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/idtentry.h>
14
15 #define DPL0 0x0
16 #define DPL3 0x3
17
18 #define DEFAULT_STACK 0
19
20 #define G(_vector, _addr, _ist, _type, _dpl, _segment) \
21 { \
22 .vector = _vector, \
23 .bits.ist = _ist, \
24 .bits.type = _type, \
25 .bits.dpl = _dpl, \
26 .bits.p = 1, \
27 .addr = _addr, \
28 .segment = _segment, \
29 }
30
31 /* Interrupt gate */
32 #define INTG(_vector, _addr) \
33 G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL0, __KERNEL_CS)
34
35 /* System interrupt gate */
36 #define SYSG(_vector, _addr) \
37 G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS)
38
39 #ifdef CONFIG_X86_64
40 /*
41 * Interrupt gate with interrupt stack. The _ist index is the index in
42 * the tss.ist[] array, but for the descriptor it needs to start at 1.
43 */
44 #define ISTG(_vector, _addr, _ist) \
45 G(_vector, _addr, _ist + 1, GATE_INTERRUPT, DPL0, __KERNEL_CS)
46 #else
47 #define ISTG(_vector, _addr, _ist) INTG(_vector, _addr)
48 #endif
49
50 /* Task gate */
51 #define TSKG(_vector, _gdt) \
52 G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
53
54 #define IDT_TABLE_SIZE (IDT_ENTRIES * sizeof(gate_desc))
55
56 static bool idt_setup_done __initdata;
57
58 /*
59 * Early traps running on the DEFAULT_STACK because the other interrupt
60 * stacks work only after cpu_init().
61 */
62 static const __initconst struct idt_data early_idts[] = {
63 INTG(X86_TRAP_DB, asm_exc_debug),
64 SYSG(X86_TRAP_BP, asm_exc_int3),
65
66 #ifdef CONFIG_X86_32
67 /*
68 * Not possible on 64-bit. See idt_setup_early_pf() for details.
69 */
70 INTG(X86_TRAP_PF, asm_exc_page_fault),
71 #endif
72 #ifdef CONFIG_INTEL_TDX_GUEST
73 INTG(X86_TRAP_VE, asm_exc_virtualization_exception),
74 #endif
75 };
76
77 /*
78 * The default IDT entries which are set up in trap_init() before
79 * cpu_init() is invoked. Interrupt stacks cannot be used at that point and
80 * the traps which use them are reinitialized with IST after cpu_init() has
81 * set up TSS.
82 */
83 static const __initconst struct idt_data def_idts[] = {
84 INTG(X86_TRAP_DE, asm_exc_divide_error),
85 ISTG(X86_TRAP_NMI, asm_exc_nmi, IST_INDEX_NMI),
86 INTG(X86_TRAP_BR, asm_exc_bounds),
87 INTG(X86_TRAP_UD, asm_exc_invalid_op),
88 INTG(X86_TRAP_NM, asm_exc_device_not_available),
89 INTG(X86_TRAP_OLD_MF, asm_exc_coproc_segment_overrun),
90 INTG(X86_TRAP_TS, asm_exc_invalid_tss),
91 INTG(X86_TRAP_NP, asm_exc_segment_not_present),
92 INTG(X86_TRAP_SS, asm_exc_stack_segment),
93 INTG(X86_TRAP_GP, asm_exc_general_protection),
94 INTG(X86_TRAP_SPURIOUS, asm_exc_spurious_interrupt_bug),
95 INTG(X86_TRAP_MF, asm_exc_coprocessor_error),
96 INTG(X86_TRAP_AC, asm_exc_alignment_check),
97 INTG(X86_TRAP_XF, asm_exc_simd_coprocessor_error),
98
99 #ifdef CONFIG_X86_32
100 TSKG(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS),
101 #else
102 ISTG(X86_TRAP_DF, asm_exc_double_fault, IST_INDEX_DF),
103 #endif
104 ISTG(X86_TRAP_DB, asm_exc_debug, IST_INDEX_DB),
105
106 #ifdef CONFIG_X86_MCE
107 ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
108 #endif
109
110 #ifdef CONFIG_X86_KERNEL_IBT
111 INTG(X86_TRAP_CP, asm_exc_control_protection),
112 #endif
113
114 #ifdef CONFIG_AMD_MEM_ENCRYPT
115 ISTG(X86_TRAP_VC, asm_exc_vmm_communication, IST_INDEX_VC),
116 #endif
117
118 SYSG(X86_TRAP_OF, asm_exc_overflow),
119 #if defined(CONFIG_IA32_EMULATION)
120 SYSG(IA32_SYSCALL_VECTOR, entry_INT80_compat),
121 #elif defined(CONFIG_X86_32)
122 SYSG(IA32_SYSCALL_VECTOR, entry_INT80_32),
123 #endif
124 };
125
126 /*
127 * The APIC and SMP idt entries
128 */
129 static const __initconst struct idt_data apic_idts[] = {
130 #ifdef CONFIG_SMP
131 INTG(RESCHEDULE_VECTOR, asm_sysvec_reschedule_ipi),
132 INTG(CALL_FUNCTION_VECTOR, asm_sysvec_call_function),
133 INTG(CALL_FUNCTION_SINGLE_VECTOR, asm_sysvec_call_function_single),
134 INTG(IRQ_MOVE_CLEANUP_VECTOR, asm_sysvec_irq_move_cleanup),
135 INTG(REBOOT_VECTOR, asm_sysvec_reboot),
136 #endif
137
138 #ifdef CONFIG_X86_THERMAL_VECTOR
139 INTG(THERMAL_APIC_VECTOR, asm_sysvec_thermal),
140 #endif
141
142 #ifdef CONFIG_X86_MCE_THRESHOLD
143 INTG(THRESHOLD_APIC_VECTOR, asm_sysvec_threshold),
144 #endif
145
146 #ifdef CONFIG_X86_MCE_AMD
147 INTG(DEFERRED_ERROR_VECTOR, asm_sysvec_deferred_error),
148 #endif
149
150 #ifdef CONFIG_X86_LOCAL_APIC
151 INTG(LOCAL_TIMER_VECTOR, asm_sysvec_apic_timer_interrupt),
152 INTG(X86_PLATFORM_IPI_VECTOR, asm_sysvec_x86_platform_ipi),
153 # ifdef CONFIG_HAVE_KVM
154 INTG(POSTED_INTR_VECTOR, asm_sysvec_kvm_posted_intr_ipi),
155 INTG(POSTED_INTR_WAKEUP_VECTOR, asm_sysvec_kvm_posted_intr_wakeup_ipi),
156 INTG(POSTED_INTR_NESTED_VECTOR, asm_sysvec_kvm_posted_intr_nested_ipi),
157 # endif
158 # ifdef CONFIG_IRQ_WORK
159 INTG(IRQ_WORK_VECTOR, asm_sysvec_irq_work),
160 # endif
161 INTG(SPURIOUS_APIC_VECTOR, asm_sysvec_spurious_apic_interrupt),
162 INTG(ERROR_APIC_VECTOR, asm_sysvec_error_interrupt),
163 #endif
164 };
165
166 /* Must be page-aligned because the real IDT is used in the cpu entry area */
167 static gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;
168
169 static struct desc_ptr idt_descr __ro_after_init = {
170 .size = IDT_TABLE_SIZE - 1,
171 .address = (unsigned long) idt_table,
172 };
173
load_current_idt(void)174 void load_current_idt(void)
175 {
176 lockdep_assert_irqs_disabled();
177 load_idt(&idt_descr);
178 }
179
180 #ifdef CONFIG_X86_F00F_BUG
idt_is_f00f_address(unsigned long address)181 bool idt_is_f00f_address(unsigned long address)
182 {
183 return ((address - idt_descr.address) >> 3) == 6;
184 }
185 #endif
186
187 static __init void
idt_setup_from_table(gate_desc * idt,const struct idt_data * t,int size,bool sys)188 idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size, bool sys)
189 {
190 gate_desc desc;
191
192 for (; size > 0; t++, size--) {
193 idt_init_desc(&desc, t);
194 write_idt_entry(idt, t->vector, &desc);
195 if (sys)
196 set_bit(t->vector, system_vectors);
197 }
198 }
199
set_intr_gate(unsigned int n,const void * addr)200 static __init void set_intr_gate(unsigned int n, const void *addr)
201 {
202 struct idt_data data;
203
204 init_idt_data(&data, n, addr);
205
206 idt_setup_from_table(idt_table, &data, 1, false);
207 }
208
209 /**
210 * idt_setup_early_traps - Initialize the idt table with early traps
211 *
212 * On X8664 these traps do not use interrupt stacks as they can't work
213 * before cpu_init() is invoked and sets up TSS. The IST variants are
214 * installed after that.
215 */
idt_setup_early_traps(void)216 void __init idt_setup_early_traps(void)
217 {
218 idt_setup_from_table(idt_table, early_idts, ARRAY_SIZE(early_idts),
219 true);
220 load_idt(&idt_descr);
221 }
222
223 /**
224 * idt_setup_traps - Initialize the idt table with default traps
225 */
idt_setup_traps(void)226 void __init idt_setup_traps(void)
227 {
228 idt_setup_from_table(idt_table, def_idts, ARRAY_SIZE(def_idts), true);
229 }
230
231 #ifdef CONFIG_X86_64
232 /*
233 * Early traps running on the DEFAULT_STACK because the other interrupt
234 * stacks work only after cpu_init().
235 */
236 static const __initconst struct idt_data early_pf_idts[] = {
237 INTG(X86_TRAP_PF, asm_exc_page_fault),
238 };
239
240 /**
241 * idt_setup_early_pf - Initialize the idt table with early pagefault handler
242 *
243 * On X8664 this does not use interrupt stacks as they can't work before
244 * cpu_init() is invoked and sets up TSS. The IST variant is installed
245 * after that.
246 *
247 * Note, that X86_64 cannot install the real #PF handler in
248 * idt_setup_early_traps() because the memory initialization needs the #PF
249 * handler from the early_idt_handler_array to initialize the early page
250 * tables.
251 */
idt_setup_early_pf(void)252 void __init idt_setup_early_pf(void)
253 {
254 idt_setup_from_table(idt_table, early_pf_idts,
255 ARRAY_SIZE(early_pf_idts), true);
256 }
257 #endif
258
idt_map_in_cea(void)259 static void __init idt_map_in_cea(void)
260 {
261 /*
262 * Set the IDT descriptor to a fixed read-only location in the cpu
263 * entry area, so that the "sidt" instruction will not leak the
264 * location of the kernel, and to defend the IDT against arbitrary
265 * memory write vulnerabilities.
266 */
267 cea_set_pte(CPU_ENTRY_AREA_RO_IDT_VADDR, __pa_symbol(idt_table),
268 PAGE_KERNEL_RO);
269 idt_descr.address = CPU_ENTRY_AREA_RO_IDT;
270 }
271
272 /**
273 * idt_setup_apic_and_irq_gates - Setup APIC/SMP and normal interrupt gates
274 */
idt_setup_apic_and_irq_gates(void)275 void __init idt_setup_apic_and_irq_gates(void)
276 {
277 int i = FIRST_EXTERNAL_VECTOR;
278 void *entry;
279
280 idt_setup_from_table(idt_table, apic_idts, ARRAY_SIZE(apic_idts), true);
281
282 for_each_clear_bit_from(i, system_vectors, FIRST_SYSTEM_VECTOR) {
283 entry = irq_entries_start + IDT_ALIGN * (i - FIRST_EXTERNAL_VECTOR);
284 set_intr_gate(i, entry);
285 }
286
287 #ifdef CONFIG_X86_LOCAL_APIC
288 for_each_clear_bit_from(i, system_vectors, NR_VECTORS) {
289 /*
290 * Don't set the non assigned system vectors in the
291 * system_vectors bitmap. Otherwise they show up in
292 * /proc/interrupts.
293 */
294 entry = spurious_entries_start + IDT_ALIGN * (i - FIRST_SYSTEM_VECTOR);
295 set_intr_gate(i, entry);
296 }
297 #endif
298 /* Map IDT into CPU entry area and reload it. */
299 idt_map_in_cea();
300 load_idt(&idt_descr);
301
302 /* Make the IDT table read only */
303 set_memory_ro((unsigned long)&idt_table, 1);
304
305 idt_setup_done = true;
306 }
307
308 /**
309 * idt_setup_early_handler - Initializes the idt table with early handlers
310 */
idt_setup_early_handler(void)311 void __init idt_setup_early_handler(void)
312 {
313 int i;
314
315 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
316 set_intr_gate(i, early_idt_handler_array[i]);
317 #ifdef CONFIG_X86_32
318 for ( ; i < NR_VECTORS; i++)
319 set_intr_gate(i, early_ignore_irq);
320 #endif
321 load_idt(&idt_descr);
322 }
323
324 /**
325 * idt_invalidate - Invalidate interrupt descriptor table
326 */
idt_invalidate(void)327 void idt_invalidate(void)
328 {
329 static const struct desc_ptr idt = { .address = 0, .size = 0 };
330
331 load_idt(&idt);
332 }
333
alloc_intr_gate(unsigned int n,const void * addr)334 void __init alloc_intr_gate(unsigned int n, const void *addr)
335 {
336 if (WARN_ON(n < FIRST_SYSTEM_VECTOR))
337 return;
338
339 if (WARN_ON(idt_setup_done))
340 return;
341
342 if (!WARN_ON(test_and_set_bit(n, system_vectors)))
343 set_intr_gate(n, addr);
344 }
345