Commit f9912ada authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner

x86/entry: Remove debug IDT frobbing

This is all unused now.
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.245019500@infradead.org

parent 84b6a349
......@@ -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;
......
......@@ -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);
......
......@@ -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;
......
......@@ -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
/**
......
......@@ -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();
}
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