Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH] x86: Alias memset to __builtin_memset. | Date | Fri, 27 Mar 2020 15:06:14 +1100 |
| |
Clement Courbet <courbet@google.com> writes: > I discussed with the original authors who added freestanding to our > build. It turns out that it was added globally but this was just to > to workaround powerpc not compiling under clang, but they felt the > fix was appropriate globally. > > Now Nick has dug up https://lkml.org/lkml/2019/8/29/1300, which > advises against freestanding. Also, I've did some research and > discovered that the original reason for using freestanding for > powerpc has been fixed here: > https://lore.kernel.org/linuxppc-dev/20191119045712.39633-3-natechancellor@gmail.com/ > > I'm going to remove -ffreestanding from downstream, so we don't really need > this anymore, sorry for waisting people's time. > > I wonder if the freestanding fix from the aforementioned patch is really needed > though. I think that clang is actually right to point out the issue. > I don't see any reason why setjmp()/longjmp() are declared as taking longs > rather than ints. The implementation looks like it only ever propagates the > value (in longjmp) or sets it to 1 (in setjmp), and we only ever call longjmp > with integer parameters. But I'm not a PowerPC expert, so I might > be misreading the code. > > > So it seems that we could just remove freestanding altogether and rewrite the > code to: > > diff --git a/arch/powerpc/include/asm/setjmp.h b/arch/powerpc/include/asm/setjmp.h > index 279d03a1eec6..7941ae68fe21 100644 > --- a/arch/powerpc/include/asm/setjmp.h > +++ b/arch/powerpc/include/asm/setjmp.h > @@ -12,7 +12,9 @@ > > #define JMP_BUF_LEN 23 > -extern long setjmp(long *); > -extern void longjmp(long *, long); > +typedef long * jmp_buf; > + > +extern int setjmp(jmp_buf); > +extern void longjmp(jmp_buf, int); > > I'm happy to send a patch for this, and get rid of more -ffreestanding. > Opinions ?
If it works then it looks like a much better fix than using -ffreestanding.
Please submit a patch with a change log etc. and I'd be happy to merge it.
cheers
| |