[RFC 10/30] x86/vdso: Replace hex int80 CFI annotations with gas directives

From: Andy Lutomirski
Date: Tue Sep 01 2015 - 18:50:39 EST


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@xxxxxxxxxx>
---
arch/x86/entry/vdso/vdso32/system_call.S | 48 ++++++--------------------------
1 file changed, 8 insertions(+), 40 deletions(-)

diff --git a/arch/x86/entry/vdso/vdso32/system_call.S b/arch/x86/entry/vdso/vdso32/system_call.S
index b15b7c01aedb..b52cbfbe119e 100644
--- 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
--
2.4.3

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