kernel-fxtec-pro1x/arch/um/sys-x86_64/stub_segv.c
Jeff Dike 17d469715c [PATCH] uml: properly invoke x86_64 system calls
This patch makes stub_segv use the stub_syscall macros.  This was needed
anyway, but the bug that prompted this was the discovery that gcc was storing
stuff in RCX, which is trashed across a system call.  This is exactly the sort
of problem that the new macros fix.

There is a stub_syscall0 for getpid.  stub_segv was changed to be a libc file,
and that caused some include changes.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-22 09:13:41 -08:00

51 lines
1.4 KiB
C

/*
* Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
* Licensed under the GPL
*/
#include <stddef.h>
#include <signal.h>
#include <linux/compiler.h>
#include <asm/unistd.h>
#include "uml-config.h"
#include "sysdep/sigcontext.h"
#include "sysdep/faultinfo.h"
#include "sysdep/stub.h"
/* Copied from sys-x86_64/signal.c - Can't find an equivalent definition
* in the libc headers anywhere.
*/
struct rt_sigframe
{
char *pretcode;
struct ucontext uc;
struct siginfo info;
};
/* Copied here from <linux/kernel.h> - we're userspace. */
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
void __attribute__ ((__section__ (".__syscall_stub")))
stub_segv_handler(int sig)
{
struct ucontext *uc;
int pid;
__asm__("movq %%rdx, %0" : "=g" (uc) :);
GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
&uc->uc_mcontext);
pid = stub_syscall0(__NR_getpid);
stub_syscall2(__NR_kill, pid, SIGUSR1);
/* sys_sigreturn expects that the stack pointer will be 8 bytes into
* the signal frame. So, we use the ucontext pointer, which we know
* already, to get the signal frame pointer, and add 8 to that.
*/
__asm__("movq %0, %%rsp; movq %1, %%rax ; syscall": :
"g" ((unsigned long) container_of(uc, struct rt_sigframe,
uc) + 8),
"g" (__NR_rt_sigreturn));
}