ar3, [A0StP++#(-8)]
+ GETL D0Ar6, D1Ar5, [A0StP++#(-8)]
+ MOV PC, D0.4
+#else
+
+ .global _mcount_wrapper
+ .type _mcount_wrapper,function
+_mcount_wrapper:
+ MOVT D0Re0,#HI(_function_trace_stop)
+ ADD D0Re0,D0Re0,#LO(_function_trace_stop)
+ GETD D0Re0,[D0Re0]
+ CMP D0Re0,#0
+ BEQ $Lcall_mcount
+ MOV PC,D0.4
+$Lcall_mcount:
+ MSETL [A0StP], D0Ar6, D0Ar4, D0Ar2, D0.4
+ MOV D1Ar1, D0.4
+ MOV D0Ar2, D1RtP
+ MOVT D0Re0,#HI(_ftrace_trace_function)
+ ADD D0Re0,D0Re0,#LO(_ftrace_trace_function)
+ GET D1Ar3,[D0Re0]
+ MOVT D1Re0,#HI(_ftrace_stub)
+ ADD D1Re0,D1Re0,#LO(_ftrace_stub)
+ CMP D1Ar3,D1Re0
+ BEQ $Ltrace_exit
+ MOV D1RtP,D1Ar3
+ SUB D1Ar1,D1Ar1,#MCOUNT_INSN_SIZE
+ SWAP PC,D1RtP
+$Ltrace_exit:
+ GETL D0.4, D1RtP, [A0StP++#(-8)]
+ GETL D0Ar2, D1Ar1, [A0StP++#(-8)]
+ GETL D0Ar4, D1Ar3, [A0StP++#(-8)]
+ GETL D0Ar6, D1Ar5, [A0StP++#(-8)]
+ MOV PC, D0.4
+
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+ .global _ftrace_stub
+_ftrace_stub:
+ MOV PC,D1RtP
diff --git a/arch/metag/kernel/metag_ksyms.c b/arch/metag/kernel/metag_ksyms.c
index c73ebd3..3cc4d1d 100644
--- a/arch/metag/kernel/metag_ksyms.c
+++ b/arch/metag/kernel/metag_ksyms.c
@@ -10,6 +10,7 @@
#include <asm/checksum.h>
#include <asm/uaccess.h>
#include <asm/traps.h>
+#include <asm/ftrace.h>
#include <asm/tbx.h>

/* uaccess symbols */
@@ -73,3 +74,7 @@ EXPORT_SYMBOL(div_s64);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memmove);
+
+#ifdef CONFIG_FUNCTION_TRACER
+EXPORT_SYMBOL(mcount_wrapper);
+#endif
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index ee52cb8..9c22317 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -33,6 +33,13 @@
#include <string.h>
#include <unistd.h>

+#ifndef EM_METAG
+/* Remove this when these make it to the standard system elf.h. */
+#define EM_METAG 174
+#define R_METAG_ADDR32 2
+#define R_METAG_NONE 3
+#endif
+
static int fd_map; /* File descriptor for file being modified. */
static int mmap_failed; /* Boolean flag. */
static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
@@ -341,6 +348,12 @@ do_file(char const *const fname)
altmcount = "__gnu_mcount_nc";
break;
case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
+ case EM_METAG: reltype = R_METAG_ADDR32;
+ altmcount = "_mcount_wrapper";
+ rel_type_nop = R_METAG_NONE;
+ /* We happen to have the same requirement as MIPS */
+ is_fake_mcount32 = MIPS32_is_fake_mcount;
+ break;
case EM_MIPS: /* reltype: e_class */ gpfx = '_'; break;
case EM_PPC: reltype = R_PPC_ADDR32; gpfx = '_'; break;
case EM_PPC64: reltype = R_PPC64_ADDR64; gpfx = '_'; break;
--
1.7.7.6



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