FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/sigtramp.s

     /*-
      * Copyright (c) 1990 The Regents of the University of California.
      * All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * William Jolitz.
      *
      * 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.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
     *
     *      from: @(#)locore.s      7.3 (Berkeley) 5/13/91
     * $FreeBSD$
     *
     *              originally from: locore.s, by William F. Jolitz
     *
     *              Substantially rewritten by David Greenman, Rod Grimes,
     *                      Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp
     *                      and many others.
     */
    
    #include <sys/syscall.h>
    #include <machine/asmacros.h>
    #include <machine/psl.h>
    
    #include "assym.inc"
    
    /*
     * Signal trampoline, copied to top of user stack
     */
    NON_GPROF_ENTRY(sigcode)
            calll   *SIGF_HANDLER(%esp)
            leal    SIGF_UC(%esp),%eax      /* get ucontext */
            pushl   %eax
            testl   $PSL_VM,UC_EFLAGS(%eax)
            jne     1f
            mov     UC_GS(%eax),%gs         /* restore %gs */
    1:
            movl    $SYS_sigreturn,%eax
            pushl   %eax                    /* junk to fake return addr. */
            int     $0x80                   /* enter kernel with args */
                                            /* on stack */
    1:
            jmp     1b
    
    #ifdef COMPAT_FREEBSD4
            ALIGN_TEXT
    freebsd4_sigcode:
            calll   *SIGF_HANDLER(%esp)
            leal    SIGF_UC4(%esp),%eax     /* get ucontext */
            pushl   %eax
            testl   $PSL_VM,UC4_EFLAGS(%eax)
            jne     1f
            mov     UC4_GS(%eax),%gs        /* restore %gs */
    1:
            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
    osigcode:
            call    *SIGF_HANDLER(%esp)     /* call signal handler */
            lea     SIGF_SC(%esp),%eax      /* get sigcontext */
            pushl   %eax
            testl   $PSL_VM,SC_PS(%eax)
            jne     9f
            mov     SC_GS(%eax),%gs         /* restore %gs */
    9:
            movl    $103,%eax               /* 3.x SYS_sigreturn */
            pushl   %eax                    /* junk to fake return addr. */
            int     $0x80                   /* enter kernel with args */
    0:      jmp     0b
    
    /*
    * 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
   lcall_tramp:
           int     $0x80
   1:      jmp     1b
   
   #endif /* COMPAT_43 */
   
           ALIGN_TEXT
   esigcode:
   
           .data
           .globl  szsigcode
   szsigcode:
           .long   esigcode-sigcode
   #ifdef COMPAT_FREEBSD4
           .globl  szfreebsd4_sigcode
   szfreebsd4_sigcode:
           .long   esigcode-freebsd4_sigcode
   #endif
   #ifdef COMPAT_43
           .globl  szosigcode
   szosigcode:
           .long   esigcode-osigcode
           .globl  sz_lcall_tramp
   sz_lcall_tramp:
           .long   esigcode-lcall_tramp
   #endif

Cache object: cee2c97a6f4f171a4523b8e2fc99d537