Re: [PATCH] um: Fix check for _xstate for older hosts

[Florian Fainelli <f.fainelli@gmail.com>]

On 07/24/2017 05:46 AM, Richard Weinberger wrote:
> On Wed, Jul 19, 2017 at 1:43 AM, Florian Fainelli <f.fainelli@gmail.com> wrote:
>> Commit 0a987645672e ("um: Allow building and running on older
>> hosts") attempted to check for PTRACE_{GET,SET}REGSET under the premise
>> that these ptrace(2) parameters were directly linked with the presence
>> of the _xstate structure.
>>
>> After Richard's commit 61e8d462457f ("um: Correctly check for
>> PTRACE_GETRESET/SETREGSET") which properly included linux/ptrace.h
>> instead of asm/ptrace.h, we could get into the original build failure
>> that I reported:
>>
>> arch/x86/um/user-offsets.c: In function 'foo':
>> arch/x86/um/user-offsets.c:54: error: invalid application of 'sizeof' to
>> incomplete type 'struct _xstate'
>>
>> On this particular host, we do have PTRACE_GETREGSET and
>> PTRACE_SETREGSET defined in linux/ptrace.h, but not the structure
>> _xstate that should be pulled from the following include chain: signal.h
>> -> bits/sigcontext.h.
>>
>> Correctly fix this by checking for FP_XSTATE_MAGIC1 which is the correct
>> way to see if struct _xstate is available or not on the host.
>>
>> Fixes: 61e8d462457f ("um: Correctly check for PTRACE_GETRESET/SETREGSET")
>> Fixes: 0a987645672e ("um: Allow building and running on older hosts")
>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>> ---
>>  arch/x86/um/user-offsets.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
>> index ae4cd58c0c7a..02250b2633b8 100644
>> --- a/arch/x86/um/user-offsets.c
>> +++ b/arch/x86/um/user-offsets.c
>> @@ -50,7 +50,7 @@ void foo(void)
>>         DEFINE(HOST_GS, GS);
>>         DEFINE(HOST_ORIG_AX, ORIG_EAX);
>>  #else
>> -#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
>> +#ifdef FP_XSTATE_MAGIC1
>>         DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
>>  #else
>>         DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
>> --
>> 2.9.3
>>
> 
> Applied, thanks for fixing!

Can you submit this to Linus before v4.13 is released? Thank you!
-- 
Florian