diff options
Diffstat (limited to 'arch/x86/kernel/setup_percpu.c')
| -rw-r--r-- | arch/x86/kernel/setup_percpu.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index be1ff34db11..daeedf82c15 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -66,6 +66,16 @@ static void __init setup_node_to_cpumask_map(void); static inline void setup_node_to_cpumask_map(void) { } #endif +/* + * Define load_pda_offset() and per-cpu __pda for x86_64. + * load_pda_offset() is responsible for loading the offset of pda into + * %gs. + * + * On SMP, pda offset also duals as percpu base address and thus it + * should be at the start of per-cpu area. To achieve this, it's + * preallocated in vmlinux_64.lds.S directly instead of using + * DEFINE_PER_CPU(). + */ #ifdef CONFIG_X86_64 void __cpuinit load_pda_offset(int cpu) { @@ -74,6 +84,10 @@ void __cpuinit load_pda_offset(int cpu) wrmsrl(MSR_GS_BASE, cpu_pda(cpu)); mb(); } +#ifndef CONFIG_SMP +DEFINE_PER_CPU(struct x8664_pda, __pda); +EXPORT_PER_CPU_SYMBOL(__pda); +#endif #endif /* CONFIG_SMP && CONFIG_X86_64 */ @@ -180,8 +194,6 @@ void __init setup_per_cpu_areas(void) memcpy(ptr, __per_cpu_load, __per_cpu_end - __per_cpu_start); per_cpu_offset(cpu) = ptr - __per_cpu_start; #ifdef CONFIG_X86_64 - cpu_pda(cpu) = (void *)ptr; - /* * CPU0 modified pda in the init data area, reload pda * offset for CPU0 and clear the area for others. |