diff options
| -rw-r--r-- | arch/x86/kernel/process_64.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index ad213494a22..4a93c98a60a 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -500,7 +500,6 @@ static inline void __switch_to_xtra(struct task_struct *prev_p, { struct thread_struct *prev, *next; unsigned long debugctl; - unsigned long ds_prev = 0, ds_next = 0; prev = &prev_p->thread, next = &next_p->thread; @@ -508,17 +507,23 @@ static inline void __switch_to_xtra(struct task_struct *prev_p, debugctl = prev->debugctlmsr; #ifdef CONFIG_X86_DS - if (prev->ds_ctx) - ds_prev = (unsigned long)prev->ds_ctx->ds; - if (next->ds_ctx) - ds_next = (unsigned long)next->ds_ctx->ds; - - if (ds_next != ds_prev) { - /* we clear debugctl to make sure DS - * is not in use when we change it */ - debugctl = 0; - update_debugctlmsr(0); - wrmsrl(MSR_IA32_DS_AREA, ds_next); + { + unsigned long ds_prev = 0, ds_next = 0; + + if (prev->ds_ctx) + ds_prev = (unsigned long)prev->ds_ctx->ds; + if (next->ds_ctx) + ds_next = (unsigned long)next->ds_ctx->ds; + + if (ds_next != ds_prev) { + /* + * We clear debugctl to make sure DS + * is not in use when we change it: + */ + debugctl = 0; + update_debugctlmsr(0); + wrmsrl(MSR_IA32_DS_AREA, ds_next); + } } #endif /* CONFIG_X86_DS */ |