| Message ID | 1525268700-10631-6-git-send-email-changbin.du@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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); > } > -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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); return __fix_to_virt(idx); }