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);
+}