/* * 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 "../../i386/kernel/vsyscall-note.S"