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@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/vdso/vdso32/int80.S b/arch/x86/vdso/vdso32/int80.S
index be4b7a9a7cdd0d36ec181d29b0c3c7b9ec6a9179..b15b7c01aedbeab4d832b462bbbfe73a341f4fe3 100644 (file)
--- 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 fe88d34f822f8b6ccc6b38aad6e835f62d9e4802..5415b5613d5545b68dc88ee08de03f1061c48f8c 100644 (file)
--- 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 902d5fc11f1b4538d23833816c3087da1e60d9d4..e2800affa754d66d8ac3533f25834f0412ec9aee 100644 (file)
--- 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