提交 17d46971 编写于 作者: J Jeff Dike 提交者: Linus Torvalds

[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: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 e23181de
......@@ -16,6 +16,15 @@ extern void stub_clone_handler(void);
#define STUB_MMAP_NR __NR_mmap2
#define MMAP_OFFSET(o) ((o) >> PAGE_SHIFT)
static inline long stub_syscall0(long syscall)
{
long ret;
__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall));
return ret;
}
static inline long stub_syscall1(long syscall, long arg1)
{
long ret;
......
......@@ -6,7 +6,6 @@
#ifndef __SYSDEP_STUB_H
#define __SYSDEP_STUB_H
#include <asm/ptrace.h>
#include <asm/unistd.h>
#include <sysdep/ptrace_user.h>
......@@ -20,6 +19,17 @@ extern void stub_clone_handler(void);
#define __syscall_clobber "r11","rcx","memory"
#define __syscall "syscall"
static inline long stub_syscall0(long syscall)
{
long ret;
__asm__ volatile (__syscall
: "=a" (ret)
: "0" (syscall) : __syscall_clobber );
return ret;
}
static inline long stub_syscall2(long syscall, long arg1, long arg2)
{
long ret;
......
......@@ -5,7 +5,7 @@ obj-y = bitops.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
obj-$(CONFIG_HIGHMEM) += highmem.o
obj-$(CONFIG_MODULES) += module.o
USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o
USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o stub_segv.o
SYMLINKS = bitops.c semaphore.c highmem.c module.c
......
......@@ -3,9 +3,11 @@
* Licensed under the GPL
*/
#include <asm/signal.h>
#include <signal.h>
#include <sys/select.h> /* The only way I can see to get sigset_t */
#include <asm/unistd.h>
#include "uml-config.h"
#include "sysdep/stub.h"
#include "sysdep/sigcontext.h"
#include "sysdep/faultinfo.h"
......@@ -13,13 +15,14 @@ void __attribute__ ((__section__ (".__syscall_stub")))
stub_segv_handler(int sig)
{
struct sigcontext *sc = (struct sigcontext *) (&sig + 1);
int pid;
GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
sc);
__asm__("movl %0, %%eax ; int $0x80": : "g" (__NR_getpid));
__asm__("movl %%eax, %%ebx ; movl %0, %%eax ; movl %1, %%ecx ;"
"int $0x80": : "g" (__NR_kill), "g" (SIGUSR1));
pid = stub_syscall0(__NR_getpid);
stub_syscall2(__NR_kill, pid, SIGUSR1);
/* Load pointer to sigcontext into esp, since we need to leave
* the stack in its original form when we do the sigreturn here, by
* hand.
......
......@@ -12,7 +12,7 @@ lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o ldt.o mem.o memcpy.o \
obj-y := ksyms.o
obj-$(CONFIG_MODULES) += module.o um_module.o
USER_OBJS := ptrace_user.o sigcontext.o
USER_OBJS := ptrace_user.o sigcontext.o stub_segv.o
SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c ldt.c memcpy.S \
thunk.S module.c
......
......@@ -3,14 +3,14 @@
* Licensed under the GPL
*/
#include <asm/signal.h>
#include <stddef.h>
#include <signal.h>
#include <linux/compiler.h>
#include <asm/unistd.h>
#include <asm/ucontext.h>
#include "uml-config.h"
#include "sysdep/sigcontext.h"
#include "sysdep/faultinfo.h"
#include <stddef.h>
#include "sysdep/stub.h"
/* Copied from sys-x86_64/signal.c - Can't find an equivalent definition
* in the libc headers anywhere.
......@@ -31,21 +31,21 @@ 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);
__asm__("movq %0, %%rax ; syscall": : "g" (__NR_getpid));
__asm__("movq %%rax, %%rdi ; movq %0, %%rax ; movq %1, %%rsi ;"
"syscall": : "g" (__NR_kill), "g" (SIGUSR1) :
"%rdi", "%rax", "%rsi");
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": :
__asm__("movq %0, %%rsp; movq %1, %%rax ; syscall": :
"g" ((unsigned long) container_of(uc, struct rt_sigframe,
uc) + 8));
__asm__("movq %0, %%rax ; syscall" : : "g" (__NR_rt_sigreturn));
uc) + 8),
"g" (__NR_rt_sigreturn));
}
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