diff options
Diffstat (limited to 'arch/arm/include/asm/compiler.h')
| -rw-r--r-- | arch/arm/include/asm/compiler.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/arm/include/asm/compiler.h b/arch/arm/include/asm/compiler.h index 8155db2f7fa..009eafa2ea0 100644 --- a/arch/arm/include/asm/compiler.h +++ b/arch/arm/include/asm/compiler.h @@ -11,5 +11,37 @@ */ #define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t" +#if defined(CONFIG_SMP) && !defined(CONFIG_CPU_V6) +/* + * Read TPIDRPRW. + * GCC requires a workaround as it does not treat a "memory" clobber on a + * non-volatile asm block as a side-effect. + * We want to allow caching the value, so for GCC avoid using volatile and + * instead use a fake stack read to hazard against barrier(). + */ +#if defined(__clang__) +static inline unsigned long read_TPIDRPRW(void) +{ + unsigned long off; + + /* + * Read TPIDRPRW. + */ + asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off) : : "memory"); + + return off; +} +#else +static inline unsigned long read_TPIDRPRW(void) +{ + unsigned long off; + register unsigned long *sp asm ("sp"); + + asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off) : "Q" (*sp)); + + return off; +} +#endif +#endif #endif /* __ASM_ARM_COMPILER_H */ |