mirror of
https://github.com/torvalds/linux.git
synced 2024-11-13 23:51:39 +00:00
da2e9e1ff4
Mark unwind info for signal trampolines using the new S augmentation flag introduced in: http://gcc.gnu.org/PR26208. GCC 4.2 (or patched earlier GCC) will be able to special case unwinding through frames right above signal trampolines. As the augmentations start with z flag and S is at the very end of the augmentation string, older GCCs will just skip the S flag as unknown (that's why an augmentation flag was chosen over say a new CFA opcode). Signed-off-by: Jakub Jelinek <jakub@redhat.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
144 lines
4.8 KiB
ArmAsm
144 lines
4.8 KiB
ArmAsm
/*
|
|
* Common code for the sigreturn entry points on the vsyscall page.
|
|
* So far this code is the same for both int80 and sysenter versions.
|
|
* This file is #include'd by vsyscall-*.S to define them after the
|
|
* vsyscall entry point. The kernel assumes that the addresses of these
|
|
* routines are constant for all vsyscall implementations.
|
|
*/
|
|
|
|
#include <asm/unistd.h>
|
|
#include <asm/asm-offsets.h>
|
|
|
|
|
|
/* XXX
|
|
Should these be named "_sigtramp" or something?
|
|
*/
|
|
|
|
.text
|
|
.org __kernel_vsyscall+32,0x90
|
|
.globl __kernel_sigreturn
|
|
.type __kernel_sigreturn,@function
|
|
__kernel_sigreturn:
|
|
.LSTART_sigreturn:
|
|
popl %eax /* XXX does this mean it needs unwind info? */
|
|
movl $__NR_sigreturn, %eax
|
|
int $0x80
|
|
.LEND_sigreturn:
|
|
.size __kernel_sigreturn,.-.LSTART_sigreturn
|
|
|
|
.balign 32
|
|
.globl __kernel_rt_sigreturn
|
|
.type __kernel_rt_sigreturn,@function
|
|
__kernel_rt_sigreturn:
|
|
.LSTART_rt_sigreturn:
|
|
movl $__NR_rt_sigreturn, %eax
|
|
int $0x80
|
|
.LEND_rt_sigreturn:
|
|
.size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn
|
|
.balign 32
|
|
.previous
|
|
|
|
.section .eh_frame,"a",@progbits
|
|
.LSTARTFRAMEDLSI1:
|
|
.long .LENDCIEDLSI1-.LSTARTCIEDLSI1
|
|
.LSTARTCIEDLSI1:
|
|
.long 0 /* CIE ID */
|
|
.byte 1 /* Version number */
|
|
.string "zRS" /* 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 0 /* DW_CFA_nop */
|
|
.align 4
|
|
.LENDCIEDLSI1:
|
|
.long .LENDFDEDLSI1-.LSTARTFDEDLSI1 /* Length FDE */
|
|
.LSTARTFDEDLSI1:
|
|
.long .LSTARTFDEDLSI1-.LSTARTFRAMEDLSI1 /* CIE pointer */
|
|
/* HACK: The dwarf2 unwind routines will subtract 1 from the
|
|
return address to get an address in the middle of the
|
|
presumed call instruction. Since we didn't get here via
|
|
a call, we need to include the nop before the real start
|
|
to make up for it. */
|
|
.long .LSTART_sigreturn-1-. /* PC-relative start address */
|
|
.long .LEND_sigreturn-.LSTART_sigreturn+1
|
|
.uleb128 0 /* Augmentation */
|
|
/* What follows are the instructions for the table generation.
|
|
We record the locations of each register saved. This is
|
|
complicated by the fact that the "CFA" is always assumed to
|
|
be the value of the stack pointer in the caller. This means
|
|
that we must define the CFA of this body of code to be the
|
|
saved value of the stack pointer in the sigcontext. Which
|
|
also means that there is no fixed relation to the other
|
|
saved registers, which means that we must use DW_CFA_expression
|
|
to compute their addresses. It also means that when we
|
|
adjust the stack with the popl, we have to do it all over again. */
|
|
|
|
#define do_cfa_expr(offset) \
|
|
.byte 0x0f; /* DW_CFA_def_cfa_expression */ \
|
|
.uleb128 1f-0f; /* length */ \
|
|
0: .byte 0x74; /* DW_OP_breg4 */ \
|
|
.sleb128 offset; /* offset */ \
|
|
.byte 0x06; /* DW_OP_deref */ \
|
|
1:
|
|
|
|
#define do_expr(regno, offset) \
|
|
.byte 0x10; /* DW_CFA_expression */ \
|
|
.uleb128 regno; /* regno */ \
|
|
.uleb128 1f-0f; /* length */ \
|
|
0: .byte 0x74; /* DW_OP_breg4 */ \
|
|
.sleb128 offset; /* offset */ \
|
|
1:
|
|
|
|
do_cfa_expr(SIGCONTEXT_esp+4)
|
|
do_expr(0, SIGCONTEXT_eax+4)
|
|
do_expr(1, SIGCONTEXT_ecx+4)
|
|
do_expr(2, SIGCONTEXT_edx+4)
|
|
do_expr(3, SIGCONTEXT_ebx+4)
|
|
do_expr(5, SIGCONTEXT_ebp+4)
|
|
do_expr(6, SIGCONTEXT_esi+4)
|
|
do_expr(7, SIGCONTEXT_edi+4)
|
|
do_expr(8, SIGCONTEXT_eip+4)
|
|
|
|
.byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */
|
|
|
|
do_cfa_expr(SIGCONTEXT_esp)
|
|
do_expr(0, SIGCONTEXT_eax)
|
|
do_expr(1, SIGCONTEXT_ecx)
|
|
do_expr(2, SIGCONTEXT_edx)
|
|
do_expr(3, SIGCONTEXT_ebx)
|
|
do_expr(5, SIGCONTEXT_ebp)
|
|
do_expr(6, SIGCONTEXT_esi)
|
|
do_expr(7, SIGCONTEXT_edi)
|
|
do_expr(8, SIGCONTEXT_eip)
|
|
|
|
.align 4
|
|
.LENDFDEDLSI1:
|
|
|
|
.long .LENDFDEDLSI2-.LSTARTFDEDLSI2 /* Length FDE */
|
|
.LSTARTFDEDLSI2:
|
|
.long .LSTARTFDEDLSI2-.LSTARTFRAMEDLSI1 /* CIE pointer */
|
|
/* HACK: See above wrt unwind library assumptions. */
|
|
.long .LSTART_rt_sigreturn-1-. /* PC-relative start address */
|
|
.long .LEND_rt_sigreturn-.LSTART_rt_sigreturn+1
|
|
.uleb128 0 /* Augmentation */
|
|
/* What follows are the instructions for the table generation.
|
|
We record the locations of each register saved. This is
|
|
slightly less complicated than the above, since we don't
|
|
modify the stack pointer in the process. */
|
|
|
|
do_cfa_expr(RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_esp)
|
|
do_expr(0, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_eax)
|
|
do_expr(1, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_ecx)
|
|
do_expr(2, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_edx)
|
|
do_expr(3, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_ebx)
|
|
do_expr(5, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_ebp)
|
|
do_expr(6, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_esi)
|
|
do_expr(7, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_edi)
|
|
do_expr(8, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_eip)
|
|
|
|
.align 4
|
|
.LENDFDEDLSI2:
|
|
.previous
|