x86/entry: Remove debug IDT frobbing (f9912ada) · Commits · EulixOS / Software / Kernel

arch/x86/include/asm/debugreg.h

+0 −19

Original line number	Diff line number	Diff line
		@@ -94,25 +94,6 @@ extern void aout_dump_debugregs(struct user *dump);

		extern void hw_breakpoint_restore(void);

		#ifdef CONFIG_X86_64
		DECLARE_PER_CPU(int, debug_stack_usage);
		static inline void debug_stack_usage_inc(void)
		{
		__this_cpu_inc(debug_stack_usage);
		}
		static inline void debug_stack_usage_dec(void)
		{
		__this_cpu_dec(debug_stack_usage);
		}
		void debug_stack_set_zero(void);
		void debug_stack_reset(void);
		#else /* !X86_64 */
		static inline void debug_stack_set_zero(void) { }
		static inline void debug_stack_reset(void) { }
		static inline void debug_stack_usage_inc(void) { }
		static inline void debug_stack_usage_dec(void) { }
		#endif /* X86_64 */

		static __always_inline unsigned long local_db_save(void)
		{
		unsigned long dr7;

arch/x86/include/asm/desc.h

+1 −33

Original line number	Diff line number	Diff line
		@@ -42,8 +42,6 @@ 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 const struct desc_ptr debug_idt_descr;
		extern gate_desc debug_idt_table[];

		struct gdt_page {
		struct desc_struct gdt[GDT_ENTRIES];
		@@ -390,31 +388,6 @@ void alloc_intr_gate(unsigned int n, const void *addr);

		extern unsigned long system_vectors[];

		#ifdef CONFIG_X86_64
		DECLARE_PER_CPU(u32, debug_idt_ctr);
		static __always_inline bool is_debug_idt_enabled(void)
		{
		if (this_cpu_read(debug_idt_ctr))
		return true;

		return false;
		}

		static __always_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() must be called with interrupts disabled
		* to avoid races. That way the IDT will always be set back to the expected
		@@ -424,9 +397,6 @@ static inline void load_debug_idt(void)
		*/
		static __always_inline void load_current_idt(void)
		{
		if (is_debug_idt_enabled())
		load_debug_idt();
		else
		load_idt((const struct desc_ptr *)&idt_descr);
		}

		@@ -438,11 +408,9 @@ extern void idt_setup_apic_and_irq_gates(void);
		#ifdef CONFIG_X86_64
		extern void idt_setup_early_pf(void);
		extern void idt_setup_ist_traps(void);
		extern void idt_setup_debugidt_traps(void);
		#else
		static inline void idt_setup_early_pf(void) { }
		static inline void idt_setup_ist_traps(void) { }
		static inline void idt_setup_debugidt_traps(void) { }
		#endif

		extern void idt_invalidate(void *addr);

arch/x86/kernel/cpu/common.c

+0 −17

Original line number	Diff line number	Diff line
		@@ -1706,23 +1706,6 @@ void syscall_init(void)
		X86_EFLAGS_IOPL\|X86_EFLAGS_AC\|X86_EFLAGS_NT);
		}

		DEFINE_PER_CPU(int, debug_stack_usage);
		DEFINE_PER_CPU(u32, debug_idt_ctr);

		noinstr void debug_stack_set_zero(void)
		{
		this_cpu_inc(debug_idt_ctr);
		load_current_idt();
		}

		noinstr void debug_stack_reset(void)
		{
		if (WARN_ON(!this_cpu_read(debug_idt_ctr)))
		return;
		if (this_cpu_dec_return(debug_idt_ctr) == 0)
		load_current_idt();
		}

		#else /* CONFIG_X86_64 */

		DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;

arch/x86/kernel/idt.c

+0 −30

Original line number	Diff line number	Diff line
		@@ -158,14 +158,6 @@ static const __initconst struct idt_data apic_idts[] = {
		static const __initconst struct idt_data early_pf_idts[] = {
		INTG(X86_TRAP_PF, asm_exc_page_fault),
		};

		/*
		* Override for the debug_idt. Same as the default, but with interrupt
		* stack set to DEFAULT_STACK (0). Required for NMI trap handling.
		*/
		static const __initconst struct idt_data dbg_idts[] = {
		INTG(X86_TRAP_DB, asm_exc_debug),
		};
		#endif

		/* Must be page-aligned because the real IDT is used in a fixmap. */
		@@ -177,9 +169,6 @@ struct desc_ptr idt_descr __ro_after_init = {
		};

		#ifdef CONFIG_X86_64
		/* No need to be aligned, but done to keep all IDTs defined the same way. */
		gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss;

		/*
		* The exceptions which use Interrupt stacks. They are setup after
		* cpu_init() when the TSS has been initialized.
		@@ -192,15 +181,6 @@ static const __initconst struct idt_data ist_idts[] = {
		ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
		#endif
		};

		/*
		* Override for the debug_idt. Same as the default, but with interrupt
		* stack set to DEFAULT_STACK (0). Required for NMI trap handling.
		*/
		const struct desc_ptr debug_idt_descr = {
		.size = IDT_ENTRIES * 16 - 1,
		.address = (unsigned long) debug_idt_table,
		};
		#endif

		static inline void idt_init_desc(gate_desc gate, const struct idt_data d)
		@@ -292,16 +272,6 @@ void __init idt_setup_ist_traps(void)
		{
		idt_setup_from_table(idt_table, ist_idts, ARRAY_SIZE(ist_idts), true);
		}

		/**
		* idt_setup_debugidt_traps - Initialize the debug idt table with debug traps
		*/
		void __init idt_setup_debugidt_traps(void)
		{
		memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);

		idt_setup_from_table(debug_idt_table, dbg_idts, ARRAY_SIZE(dbg_idts), false);
		}
		#endif

		/**

arch/x86/kernel/traps.c

+0 −9

Original line number	Diff line number	Diff line
		@@ -798,12 +798,6 @@ static void noinstr handle_debug(struct pt_regs *regs, unsigned long dr6,
		return;
		}

		/*
		* Let others (NMI) know that the debug stack is in use
		* as we may switch to the interrupt stack.
		*/
		debug_stack_usage_inc();

		/* It's safe to allow irq's after DR6 has been saved */
		cond_local_irq_enable(regs);

		@@ -831,7 +825,6 @@ static void noinstr handle_debug(struct pt_regs *regs, unsigned long dr6,

		out:
		cond_local_irq_disable(regs);
		debug_stack_usage_dec();
		instrumentation_end();
		}

		@@ -1077,6 +1070,4 @@ void __init trap_init(void)
		cpu_init();

		idt_setup_ist_traps();

		idt_setup_debugidt_traps();
		}