linux-user: Support for restarting system calls for x86 targets

Update the x86 main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code rather than passing it
   back out as the "return code" from do_sigreturn()
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch EAX

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-5-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: Commit message tweaks; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
This commit is contained in:
Timothy E Baldwin 2016-05-12 18:47:30 +01:00 committed by Riku Voipio
parent 499b5d176a
commit 0284b03ba3
3 changed files with 36 additions and 28 deletions

View file

@ -285,6 +285,7 @@ void cpu_loop(CPUX86State *env)
CPUState *cs = CPU(x86_env_get_cpu(env));
int trapnr;
abi_ulong pc;
abi_ulong ret;
target_siginfo_t info;
for(;;) {
@ -294,28 +295,38 @@ void cpu_loop(CPUX86State *env)
switch(trapnr) {
case 0x80:
/* linux syscall from int $0x80 */
env->regs[R_EAX] = do_syscall(env,
env->regs[R_EAX],
env->regs[R_EBX],
env->regs[R_ECX],
env->regs[R_EDX],
env->regs[R_ESI],
env->regs[R_EDI],
env->regs[R_EBP],
0, 0);
ret = do_syscall(env,
env->regs[R_EAX],
env->regs[R_EBX],
env->regs[R_ECX],
env->regs[R_EDX],
env->regs[R_ESI],
env->regs[R_EDI],
env->regs[R_EBP],
0, 0);
if (ret == -TARGET_ERESTARTSYS) {
env->eip -= 2;
} else if (ret != -TARGET_QEMU_ESIGRETURN) {
env->regs[R_EAX] = ret;
}
break;
#ifndef TARGET_ABI32
case EXCP_SYSCALL:
/* linux syscall from syscall instruction */
env->regs[R_EAX] = do_syscall(env,
env->regs[R_EAX],
env->regs[R_EDI],
env->regs[R_ESI],
env->regs[R_EDX],
env->regs[10],
env->regs[8],
env->regs[9],
0, 0);
ret = do_syscall(env,
env->regs[R_EAX],
env->regs[R_EDI],
env->regs[R_ESI],
env->regs[R_EDX],
env->regs[10],
env->regs[8],
env->regs[9],
0, 0);
if (ret == -TARGET_ERESTARTSYS) {
env->eip -= 2;
} else if (ret != -TARGET_QEMU_ESIGRETURN) {
env->regs[R_EAX] = ret;
}
break;
#endif
case EXCP0B_NOSEG: