"clang does not support global register variables; this is unlikely to be implemented soon because it requires additional LLVM backend support" [1]
Workaround it by obtaining the value of gd/r9 by an inline asm routine. Note there is no set routine added for ARM at the moment, since most if not all updates of gd from c are actually not needed for ARM.
[1] http://clang.llvm.org/docs/UsersManual.html
cc: Albert ARIBAUD albert.u.boot@aribaud.net Signed-off-by: Jeroen Hofstee jeroen@myspectrum.nl --- arch/arm/include/asm/global_data.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)
diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h index 63e4ad5..c69d064 100644 --- a/arch/arm/include/asm/global_data.h +++ b/arch/arm/include/asm/global_data.h @@ -44,10 +44,35 @@ struct arch_global_data {
#include <asm-generic/global_data.h>
+#ifdef __clang__ + +#define DECLARE_GLOBAL_DATA_PTR +#define gd get_gd() + +static inline gd_t *get_gd(void) +{ + gd_t *gd_ptr; + +#ifdef CONFIG_ARM64 + /* + * Make will already error that reserving x18 is not supported at the + * time of writing, clang: error: unknown argument: '-ffixed-x18' + */ + __asm__ volatile("mov %0, x18\n" : "=r" (gd_ptr)); +#else + __asm__ volatile("mov %0, r9\n" : "=r" (gd_ptr)); +#endif + + return gd_ptr; +} + +#else + #ifdef CONFIG_ARM64 #define DECLARE_GLOBAL_DATA_PTR register volatile gd_t *gd asm ("x18") #else #define DECLARE_GLOBAL_DATA_PTR register volatile gd_t *gd asm ("r9") #endif +#endif
#endif /* __ASM_GBL_DATA_H */