fb30d64568
We were missing __volatile__ on some bits of asm in the segfault handlers. On x86_64, this was messing up the move from %rdx to uc because that was moved to after the GET_FAULTINFO_FROM_SC, which changed %rdx. Also changed the other bit of asm and the one in the i386 handler to prevent any similar occurrences. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
52 lines
1.5 KiB
C
52 lines
1.5 KiB
C
/*
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* Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
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* Licensed under the GPL
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*/
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#include <stddef.h>
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#include <signal.h>
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#include <linux/compiler.h>
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#include <asm/unistd.h>
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#include "uml-config.h"
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#include "sysdep/sigcontext.h"
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#include "sysdep/faultinfo.h"
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#include "sysdep/stub.h"
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/* Copied from sys-x86_64/signal.c - Can't find an equivalent definition
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* in the libc headers anywhere.
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*/
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struct rt_sigframe
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{
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char *pretcode;
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struct ucontext uc;
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struct siginfo info;
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};
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/* Copied here from <linux/kernel.h> - we're userspace. */
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#define container_of(ptr, type, member) ({ \
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const typeof( ((type *)0)->member ) *__mptr = (ptr); \
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(type *)( (char *)__mptr - offsetof(type,member) );})
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void __attribute__ ((__section__ (".__syscall_stub")))
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stub_segv_handler(int sig)
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{
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struct ucontext *uc;
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int pid;
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__asm__ __volatile__("movq %%rdx, %0" : "=g" (uc) :);
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GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
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&uc->uc_mcontext);
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pid = stub_syscall0(__NR_getpid);
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stub_syscall2(__NR_kill, pid, SIGUSR1);
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/* sys_sigreturn expects that the stack pointer will be 8 bytes into
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* the signal frame. So, we use the ucontext pointer, which we know
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* already, to get the signal frame pointer, and add 8 to that.
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*/
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__asm__ __volatile__("movq %0, %%rsp; movq %1, %%rax ; syscall": :
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"g" ((unsigned long)
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container_of(uc, struct rt_sigframe, uc) + 8),
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"g" (__NR_rt_sigreturn));
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}
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