x86/vdso: Replace hex int80 CFI annotations with GAS directives

Maintaining the current CFI annotations written in R'lyehian is
difficult for most of us.  Translate them to something a little
closer to English.

This will remove the CFI data for kernels built with extremely
old versions of binutils.  I think this is a fair tradeoff for
the ability for mortals to edit the asm.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/ae3ff4ff5278b4bfc1e1dab368823469866d4b71.1444091584.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/entry/vdso/vdso32/system_call.S b/arch/x86/entry/vdso/vdso32/system_call.S
index b15b7c01aedbeab4d832b462bbbfe73a341f4fe3..b52cbfbe119e9b00fcd63b943a8f4ddbf57066e8 100644 (file)
--- a/arch/x86/entry/vdso/vdso32/system_call.S
+++ b/arch/x86/entry/vdso/vdso32/system_call.S
@@ -1,6 +1,10 @@
 /*
  * Code for the vDSO.  This version uses the old int $0x80 method.
- *
+*/
+
+#include <asm/dwarf2.h>
+
+/*
  * First get the common code for the sigreturn entry points.
  * This must come first.
  */
@@ -11,46 +15,10 @@
        .type __kernel_vsyscall,@function
        ALIGN
 __kernel_vsyscall:
-.LSTART_vsyscall:
+       CFI_STARTPROC
        int $0x80
        ret
-.LEND_vsyscall:
-       .size __kernel_vsyscall,.-.LSTART_vsyscall
-       .previous
-
-       .section .eh_frame,"a",@progbits
-.LSTARTFRAMEDLSI:
-       .long .LENDCIEDLSI-.LSTARTCIEDLSI
-.LSTARTCIEDLSI:
-       .long 0                 /* CIE ID */
-       .byte 1                 /* Version number */
-       .string "zR"            /* NUL-terminated augmentation string */
-       .uleb128 1              /* Code alignment factor */
-       .sleb128 -4             /* Data alignment factor */
-       .byte 8                 /* Return address register column */
-       .uleb128 1              /* Augmentation value length */
-       .byte 0x1b              /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */
-       .byte 0x0c              /* DW_CFA_def_cfa */
-       .uleb128 4
-       .uleb128 4
-       .byte 0x88              /* DW_CFA_offset, column 0x8 */
-       .uleb128 1
-       .align 4
-.LENDCIEDLSI:
-       .long .LENDFDEDLSI-.LSTARTFDEDLSI /* Length FDE */
-.LSTARTFDEDLSI:
-       .long .LSTARTFDEDLSI-.LSTARTFRAMEDLSI /* CIE pointer */
-       .long .LSTART_vsyscall-.        /* PC-relative start address */
-       .long .LEND_vsyscall-.LSTART_vsyscall
-       .uleb128 0
-       .align 4
-.LENDFDEDLSI:
-       .previous
+       CFI_ENDPROC
 
-       /*
-        * Pad out the segment to match the size of the sysenter.S version.
-        */
-VDSO32_vsyscall_eh_frame_size = 0x40
-       .section .data,"aw",@progbits
-       .space VDSO32_vsyscall_eh_frame_size-(.LENDFDEDLSI-.LSTARTFRAMEDLSI), 0
+       .size __kernel_vsyscall,.-__kernel_vsyscall
        .previous