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Commit 629f4f9d authored by Seiji Aguchi's avatar Seiji Aguchi Committed by H. Peter Anvin
Browse files

x86: Rename variables for debugging 



Rename variables for debugging to describe meaning of them precisely.

Also, introduce a generic way to switch IDT by checking a current state,
debug on/off.

Signed-off-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C323A8.7050905@hds.com


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
parent eddc0e92

arch/x86/include/asm/desc.h

+44 −3
Original line number Diff line number Diff line
@@ -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 */

arch/x86/kernel/cpu/common.c

+8 −8
Original line number Diff line number Diff line
@@ -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 */

arch/x86/kernel/head_64.S

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -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