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Re: [Qemu-devel] [PATCH 3/3] linux-user:Signal handling for MIPS64
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH 3/3] linux-user:Signal handling for MIPS64 |
Date: |
Thu, 29 Dec 2011 12:23:16 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111220 Thunderbird/9.0 |
Am 29.12.2011 11:58, schrieb Khansa Butt:
> On Wed, Dec 14, 2011 at 9:20 PM, Richard Henderson <address@hidden> wrote:
>> On 12/07/2011 09:25 PM, address@hidden wrote:
>>> +#if defined(TARGET_MIPS64)
>>> + /* tswapal() do 64 bit swap in case of MIPS64 but
>>> + we need 32 bit swap as sa_flags is 32 bit */
>>> + k->sa_flags = bswap32(act->sa_flags);
>>> +#else
>>> k->sa_flags = tswapal(act->sa_flags);
>>> +#endif
>>
>> The condition in syscall_defs.h is TARGET_MIPS, not TARGET_MIPS64.
>> They should match, despite the fact that it doesn't actually matter
>> for the 32-bit abis.
>>
>>> #elif defined(TARGET_ABI_MIPSN64)
>>>
>>> -# warning signal handling not implemented
>>> +struct target_sigcontext {
>>> + uint32_t sc_regmask; /* Unused */
>>> + uint32_t sc_status;
>>
>> There's no reason to duplicate all this code. Yes, when someone wrote
>> this in the first place, they wrote separate sectons for each mips abi.
>> However, as you can see that huge portions of this block are identical,
>> this was obviously a mistake.
>>
>> Start by changing the original section to #elif defined(TARGET_MIPS)
>> and see what needs changing specifically for the ABIs. I'm not even
>> sure there are any differences at all.
>
> The difference lies in setup_frame(). the trampoline function needs
> syscall number
> install_sigtramp(frame->sf_code, TARGET_NR_sigreturn);
> sigreturn is not defined for MIPS64 instead it has only rt_sigreturn.
> I tried with #elif defined(TARGET_MIPS). cross compile the following
> small program and run it on
> qemu-mips64
> #include <stdio.h>
> #include <signal.h>
> #include <string.h>
> #include <unistd.h>
>
> struct sigaction act;
>
> void sighandler(int signum, siginfo_t *info, void *ptr)
> {
> printf("Received signal %d\n", signum);
> printf("Signal originates from process %lu\n",(unsigned
> long)info->si_pid);
> }
>
> int main()
> {
> printf("I am %lu\n", (unsigned long)getpid());
>
> memset(&act, 0, sizeof(act));
>
> act.sa_sigaction = sighandler;
> act.sa_flags = SA_SIGINFO;
>
> sigaction(SIGILL, &act, NULL);
>
> // Waiting
> sleep(100);
>
> return 0;
> }
>
> and again I found that only install_sigtramp line is needed to be changed.
> keeping #elif defined(TARGET_MIPS) above signal handling portion, can i use
> #if defined(TARGET_MIPS64)
> ....
> #else
> for install_sigtramp() difference
That's not the only difference - the sigcontext is different, too, for
instance. I hope to get something finished for n32 later today.
Andreas