diff options
Diffstat (limited to 'arch/x86/kernel/idt.c')
| -rw-r--r-- | arch/x86/kernel/idt.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c new file mode 100644 index 000000000..f5a3374e6 --- /dev/null +++ b/arch/x86/kernel/idt.c @@ -0,0 +1,344 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Interrupt descriptor table related code + */ +#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> +#include <asm/hw_irq.h> +#include <asm/idtentry.h> + +#define DPL0 0x0 +#define DPL3 0x3 + +#define DEFAULT_STACK 0 + +#define G(_vector, _addr, _ist, _type, _dpl, _segment) \ + { \ + .vector = _vector, \ + .bits.ist = _ist, \ + .bits.type = _type, \ + .bits.dpl = _dpl, \ + .bits.p = 1, \ + .addr = _addr, \ + .segment = _segment, \ + } + +/* Interrupt gate */ +#define INTG(_vector, _addr) \ + G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL0, __KERNEL_CS) + +/* System interrupt gate */ +#define SYSG(_vector, _addr) \ + G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS) + +#ifdef CONFIG_X86_64 +/* + * Interrupt gate with interrupt stack. The _ist index is the index in + * the tss.ist[] array, but for the descriptor it needs to start at 1. + */ +#define ISTG(_vector, _addr, _ist) \ + G(_vector, _addr, _ist + 1, GATE_INTERRUPT, DPL0, __KERNEL_CS) +#else +#define ISTG(_vector, _addr, _ist) INTG(_vector, _addr) +#endif + +/* Task gate */ +#define TSKG(_vector, _gdt) \ + G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3) + +#define IDT_TABLE_SIZE (IDT_ENTRIES * sizeof(gate_desc)) + +static bool idt_setup_done __initdata; + +/* + * Early traps running on the DEFAULT_STACK because the other interrupt + * stacks work only after cpu_init(). + */ +static const __initconst struct idt_data early_idts[] = { + INTG(X86_TRAP_DB, asm_exc_debug), + SYSG(X86_TRAP_BP, asm_exc_int3), + +#ifdef CONFIG_X86_32 + /* + * Not possible on 64-bit. See idt_setup_early_pf() for details. + */ + INTG(X86_TRAP_PF, asm_exc_page_fault), +#endif +#ifdef CONFIG_INTEL_TDX_GUEST + INTG(X86_TRAP_VE, asm_exc_virtualization_exception), +#endif +}; + +/* + * The default IDT entries which are set up in trap_init() before + * cpu_init() is invoked. Interrupt stacks cannot be used at that point and + * the traps which use them are reinitialized with IST after cpu_init() has + * set up TSS. + */ +static const __initconst struct idt_data def_idts[] = { + INTG(X86_TRAP_DE, asm_exc_divide_error), + ISTG(X86_TRAP_NMI, asm_exc_nmi, IST_INDEX_NMI), + INTG(X86_TRAP_BR, asm_exc_bounds), + INTG(X86_TRAP_UD, asm_exc_invalid_op), + INTG(X86_TRAP_NM, asm_exc_device_not_available), + INTG(X86_TRAP_OLD_MF, asm_exc_coproc_segment_overrun), + INTG(X86_TRAP_TS, asm_exc_invalid_tss), + INTG(X86_TRAP_NP, asm_exc_segment_not_present), + INTG(X86_TRAP_SS, asm_exc_stack_segment), + INTG(X86_TRAP_GP, asm_exc_general_protection), + INTG(X86_TRAP_SPURIOUS, asm_exc_spurious_interrupt_bug), + INTG(X86_TRAP_MF, asm_exc_coprocessor_error), + INTG(X86_TRAP_AC, asm_exc_alignment_check), + INTG(X86_TRAP_XF, asm_exc_simd_coprocessor_error), + +#ifdef CONFIG_X86_32 + TSKG(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS), +#else + ISTG(X86_TRAP_DF, asm_exc_double_fault, IST_INDEX_DF), +#endif + ISTG(X86_TRAP_DB, asm_exc_debug, IST_INDEX_DB), + +#ifdef CONFIG_X86_MCE + ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE), +#endif + +#ifdef CONFIG_X86_KERNEL_IBT + INTG(X86_TRAP_CP, asm_exc_control_protection), +#endif + +#ifdef CONFIG_AMD_MEM_ENCRYPT + ISTG(X86_TRAP_VC, asm_exc_vmm_communication, IST_INDEX_VC), +#endif + + SYSG(X86_TRAP_OF, asm_exc_overflow), +#if defined(CONFIG_IA32_EMULATION) + SYSG(IA32_SYSCALL_VECTOR, asm_int80_emulation), +#elif defined(CONFIG_X86_32) + SYSG(IA32_SYSCALL_VECTOR, entry_INT80_32), +#endif +}; + +/* + * The APIC and SMP idt entries + */ +static const __initconst struct idt_data apic_idts[] = { +#ifdef CONFIG_SMP + INTG(RESCHEDULE_VECTOR, asm_sysvec_reschedule_ipi), + INTG(CALL_FUNCTION_VECTOR, asm_sysvec_call_function), + INTG(CALL_FUNCTION_SINGLE_VECTOR, asm_sysvec_call_function_single), + INTG(IRQ_MOVE_CLEANUP_VECTOR, asm_sysvec_irq_move_cleanup), + INTG(REBOOT_VECTOR, asm_sysvec_reboot), +#endif + +#ifdef CONFIG_X86_THERMAL_VECTOR + INTG(THERMAL_APIC_VECTOR, asm_sysvec_thermal), +#endif + +#ifdef CONFIG_X86_MCE_THRESHOLD + INTG(THRESHOLD_APIC_VECTOR, asm_sysvec_threshold), +#endif + +#ifdef CONFIG_X86_MCE_AMD + INTG(DEFERRED_ERROR_VECTOR, asm_sysvec_deferred_error), +#endif + +#ifdef CONFIG_X86_LOCAL_APIC + INTG(LOCAL_TIMER_VECTOR, asm_sysvec_apic_timer_interrupt), + INTG(X86_PLATFORM_IPI_VECTOR, asm_sysvec_x86_platform_ipi), +# ifdef CONFIG_HAVE_KVM + INTG(POSTED_INTR_VECTOR, asm_sysvec_kvm_posted_intr_ipi), + INTG(POSTED_INTR_WAKEUP_VECTOR, asm_sysvec_kvm_posted_intr_wakeup_ipi), + INTG(POSTED_INTR_NESTED_VECTOR, asm_sysvec_kvm_posted_intr_nested_ipi), +# endif +# ifdef CONFIG_IRQ_WORK + INTG(IRQ_WORK_VECTOR, asm_sysvec_irq_work), +# endif + INTG(SPURIOUS_APIC_VECTOR, asm_sysvec_spurious_apic_interrupt), + INTG(ERROR_APIC_VECTOR, asm_sysvec_error_interrupt), +#endif +}; + +/* 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; + +static struct desc_ptr idt_descr __ro_after_init = { + .size = IDT_TABLE_SIZE - 1, + .address = (unsigned long) idt_table, +}; + +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 __init void +idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size, bool sys) +{ + gate_desc desc; + + for (; size > 0; t++, size--) { + idt_init_desc(&desc, t); + write_idt_entry(idt, t->vector, &desc); + if (sys) + set_bit(t->vector, system_vectors); + } +} + +static __init void set_intr_gate(unsigned int n, const void *addr) +{ + struct idt_data data; + + init_idt_data(&data, n, addr); + + idt_setup_from_table(idt_table, &data, 1, false); +} + +/** + * idt_setup_early_traps - Initialize the idt table with early traps + * + * On X8664 these traps do not use interrupt stacks as they can't work + * before cpu_init() is invoked and sets up TSS. The IST variants are + * installed after that. + */ +void __init idt_setup_early_traps(void) +{ + idt_setup_from_table(idt_table, early_idts, ARRAY_SIZE(early_idts), + true); + load_idt(&idt_descr); +} + +/** + * idt_setup_traps - Initialize the idt table with default traps + */ +void __init idt_setup_traps(void) +{ + idt_setup_from_table(idt_table, def_idts, ARRAY_SIZE(def_idts), true); +} + +#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), +}; + +/** + * idt_setup_early_pf - Initialize the idt table with early pagefault handler + * + * On X8664 this does not use interrupt stacks as they can't work before + * cpu_init() is invoked and sets up TSS. The IST variant is installed + * after that. + * + * Note, that X86_64 cannot install the real #PF handler in + * idt_setup_early_traps() because the memory initialization needs the #PF + * handler from the early_idt_handler_array to initialize the early page + * tables. + */ +void __init idt_setup_early_pf(void) +{ + idt_setup_from_table(idt_table, early_pf_idts, + ARRAY_SIZE(early_pf_idts), true); +} +#endif + +static void __init idt_map_in_cea(void) +{ + /* + * Set the IDT descriptor to a fixed read-only location in the cpu + * entry area, so that the "sidt" instruction will not leak the + * location of the kernel, and to defend the IDT against arbitrary + * memory write vulnerabilities. + */ + cea_set_pte(CPU_ENTRY_AREA_RO_IDT_VADDR, __pa_symbol(idt_table), + PAGE_KERNEL_RO); + idt_descr.address = CPU_ENTRY_AREA_RO_IDT; +} + +/** + * idt_setup_apic_and_irq_gates - Setup APIC/SMP and normal interrupt gates + */ +void __init idt_setup_apic_and_irq_gates(void) +{ + int i = FIRST_EXTERNAL_VECTOR; + void *entry; + + idt_setup_from_table(idt_table, apic_idts, ARRAY_SIZE(apic_idts), true); + + for_each_clear_bit_from(i, system_vectors, FIRST_SYSTEM_VECTOR) { + entry = irq_entries_start + IDT_ALIGN * (i - FIRST_EXTERNAL_VECTOR); + set_intr_gate(i, entry); + } + +#ifdef CONFIG_X86_LOCAL_APIC + for_each_clear_bit_from(i, system_vectors, NR_VECTORS) { + /* + * Don't set the non assigned system vectors in the + * system_vectors bitmap. Otherwise they show up in + * /proc/interrupts. + */ + entry = spurious_entries_start + IDT_ALIGN * (i - FIRST_SYSTEM_VECTOR); + set_intr_gate(i, entry); + } +#endif + /* Map IDT into CPU entry area and reload it. */ + 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; +} + +/** + * idt_setup_early_handler - Initializes the idt table with early handlers + */ +void __init idt_setup_early_handler(void) +{ + int i; + + for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) + set_intr_gate(i, early_idt_handler_array[i]); +#ifdef CONFIG_X86_32 + for ( ; i < NR_VECTORS; i++) + set_intr_gate(i, early_ignore_irq); +#endif + load_idt(&idt_descr); +} + +/** + * idt_invalidate - Invalidate interrupt descriptor table + */ +void idt_invalidate(void) +{ + static const struct desc_ptr idt = { .address = 0, .size = 0 }; + + load_idt(&idt); +} + +void __init alloc_intr_gate(unsigned int n, const void *addr) +{ + if (WARN_ON(n < FIRST_SYSTEM_VECTOR)) + return; + + if (WARN_ON(idt_setup_done)) + return; + + if (!WARN_ON(test_and_set_bit(n, system_vectors))) + set_intr_gate(n, addr); +} |