FreeBSD/Linux Kernel Cross Reference
sys/amd64/ia32/ia32_sigtramp.S

     /*-
      * Copyright (c) 2003 Peter Wemm
      * All rights reserved.
      *
      * Copyright (c) 2021 The FreeBSD Foundation
      *
      * Portions of this software were developed by Konstantin Belousov
      * under sponsorship from the FreeBSD Foundation.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    #include <machine/asmacros.h>
    #include <sys/syscall.h>
    
    #include "ia32_assym.h"
    
            .text
    /*
     * Signal trampoline, mapped as vdso into shared page, or copied to
     * top of user stack for old binaries.
     */
            ALIGN_TEXT
            .globl  __vdso_ia32_sigcode
    __vdso_ia32_sigcode:
            .cfi_startproc
            .cfi_signal_frame
            .cfi_def_cfa    %esp, 0
    #if 0
            .cfi_offset     %gs,  IA32_SIGF_UC + IA32_UC_GS
            .cfi_offset     %fs,  IA32_SIGF_UC + IA32_UC_FS
            .cfi_offset     %es,  IA32_SIGF_UC + IA32_UC_ES
            .cfi_offset     %ds,  IA32_SIGF_UC + IA32_UC_DS
    #endif
            .cfi_offset     %edi, IA32_SIGF_UC + IA32_UC_EDI
            .cfi_offset     %esi, IA32_SIGF_UC + IA32_UC_ESI
            .cfi_offset     %ebp, IA32_SIGF_UC + IA32_UC_EBP
            .cfi_offset     %ebx, IA32_SIGF_UC + IA32_UC_EBX
            .cfi_offset     %edx, IA32_SIGF_UC + IA32_UC_EDX
            .cfi_offset     %ecx, IA32_SIGF_UC + IA32_UC_ECX
            .cfi_offset     %eax, IA32_SIGF_UC + IA32_UC_EAX
            .cfi_offset     %eip, IA32_SIGF_UC + IA32_UC_EIP
    #if 0
            .cfi_offset     %cs,  IA32_SIGF_UC + IA32_UC_CS
            .cfi_offset     %flags, IA32_SIGF_UC + IA32_UC_EFLAGS
    #endif
            .cfi_offset     %esp, IA32_SIGF_UC + IA32_UC_ESP
    #if 0
            .cfi_offset     %ss,  IA32_SIGF_UC + IA32_UC_SS
            .cfi_offset     93 /* %fs.base */, IA32_SIGF_UC + IA32_UC_FSBASE
            .cfi_offset     94 /* %gs.base */, IA32_SIGF_UC + IA32_UC_GSBASE
    #endif
            calll   *IA32_SIGF_HANDLER(%esp)
            leal    IA32_SIGF_UC(%esp),%eax /* get ucontext */
            pushl   %eax
            .cfi_def_cfa    %esp, 4
            movl    $SYS_sigreturn,%eax
            pushl   %eax                    /* junk to fake return addr. */
            .cfi_def_cfa    %esp, 8
            int     $0x80                   /* enter kernel with args */
                                            /* on stack */
    1:
            jmp     1b
            .cfi_endproc
    
    #ifdef COMPAT_FREEBSD4
            ALIGN_TEXT
            .globl  __vdso_freebsd4_ia32_sigcode
    __vdso_freebsd4_ia32_sigcode:
            calll   *IA32_SIGF_HANDLER(%esp)
            leal    IA32_SIGF_UC4(%esp),%eax/* get ucontext */
            pushl   %eax
            movl    $344,%eax               /* 4.x SYS_sigreturn */
            pushl   %eax                    /* junk to fake return addr. */
            int     $0x80                   /* enter kernel with args */
                                            /* on stack */
    1:
            jmp     1b
   #endif
   
   #ifdef COMPAT_43
           ALIGN_TEXT
           .globl  __vdso_ia32_osigcode
   __vdso_ia32_osigcode:
           calll   *IA32_SIGF_HANDLER(%esp)/* call signal handler */
           leal    IA32_SIGF_SC(%esp),%eax /* get sigcontext */
           pushl   %eax
           movl    $103,%eax               /* 3.x SYS_sigreturn */
           pushl   %eax                    /* junk to fake return addr. */
           int     $0x80                   /* enter kernel with args */
   1:
           jmp     1b
   
   /*
    * Our lcall $7,$0 handler remains in user mode (ring 3), since lcalls
    * don't change the interrupt mask, so if this one went directly to the
    * kernel then there would be a window with interrupts enabled in kernel
    * mode, and all interrupt handlers would have to be almost as complicated
    * as the NMI handler to support this.
    *
    * Instead, convert the lcall to an int0x80 call.  The kernel does most
    * of the conversion by popping the lcall return values off the user
    * stack and returning to them instead of to here, except when the
    * conversion itself fails.  Adjusting the stack here is impossible for
    * vfork() and harder for other syscalls.
    */
           ALIGN_TEXT
           .globl  __vdso_lcall_tramp
   __vdso_lcall_tramp:
           int     $0x80
   1:      jmp     1b
   #endif
           .p2align 1

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