x86/asm: Use SYM_INNER_LABEL instead of GLOBAL

[linux-2.6-block.git] / arch / x86 / kernel / ftrace_32.S

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index 2ba914a34b066995feb4253188fde1f3313a0959..e0061dc976e1c109223f677400aaf4715dfb1520 100644 (file)
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -9,6 +9,8 @@
 #include <asm/export.h>
 #include <asm/ftrace.h>
 #include <asm/nospec-branch.h>
+#include <asm/frame.h>
+#include <asm/asm-offsets.h>
 
 # define function_hook __fentry__
 EXPORT_SYMBOL(__fentry__)
@@ -89,26 +91,38 @@ END(ftrace_caller)
 
 ENTRY(ftrace_regs_caller)
        /*
-        * i386 does not save SS and ESP when coming from kernel.
-        * Instead, to get sp, &regs->sp is used (see ptrace.h).
-        * Unfortunately, that means eflags must be at the same location
-        * as the current return ip is. We move the return ip into the
-        * regs->ip location, and move flags into the return ip location.
+        * We're here from an mcount/fentry CALL, and the stack frame looks like:
+        *
+        *  <previous context>
+        *  RET-IP
+        *
+        * The purpose of this function is to call out in an emulated INT3
+        * environment with a stack frame like:
+        *
+        *  <previous context>
+        *  gap / RET-IP
+        *  gap
+        *  gap
+        *  gap
+        *  pt_regs
+        *
+        * We do _NOT_ restore: ss, flags, cs, gs, fs, es, ds
         */
-       pushl   $__KERNEL_CS
-       pushl   4(%esp)                         /* Save the return ip */
-       pushl   $0                              /* Load 0 into orig_ax */
+       subl    $3*4, %esp      # RET-IP + 3 gaps
+       pushl   %ss             # ss
+       pushl   %esp            # points at ss
+       addl    $5*4, (%esp)    #   make it point at <previous context>
+       pushfl                  # flags
+       pushl   $__KERNEL_CS    # cs
+       pushl   7*4(%esp)       # ip <- RET-IP
+       pushl   $0              # orig_eax
+
        pushl   %gs
        pushl   %fs
        pushl   %es
        pushl   %ds
-       pushl   %eax
-
-       /* Get flags and place them into the return ip slot */
-       pushf
-       popl    %eax
-       movl    %eax, 8*4(%esp)
 
+       pushl   %eax
        pushl   %ebp
        pushl   %edi
        pushl   %esi
@@ -116,24 +130,27 @@ ENTRY(ftrace_regs_caller)
        pushl   %ecx
        pushl   %ebx
 
-       movl    12*4(%esp), %eax                /* Load ip (1st parameter) */
-       subl    $MCOUNT_INSN_SIZE, %eax         /* Adjust ip */
-       movl    15*4(%esp), %edx                /* Load parent ip (2nd parameter) */
-       movl    function_trace_op, %ecx         /* Save ftrace_pos in 3rd parameter */
-       pushl   %esp                            /* Save pt_regs as 4th parameter */
+       ENCODE_FRAME_POINTER
 
-GLOBAL(ftrace_regs_call)
+       movl    PT_EIP(%esp), %eax      # 1st argument: IP
+       subl    $MCOUNT_INSN_SIZE, %eax
+       movl    21*4(%esp), %edx        # 2nd argument: parent ip
+       movl    function_trace_op, %ecx # 3rd argument: ftrace_pos
+       pushl   %esp                    # 4th argument: pt_regs
+
+SYM_INNER_LABEL(ftrace_regs_call, SYM_L_GLOBAL)
        call    ftrace_stub
 
-       addl    $4, %esp                        /* Skip pt_regs */
+       addl    $4, %esp                # skip 4th argument
 
-       /* restore flags */
-       push    14*4(%esp)
-       popf
+       /* place IP below the new SP */
+       movl    PT_OLDESP(%esp), %eax
+       movl    PT_EIP(%esp), %ecx
+       movl    %ecx, -4(%eax)
 
-       /* Move return ip back to its original location */
-       movl    12*4(%esp), %eax
-       movl    %eax, 14*4(%esp)
+       /* place EAX below that */
+       movl    PT_EAX(%esp), %ecx
+       movl    %ecx, -8(%eax)
 
        popl    %ebx
        popl    %ecx
@@ -141,14 +158,9 @@ GLOBAL(ftrace_regs_call)
        popl    %esi
        popl    %edi
        popl    %ebp
-       popl    %eax
-       popl    %ds
-       popl    %es
-       popl    %fs
-       popl    %gs
 
-       /* use lea to not affect flags */
-       lea     3*4(%esp), %esp                 /* Skip orig_ax, ip and cs */
+       lea     -8(%eax), %esp
+       popl    %eax
 
        jmp     .Lftrace_ret