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x86/entry: Remove debug IDT frobbing

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This is all unused now.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.245019500@infradead.org
This commit is contained in:
Peter Zijlstra
2020-05-29 23:27:37 +02:00
committed by Thomas Gleixner
parent 84b6a34915
commit f9912ada82
5 changed files with 1 additions and 108 deletions
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17
arch/x86/kernel/cpu/common.c
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@@ -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;

30
arch/x86/kernel/idt.c
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@@ -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
/**

9
arch/x86/kernel/traps.c
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@@ -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();
}