Messages in this thread | | | Date | Tue, 27 Jun 2023 18:57:32 +0200 | From | Sebastian Sumpf <> | Subject | Re: [Bug report] __arch_hweight32/64 x86 |
| |
On 6/27/23 06:25, Borislav Petkov wrote: > On Mon, Jun 26, 2023 at 03:41:27PM -0700, Dave Hansen wrote: >> I'm not even sure that UML needs GENERIC_HWEIGHT. From a quick glance, >> it looks like x86 used to use GENERIC_HWEIGHT, but got arch-specific >> versions later. UML just never moved over to the arch-specific versions. > > Thanks - that could very well be the explanation. > > That bug report made me blink a couple of times since I did take extra > precaution to not clobber regs in arch/x86/lib/hweight.S as this was > part of the whole pain back then with calling a function from asm where > gcc doesn't even know we're calling a function, see: > > f5967101e9de ("x86/hweight: Get rid of the special calling convention") > >> I _think_ the attached patch might just fix the problems with the C >> version and bring the x86/UML implementation back in line with the rest >> of x86. >> >> Thoughts? > >> diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig >> index 186f13268401..76d507860be4 100644 >> --- a/arch/x86/um/Kconfig >> +++ b/arch/x86/um/Kconfig >> @@ -44,6 +44,3 @@ config ARCH_HAS_SC_SIGNALS >> >> config ARCH_REUSE_HOST_VSYSCALL_AREA >> def_bool !64BIT >> - >> -config GENERIC_HWEIGHT >> - def_bool y > > Yeah, we should do it. UML should not do anything different wrt calling > conventions so it should be able to handle the arch/x86/lib/hweight.S > versions just fine.
Thank you for the quick resolution! It fixes the problem for me and sorry for not explaining well enough.
> Richi? >
-- Sebastian Sumpf Genode Labs
http://www.genode-labs.com · http://genode.org
Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth
| |