1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Interrupt descriptor table related code
4 */
5#include <linux/interrupt.h>
6
7#include <asm/cpu_entry_area.h>
8#include <asm/set_memory.h>
9#include <asm/traps.h>
10#include <asm/proto.h>
11#include <asm/desc.h>
12#include <asm/hw_irq.h>
13#include <asm/ia32.h>
14#include <asm/idtentry.h>
15
16#define DPL0 0x0
17#define DPL3 0x3
18
19#define DEFAULT_STACK 0
20
21#define G(_vector, _addr, _ist, _type, _dpl, _segment) \
22 { \
23 .vector = _vector, \
24 .bits.ist = _ist, \
25 .bits.type = _type, \
26 .bits.dpl = _dpl, \
27 .bits.p = 1, \
28 .addr = _addr, \
29 .segment = _segment, \
30 }
31
32/* Interrupt gate */
33#define INTG(_vector, _addr) \
34 G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL0, __KERNEL_CS)
35
36/* System interrupt gate */
37#define SYSG(_vector, _addr) \
38 G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS)
39
40#ifdef CONFIG_X86_64
41/*
42 * Interrupt gate with interrupt stack. The _ist index is the index in
43 * the tss.ist[] array, but for the descriptor it needs to start at 1.
44 */
45#define ISTG(_vector, _addr, _ist) \
46 G(_vector, _addr, _ist + 1, GATE_INTERRUPT, DPL0, __KERNEL_CS)
47#else
48#define ISTG(_vector, _addr, _ist) INTG(_vector, _addr)
49#endif
50
51/* Task gate */
52#define TSKG(_vector, _gdt) \
53 G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
54
55#define IDT_TABLE_SIZE (IDT_ENTRIES * sizeof(gate_desc))
56
57static bool idt_setup_done __initdata;
58
59/*
60 * Early traps running on the DEFAULT_STACK because the other interrupt
61 * stacks work only after cpu_init().
62 */
63static const __initconst struct idt_data early_idts[] = {
64 INTG(X86_TRAP_DB, asm_exc_debug),
65 SYSG(X86_TRAP_BP, asm_exc_int3),
66
67#ifdef CONFIG_X86_32
68 /*
69 * Not possible on 64-bit. See idt_setup_early_pf() for details.
70 */
71 INTG(X86_TRAP_PF, asm_exc_page_fault),
72#endif
73#ifdef CONFIG_INTEL_TDX_GUEST
74 INTG(X86_TRAP_VE, asm_exc_virtualization_exception),
75#endif
76};
77
78/*
79 * The default IDT entries which are set up in trap_init() before
80 * cpu_init() is invoked. Interrupt stacks cannot be used at that point and
81 * the traps which use them are reinitialized with IST after cpu_init() has
82 * set up TSS.
83 */
84static const __initconst struct idt_data def_idts[] = {
85 INTG(X86_TRAP_DE, asm_exc_divide_error),
86 ISTG(X86_TRAP_NMI, asm_exc_nmi, IST_INDEX_NMI),
87 INTG(X86_TRAP_BR, asm_exc_bounds),
88 INTG(X86_TRAP_UD, asm_exc_invalid_op),
89 INTG(X86_TRAP_NM, asm_exc_device_not_available),
90 INTG(X86_TRAP_OLD_MF, asm_exc_coproc_segment_overrun),
91 INTG(X86_TRAP_TS, asm_exc_invalid_tss),
92 INTG(X86_TRAP_NP, asm_exc_segment_not_present),
93 INTG(X86_TRAP_SS, asm_exc_stack_segment),
94 INTG(X86_TRAP_GP, asm_exc_general_protection),
95 INTG(X86_TRAP_SPURIOUS, asm_exc_spurious_interrupt_bug),
96 INTG(X86_TRAP_MF, asm_exc_coprocessor_error),
97 INTG(X86_TRAP_AC, asm_exc_alignment_check),
98 INTG(X86_TRAP_XF, asm_exc_simd_coprocessor_error),
99
100#ifdef CONFIG_X86_32
101 TSKG(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS),
102#else
103 ISTG(X86_TRAP_DF, asm_exc_double_fault, IST_INDEX_DF),
104#endif
105 ISTG(X86_TRAP_DB, asm_exc_debug, IST_INDEX_DB),
106
107#ifdef CONFIG_X86_MCE
108 ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
109#endif
110
111#ifdef CONFIG_X86_CET
112 INTG(X86_TRAP_CP, asm_exc_control_protection),
113#endif
114
115#ifdef CONFIG_AMD_MEM_ENCRYPT
116 ISTG(X86_TRAP_VC, asm_exc_vmm_communication, IST_INDEX_VC),
117#endif
118
119 SYSG(X86_TRAP_OF, asm_exc_overflow),
120};
121
122static const struct idt_data ia32_idt[] __initconst = {
123#if defined(CONFIG_IA32_EMULATION)
124 SYSG(IA32_SYSCALL_VECTOR, asm_int80_emulation),
125#elif defined(CONFIG_X86_32)
126 SYSG(IA32_SYSCALL_VECTOR, entry_INT80_32),
127#endif
128};
129
130/*
131 * The APIC and SMP idt entries
132 */
133static const __initconst struct idt_data apic_idts[] = {
134#ifdef CONFIG_SMP
135 INTG(RESCHEDULE_VECTOR, asm_sysvec_reschedule_ipi),
136 INTG(CALL_FUNCTION_VECTOR, asm_sysvec_call_function),
137 INTG(CALL_FUNCTION_SINGLE_VECTOR, asm_sysvec_call_function_single),
138 INTG(REBOOT_VECTOR, asm_sysvec_reboot),
139#endif
140
141#ifdef CONFIG_X86_THERMAL_VECTOR
142 INTG(THERMAL_APIC_VECTOR, asm_sysvec_thermal),
143#endif
144
145#ifdef CONFIG_X86_MCE_THRESHOLD
146 INTG(THRESHOLD_APIC_VECTOR, asm_sysvec_threshold),
147#endif
148
149#ifdef CONFIG_X86_MCE_AMD
150 INTG(DEFERRED_ERROR_VECTOR, asm_sysvec_deferred_error),
151#endif
152
153#ifdef CONFIG_X86_LOCAL_APIC
154 INTG(LOCAL_TIMER_VECTOR, asm_sysvec_apic_timer_interrupt),
155 INTG(X86_PLATFORM_IPI_VECTOR, asm_sysvec_x86_platform_ipi),
156# if IS_ENABLED(CONFIG_KVM)
157 INTG(POSTED_INTR_VECTOR, asm_sysvec_kvm_posted_intr_ipi),
158 INTG(POSTED_INTR_WAKEUP_VECTOR, asm_sysvec_kvm_posted_intr_wakeup_ipi),
159 INTG(POSTED_INTR_NESTED_VECTOR, asm_sysvec_kvm_posted_intr_nested_ipi),
160# endif
161# ifdef CONFIG_IRQ_WORK
162 INTG(IRQ_WORK_VECTOR, asm_sysvec_irq_work),
163# endif
164 INTG(SPURIOUS_APIC_VECTOR, asm_sysvec_spurious_apic_interrupt),
165 INTG(ERROR_APIC_VECTOR, asm_sysvec_error_interrupt),
166# ifdef CONFIG_X86_POSTED_MSI
167 INTG(POSTED_MSI_NOTIFICATION_VECTOR, asm_sysvec_posted_msi_notification),
168# endif
169#endif
170};
171
172/* Must be page-aligned because the real IDT is used in the cpu entry area */
173static gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;
174
175static struct desc_ptr idt_descr __ro_after_init = {
176 .size = IDT_TABLE_SIZE - 1,
177 .address = (unsigned long) idt_table,
178};
179
180void load_current_idt(void)
181{
182 lockdep_assert_irqs_disabled();
183 load_idt(dtr: &idt_descr);
184}
185
186#ifdef CONFIG_X86_F00F_BUG
187bool idt_is_f00f_address(unsigned long address)
188{
189 return ((address - idt_descr.address) >> 3) == 6;
190}
191#endif
192
193static __init void
194idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size, bool sys)
195{
196 gate_desc desc;
197
198 for (; size > 0; t++, size--) {
199 idt_init_desc(gate: &desc, d: t);
200 write_idt_entry(dt: idt, entry: t->vector, g: &desc);
201 if (sys)
202 set_bit(nr: t->vector, addr: system_vectors);
203 }
204}
205
206static __init void set_intr_gate(unsigned int n, const void *addr)
207{
208 struct idt_data data;
209
210 init_idt_data(data: &data, n, addr);
211
212 idt_setup_from_table(idt: idt_table, t: &data, size: 1, sys: false);
213}
214
215/**
216 * idt_setup_early_traps - Initialize the idt table with early traps
217 *
218 * On X8664 these traps do not use interrupt stacks as they can't work
219 * before cpu_init() is invoked and sets up TSS. The IST variants are
220 * installed after that.
221 */
222void __init idt_setup_early_traps(void)
223{
224 idt_setup_from_table(idt: idt_table, t: early_idts, ARRAY_SIZE(early_idts),
225 sys: true);
226 load_idt(dtr: &idt_descr);
227}
228
229/**
230 * idt_setup_traps - Initialize the idt table with default traps
231 */
232void __init idt_setup_traps(void)
233{
234 idt_setup_from_table(idt: idt_table, t: def_idts, ARRAY_SIZE(def_idts), sys: true);
235
236 if (ia32_enabled())
237 idt_setup_from_table(idt: idt_table, t: ia32_idt, ARRAY_SIZE(ia32_idt), sys: true);
238}
239
240#ifdef CONFIG_X86_64
241/*
242 * Early traps running on the DEFAULT_STACK because the other interrupt
243 * stacks work only after cpu_init().
244 */
245static const __initconst struct idt_data early_pf_idts[] = {
246 INTG(X86_TRAP_PF, asm_exc_page_fault),
247};
248
249/**
250 * idt_setup_early_pf - Initialize the idt table with early pagefault handler
251 *
252 * On X8664 this does not use interrupt stacks as they can't work before
253 * cpu_init() is invoked and sets up TSS. The IST variant is installed
254 * after that.
255 *
256 * Note, that X86_64 cannot install the real #PF handler in
257 * idt_setup_early_traps() because the memory initialization needs the #PF
258 * handler from the early_idt_handler_array to initialize the early page
259 * tables.
260 */
261void __init idt_setup_early_pf(void)
262{
263 idt_setup_from_table(idt: idt_table, t: early_pf_idts,
264 ARRAY_SIZE(early_pf_idts), sys: true);
265}
266#endif
267
268static void __init idt_map_in_cea(void)
269{
270 /*
271 * Set the IDT descriptor to a fixed read-only location in the cpu
272 * entry area, so that the "sidt" instruction will not leak the
273 * location of the kernel, and to defend the IDT against arbitrary
274 * memory write vulnerabilities.
275 */
276 cea_set_pte(CPU_ENTRY_AREA_RO_IDT_VADDR, __pa_symbol(idt_table),
277 PAGE_KERNEL_RO);
278 idt_descr.address = CPU_ENTRY_AREA_RO_IDT;
279}
280
281/**
282 * idt_setup_apic_and_irq_gates - Setup APIC/SMP and normal interrupt gates
283 */
284void __init idt_setup_apic_and_irq_gates(void)
285{
286 int i = FIRST_EXTERNAL_VECTOR;
287 void *entry;
288
289 idt_setup_from_table(idt: idt_table, t: apic_idts, ARRAY_SIZE(apic_idts), sys: true);
290
291 for_each_clear_bit_from(i, system_vectors, FIRST_SYSTEM_VECTOR) {
292 entry = irq_entries_start + IDT_ALIGN * (i - FIRST_EXTERNAL_VECTOR);
293 set_intr_gate(n: i, addr: entry);
294 }
295
296#ifdef CONFIG_X86_LOCAL_APIC
297 for_each_clear_bit_from(i, system_vectors, NR_VECTORS) {
298 /*
299 * Don't set the non assigned system vectors in the
300 * system_vectors bitmap. Otherwise they show up in
301 * /proc/interrupts.
302 */
303 entry = spurious_entries_start + IDT_ALIGN * (i - FIRST_SYSTEM_VECTOR);
304 set_intr_gate(n: i, addr: entry);
305 }
306#endif
307 /* Map IDT into CPU entry area and reload it. */
308 idt_map_in_cea();
309 load_idt(dtr: &idt_descr);
310
311 /* Make the IDT table read only */
312 set_memory_ro(addr: (unsigned long)&idt_table, numpages: 1);
313
314 idt_setup_done = true;
315}
316
317/**
318 * idt_setup_early_handler - Initializes the idt table with early handlers
319 */
320void __init idt_setup_early_handler(void)
321{
322 int i;
323
324 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
325 set_intr_gate(n: i, addr: early_idt_handler_array[i]);
326#ifdef CONFIG_X86_32
327 for ( ; i < NR_VECTORS; i++)
328 set_intr_gate(i, early_ignore_irq);
329#endif
330 load_idt(dtr: &idt_descr);
331}
332
333/**
334 * idt_invalidate - Invalidate interrupt descriptor table
335 */
336void idt_invalidate(void)
337{
338 static const struct desc_ptr idt = { .address = 0, .size = 0 };
339
340 load_idt(dtr: &idt);
341}
342
343void __init idt_install_sysvec(unsigned int n, const void *function)
344{
345 if (WARN_ON(n < FIRST_SYSTEM_VECTOR))
346 return;
347
348 if (WARN_ON(idt_setup_done))
349 return;
350
351 if (!WARN_ON(test_and_set_bit(n, system_vectors)))
352 set_intr_gate(n, addr: function);
353}
354

source code of linux/arch/x86/kernel/idt.c