diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/current.h | 5 | ||||
| -rw-r--r-- | arch/x86/include/asm/percpu.h | 7 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 2 |
3 files changed, 11 insertions, 3 deletions
diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h index 9fbd7cb2dc86..c8c5674d69f6 100644 --- a/arch/x86/include/asm/current.h +++ b/arch/x86/include/asm/current.h @@ -37,12 +37,13 @@ static_assert(sizeof(struct pcpu_hot) == 64); DECLARE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot); /* const-qualified alias to pcpu_hot, aliased by linker. */ -extern const struct pcpu_hot __percpu_seg_override const_pcpu_hot; +DECLARE_PER_CPU_ALIGNED(const struct pcpu_hot __percpu_seg_override, + const_pcpu_hot); static __always_inline struct task_struct *get_current(void) { if (IS_ENABLED(CONFIG_USE_X86_SEG_SUPPORT)) - return const_pcpu_hot.current_task; + return this_cpu_read_const(const_pcpu_hot.current_task); return this_cpu_read_stable(pcpu_hot.current_task); } diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index 0f12b2004b94..3859abad19ec 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -28,6 +28,7 @@ #else /* ...!ASSEMBLY */ +#include <linux/build_bug.h> #include <linux/kernel.h> #include <linux/stringify.h> @@ -462,6 +463,7 @@ do { \ #define this_cpu_write_8(pcp, val) __raw_cpu_write(volatile, pcp, val) #endif +#define this_cpu_read_const(pcp) __raw_cpu_read(, pcp) #else /* CONFIG_USE_X86_SEG_SUPPORT */ #define raw_cpu_read_1(pcp) percpu_from_op(1, , "mov", pcp) @@ -486,6 +488,11 @@ do { \ #define this_cpu_write_8(pcp, val) percpu_to_op(8, volatile, "mov", (pcp), val) #endif +/* + * The generic per-cpu infrastrucutre is not suitable for + * reading const-qualified variables. + */ +#define this_cpu_read_const(pcp) ({ BUILD_BUG(); (typeof(pcp))0; }) #endif /* CONFIG_USE_X86_SEG_SUPPORT */ #define raw_cpu_add_1(pcp, val) percpu_add_op(1, , (pcp), val) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index f20e87632669..a94a857152c4 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -519,7 +519,7 @@ static __always_inline unsigned long current_top_of_stack(void) * entry trampoline. */ if (IS_ENABLED(CONFIG_USE_X86_SEG_SUPPORT)) - return const_pcpu_hot.top_of_stack; + return this_cpu_read_const(const_pcpu_hot.top_of_stack); return this_cpu_read_stable(pcpu_hot.top_of_stack); } |