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

[Richard Weinberger]

Am Freitag, 18. August 2017, 23:40:36 CEST schrieb Florian Fainelli:
> On 07/24/2017 05:46 AM, Richard Weinberger wrote:
> > On Wed, Jul 19, 2017 at 1:43 AM, Florian Fainelli <f.fainelli@xxxxxxxxx> 
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@xxxxxxxxx>
> >> ---
> >> 
> >>  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!

Sure. The UML queue is just a bit slow, sorry for that.

Thanks,
//richard

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