Messages in this thread | | | Date | Tue, 7 Feb 2023 09:53:48 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH] x86/vdso: Fake 32bit VDSO build on 64bit compile for vgetcpu. |
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On Tue, Feb 07, 2023 at 11:46:33AM +0100, Sebastian Andrzej Siewior wrote: > The 64bit register constrains in __arch_hweight64() can not be > fulfilled in a 32bit build. The function is only declared, not used > within vclock_gettime.c and gcc does not care. LLVM complains and > aborts. > > Move the "fake a 32 bit kernel configuration" bits from vclock_gettime.c > into a common header file. Use this from vclock_gettime.c and vgetcpu.c. > > Fixes: 92d33063c081a ("x86/vdso: Provide getcpu for x86-32.") > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Thank you so much for the fix! Boris inquired why this happens with clang and I wrote a little blurb here if that is helpful at all:
https://lore.kernel.org/Y+J+UQ1vAKr6RHuH@dev-arch.thelio-3990X/
Regardless, this works for me.
Tested-by: Nathan Chancellor <nathan@kernel.org>
> --- > arch/x86/entry/vdso/vdso32/fake_32bit_build.h | 25 +++++++++++++++++ > arch/x86/entry/vdso/vdso32/vclock_gettime.c | 27 +------------------ > arch/x86/entry/vdso/vdso32/vgetcpu.c | 1 + > 3 files changed, 27 insertions(+), 26 deletions(-) > create mode 100644 arch/x86/entry/vdso/vdso32/fake_32bit_build.h > > diff --git a/arch/x86/entry/vdso/vdso32/fake_32bit_build.h b/arch/x86/entry/vdso/vdso32/fake_32bit_build.h > new file mode 100644 > index 0000000000000..db1b15f686e32 > --- /dev/null > +++ b/arch/x86/entry/vdso/vdso32/fake_32bit_build.h > @@ -0,0 +1,25 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifdef CONFIG_X86_64 > + > +/* > + * in case of a 32 bit VDSO for a 64 bit kernel fake a 32 bit kernel > + * configuration > + */ > +#undef CONFIG_64BIT > +#undef CONFIG_X86_64 > +#undef CONFIG_COMPAT > +#undef CONFIG_PGTABLE_LEVELS > +#undef CONFIG_ILLEGAL_POINTER_VALUE > +#undef CONFIG_SPARSEMEM_VMEMMAP > +#undef CONFIG_NR_CPUS > +#undef CONFIG_PARAVIRT_XXL > + > +#define CONFIG_X86_32 1 > +#define CONFIG_PGTABLE_LEVELS 2 > +#define CONFIG_PAGE_OFFSET 0 > +#define CONFIG_ILLEGAL_POINTER_VALUE 0 > +#define CONFIG_NR_CPUS 1 > + > +#define BUILD_VDSO32_64 > + > +#endif > diff --git a/arch/x86/entry/vdso/vdso32/vclock_gettime.c b/arch/x86/entry/vdso/vdso32/vclock_gettime.c > index 283ed9d004267..86981decfea83 100644 > --- a/arch/x86/entry/vdso/vdso32/vclock_gettime.c > +++ b/arch/x86/entry/vdso/vdso32/vclock_gettime.c > @@ -1,29 +1,4 @@ > // SPDX-License-Identifier: GPL-2.0 > #define BUILD_VDSO32 > - > -#ifdef CONFIG_X86_64 > - > -/* > - * in case of a 32 bit VDSO for a 64 bit kernel fake a 32 bit kernel > - * configuration > - */ > -#undef CONFIG_64BIT > -#undef CONFIG_X86_64 > -#undef CONFIG_COMPAT > -#undef CONFIG_PGTABLE_LEVELS > -#undef CONFIG_ILLEGAL_POINTER_VALUE > -#undef CONFIG_SPARSEMEM_VMEMMAP > -#undef CONFIG_NR_CPUS > -#undef CONFIG_PARAVIRT_XXL > - > -#define CONFIG_X86_32 1 > -#define CONFIG_PGTABLE_LEVELS 2 > -#define CONFIG_PAGE_OFFSET 0 > -#define CONFIG_ILLEGAL_POINTER_VALUE 0 > -#define CONFIG_NR_CPUS 1 > - > -#define BUILD_VDSO32_64 > - > -#endif > - > +#include "fake_32bit_build.h" > #include "../vclock_gettime.c" > diff --git a/arch/x86/entry/vdso/vdso32/vgetcpu.c b/arch/x86/entry/vdso/vdso32/vgetcpu.c > index b777f84ffae9b..3a9791f5e9989 100644 > --- a/arch/x86/entry/vdso/vdso32/vgetcpu.c > +++ b/arch/x86/entry/vdso/vdso32/vgetcpu.c > @@ -1,2 +1,3 @@ > // SPDX-License-Identifier: GPL-2.0 > +#include "fake_32bit_build.h" > #include "../vgetcpu.c" > -- > 2.39.1 >
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