mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

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

Browse Source 
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: Timothy 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: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: Commit message tweaks; drop TARGET_USE_ERESTARTSYS define;
 drop whitespace changes]
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 18:47:44 +01:00 committed by Riku Voipio
parent d7749ab770
commit 4134ecfeb9
3 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
linux-user/main.c
View File

@ -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

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

@ -26,4 +26,5 @@ static inline abi_ulong get_sp_from_cpustate(CPUMBState *state)
return state->regs[14];
}
#endif /* TARGET_SIGNAL_H */

2
linux-user/signal.c
View File

@ -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);
}