diff options
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 3de7480e4f32..c2eada1056de 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -487,6 +487,9 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]); #endif +static DEFINE_PER_CPU_PAGE_ALIGNED(struct SYSENTER_stack_page, + SYSENTER_stack_storage); + static void __init set_percpu_fixmap_pages(int idx, void *ptr, int pages, pgprot_t prot) { @@ -500,23 +503,29 @@ static void __init setup_cpu_entry_area(int cpu) #ifdef CONFIG_X86_64 extern char _entry_trampoline[]; - /* On 64-bit systems, we use a read-only fixmap GDT. */ + /* On 64-bit systems, we use a read-only fixmap GDT and TSS. */ pgprot_t gdt_prot = PAGE_KERNEL_RO; + pgprot_t tss_prot = PAGE_KERNEL_RO; #else /* * On native 32-bit systems, the GDT cannot be read-only because * our double fault handler uses a task gate, and entering through - * a task gate needs to change an available TSS to busy. If the GDT - * is read-only, that will triple fault. + * a task gate needs to change an available TSS to busy. If the + * GDT is read-only, that will triple fault. The TSS cannot be + * read-only because the CPU writes to it on task switches. * - * On Xen PV, the GDT must be read-only because the hypervisor requires - * it. + * On Xen PV, the GDT must be read-only because the hypervisor + * requires it. */ pgprot_t gdt_prot = boot_cpu_has(X86_FEATURE_XENPV) ? PAGE_KERNEL_RO : PAGE_KERNEL; + pgprot_t tss_prot = PAGE_KERNEL; #endif __set_fixmap(get_cpu_entry_area_index(cpu, gdt), get_cpu_gdt_paddr(cpu), gdt_prot); + set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, SYSENTER_stack_page), + per_cpu_ptr(&SYSENTER_stack_storage, cpu), 1, + PAGE_KERNEL); /* * The Intel SDM says (Volume 3, 7.2.1): @@ -539,9 +548,9 @@ static void __init setup_cpu_entry_area(int cpu) offsetofend(struct tss_struct, x86_tss)) & PAGE_MASK); BUILD_BUG_ON(sizeof(struct tss_struct) % PAGE_SIZE != 0); set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, tss), - &per_cpu(cpu_tss, cpu), + &per_cpu(cpu_tss_rw, cpu), sizeof(struct tss_struct) / PAGE_SIZE, - PAGE_KERNEL); + tss_prot); #ifdef CONFIG_X86_32 per_cpu(cpu_entry_area, cpu) = get_cpu_entry_area(cpu); @@ -1305,7 +1314,7 @@ void enable_sep_cpu(void) return; cpu = get_cpu(); - tss = &per_cpu(cpu_tss, cpu); + tss = &per_cpu(cpu_tss_rw, cpu); /* * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field -- @@ -1575,7 +1584,7 @@ void cpu_init(void) if (cpu) load_ucode_ap(); - t = &per_cpu(cpu_tss, cpu); + t = &per_cpu(cpu_tss_rw, cpu); oist = &per_cpu(orig_ist, cpu); #ifdef CONFIG_NUMA @@ -1667,7 +1676,7 @@ void cpu_init(void) { int cpu = smp_processor_id(); struct task_struct *curr = current; - struct tss_struct *t = &per_cpu(cpu_tss, cpu); + struct tss_struct *t = &per_cpu(cpu_tss_rw, cpu); wait_for_master_cpu(cpu); |