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/*
* Common code for the sigreturn entry points in vDSO images.
* So far this code is the same for both int80 and sysenter versions.
* This file is #include'd by int80.S et al to define them first thing.
* The kernel assumes that the addresses of these routines are constant
* for all vDSO implementations.
*/
#include <linux/linkage.h>
#include <asm/unistd_32.h>
#include <asm/asm-offsets.h>
#ifndef SYSCALL_ENTER_KERNEL
#define SYSCALL_ENTER_KERNEL int $0x80
#endif
.text
.globl __kernel_sigreturn
.type __kernel_sigreturn,@function
nop /* this guy is needed for .LSTARTFDEDLSI1 below (watch for HACK) */
ALIGN
__kernel_sigreturn:
.LSTART_sigreturn:
popl %eax /* XXX does this mean it needs unwind info? */
movl $__NR_sigreturn, %eax
SYSCALL_ENTER_KERNEL
.LEND_sigreturn:
nop
.size __kernel_sigreturn,.-.LSTART_sigreturn
.globl __kernel_rt_sigreturn
.type __kernel_rt_sigreturn,@function
ALIGN
__kernel_rt_sigreturn:
.LSTART_rt_sigreturn:
movl $__NR_rt_sigreturn, %eax
SYSCALL_ENTER_KERNEL
.LEND_rt_sigreturn:
nop
.size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn
.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(IA32_SIGCONTEXT_sp+4)
do_expr(0, IA32_SIGCONTEXT_ax+4)
do_expr(1, IA32_SIGCONTEXT_cx+4)
do_expr(2, IA32_SIGCONTEXT_dx+4)
do_expr(3, IA32_SIGCONTEXT_bx+4)
do_expr(5, IA32_SIGCONTEXT_bp+4)
do_expr(6, IA32_SIGCONTEXT_si+4)
do_expr(7, IA32_SIGCONTEXT_di+4)
do_expr(8, IA32_SIGCONTEXT_ip+4)
.byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */
do_cfa_expr(IA32_SIGCONTEXT_sp)
do_expr(0, IA32_SIGCONTEXT_ax)
do_expr(1, IA32_SIGCONTEXT_cx)
do_expr(2, IA32_SIGCONTEXT_dx)
do_expr(3, IA32_SIGCONTEXT_bx)
do_expr(5, IA32_SIGCONTEXT_bp)
do_expr(6, IA32_SIGCONTEXT_si)
do_expr(7, IA32_SIGCONTEXT_di)
do_expr(8, IA32_SIGCONTEXT_ip)
.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(IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_sp)
do_expr(0, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ax)
do_expr(1, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_cx)
do_expr(2, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_dx)
do_expr(3, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_bx)
do_expr(5, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_bp)
do_expr(6, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_si)
do_expr(7, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_di)
do_expr(8, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ip)
.align 4
.LENDFDEDLSI2:
.previous
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