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ftrace: add basic support for gcc profiler instrumentation

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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>
This commit is contained in:
Arnaldo Carvalho de Melo
2008-05-12 21:20:42 +02:00
committed by Thomas Gleixner
parent 6e766410c4
commit 16444a8a40
10 changed files with 256 additions and 0 deletions
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27
arch/x86/kernel/entry_32.S
View File

@@ -1109,6 +1109,33 @@ ENDPROC(xen_failsafe_callback)
#endif /* CONFIG_XEN */
#ifdef CONFIG_FTRACE
ENTRY(mcount)
cmpl $ftrace_stub, ftrace_trace_function
jnz trace
.globl ftrace_stub
ftrace_stub:
ret
/* taken from glibc */
trace:
pushl %eax
pushl %ecx
pushl %edx
movl 0xc(%esp), %eax
movl 0x4(%ebp), %edx
call *ftrace_trace_function
popl %edx
popl %ecx
popl %eax
jmp ftrace_stub
END(mcount)
#endif
.section .rodata,"a"
#include "syscall_table_32.S"

37
arch/x86/kernel/entry_64.S
View File

@@ -54,6 +54,43 @@
.code64
#ifdef CONFIG_FTRACE
ENTRY(mcount)
cmpq $ftrace_stub, ftrace_trace_function
jnz trace
.globl ftrace_stub
ftrace_stub:
retq
trace:
/* taken from glibc */
subq $0x38, %rsp
movq %rax, (%rsp)
movq %rcx, 8(%rsp)
movq %rdx, 16(%rsp)
movq %rsi, 24(%rsp)
movq %rdi, 32(%rsp)
movq %r8, 40(%rsp)
movq %r9, 48(%rsp)
movq 0x38(%rsp), %rdi
movq 8(%rbp), %rsi
call *ftrace_trace_function
movq 48(%rsp), %r9
movq 40(%rsp), %r8
movq 32(%rsp), %rdi
movq 24(%rsp), %rsi
movq 16(%rsp), %rdx
movq 8(%rsp), %rcx
movq (%rsp), %rax
addq $0x38, %rsp
jmp ftrace_stub
END(mcount)
#endif
#ifndef CONFIG_PREEMPT
#define retint_kernel retint_restore_args
#endif