On 05/18/2010 01:10 PM, Eric Dumazet wrote: > > Might be time to change Documentation/Changes about gcc requirements ... > > # make > CHK include/linux/version.h > CHK include/generated/utsrelease.h > CALL scripts/checksyscalls.sh > CHK include/generated/compile.h > CC arch/x86/kernel/process_32.o > /usr/src/linux-2.6/arch/x86/include/asm/cpufeature.h: In function > `prepare_to_copy': > /usr/src/linux-2.6/arch/x86/include/asm/cpufeature.h:315: warning: asm > operand 1 probably doesn't match constraints > /usr/src/linux-2.6/arch/x86/include/asm/cpufeature.h:315: error: > impossible constraint in `asm' > /usr/src/linux-2.6/arch/x86/include/asm/cpufeature.h:313: warning: > 'flag' might be used uninitialized in this function > make[2]: *** [arch/x86/kernel/process_32.o] Error 1 > make[1]: *** [arch/x86/kernel] Error 2 > make: *** [arch/x86] Error 2 > # gcc -v > Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.6/specs > Configured with: ../configure --prefix=/usr --mandir=/usr/share/man > --infodir=/usr/share/info --enable-shared --enable-threads=posix > --disable-checking --with-system-zlib --enable-__cxa_atexit > --disable-libunwind-exceptions --enable-java-awt=gtk > --host=i386-redhat-linux > Thread model: posix > gcc version 3.4.6 20060404 (Red Hat 3.4.6-10) > Here is the fallback patch if you want to test it. -hpa
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index dca9c54..4681459 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -332,6 +332,7 @@ static __always_inline __pure bool __static_cpu_has(u8 bit) #endif } +#if __GNUC__ >= 4 #define static_cpu_has(bit) \ ( \ __builtin_constant_p(boot_cpu_has(bit)) ? \ @@ -340,6 +341,12 @@ static __always_inline __pure bool __static_cpu_has(u8 bit) __static_cpu_has(bit) : \ boot_cpu_has(bit) \ ) +#else +/* + * gcc 3.x is too stupid to do the static test; fall back to dynamic. + */ +#define static_cpu_has(bit) boot_cpu_has(bit) +#endif #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
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