diff options
| -rw-r--r-- | arch/x86/include/asm/desc.h | 47 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 16 | ||||
| -rw-r--r-- | arch/x86/kernel/head_64.S | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 2 |
4 files changed, 54 insertions, 13 deletions
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 8bf1c06070d..af290b8f124 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -36,8 +36,8 @@ 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[]; +extern struct desc_ptr debug_idt_descr; +extern gate_desc debug_idt_table[]; struct gdt_page { struct desc_struct gdt[GDT_ENTRIES]; @@ -316,7 +316,7 @@ 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); + write_idt_entry(debug_idt_table, gate, &s); } #endif @@ -405,4 +405,45 @@ static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist) _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS); } +#ifdef CONFIG_X86_64 +DECLARE_PER_CPU(u32, debug_idt_ctr); +static inline bool is_debug_idt_enabled(void) +{ + if (this_cpu_read(debug_idt_ctr)) + return true; + + return false; +} + +static inline void load_debug_idt(void) +{ + load_idt((const struct desc_ptr *)&debug_idt_descr); +} +#else +static inline bool is_debug_idt_enabled(void) +{ + return false; +} + +static inline void load_debug_idt(void) +{ +} +#endif + +/* + * the load_current_idt() is called with interrupt disabled by local_irq_save() + * to avoid races. That way the IDT will always be set back to the expected + * descriptor. + */ +static inline void load_current_idt(void) +{ + unsigned long flags; + + local_irq_save(flags); + if (is_debug_idt_enabled()) + load_debug_idt(); + else + load_idt((const struct desc_ptr *)&idt_descr); + local_irq_restore(flags); +} #endif /* _ASM_X86_DESC_H */ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 22018f70a67..8f6a0f909d6 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1071,8 +1071,8 @@ __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 }; +struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1, + (unsigned long) debug_idt_table }; DEFINE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __aligned(PAGE_SIZE); @@ -1148,20 +1148,20 @@ int is_debug_stack(unsigned long addr) addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ)); } -static DEFINE_PER_CPU(u32, debug_stack_use_ctr); +DEFINE_PER_CPU(u32, debug_idt_ctr); void debug_stack_set_zero(void) { - this_cpu_inc(debug_stack_use_ctr); - load_idt((const struct desc_ptr *)&nmi_idt_descr); + this_cpu_inc(debug_idt_ctr); + load_current_idt(); } void debug_stack_reset(void) { - if (WARN_ON(!this_cpu_read(debug_stack_use_ctr))) + if (WARN_ON(!this_cpu_read(debug_idt_ctr))) return; - if (this_cpu_dec_return(debug_stack_use_ctr) == 0) - load_idt((const struct desc_ptr *)&idt_descr); + if (this_cpu_dec_return(debug_idt_ctr) == 0) + load_current_idt(); } #else /* CONFIG_X86_64 */ diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 321d65ebaff..84fb779d5b7 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -518,7 +518,7 @@ ENTRY(idt_table) .skip IDT_ENTRIES * 16 .align L1_CACHE_BYTES -ENTRY(nmi_idt_table) +ENTRY(debug_idt_table) .skip IDT_ENTRIES * 16 __PAGE_ALIGNED_BSS diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 772e2a846de..d27182d6ed2 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -785,7 +785,7 @@ void __init trap_init(void) x86_init.irqs.trap_init(); #ifdef CONFIG_X86_64 - memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16); + memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16); set_nmi_gate(X86_TRAP_DB, &debug); set_nmi_gate(X86_TRAP_BP, &int3); #endif |