The following commit has been merged into the x86/entry branch of tip: Commit-ID: 5980d208e5ef28455e9e8b08f6250b443a2f0893 Gitweb: https://git.kernel.org/tip/5980d208e5ef28455e9e8b08f6250b443a2f0893 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Thu, 28 May 2020 16:53:20 +02:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Sat, 30 May 2020 11:50:13 +02:00 x86/idt: Consolidate idt functionality - 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@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20200528145523.084915381@xxxxxxxxxxxxx --- arch/x86/include/asm/desc.h | 17 +--------- arch/x86/kernel/idt.c | 63 +++++++++++++++++++++--------------- arch/x86/mm/fault.c | 16 ++------- 3 files changed, 44 insertions(+), 52 deletions(-) diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 07632f3..1ced11d 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -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); diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 902cdd0..85e3e22 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -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; } diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 9c57fb8..e4625f4 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -555,21 +555,13 @@ 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;
![]() |