arch/um/sys-x86_64/stub_segv.c

   1 /*
   2  * Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <asm/signal.h>
   7 #include <linux/compiler.h>
   8 #include <asm/unistd.h>
   9 #include <asm/ucontext.h>
  10 #include "uml-config.h"
  11 #include "sysdep/sigcontext.h"
  12 #include "sysdep/faultinfo.h"
  13
  14 void __attribute__ ((__section__ (".__syscall_stub")))
  15 stub_segv_handler(int sig)
  16 {
  17         struct ucontext *uc;
  18
  19         __asm__("movq %%rdx, %0" : "=g" (uc) :);
  20         GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
  21                               &uc->uc_mcontext);
  22
  23         __asm__("movq %0, %%rax ; syscall": : "g" (__NR_getpid));
  24         __asm__("movq %%rax, %%rdi ; movq %0, %%rax ; movq %1, %%rsi ;"
  25                 "syscall": : "g" (__NR_kill), "g" (SIGUSR1));
  26         /* Two popqs to restore the stack to the state just before entering
  27          * the handler, one pops the return address, the other pops the frame
  28          * pointer.
  29          */
  30         __asm__("popq %%rax ; popq %%rax ; movq %0, %%rax ; syscall" : : "g"
  31                 (__NR_rt_sigreturn));
  32 }