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x86/idt: Consolidate idt functionality

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- Move load_current_idt() out of line and replace the hideous comment with
   a lockdep assert. This allows to make idt_table and idt_descr static.

 - Mark idt_table read only after the IDT initialization is complete.

 - Shuffle code around to consolidate the #ifdef sections into one.

 - Adapt the F00F bug code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528145523.084915381@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-05-28 16:53:20 +02:00
parent 00229a5430
commit 3e77abda65
3 changed files with 44 additions and 52 deletions
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17
arch/x86/include/asm/desc.h
View File

@ -40,9 +40,6 @@ static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *in
desc->l = 0;
}
extern struct desc_ptr idt_descr;
extern gate_desc idt_table[];
struct gdt_page {
struct desc_struct gdt[GDT_ENTRIES];
} __attribute__((aligned(PAGE_SIZE)));
@ -388,22 +385,12 @@ void alloc_intr_gate(unsigned int n, const void *addr);
extern unsigned long system_vectors[];
/*
* 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
* descriptor. It's also called when a CPU is being initialized, and
* that doesn't need to disable interrupts, as nothing should be
* bothering the CPU then.
*/
static __always_inline void load_current_idt(void)
{
load_idt((const struct desc_ptr *)&idt_descr);
}
extern void load_current_idt(void);
extern void idt_setup_early_handler(void);
extern void idt_setup_early_traps(void);
extern void idt_setup_traps(void);
extern void idt_setup_apic_and_irq_gates(void);
extern bool idt_is_f00f_address(unsigned long address);
#ifdef CONFIG_X86_64
extern void idt_setup_early_pf(void);

63
arch/x86/kernel/idt.c
View File

@ -5,6 +5,7 @@
#include <linux/interrupt.h>
#include <asm/cpu_entry_area.h>
#include <asm/set_memory.h>
#include <asm/traps.h>
#include <asm/proto.h>
#include <asm/desc.h>
@ -156,37 +157,25 @@ static const __initconst struct idt_data apic_idts[] = {
#endif
};
#ifdef CONFIG_X86_64
/*
* Early traps running on the DEFAULT_STACK because the other interrupt
* stacks work only after cpu_init().
*/
static const __initconst struct idt_data early_pf_idts[] = {
INTG(X86_TRAP_PF, asm_exc_page_fault),
};
#endif
/* Must be page-aligned because the real IDT is used in a fixmap. */
gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;
/* Must be page-aligned because the real IDT is used in the cpu entry area */
static gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;
struct desc_ptr idt_descr __ro_after_init = {
.size = IDT_TABLE_SIZE - 1,
.address = (unsigned long) idt_table,
};
#ifdef CONFIG_X86_64
/*
* The exceptions which use Interrupt stacks. They are setup after
* cpu_init() when the TSS has been initialized.
*/
static const __initconst struct idt_data ist_idts[] = {
ISTG(X86_TRAP_DB, asm_exc_debug, IST_INDEX_DB),
ISTG(X86_TRAP_NMI, asm_exc_nmi, IST_INDEX_NMI),
ISTG(X86_TRAP_DF, asm_exc_double_fault, IST_INDEX_DF),
#ifdef CONFIG_X86_MCE
ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
#endif
};
void load_current_idt(void)
{
lockdep_assert_irqs_disabled();
load_idt(&idt_descr);
}
#ifdef CONFIG_X86_F00F_BUG
bool idt_is_f00f_address(unsigned long address)
{
return ((address - idt_descr.address) >> 3) == 6;
}
#endif
static inline void idt_init_desc(gate_desc *gate, const struct idt_data *d)
@ -255,6 +244,27 @@ void __init idt_setup_traps(void)
}
#ifdef CONFIG_X86_64
/*
* Early traps running on the DEFAULT_STACK because the other interrupt
* stacks work only after cpu_init().
*/
static const __initconst struct idt_data early_pf_idts[] = {
INTG(X86_TRAP_PF, asm_exc_page_fault),
};
/*
* The exceptions which use Interrupt stacks. They are setup after
* cpu_init() when the TSS has been initialized.
*/
static const __initconst struct idt_data ist_idts[] = {
ISTG(X86_TRAP_DB, asm_exc_debug, IST_INDEX_DB),
ISTG(X86_TRAP_NMI, asm_exc_nmi, IST_INDEX_NMI),
ISTG(X86_TRAP_DF, asm_exc_double_fault, IST_INDEX_DF),
#ifdef CONFIG_X86_MCE
ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
#endif
};
/**
* idt_setup_early_pf - Initialize the idt table with early pagefault handler
*
@ -325,6 +335,9 @@ void __init idt_setup_apic_and_irq_gates(void)
idt_map_in_cea();
load_idt(&idt_descr);
/* Make the IDT table read only */
set_memory_ro((unsigned long)&idt_table, 1);
idt_setup_done = true;
}

16
arch/x86/mm/fault.c
View File

@ -414,21 +414,13 @@ static int is_errata100(struct pt_regs *regs, unsigned long address)
return 0;
}
/* Pentium F0 0F C7 C8 bug workaround: */
static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
{
#ifdef CONFIG_X86_F00F_BUG
unsigned long nr;
/*
* Pentium F0 0F C7 C8 bug workaround:
*/
if (boot_cpu_has_bug(X86_BUG_F00F)) {
nr = (address - idt_descr.address) >> 3;
if (nr == 6) {
handle_invalid_op(regs);
return 1;
}
if (boot_cpu_has_bug(X86_BUG_F00F) && idt_is_f00f_address(address)) {
handle_invalid_op(regs);
return 1;
}
#endif
return 0;