diff options
Diffstat (limited to 'arch/x86/ia32/vsyscall-sigreturn.S')
-rw-r--r-- | arch/x86/ia32/vsyscall-sigreturn.S | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/x86/ia32/vsyscall-sigreturn.S b/arch/x86/ia32/vsyscall-sigreturn.S new file mode 100644 index 000000000000..b383be00baec --- /dev/null +++ b/arch/x86/ia32/vsyscall-sigreturn.S @@ -0,0 +1,143 @@ +/* + * Common code for the sigreturn entry points on the vsyscall page. + * This code uses SYSCALL_ENTER_KERNEL (either syscall or int $0x80) + * to enter the kernel. + * This file is #include'd by vsyscall-*.S to define them after the + * vsyscall entry point. The addresses we get for these entry points + * by doing ".balign 32" must match in both versions of the page. + */ + + .code32 + .section .text.sigreturn,"ax" + .balign 32 + .globl __kernel_sigreturn + .type __kernel_sigreturn,@function +__kernel_sigreturn: +.LSTART_sigreturn: + popl %eax + movl $__NR_ia32_sigreturn, %eax + SYSCALL_ENTER_KERNEL +.LEND_sigreturn: + .size __kernel_sigreturn,.-.LSTART_sigreturn + + .section .text.rtsigreturn,"ax" + .balign 32 + .globl __kernel_rt_sigreturn + .type __kernel_rt_sigreturn,@function +__kernel_rt_sigreturn: +.LSTART_rt_sigreturn: + movl $__NR_ia32_rt_sigreturn, %eax + SYSCALL_ENTER_KERNEL +.LEND_rt_sigreturn: + .size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn + + .section .eh_frame,"a",@progbits +.LSTARTFRAMES: + .long .LENDCIES-.LSTARTCIES +.LSTARTCIES: + .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 0x0c /* DW_CFA_def_cfa */ + .uleb128 4 + .uleb128 4 + .byte 0x88 /* DW_CFA_offset, column 0x8 */ + .uleb128 1 + .align 4 +.LENDCIES: + + .long .LENDFDE2-.LSTARTFDE2 /* Length FDE */ +.LSTARTFDE2: + .long .LSTARTFDE2-.LSTARTFRAMES /* 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 length */ + /* 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_esp+4) + do_expr(0, IA32_SIGCONTEXT_eax+4) + do_expr(1, IA32_SIGCONTEXT_ecx+4) + do_expr(2, IA32_SIGCONTEXT_edx+4) + do_expr(3, IA32_SIGCONTEXT_ebx+4) + do_expr(5, IA32_SIGCONTEXT_ebp+4) + do_expr(6, IA32_SIGCONTEXT_esi+4) + do_expr(7, IA32_SIGCONTEXT_edi+4) + do_expr(8, IA32_SIGCONTEXT_eip+4) + + .byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */ + + do_cfa_expr(IA32_SIGCONTEXT_esp) + do_expr(0, IA32_SIGCONTEXT_eax) + do_expr(1, IA32_SIGCONTEXT_ecx) + do_expr(2, IA32_SIGCONTEXT_edx) + do_expr(3, IA32_SIGCONTEXT_ebx) + do_expr(5, IA32_SIGCONTEXT_ebp) + do_expr(6, IA32_SIGCONTEXT_esi) + do_expr(7, IA32_SIGCONTEXT_edi) + do_expr(8, IA32_SIGCONTEXT_eip) + + .align 4 +.LENDFDE2: + + .long .LENDFDE3-.LSTARTFDE3 /* Length FDE */ +.LSTARTFDE3: + .long .LSTARTFDE3-.LSTARTFRAMES /* 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_esp) + do_expr(0, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eax) + do_expr(1, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ecx) + do_expr(2, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edx) + do_expr(3, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebx) + do_expr(5, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebp) + do_expr(6, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_esi) + do_expr(7, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edi) + do_expr(8, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eip) + + .align 4 +.LENDFDE3: + +#include "../../x86/kernel/vsyscall-note_32.S" + |