From c65a2abb6c0a9ab1c70f5241716066c9480ce96a Mon Sep 17 00:00:00 2001 From: Jeroen Hofstee Date: Wed, 30 Jul 2014 21:54:52 +0200 Subject: [PATCH] ARM: make gd a function for clang "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 Signed-off-by: Jeroen Hofstee --- 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 +#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 */ -- 2.7.4