The kernel uses orig_rax/orig_eax to store the syscall number before
a syscall. One can see this value in core dumps and ptrace.
Signed-off-by: Ilya Leoshkevich <i...@linux.ibm.com>
---
linux-user/elfload.c | 4 ++--
linux-user/i386/cpu_loop.c | 3 +++
linux-user/qemu.h | 5 +++++
3 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 05292c27776..2d73382ae6b 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -203,7 +203,7 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs,
const CPUX86State *en
(*regs)[12] = tswapreg(env->regs[R_EDX]);
(*regs)[13] = tswapreg(env->regs[R_ESI]);
(*regs)[14] = tswapreg(env->regs[R_EDI]);
- (*regs)[15] = tswapreg(env->regs[R_EAX]); /* XXX */
+ (*regs)[15] = tswapreg(get_task_state(env_cpu_const(env))->orig_ax);
(*regs)[16] = tswapreg(env->eip);
(*regs)[17] = tswapreg(env->segs[R_CS].selector & 0xffff);
(*regs)[18] = tswapreg(env->eflags);
@@ -306,7 +306,7 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs,
const CPUX86State *en
(*regs)[8] = tswapreg(env->segs[R_ES].selector & 0xffff);
(*regs)[9] = tswapreg(env->segs[R_FS].selector & 0xffff);
(*regs)[10] = tswapreg(env->segs[R_GS].selector & 0xffff);
- (*regs)[11] = tswapreg(env->regs[R_EAX]); /* XXX */
+ (*regs)[11] = tswapreg(get_task_state(env_cpu_const(env))->orig_ax);
(*regs)[12] = tswapreg(env->eip);
(*regs)[13] = tswapreg(env->segs[R_CS].selector & 0xffff);
(*regs)[14] = tswapreg(env->eflags);
diff --git a/linux-user/i386/cpu_loop.c b/linux-user/i386/cpu_loop.c
index 92beb6830cc..7a35215278a 100644
--- a/linux-user/i386/cpu_loop.c
+++ b/linux-user/i386/cpu_loop.c
@@ -172,6 +172,7 @@ static void emulate_vsyscall(CPUX86State *env)
/*
* Perform the syscall. None of the vsyscalls should need restarting.
*/
+ get_task_state(env_cpu(env))->orig_ax = syscall;
ret = do_syscall(env, syscall, env->regs[R_EDI], env->regs[R_ESI],
env->regs[R_EDX], env->regs[10], env->regs[8],
env->regs[9], 0, 0);
@@ -221,6 +222,7 @@ void cpu_loop(CPUX86State *env)
case EXCP_SYSCALL:
#endif
/* linux syscall from int $0x80 */
+ get_task_state(cs)->orig_ax = env->regs[R_EAX];
ret = do_syscall(env,
env->regs[R_EAX],
env->regs[R_EBX],
@@ -239,6 +241,7 @@ void cpu_loop(CPUX86State *env)
#ifdef TARGET_X86_64
case EXCP_SYSCALL:
/* linux syscall from syscall instruction. */
+ get_task_state(cs)->orig_ax = env->regs[R_EAX];
ret = do_syscall(env,
env->regs[R_EAX],
env->regs[R_EDI],
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index a2961f503f4..85ba5a53869 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -159,6 +159,11 @@ struct TaskState {
/* Start time of task after system boot in clock ticks */
uint64_t start_boottime;
+
+#if defined(TARGET_I386)
+ /* Last syscall number. */
+ target_ulong orig_ax;
+#endif
};
abi_long do_brk(abi_ulong new_brk);
--
2.45.2
