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authorArnaldo Carvalho de Melo <acme@ghostprotocols.net>2008-05-12 15:20:42 -0400
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 14:31:58 -0400
commit16444a8a40d4c7b4f6de34af0cae1f76a4f6c901 (patch)
tree9c290bcdbdc1ecf8f578c30b3b36914e14fdaacc /arch
parent6e766410c4babd37bc7cd5e25009c179781742c8 (diff)
ftrace: add basic support for gcc profiler instrumentation
If CONFIG_FTRACE is selected and /proc/sys/kernel/ftrace_enabled is set to a non-zero value the ftrace routine will be called everytime we enter a kernel function that is not marked with the "notrace" attribute. The ftrace routine will then call a registered function if a function happens to be registered. [ This code has been highly hacked by Steven Rostedt and Ingo Molnar, so don't blame Arnaldo for all of this ;-) ] Update: It is now possible to register more than one ftrace function. If only one ftrace function is registered, that will be the function that ftrace calls directly. If more than one function is registered, then ftrace will call a function that will loop through the functions to call. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/kernel/entry_32.S27
-rw-r--r--arch/x86/kernel/entry_64.S37
3 files changed, 65 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fe361ae7ef2f..c742dfeb0dbe 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -23,6 +23,7 @@ config X86
23 select HAVE_OPROFILE 23 select HAVE_OPROFILE
24 select HAVE_KPROBES 24 select HAVE_KPROBES
25 select HAVE_KRETPROBES 25 select HAVE_KRETPROBES
26 select HAVE_FTRACE
26 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64) 27 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
27 select HAVE_ARCH_KGDB if !X86_VOYAGER 28 select HAVE_ARCH_KGDB if !X86_VOYAGER
28 29
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 2a609dc3271c..f47b9b5440d2 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1109,6 +1109,33 @@ ENDPROC(xen_failsafe_callback)
1109 1109
1110#endif /* CONFIG_XEN */ 1110#endif /* CONFIG_XEN */
1111 1111
1112#ifdef CONFIG_FTRACE
1113ENTRY(mcount)
1114 cmpl $ftrace_stub, ftrace_trace_function
1115 jnz trace
1116
1117.globl ftrace_stub
1118ftrace_stub:
1119 ret
1120
1121 /* taken from glibc */
1122trace:
1123 pushl %eax
1124 pushl %ecx
1125 pushl %edx
1126 movl 0xc(%esp), %eax
1127 movl 0x4(%ebp), %edx
1128
1129 call *ftrace_trace_function
1130
1131 popl %edx
1132 popl %ecx
1133 popl %eax
1134
1135 jmp ftrace_stub
1136END(mcount)
1137#endif
1138
1112.section .rodata,"a" 1139.section .rodata,"a"
1113#include "syscall_table_32.S" 1140#include "syscall_table_32.S"
1114 1141
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 556a8df522a7..f046e0c64883 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -54,6 +54,43 @@
54 54
55 .code64 55 .code64
56 56
57#ifdef CONFIG_FTRACE
58ENTRY(mcount)
59 cmpq $ftrace_stub, ftrace_trace_function
60 jnz trace
61.globl ftrace_stub
62ftrace_stub:
63 retq
64
65trace:
66 /* taken from glibc */
67 subq $0x38, %rsp
68 movq %rax, (%rsp)
69 movq %rcx, 8(%rsp)
70 movq %rdx, 16(%rsp)
71 movq %rsi, 24(%rsp)
72 movq %rdi, 32(%rsp)
73 movq %r8, 40(%rsp)
74 movq %r9, 48(%rsp)
75
76 movq 0x38(%rsp), %rdi
77 movq 8(%rbp), %rsi
78
79 call *ftrace_trace_function
80
81 movq 48(%rsp), %r9
82 movq 40(%rsp), %r8
83 movq 32(%rsp), %rdi
84 movq 24(%rsp), %rsi
85 movq 16(%rsp), %rdx
86 movq 8(%rsp), %rcx
87 movq (%rsp), %rax
88 addq $0x38, %rsp
89
90 jmp ftrace_stub
91END(mcount)
92#endif
93
57#ifndef CONFIG_PREEMPT 94#ifndef CONFIG_PREEMPT
58#define retint_kernel retint_restore_args 95#define retint_kernel retint_restore_args
59#endif 96#endif