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 57 static 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 */ 63 static 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 */ 84 static 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 }; 121 122 static 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 */ 133 static 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 #endif 167 }; 168 169 /* Must be page-aligned because the real IDT is used in the cpu entry area */ 170 static gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss; 171 172 static struct desc_ptr idt_descr __ro_after_init = { 173 .size = IDT_TABLE_SIZE - 1, 174 .address = (unsigned long) idt_table, 175 }; 176 177 void load_current_idt(void) 178 { 179 lockdep_assert_irqs_disabled(); 180 load_idt(&idt_descr); 181 } 182 183 #ifdef CONFIG_X86_F00F_BUG 184 bool idt_is_f00f_address(unsigned long address) 185 { 186 return ((address - idt_descr.address) >> 3) == 6; 187 } 188 #endif 189 190 static __init void 191 idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size, bool sys) 192 { 193 gate_desc desc; 194 195 for (; size > 0; t++, size--) { 196 idt_init_desc(&desc, t); 197 write_idt_entry(idt, t->vector, &desc); 198 if (sys) 199 set_bit(t->vector, system_vectors); 200 } 201 } 202 203 static __init void set_intr_gate(unsigned int n, const void *addr) 204 { 205 struct idt_data data; 206 207 init_idt_data(&data, n, addr); 208 209 idt_setup_from_table(idt_table, &data, 1, false); 210 } 211 212 /** 213 * idt_setup_early_traps - Initialize the idt table with early traps 214 * 215 * On X8664 these traps do not use interrupt stacks as they can't work 216 * before cpu_init() is invoked and sets up TSS. The IST variants are 217 * installed after that. 218 */ 219 void __init idt_setup_early_traps(void) 220 { 221 idt_setup_from_table(idt_table, early_idts, ARRAY_SIZE(early_idts), 222 true); 223 load_idt(&idt_descr); 224 } 225 226 /** 227 * idt_setup_traps - Initialize the idt table with default traps 228 */ 229 void __init idt_setup_traps(void) 230 { 231 idt_setup_from_table(idt_table, def_idts, ARRAY_SIZE(def_idts), true); 232 233 if (ia32_enabled()) 234 idt_setup_from_table(idt_table, ia32_idt, ARRAY_SIZE(ia32_idt), true); 235 } 236 237 #ifdef CONFIG_X86_64 238 /* 239 * Early traps running on the DEFAULT_STACK because the other interrupt 240 * stacks work only after cpu_init(). 241 */ 242 static const __initconst struct idt_data early_pf_idts[] = { 243 INTG(X86_TRAP_PF, asm_exc_page_fault), 244 }; 245 246 /** 247 * idt_setup_early_pf - Initialize the idt table with early pagefault handler 248 * 249 * On X8664 this does not use interrupt stacks as they can't work before 250 * cpu_init() is invoked and sets up TSS. The IST variant is installed 251 * after that. 252 * 253 * Note, that X86_64 cannot install the real #PF handler in 254 * idt_setup_early_traps() because the memory initialization needs the #PF 255 * handler from the early_idt_handler_array to initialize the early page 256 * tables. 257 */ 258 void __init idt_setup_early_pf(void) 259 { 260 idt_setup_from_table(idt_table, early_pf_idts, 261 ARRAY_SIZE(early_pf_idts), true); 262 } 263 #endif 264 265 static void __init idt_map_in_cea(void) 266 { 267 /* 268 * Set the IDT descriptor to a fixed read-only location in the cpu 269 * entry area, so that the "sidt" instruction will not leak the 270 * location of the kernel, and to defend the IDT against arbitrary 271 * memory write vulnerabilities. 272 */ 273 cea_set_pte(CPU_ENTRY_AREA_RO_IDT_VADDR, __pa_symbol(idt_table), 274 PAGE_KERNEL_RO); 275 idt_descr.address = CPU_ENTRY_AREA_RO_IDT; 276 } 277 278 /** 279 * idt_setup_apic_and_irq_gates - Setup APIC/SMP and normal interrupt gates 280 */ 281 void __init idt_setup_apic_and_irq_gates(void) 282 { 283 int i = FIRST_EXTERNAL_VECTOR; 284 void *entry; 285 286 idt_setup_from_table(idt_table, apic_idts, ARRAY_SIZE(apic_idts), true); 287 288 for_each_clear_bit_from(i, system_vectors, FIRST_SYSTEM_VECTOR) { 289 entry = irq_entries_start + IDT_ALIGN * (i - FIRST_EXTERNAL_VECTOR); 290 set_intr_gate(i, entry); 291 } 292 293 #ifdef CONFIG_X86_LOCAL_APIC 294 for_each_clear_bit_from(i, system_vectors, NR_VECTORS) { 295 /* 296 * Don't set the non assigned system vectors in the 297 * system_vectors bitmap. Otherwise they show up in 298 * /proc/interrupts. 299 */ 300 entry = spurious_entries_start + IDT_ALIGN * (i - FIRST_SYSTEM_VECTOR); 301 set_intr_gate(i, entry); 302 } 303 #endif 304 /* Map IDT into CPU entry area and reload it. */ 305 idt_map_in_cea(); 306 load_idt(&idt_descr); 307 308 /* Make the IDT table read only */ 309 set_memory_ro((unsigned long)&idt_table, 1); 310 311 idt_setup_done = true; 312 } 313 314 /** 315 * idt_setup_early_handler - Initializes the idt table with early handlers 316 */ 317 void __init idt_setup_early_handler(void) 318 { 319 int i; 320 321 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) 322 set_intr_gate(i, early_idt_handler_array[i]); 323 #ifdef CONFIG_X86_32 324 for ( ; i < NR_VECTORS; i++) 325 set_intr_gate(i, early_ignore_irq); 326 #endif 327 load_idt(&idt_descr); 328 } 329 330 /** 331 * idt_invalidate - Invalidate interrupt descriptor table 332 */ 333 void idt_invalidate(void) 334 { 335 static const struct desc_ptr idt = { .address = 0, .size = 0 }; 336 337 load_idt(&idt); 338 } 339 340 void __init idt_install_sysvec(unsigned int n, const void *function) 341 { 342 if (WARN_ON(n < FIRST_SYSTEM_VECTOR)) 343 return; 344 345 if (WARN_ON(idt_setup_done)) 346 return; 347 348 if (!WARN_ON(test_and_set_bit(n, system_vectors))) 349 set_intr_gate(n, function); 350 } 351