Messages in this thread | | | Date | Wed, 2 May 2018 10:19:30 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v2 5/5] asm-generic: fix build error in fix_to_virt with CONFIG_DEBUG_EXPERIENCE |
| |
On Wed, 2 May 2018 21:45:00 +0800 changbin.du@intel.com wrote:
> From: Changbin Du <changbin.du@intel.com> > > With '-Og' optimization level, GCC would not optimize a count for a loop > as a constant value. But BUILD_BUG_ON() only accept compile-time constant > values. > > arch/arm/mm/mmu.o: In function `fix_to_virt': > /home/changbin/work/linux/./include/asm-generic/fixmap.h:31: undefined reference to `__compiletime_assert_31' > Makefile:1051: recipe for target 'vmlinux' failed > make: *** [vmlinux] Error 1 > > Signed-off-by: Changbin Du <changbin.du@intel.com> > --- > include/asm-generic/fixmap.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h > index 827e4d3..a6576d4 100644 > --- a/include/asm-generic/fixmap.h > +++ b/include/asm-generic/fixmap.h > @@ -28,7 +28,8 @@ > */ > static __always_inline unsigned long fix_to_virt(const unsigned int idx) > { > - BUILD_BUG_ON(idx >= __end_of_fixed_addresses); > + BUILD_BUG_ON(__builtin_constant_p(idx) && > + idx >= __end_of_fixed_addresses);
Hmm, this changes the check slightly. Perhaps we should only do this when your config is active:
{ BUILD_BUG_ON( /* CONFIG_DEBUG_OPTIMIZE may cause idx not to be constant */ #ifdef CONFIG_DEBUG_OPTIMIZE __builtin_constant_p(idx) && #endif idx >= __end_of_fixed_addresses);
}
-- Steve
> return __fix_to_virt(idx); > } >
| |