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
14 #define DPL0 0x0
15 #define DPL3 0x3
16
17 #define DEFAULT_STACK 0
18
19 #define G(_vector, _addr, _ist, _type, _dpl, _segment) \
20 { \
21 .vector = _vector, \
22 .bits.ist = _ist, \
23 .bits.type = _type, \
24 .bits.dpl = _dpl, \
25 .bits.p = 1, \
26 .addr = _addr, \
27 .segment = _segment, \
28 }
29
30 /* Interrupt gate */
31 #define INTG(_vector, _addr) \
32 G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL0, __KERNEL_CS)
33
34 /* System interrupt gate */
35 #define SYSG(_vector, _addr) \
36 G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS)
37
38 /*
39 * Interrupt gate with interrupt stack. The _ist index is the index in
40 * the tss.ist[] array, but for the descriptor it needs to start at 1.
41 */
42 #define ISTG(_vector, _addr, _ist) \
43 G(_vector, _addr, _ist + 1, GATE_INTERRUPT, DPL0, __KERNEL_CS)
44
45 /* Task gate */
46 #define TSKG(_vector, _gdt) \
47 G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
48
49 #define IDT_TABLE_SIZE (IDT_ENTRIES * sizeof(gate_desc))
50
51 static bool idt_setup_done __initdata;
52
53 /*
54 * Early traps running on the DEFAULT_STACK because the other interrupt
55 * stacks work only after cpu_init().
56 */
57 static const __initconst struct idt_data early_idts[] = {
58 INTG(X86_TRAP_DB, asm_exc_debug),
59 SYSG(X86_TRAP_BP, asm_exc_int3),
60
61 #ifdef CONFIG_X86_32
62 /*
63 * Not possible on 64-bit. See idt_setup_early_pf() for details.
64 */
65 INTG(X86_TRAP_PF, asm_exc_page_fault),
66 #endif
67 };
68
69 /*
70 * The default IDT entries which are set up in trap_init() before
71 * cpu_init() is invoked. Interrupt stacks cannot be used at that point and
72 * the traps which use them are reinitialized with IST after cpu_init() has
73 * set up TSS.
74 */
75 static const __initconst struct idt_data def_idts[] = {
76 INTG(X86_TRAP_DE, asm_exc_divide_error),
77 INTG(X86_TRAP_NMI, asm_exc_nmi),
78 INTG(X86_TRAP_BR, asm_exc_bounds),
79 INTG(X86_TRAP_UD, asm_exc_invalid_op),
80 INTG(X86_TRAP_NM, asm_exc_device_not_available),
81 INTG(X86_TRAP_OLD_MF, asm_exc_coproc_segment_overrun),
82 INTG(X86_TRAP_TS, asm_exc_invalid_tss),
83 INTG(X86_TRAP_NP, asm_exc_segment_not_present),
84 INTG(X86_TRAP_SS, asm_exc_stack_segment),
85 INTG(X86_TRAP_GP, asm_exc_general_protection),
86 INTG(X86_TRAP_SPURIOUS, asm_exc_spurious_interrupt_bug),
87 INTG(X86_TRAP_MF, asm_exc_coprocessor_error),
88 INTG(X86_TRAP_AC, asm_exc_alignment_check),
89 INTG(X86_TRAP_XF, asm_exc_simd_coprocessor_error),
90
91 #ifdef CONFIG_X86_32
92 TSKG(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS),
93 #else
94 INTG(X86_TRAP_DF, asm_exc_double_fault),
95 #endif
96 INTG(X86_TRAP_DB, asm_exc_debug),
97
98 #ifdef CONFIG_X86_MCE
99 INTG(X86_TRAP_MC, asm_exc_machine_check),
100 #endif
101
102 SYSG(X86_TRAP_OF, asm_exc_overflow),
103 #if defined(CONFIG_IA32_EMULATION)
104 SYSG(IA32_SYSCALL_VECTOR, entry_INT80_compat),
105 #elif defined(CONFIG_X86_32)
106 SYSG(IA32_SYSCALL_VECTOR, entry_INT80_32),
107 #endif
108 };
109
110 /*
111 * The APIC and SMP idt entries
112 */
113 static const __initconst struct idt_data apic_idts[] = {
114 #ifdef CONFIG_SMP
115 INTG(RESCHEDULE_VECTOR, asm_sysvec_reschedule_ipi),
116 INTG(CALL_FUNCTION_VECTOR, asm_sysvec_call_function),
117 INTG(CALL_FUNCTION_SINGLE_VECTOR, asm_sysvec_call_function_single),
118 INTG(IRQ_MOVE_CLEANUP_VECTOR, asm_sysvec_irq_move_cleanup),
119 INTG(REBOOT_VECTOR, asm_sysvec_reboot),
120 #endif
121
122 #ifdef CONFIG_X86_THERMAL_VECTOR
123 INTG(THERMAL_APIC_VECTOR, asm_sysvec_thermal),
124 #endif
125
126 #ifdef CONFIG_X86_MCE_THRESHOLD
127 INTG(THRESHOLD_APIC_VECTOR, asm_sysvec_threshold),
128 #endif
129
130 #ifdef CONFIG_X86_MCE_AMD
131 INTG(DEFERRED_ERROR_VECTOR, asm_sysvec_deferred_error),
132 #endif
133
134 #ifdef CONFIG_X86_LOCAL_APIC
135 INTG(LOCAL_TIMER_VECTOR, asm_sysvec_apic_timer_interrupt),
136 INTG(X86_PLATFORM_IPI_VECTOR, asm_sysvec_x86_platform_ipi),
137 # ifdef CONFIG_HAVE_KVM
138 INTG(POSTED_INTR_VECTOR, asm_sysvec_kvm_posted_intr_ipi),
139 INTG(POSTED_INTR_WAKEUP_VECTOR, asm_sysvec_kvm_posted_intr_wakeup_ipi),
140 INTG(POSTED_INTR_NESTED_VECTOR, asm_sysvec_kvm_posted_intr_nested_ipi),
141 # endif
142 # ifdef CONFIG_IRQ_WORK
143 INTG(IRQ_WORK_VECTOR, asm_sysvec_irq_work),
144 # endif
145 INTG(SPURIOUS_APIC_VECTOR, asm_sysvec_spurious_apic_interrupt),
146 INTG(ERROR_APIC_VECTOR, asm_sysvec_error_interrupt),
147 #endif
148 };
149
150 /* Must be page-aligned because the real IDT is used in the cpu entry area */
151 static gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;
152
153 static struct desc_ptr idt_descr __ro_after_init = {
154 .size = IDT_TABLE_SIZE - 1,
155 .address = (unsigned long) idt_table,
156 };
157
load_current_idt(void)158 void load_current_idt(void)
159 {
160 lockdep_assert_irqs_disabled();
161 load_idt(&idt_descr);
162 }
163
164 #ifdef CONFIG_X86_F00F_BUG
idt_is_f00f_address(unsigned long address)165 bool idt_is_f00f_address(unsigned long address)
166 {
167 return ((address - idt_descr.address) >> 3) == 6;
168 }
169 #endif
170
171 static __init void
idt_setup_from_table(gate_desc * idt,const struct idt_data * t,int size,bool sys)172 idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size, bool sys)
173 {
174 gate_desc desc;
175
176 for (; size > 0; t++, size--) {
177 idt_init_desc(&desc, t);
178 write_idt_entry(idt, t->vector, &desc);
179 if (sys)
180 set_bit(t->vector, system_vectors);
181 }
182 }
183
set_intr_gate(unsigned int n,const void * addr)184 static __init void set_intr_gate(unsigned int n, const void *addr)
185 {
186 struct idt_data data;
187
188 init_idt_data(&data, n, addr);
189
190 idt_setup_from_table(idt_table, &data, 1, false);
191 }
192
193 /**
194 * idt_setup_early_traps - Initialize the idt table with early traps
195 *
196 * On X8664 these traps do not use interrupt stacks as they can't work
197 * before cpu_init() is invoked and sets up TSS. The IST variants are
198 * installed after that.
199 */
idt_setup_early_traps(void)200 void __init idt_setup_early_traps(void)
201 {
202 idt_setup_from_table(idt_table, early_idts, ARRAY_SIZE(early_idts),
203 true);
204 load_idt(&idt_descr);
205 }
206
207 /**
208 * idt_setup_traps - Initialize the idt table with default traps
209 */
idt_setup_traps(void)210 void __init idt_setup_traps(void)
211 {
212 idt_setup_from_table(idt_table, def_idts, ARRAY_SIZE(def_idts), true);
213 }
214
215 #ifdef CONFIG_X86_64
216 /*
217 * Early traps running on the DEFAULT_STACK because the other interrupt
218 * stacks work only after cpu_init().
219 */
220 static const __initconst struct idt_data early_pf_idts[] = {
221 INTG(X86_TRAP_PF, asm_exc_page_fault),
222 };
223
224 /*
225 * The exceptions which use Interrupt stacks. They are setup after
226 * cpu_init() when the TSS has been initialized.
227 */
228 static const __initconst struct idt_data ist_idts[] = {
229 ISTG(X86_TRAP_DB, asm_exc_debug, IST_INDEX_DB),
230 ISTG(X86_TRAP_NMI, asm_exc_nmi, IST_INDEX_NMI),
231 ISTG(X86_TRAP_DF, asm_exc_double_fault, IST_INDEX_DF),
232 #ifdef CONFIG_X86_MCE
233 ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
234 #endif
235 #ifdef CONFIG_AMD_MEM_ENCRYPT
236 ISTG(X86_TRAP_VC, asm_exc_vmm_communication, IST_INDEX_VC),
237 #endif
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 intialization 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
258 /**
259 * idt_setup_ist_traps - Initialize the idt table with traps using IST
260 */
idt_setup_ist_traps(void)261 void __init idt_setup_ist_traps(void)
262 {
263 idt_setup_from_table(idt_table, ist_idts, ARRAY_SIZE(ist_idts), true);
264 }
265 #endif
266
idt_map_in_cea(void)267 static void __init idt_map_in_cea(void)
268 {
269 /*
270 * Set the IDT descriptor to a fixed read-only location in the cpu
271 * entry area, so that the "sidt" instruction will not leak the
272 * location of the kernel, and to defend the IDT against arbitrary
273 * memory write vulnerabilities.
274 */
275 cea_set_pte(CPU_ENTRY_AREA_RO_IDT_VADDR, __pa_symbol(idt_table),
276 PAGE_KERNEL_RO);
277 idt_descr.address = CPU_ENTRY_AREA_RO_IDT;
278 }
279
280 /**
281 * idt_setup_apic_and_irq_gates - Setup APIC/SMP and normal interrupt gates
282 */
idt_setup_apic_and_irq_gates(void)283 void __init idt_setup_apic_and_irq_gates(void)
284 {
285 int i = FIRST_EXTERNAL_VECTOR;
286 void *entry;
287
288 idt_setup_from_table(idt_table, apic_idts, ARRAY_SIZE(apic_idts), true);
289
290 for_each_clear_bit_from(i, system_vectors, FIRST_SYSTEM_VECTOR) {
291 entry = irq_entries_start + 8 * (i - FIRST_EXTERNAL_VECTOR);
292 set_intr_gate(i, entry);
293 }
294
295 #ifdef CONFIG_X86_LOCAL_APIC
296 for_each_clear_bit_from(i, system_vectors, NR_VECTORS) {
297 /*
298 * Don't set the non assigned system vectors in the
299 * system_vectors bitmap. Otherwise they show up in
300 * /proc/interrupts.
301 */
302 entry = spurious_entries_start + 8 * (i - FIRST_SYSTEM_VECTOR);
303 set_intr_gate(i, entry);
304 }
305 #endif
306 /* Map IDT into CPU entry area and reload it. */
307 idt_map_in_cea();
308 load_idt(&idt_descr);
309
310 /* Make the IDT table read only */
311 set_memory_ro((unsigned long)&idt_table, 1);
312
313 idt_setup_done = true;
314 }
315
316 /**
317 * idt_setup_early_handler - Initializes the idt table with early handlers
318 */
idt_setup_early_handler(void)319 void __init idt_setup_early_handler(void)
320 {
321 int i;
322
323 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
324 set_intr_gate(i, early_idt_handler_array[i]);
325 #ifdef CONFIG_X86_32
326 for ( ; i < NR_VECTORS; i++)
327 set_intr_gate(i, early_ignore_irq);
328 #endif
329 load_idt(&idt_descr);
330 }
331
332 /**
333 * idt_invalidate - Invalidate interrupt descriptor table
334 * @addr: The virtual address of the 'invalid' IDT
335 */
idt_invalidate(void * addr)336 void idt_invalidate(void *addr)
337 {
338 struct desc_ptr idt = { .address = (unsigned long) addr, .size = 0 };
339
340 load_idt(&idt);
341 }
342
alloc_intr_gate(unsigned int n,const void * addr)343 void __init alloc_intr_gate(unsigned int n, const void *addr)
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);
353 }
354