提交 4134ecfe 编写于 作者: T Timothy E Baldwin 提交者: Riku Voipio

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

Update the Microblaze 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 on sigreturn
 * 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 in passing fixes a bug where we were corrupting
the guest r[3] on sigreturn with the guest's r[10] because
do_sigreturn() was returning env->regs[10] but the register for
syscall return values is env->regs[3].
Signed-off-by: NTimothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-11-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
[PMM: Commit message tweaks; drop TARGET_USE_ERESTARTSYS define;
 drop whitespace changes]
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRiku Voipio <riku.voipio@linaro.org>
上级 d7749ab7
......@@ -2982,7 +2982,12 @@ void cpu_loop(CPUMBState *env)
env->regs[9],
env->regs[10],
0, 0);
env->regs[3] = ret;
if (ret == -TARGET_ERESTARTSYS) {
/* Wind back to before the syscall. */
env->sregs[SR_PC] -= 4;
} else if (ret != -TARGET_QEMU_ESIGRETURN) {
env->regs[3] = ret;
}
/* All syscall exits result in guest r14 being equal to the
* PC we return to, because the kernel syscall exit "rtbd" does
* this. (This is true even for sigreturn(); note that r14 is
......
......@@ -26,4 +26,5 @@ static inline abi_ulong get_sp_from_cpustate(CPUMBState *state)
return state->regs[14];
}
#endif /* TARGET_SIGNAL_H */
......@@ -3618,7 +3618,7 @@ long do_sigreturn(CPUMBState *env)
env->regs[14] = env->sregs[SR_PC];
unlock_user_struct(frame, frame_addr, 0);
return env->regs[10];
return -TARGET_QEMU_ESIGRETURN;
badframe:
force_sig(TARGET_SIGSEGV);
}
......
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