[Qemu-devel] [PATCH v2 00/13] linux-user: __{get, put}_user return value cleanup

[Qemu-devel] [PATCH v2 00/13] linux-user: __{get, put}_user return value cleanup

[riku.voipio]

From: Riku Voipio <riku.voipio@linaro.org>

This series is a cleanup and gcc-4.9 buildfix:

linux-user/syscall.c: In function ‘host_to_target_stat64’:
linux-user/qemu.h:301:19: error: right-hand operand of comma expression has no 
effect [-Werror=unused-value]
      ((hptr), (x)), 0)

removing the unused 0 moves the bar:

linux-user/main.c: In function ‘arm_kernel_cmpxchg64_helper’:
linux-user/qemu.h:330:15: error: void value not ignored as it ought to be
         __ret = __put_user((x), __hptr);    \

And after fixing that, we see there is a lot of reading the return
value of __put_user and __get_user in signal.c. A lot of this code
has been copied from kernel, where the accessor functions might fail
Qemu uses different model of accessing. Access is already checked in
lock_user(), and thus __put/__get user cannot fail.

So this patchset clears signal.c from reading __get_user and
__put_user return values, and then fixes the definitions of the macros.

Riku

Riku Voipio (13):
  signal/all: remove __get/__put_user return value reading
  signal/x86/setup_frame: __put_user cleanup
  signal/all: remove return value from copy_siginfo_to_user
  signal/all: remove return value from setup_sigcontext
  signal/all: remove return value from restore_sigcontext
  signal/sparc/restore_fpu_state: remove
  signal/all/do_sigaltstack remove __get_user value check
  signal/all/do_sigreturn - remove __get_user checks
  signal/all/setup_frame remove __put_user checks
  signal/ppc/{save,restore}_user_regs remove __put/get error checks
  signal/sparc64_set_context: remove __get_user checks
  signal/ppc/do_setcontext remove __get_user return check
  linux-user: fix gcc-4.9 compiler error on __{get,put]}_user

 linux-user/qemu.h   |   12 +-
 linux-user/signal.c | 1249 +++++++++++++++++++++------------------------------
 2 files changed, 513 insertions(+), 748 deletions(-)

-- 
2.0.0.rc2

Re: [Qemu-devel] [PATCH v2 00/13] linux-user: __{get, put}_user return value cleanup

[Peter Maydell]

On 6 June 2014 10:46,  <riku.voipio@linaro.org> wrote:
> From: Riku Voipio <riku.voipio@linaro.org>
>
> This series is a cleanup and gcc-4.9 buildfix:
>
> linux-user/syscall.c: In function ‘host_to_target_stat64’:
> linux-user/qemu.h:301:19: error: right-hand operand of comma expression has no
> effect [-Werror=unused-value]
>       ((hptr), (x)), 0)
>
> removing the unused 0 moves the bar:
>
> linux-user/main.c: In function ‘arm_kernel_cmpxchg64_helper’:
> linux-user/qemu.h:330:15: error: void value not ignored as it ought to be
>          __ret = __put_user((x), __hptr);    \
>
> And after fixing that, we see there is a lot of reading the return
> value of __put_user and __get_user in signal.c. A lot of this code
> has been copied from kernel, where the accessor functions might fail
> Qemu uses different model of accessing. Access is already checked in
> lock_user(), and thus __put/__get user cannot fail.
>
> So this patchset clears signal.c from reading __get_user and
> __put_user return values, and then fixes the definitions of the macros.

Other than the issue about ARM valid_user_regs(),
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM

Re: [Qemu-devel] [PATCH v2 00/13] linux-user: __{get, put}_user return value cleanup

[Riku Voipio]

On 8 June 2014 00:40, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 6 June 2014 10:46,  <riku.voipio@linaro.org> wrote:
>> From: Riku Voipio <riku.voipio@linaro.org>
>>
>> This series is a cleanup and gcc-4.9 buildfix:
>>
>> linux-user/syscall.c: In function ‘host_to_target_stat64’:
>> linux-user/qemu.h:301:19: error: right-hand operand of comma expression has no
>> effect [-Werror=unused-value]
>>       ((hptr), (x)), 0)
>>
>> removing the unused 0 moves the bar:
>>
>> linux-user/main.c: In function ‘arm_kernel_cmpxchg64_helper’:
>> linux-user/qemu.h:330:15: error: void value not ignored as it ought to be
>>          __ret = __put_user((x), __hptr);    \
>>
>> And after fixing that, we see there is a lot of reading the return
>> value of __put_user and __get_user in signal.c. A lot of this code
>> has been copied from kernel, where the accessor functions might fail
>> Qemu uses different model of accessing. Access is already checked in
>> lock_user(), and thus __put/__get user cannot fail.
>>
>> So this patchset clears signal.c from reading __get_user and
>> __put_user return values, and then fixes the definitions of the macros.
>
> Other than the issue about ARM valid_user_regs(),
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

Ok, I've updated the two mentioned patches and added your reviewed-by.
I think instead of sending v3 round of the patches to the list, I'll
just send them in the linux-user pull req[1] - people are already
itching got gcc-4.9 builds. Even in the pull request people can still
comment if there are other issues with the patches.

Riku

[1] https://git.linaro.org/people/riku.voipio/qemu.git/shortlog/refs/heads/linux-user-for-upstream