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[Qemu-devel] [PATCH 04/10] linux-user: Fix syscall instruction usermode
From: |
riku . voipio |
Subject: |
[Qemu-devel] [PATCH 04/10] linux-user: Fix syscall instruction usermode emulation on X86_64 |
Date: |
Tue, 12 Aug 2014 16:42:14 +0300 |
From: Jincheng Miao <address@hidden>
Currently syscall instruction is buggy on user mode X86_64,
the EIP is updated after do_syscall(), that is too late for
clone(). Because clone() will create a thread at the env->EIP
(the address of syscall insn), and then child thread enters
do_syscall() again, that is not expected. Sometimes it is tragic.
User mode syscall insn emulation is not used MSR, so the
action should be same to INT 0x80. INT 0x80 will update EIP in
do_interrupt(), ditto for syscall() for consistency.
Signed-off-by: Jincheng Miao <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
Signed-off-by: Riku Voipio <address@hidden>
---
linux-user/main.c | 1 -
target-i386/seg_helper.c | 4 ++--
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/linux-user/main.c b/linux-user/main.c
index c5878f9..bc1ff46 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -309,7 +309,6 @@ void cpu_loop(CPUX86State *env)
env->regs[8],
env->regs[9],
0, 0);
- env->eip = env->exception_next_eip;
break;
#endif
case EXCP0B_NOSEG:
diff --git a/target-i386/seg_helper.c b/target-i386/seg_helper.c
index 2d970d0..13eefba 100644
--- a/target-i386/seg_helper.c
+++ b/target-i386/seg_helper.c
@@ -1127,8 +1127,8 @@ static void do_interrupt_user(CPUX86State *env, int
intno, int is_int,
/* Since we emulate only user space, we cannot do more than
exiting the emulation with the suitable exception and error
- code */
- if (is_int) {
+ code. So update EIP for INT 0x80 and EXCP_SYSCALL. */
+ if (is_int || intno == EXCP_SYSCALL) {
env->eip = next_eip;
}
}
--
2.0.1
- [Qemu-devel] [PATCH 00/10] linux-user update, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 01/10] linux-user: /proc/self/maps content, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 06/10] linux-user: fix readlink handling with magic exe symlink, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 09/10] linux-user: support {name_to, open_by}_handle_at syscalls, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 10/10] linux-user: add setns and unshare, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 03/10] linux-user: make binfmt flag O require P, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 05/10] linux-user: Fix conversion of sigevent argument to timer_create, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 08/10] linux-user: support ioprio_{get, set} syscalls, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 07/10] linux-user: support timerfd_{create, gettime, settime} syscalls, riku . voipio, 2014/08/12
- [Qemu-devel] [PATCH 04/10] linux-user: Fix syscall instruction usermode emulation on X86_64,
riku . voipio <=
- [Qemu-devel] [PATCH 02/10] linux-user: redirect openat calls, riku . voipio, 2014/08/12