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xianfeng |
/*
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* Common code for the sigreturn entry points on the vsyscall page.
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* This code uses SYSCALL_ENTER_KERNEL (either syscall or int $0x80)
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* to enter the kernel.
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* This file is #include'd by vsyscall-*.S to define them after the
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* vsyscall entry point. The addresses we get for these entry points
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* by doing ".balign 32" must match in both versions of the page.
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*/
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.code32
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.section .text.sigreturn,"ax"
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.balign 32
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.globl __kernel_sigreturn
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.type __kernel_sigreturn,@function
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__kernel_sigreturn:
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.LSTART_sigreturn:
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popl %eax
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movl $__NR_ia32_sigreturn, %eax
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SYSCALL_ENTER_KERNEL
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.LEND_sigreturn:
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.size __kernel_sigreturn,.-.LSTART_sigreturn
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.section .text.rtsigreturn,"ax"
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.balign 32
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.globl __kernel_rt_sigreturn
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.type __kernel_rt_sigreturn,@function
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__kernel_rt_sigreturn:
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.LSTART_rt_sigreturn:
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movl $__NR_ia32_rt_sigreturn, %eax
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SYSCALL_ENTER_KERNEL
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.LEND_rt_sigreturn:
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.size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn
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.section .eh_frame,"a",@progbits
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.LSTARTFRAMES:
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.long .LENDCIES-.LSTARTCIES
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.LSTARTCIES:
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.long 0 /* CIE ID */
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.byte 1 /* Version number */
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.string "zRS" /* NUL-terminated augmentation string */
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.uleb128 1 /* Code alignment factor */
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.sleb128 -4 /* Data alignment factor */
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.byte 8 /* Return address register column */
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.uleb128 1 /* Augmentation value length */
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.byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */
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.byte 0x0c /* DW_CFA_def_cfa */
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.uleb128 4
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.uleb128 4
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.byte 0x88 /* DW_CFA_offset, column 0x8 */
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.uleb128 1
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.align 4
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.LENDCIES:
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.long .LENDFDE2-.LSTARTFDE2 /* Length FDE */
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.LSTARTFDE2:
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.long .LSTARTFDE2-.LSTARTFRAMES /* CIE pointer */
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/* HACK: The dwarf2 unwind routines will subtract 1 from the
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return address to get an address in the middle of the
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presumed call instruction. Since we didn't get here via
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a call, we need to include the nop before the real start
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to make up for it. */
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.long .LSTART_sigreturn-1-. /* PC-relative start address */
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.long .LEND_sigreturn-.LSTART_sigreturn+1
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.uleb128 0 /* Augmentation length */
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/* What follows are the instructions for the table generation.
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We record the locations of each register saved. This is
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complicated by the fact that the "CFA" is always assumed to
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be the value of the stack pointer in the caller. This means
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that we must define the CFA of this body of code to be the
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saved value of the stack pointer in the sigcontext. Which
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also means that there is no fixed relation to the other
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saved registers, which means that we must use DW_CFA_expression
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to compute their addresses. It also means that when we
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adjust the stack with the popl, we have to do it all over again. */
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#define do_cfa_expr(offset) \
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.byte 0x0f; /* DW_CFA_def_cfa_expression */ \
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.uleb128 1f-0f; /* length */ \
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0: .byte 0x74; /* DW_OP_breg4 */ \
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.sleb128 offset; /* offset */ \
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.byte 0x06; /* DW_OP_deref */ \
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1:
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#define do_expr(regno, offset) \
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.byte 0x10; /* DW_CFA_expression */ \
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.uleb128 regno; /* regno */ \
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.uleb128 1f-0f; /* length */ \
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0: .byte 0x74; /* DW_OP_breg4 */ \
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.sleb128 offset; /* offset */ \
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1:
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do_cfa_expr(IA32_SIGCONTEXT_esp+4)
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do_expr(0, IA32_SIGCONTEXT_eax+4)
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do_expr(1, IA32_SIGCONTEXT_ecx+4)
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do_expr(2, IA32_SIGCONTEXT_edx+4)
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do_expr(3, IA32_SIGCONTEXT_ebx+4)
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do_expr(5, IA32_SIGCONTEXT_ebp+4)
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do_expr(6, IA32_SIGCONTEXT_esi+4)
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do_expr(7, IA32_SIGCONTEXT_edi+4)
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do_expr(8, IA32_SIGCONTEXT_eip+4)
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.byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */
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do_cfa_expr(IA32_SIGCONTEXT_esp)
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do_expr(0, IA32_SIGCONTEXT_eax)
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do_expr(1, IA32_SIGCONTEXT_ecx)
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do_expr(2, IA32_SIGCONTEXT_edx)
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do_expr(3, IA32_SIGCONTEXT_ebx)
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do_expr(5, IA32_SIGCONTEXT_ebp)
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do_expr(6, IA32_SIGCONTEXT_esi)
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do_expr(7, IA32_SIGCONTEXT_edi)
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do_expr(8, IA32_SIGCONTEXT_eip)
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.align 4
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.LENDFDE2:
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.long .LENDFDE3-.LSTARTFDE3 /* Length FDE */
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.LSTARTFDE3:
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.long .LSTARTFDE3-.LSTARTFRAMES /* CIE pointer */
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/* HACK: See above wrt unwind library assumptions. */
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.long .LSTART_rt_sigreturn-1-. /* PC-relative start address */
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.long .LEND_rt_sigreturn-.LSTART_rt_sigreturn+1
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.uleb128 0 /* Augmentation */
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/* What follows are the instructions for the table generation.
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We record the locations of each register saved. This is
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slightly less complicated than the above, since we don't
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modify the stack pointer in the process. */
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do_cfa_expr(IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_esp)
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do_expr(0, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eax)
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do_expr(1, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ecx)
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do_expr(2, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edx)
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do_expr(3, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebx)
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do_expr(5, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebp)
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do_expr(6, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_esi)
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do_expr(7, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edi)
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do_expr(8, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eip)
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.align 4
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.LENDFDE3:
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#include "../../x86/kernel/vsyscall-note_32.S"
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