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Re: [Qemu-ppc] [Qemu-devel] [PATCH 10/12] linux-user: clock_nanosleep er
From: |
Peter Maydell |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [PATCH 10/12] linux-user: clock_nanosleep errno Handling on PPC |
Date: |
Mon, 4 Aug 2014 18:42:42 +0100 |
On 4 August 2014 17:45, Tom Musta <address@hidden> wrote:
> The clock_nanosleep syscall is unusual in that it returns positive
> numbers in error handling situations, versus returning -1 and setting
> errno, or returning a negative errno value. On POWER, the kernel will
> set the SO bit of CR0 to indicate failure in a syscall. QEMU has
> generic handling to do this for syscalls with standard return values.
>
> Add special case code for clock_nanosleep to handle CR0 properly.
>
> Signed-off-by: Tom Musta <address@hidden>
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 95cee0b..5660520 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -8993,6 +8993,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
> arg1,
> ret = get_errno(clock_nanosleep(arg1, arg2, &ts, arg4 ? &ts : NULL));
> if (arg4)
> host_to_target_timespec(arg4, &ts);
> +
> +#if defined(TARGET_PPC) || defined(TARGET_PPC64)
> + /* clock_nanosleep is odd in that it returns positive errno values.
> + * On PPC, CR0 bit 3 should be set in such a situation. */
> + if (ret) {
> + ((CPUPPCState *)cpu_env)->crf[0] |= 1;
> + }
> +#endif
> break;
> }
> #endif
New target-specific ifdefs in syscall.c make me sad, but the
alternative would be to upend the do_syscall() calling
convention to pass return value and success/failure separately
or something, which is clearly ludicrous for this corner case. So
Reviewed-by: Peter Maydell <address@hidden>
thanks
-- PMM
- [Qemu-ppc] [PATCH 06/12] linux-user: Detect Negative Message Sizes in msgsnd System Call, (continued)
- [Qemu-ppc] [PATCH 06/12] linux-user: Detect Negative Message Sizes in msgsnd System Call, Tom Musta, 2014/08/04
- [Qemu-ppc] [PATCH 07/12] linux-user: Handle NULL argument to sched_{get, set}param, Tom Musta, 2014/08/04
- [Qemu-ppc] [PATCH 08/12] linux-user: Detect fault in sched_rr_get_interval, Tom Musta, 2014/08/04
- [Qemu-ppc] [PATCH 09/12] linux-user: Minimum Sig Handler Stack Size for PPC64 ELF V2, Tom Musta, 2014/08/04
- [Qemu-ppc] [PATCH 10/12] linux-user: clock_nanosleep errno Handling on PPC, Tom Musta, 2014/08/04
- [Qemu-ppc] [PATCH 11/12] linux-user: Support target-to-host translation of mlockall argument, Tom Musta, 2014/08/04
- [Qemu-ppc] [PATCH 12/12] linux-user: writev Partial Writes, Tom Musta, 2014/08/04
- Re: [Qemu-ppc] [Qemu-devel] [PATCH 00/12] target-ppc: Linux-User Mode Bug Fixes for Power, Riku Voipio, 2014/08/12