ftrace: add basic support for gcc profiler instrumentation

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / entry_64.S

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 2ad9a1bc6a73fafd6ea8e34b9117877eb2e736dd..f046e0c6488391416f28e6a747893c85d76d5e10 100644 (file)
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -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 
@@ -319,19 +356,17 @@ badsys:
        /* Do syscall tracing */
 tracesys:                       
        SAVE_REST
-       movq $-ENOSYS,RAX(%rsp)
+       movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
        FIXUP_TOP_OF_STACK %rdi
        movq %rsp,%rdi
        call syscall_trace_enter
        LOAD_ARGS ARGOFFSET  /* reload args from stack in case ptrace changed it */
        RESTORE_REST
        cmpq $__NR_syscall_max,%rax
-       movq $-ENOSYS,%rcx
-       cmova %rcx,%rax
-       ja  1f
+       ja   int_ret_from_sys_call      /* RAX(%rsp) set to -ENOSYS above */
        movq %r10,%rcx  /* fixup for C */
        call *sys_call_table(,%rax,8)
-1:     movq %rax,RAX-ARGOFFSET(%rsp)
+       movq %rax,RAX-ARGOFFSET(%rsp)
        /* Use IRET because user could have changed frame */
                
 /* 
@@ -453,6 +488,7 @@ ENTRY(stub_execve)
        CFI_REGISTER rip, r11
        SAVE_REST
        FIXUP_TOP_OF_STACK %r11
+       movq %rsp, %rcx
        call sys_execve
        RESTORE_TOP_OF_STACK %r11
        movq %rax,RAX(%rsp)
@@ -1036,15 +1072,16 @@ ENDPROC(child_rip)
  *     rdi: name, rsi: argv, rdx: envp
  *
  * We want to fallback into:
- *     extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs regs)
+ *     extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs *regs)
  *
  * do_sys_execve asm fallback arguments:
- *     rdi: name, rsi: argv, rdx: envp, fake frame on the stack
+ *     rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack
  */
 ENTRY(kernel_execve)
        CFI_STARTPROC
        FAKE_STACK_FRAME $0
        SAVE_ALL        
+       movq %rsp,%rcx
        call sys_execve
        movq %rax, RAX(%rsp)    
        RESTORE_REST