diff options
| -rw-r--r-- | arch/x86/include/asm/desc.h | 12 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 22 | ||||
| -rw-r--r-- | arch/x86/kernel/head_64.S | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi.c | 15 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 6 |
6 files changed, 65 insertions, 0 deletions
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 41935fadfdf..e95822d683f 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -35,6 +35,8 @@ static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *in extern struct desc_ptr idt_descr; extern gate_desc idt_table[]; +extern struct desc_ptr nmi_idt_descr; +extern gate_desc nmi_idt_table[]; struct gdt_page { struct desc_struct gdt[GDT_ENTRIES]; @@ -307,6 +309,16 @@ static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit) desc->limit = (limit >> 16) & 0xf; } +#ifdef CONFIG_X86_64 +static inline void set_nmi_gate(int gate, void *addr) +{ + gate_desc s; + + pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS); + write_idt_entry(nmi_idt_table, gate, &s); +} +#endif + static inline void _set_gate(int gate, unsigned type, void *addr, unsigned dpl, unsigned ist, unsigned seg) { diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index b650435ffb5..4b39d6d7e3a 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -402,6 +402,9 @@ DECLARE_PER_CPU(char *, irq_stack_ptr); DECLARE_PER_CPU(unsigned int, irq_count); extern unsigned long kernel_eflags; extern asmlinkage void ignore_sysret(void); +int is_debug_stack(unsigned long addr); +void debug_stack_set_zero(void); +void debug_stack_reset(void); #else /* X86_64 */ #ifdef CONFIG_CC_STACKPROTECTOR /* @@ -416,6 +419,9 @@ struct stack_canary { }; DECLARE_PER_CPU_ALIGNED(struct stack_canary, stack_canary); #endif +static inline int is_debug_stack(unsigned long addr) { return 0; } +static inline void debug_stack_set_zero(void) { } +static inline void debug_stack_reset(void) { } #endif /* X86_64 */ extern unsigned int xstate_size; diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index aa003b13a83..caa404556b9 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1026,6 +1026,8 @@ __setup("clearcpuid=", setup_disablecpuid); #ifdef CONFIG_X86_64 struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table }; +struct desc_ptr nmi_idt_descr = { NR_VECTORS * 16 - 1, + (unsigned long) nmi_idt_table }; DEFINE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __aligned(PAGE_SIZE); @@ -1090,6 +1092,24 @@ unsigned long kernel_eflags; */ DEFINE_PER_CPU(struct orig_ist, orig_ist); +static DEFINE_PER_CPU(unsigned long, debug_stack_addr); + +int is_debug_stack(unsigned long addr) +{ + return addr <= __get_cpu_var(debug_stack_addr) && + addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ); +} + +void debug_stack_set_zero(void) +{ + load_idt((const struct desc_ptr *)&nmi_idt_descr); +} + +void debug_stack_reset(void) +{ + load_idt((const struct desc_ptr *)&idt_descr); +} + #else /* CONFIG_X86_64 */ DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task; @@ -1208,6 +1228,8 @@ void __cpuinit cpu_init(void) estacks += exception_stack_sizes[v]; oist->ist[v] = t->x86_tss.ist[v] = (unsigned long)estacks; + if (v == DEBUG_STACK-1) + per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks; } } diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index e11e39478a4..40f4eb3766d 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -417,6 +417,10 @@ ENTRY(phys_base) ENTRY(idt_table) .skip IDT_ENTRIES * 16 + .align L1_CACHE_BYTES +ENTRY(nmi_idt_table) + .skip IDT_ENTRIES * 16 + __PAGE_ALIGNED_BSS .align PAGE_SIZE ENTRY(empty_zero_page) diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index e88f37b58dd..de8d4b333f4 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -408,6 +408,18 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs) dotraplinkage notrace __kprobes void do_nmi(struct pt_regs *regs, long error_code) { + int update_debug_stack = 0; + + /* + * If we interrupted a breakpoint, it is possible that + * the nmi handler will have breakpoints too. We need to + * change the IDT such that breakpoints that happen here + * continue to use the NMI stack. + */ + if (unlikely(is_debug_stack(regs->sp))) { + debug_stack_set_zero(); + update_debug_stack = 1; + } nmi_enter(); inc_irq_stat(__nmi_count); @@ -416,6 +428,9 @@ do_nmi(struct pt_regs *regs, long error_code) default_do_nmi(regs); nmi_exit(); + + if (unlikely(update_debug_stack)) + debug_stack_reset(); } void stop_nmi(void) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index a8e3eb83466..a93c5cabc36 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -723,4 +723,10 @@ void __init trap_init(void) cpu_init(); x86_init.irqs.trap_init(); + +#ifdef CONFIG_X86_64 + memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16); + set_nmi_gate(1, &debug); + set_nmi_gate(3, &int3); +#endif } |