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Date: Thu, 6 Dec 2007 17:14:29 -0800 (PST) From: Roland McGrath <roland@...hat.com> To: Andrew Morton <akpm@...ux-foundation.org>, Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de> Cc: Laurent Riffard <laurent.riffard@...e.fr>, Miles Lane <miles.lane@...il.com>, linux-kernel@...r.kernel.org Subject: [PATCH x86/mm] x86 vDSO: canonicalize sysenter .eh_frame Some assembler versions automagically optimize .eh_frame contents, changing their size. The CFI in sysenter.S was not using optimal formatting, so it would be changed by newer/smarter assemblers. This ran afoul of the wired constant for padding out the other vDSO images to match its size. This changes the original hand-coded source to use the optimal format encoding for its operations. That leaves nothing more for a fancy assembler to do, so the sizes will match the wired-in expected size regardless of the assembler version. Signed-off-by: Roland McGrath <roland@...hat.com> --- arch/x86/vdso/vdso32/int80.S | 2 +- arch/x86/vdso/vdso32/syscall.S | 2 +- arch/x86/vdso/vdso32/sysenter.S | 18 ++++++------------ 3 files changed, 8 insertions(+), 14 deletions(-) diff --git a/arch/x86/vdso/vdso32/int80.S b/arch/x86/vdso/vdso32/int80.S index be4b7a9..b15b7c0 100644 --- a/arch/x86/vdso/vdso32/int80.S +++ b/arch/x86/vdso/vdso32/int80.S @@ -50,7 +50,7 @@ __kernel_vsyscall: /* * Pad out the segment to match the size of the sysenter.S version. */ -VDSO32_vsyscall_eh_frame_size = 0x44 +VDSO32_vsyscall_eh_frame_size = 0x40 .section .data,"aw",@progbits .space VDSO32_vsyscall_eh_frame_size-(.LENDFDEDLSI-.LSTARTFRAMEDLSI), 0 .previous diff --git a/arch/x86/vdso/vdso32/syscall.S b/arch/x86/vdso/vdso32/syscall.S index fe88d34..5415b56 100644 --- a/arch/x86/vdso/vdso32/syscall.S +++ b/arch/x86/vdso/vdso32/syscall.S @@ -71,7 +71,7 @@ __kernel_vsyscall: /* * Pad out the segment to match the size of the sysenter.S version. */ -VDSO32_vsyscall_eh_frame_size = 0x44 +VDSO32_vsyscall_eh_frame_size = 0x40 .section .data,"aw",@progbits .space VDSO32_vsyscall_eh_frame_size-(.LENDFDE1-.LSTARTFRAME), 0 .previous diff --git a/arch/x86/vdso/vdso32/sysenter.S b/arch/x86/vdso/vdso32/sysenter.S index 902d5fc..e2800af 100644 --- a/arch/x86/vdso/vdso32/sysenter.S +++ b/arch/x86/vdso/vdso32/sysenter.S @@ -84,31 +84,25 @@ VDSO32_SYSENTER_RETURN: /* Symbol used by sysenter.c via vdso32-syms.h */ .uleb128 0 /* What follows are the instructions for the table generation. We have to record all changes of the stack pointer. */ - .byte 0x04 /* DW_CFA_advance_loc4 */ - .long .Lpush_ecx-.LSTART_vsyscall + .byte 0x40 + (.Lpush_ecx-.LSTART_vsyscall) /* DW_CFA_advance_loc */ .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x08 /* RA at offset 8 now */ - .byte 0x04 /* DW_CFA_advance_loc4 */ - .long .Lpush_edx-.Lpush_ecx + .byte 0x40 + (.Lpush_edx-.Lpush_ecx) /* DW_CFA_advance_loc */ .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x0c /* RA at offset 12 now */ - .byte 0x04 /* DW_CFA_advance_loc4 */ - .long .Lenter_kernel-.Lpush_edx + .byte 0x40 + (.Lenter_kernel-.Lpush_edx) /* DW_CFA_advance_loc */ .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x10 /* RA at offset 16 now */ .byte 0x85, 0x04 /* DW_CFA_offset %ebp -16 */ /* Finally the epilogue. */ - .byte 0x04 /* DW_CFA_advance_loc4 */ - .long .Lpop_ebp-.Lenter_kernel + .byte 0x40 + (.Lpop_ebp-.Lenter_kernel) /* DW_CFA_advance_loc */ .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x0c /* RA at offset 12 now */ .byte 0xc5 /* DW_CFA_restore %ebp */ - .byte 0x04 /* DW_CFA_advance_loc4 */ - .long .Lpop_edx-.Lpop_ebp + .byte 0x40 + (.Lpop_edx-.Lpop_ebp) /* DW_CFA_advance_loc */ .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x08 /* RA at offset 8 now */ - .byte 0x04 /* DW_CFA_advance_loc4 */ - .long .Lpop_ecx-.Lpop_edx + .byte 0x40 + (.Lpop_ecx-.Lpop_edx) /* DW_CFA_advance_loc */ .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x04 /* RA at offset 4 now */ .align 4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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