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

Update the tilegx main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * return -TARGET_QEMU_ESIGRETURN from sigreturn rather than current R_RE
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Note that this fixes a bug where a sigreturn which happened to have
an errno value in TILEGX_R_RE would incorrectly cause TILEGX_R_ERR
to get set.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
This commit is contained in:
Peter Maydell 2016-05-12 18:47:42 +01:00 committed by Riku Voipio
parent 6205086558
commit a9175169cc
3 changed files with 15 additions and 9 deletions
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21
linux-user/main.c
View File

@ -3706,15 +3706,20 @@ void cpu_loop(CPUTLGState *env)
cpu_exec_end(cs);
switch (trapnr) {
case TILEGX_EXCP_SYSCALL:
env->regs[TILEGX_R_RE] = do_syscall(env, env->regs[TILEGX_R_NR],
env->regs[0], env->regs[1],
env->regs[2], env->regs[3],
env->regs[4], env->regs[5],
env->regs[6], env->regs[7]);
env->regs[TILEGX_R_ERR] = TILEGX_IS_ERRNO(env->regs[TILEGX_R_RE])
? - env->regs[TILEGX_R_RE]
: 0;
{
abi_ulong ret = do_syscall(env, env->regs[TILEGX_R_NR],
env->regs[0], env->regs[1],
env->regs[2], env->regs[3],
env->regs[4], env->regs[5],
env->regs[6], env->regs[7]);
if (ret == -TARGET_ERESTARTSYS) {
env->pc -= 8;
} else if (ret != -TARGET_QEMU_ESIGRETURN) {
env->regs[TILEGX_R_RE] = ret;
env->regs[TILEGX_R_ERR] = TILEGX_IS_ERRNO(ret) ? -ret : 0;
}
break;
}
case TILEGX_EXCP_OPCODE_EXCH:
do_exch(env, true, false);
break;

2
linux-user/signal.c
View File

@ -5709,7 +5709,7 @@ long do_rt_sigreturn(CPUTLGState *env)
}
unlock_user_struct(frame, frame_addr, 0);
return env->regs[TILEGX_R_RE];
return -TARGET_QEMU_ESIGRETURN;
badframe:

1
linux-user/tilegx/target_signal.h
View File

@ -25,4 +25,5 @@ static inline abi_ulong get_sp_from_cpustate(CPUTLGState *state)
return state->regs[TILEGX_R_SP];
}
#endif /* TARGET_SIGNAL_H */