diff options
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 58094a1f9e9d..3cf1590ec9ce 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -448,6 +448,26 @@ void load_percpu_segment(int cpu) load_stack_canary_segment(); } +/* Used by XEN to force the GDT read-only when required */ +pgprot_t pg_fixmap_gdt_flags = PAGE_KERNEL; + +/* Setup the fixmap mapping only once per-processor */ +static inline void setup_fixmap_gdt(int cpu) +{ + __set_fixmap(get_cpu_gdt_ro_index(cpu), + __pa(get_cpu_gdt_rw(cpu)), pg_fixmap_gdt_flags); +} + +/* Load a fixmap remapping of the per-cpu GDT */ +void load_fixmap_gdt(int cpu) +{ + struct desc_ptr gdt_descr; + + gdt_descr.address = (long)get_cpu_gdt_ro(cpu); + gdt_descr.size = GDT_SIZE - 1; + load_gdt(&gdt_descr); +} + /* * Current gdt points %fs at the "master" per-cpu area: after this, * it's on the real one. @@ -456,11 +476,10 @@ void switch_to_new_gdt(int cpu) { struct desc_ptr gdt_descr; - gdt_descr.address = (long)get_cpu_gdt_table(cpu); + gdt_descr.address = (long)get_cpu_gdt_rw(cpu); gdt_descr.size = GDT_SIZE - 1; load_gdt(&gdt_descr); /* Reload the per-cpu base */ - load_percpu_segment(cpu); } @@ -1526,6 +1545,9 @@ void cpu_init(void) if (is_uv_system()) uv_cpu_init(); + + setup_fixmap_gdt(cpu); + load_fixmap_gdt(cpu); } #else @@ -1581,6 +1603,9 @@ void cpu_init(void) dbg_restore_debug_regs(); fpu__init_cpu(); + + setup_fixmap_gdt(cpu); + load_fixmap_gdt(cpu); } #endif |