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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * The FRED specific kernel/user entry functions which are invoked from
4 * assembly code and dispatch to the associated handlers.
5 */
6#include <linux/kernel.h>
7#include <linux/kdebug.h>
8#include <linux/nospec.h>
9
10#include <asm/desc.h>
11#include <asm/fred.h>
12#include <asm/idtentry.h>
13#include <asm/syscall.h>
14#include <asm/trapnr.h>
15#include <asm/traps.h>
16
17/* FRED EVENT_TYPE_OTHER vector numbers */
18#define FRED_SYSCALL 1
19#define FRED_SYSENTER 2
20
21static noinstr void fred_bad_type(struct pt_regs *regs, unsigned long error_code)
22{
23 irqentry_state_t irq_state = irqentry_nmi_enter(regs);
24
25 instrumentation_begin();
26
27 /* Panic on events from a high stack level */
28 if (regs->fred_cs.sl > 0) {
29 pr_emerg("PANIC: invalid or fatal FRED event; event type %u "
30 "vector %u error 0x%lx aux 0x%lx at %04x:%016lx\n",
31 regs->fred_ss.type, regs->fred_ss.vector, error_code,
32 fred_event_data(regs), regs->cs, regs->ip);
33 die("invalid or fatal FRED event", regs, error_code);
34 panic("invalid or fatal FRED event");
35 } else {
36 unsigned long flags = oops_begin();
37 int sig = SIGKILL;
38
39 pr_alert("BUG: invalid or fatal FRED event; event type %u "
40 "vector %u error 0x%lx aux 0x%lx at %04x:%016lx\n",
41 regs->fred_ss.type, regs->fred_ss.vector, error_code,
42 fred_event_data(regs), regs->cs, regs->ip);
43
44 if (__die("Invalid or fatal FRED event", regs, error_code))
45 sig = 0;
46
47 oops_end(flags, regs, sig);
48 }
49
50 instrumentation_end();
51 irqentry_nmi_exit(regs, irq_state);
52}
53
54static noinstr void fred_intx(struct pt_regs *regs)
55{
56 switch (regs->fred_ss.vector) {
57 /* Opcode 0xcd, 0x3, NOT INT3 (opcode 0xcc) */
58 case X86_TRAP_BP:
59 return exc_int3(regs);
60
61 /* Opcode 0xcd, 0x4, NOT INTO (opcode 0xce) */
62 case X86_TRAP_OF:
63 return exc_overflow(regs);
64
65#ifdef CONFIG_IA32_EMULATION
66 /* INT80 */
67 case IA32_SYSCALL_VECTOR:
68 if (ia32_enabled())
69 return fred_int80_emulation(regs);
70 fallthrough;
71#endif
72
73 default:
74 return exc_general_protection(regs, 0);
75 }
76}
77
78static __always_inline void fred_other(struct pt_regs *regs)
79{
80 /* The compiler can fold these conditions into a single test */
81 if (likely(regs->fred_ss.vector == FRED_SYSCALL && regs->fred_ss.lm)) {
82 regs->orig_ax = regs->ax;
83 regs->ax = -ENOSYS;
84 do_syscall_64(regs, regs->orig_ax);
85 return;
86 } else if (ia32_enabled() &&
87 likely(regs->fred_ss.vector == FRED_SYSENTER && !regs->fred_ss.lm)) {
88 regs->orig_ax = regs->ax;
89 regs->ax = -ENOSYS;
90 do_fast_syscall_32(regs);
91 return;
92 } else {
93 exc_invalid_op(regs);
94 return;
95 }
96}
97
98#define SYSVEC(_vector, _function) [_vector - FIRST_SYSTEM_VECTOR] = fred_sysvec_##_function
99
100static idtentry_t sysvec_table[NR_SYSTEM_VECTORS] __ro_after_init = {
101 SYSVEC(ERROR_APIC_VECTOR, error_interrupt),
102 SYSVEC(SPURIOUS_APIC_VECTOR, spurious_apic_interrupt),
103 SYSVEC(LOCAL_TIMER_VECTOR, apic_timer_interrupt),
104 SYSVEC(X86_PLATFORM_IPI_VECTOR, x86_platform_ipi),
105
106 SYSVEC(RESCHEDULE_VECTOR, reschedule_ipi),
107 SYSVEC(CALL_FUNCTION_SINGLE_VECTOR, call_function_single),
108 SYSVEC(CALL_FUNCTION_VECTOR, call_function),
109 SYSVEC(REBOOT_VECTOR, reboot),
110
111 SYSVEC(THRESHOLD_APIC_VECTOR, threshold),
112 SYSVEC(DEFERRED_ERROR_VECTOR, deferred_error),
113 SYSVEC(THERMAL_APIC_VECTOR, thermal),
114
115 SYSVEC(IRQ_WORK_VECTOR, irq_work),
116
117 SYSVEC(POSTED_INTR_VECTOR, kvm_posted_intr_ipi),
118 SYSVEC(POSTED_INTR_WAKEUP_VECTOR, kvm_posted_intr_wakeup_ipi),
119 SYSVEC(POSTED_INTR_NESTED_VECTOR, kvm_posted_intr_nested_ipi),
120};
121
122static bool fred_setup_done __initdata;
123
124void __init fred_install_sysvec(unsigned int sysvec, idtentry_t handler)
125{
126 if (WARN_ON_ONCE(sysvec < FIRST_SYSTEM_VECTOR))
127 return;
128
129 if (WARN_ON_ONCE(fred_setup_done))
130 return;
131
132 if (!WARN_ON_ONCE(sysvec_table[sysvec - FIRST_SYSTEM_VECTOR]))
133 sysvec_table[sysvec - FIRST_SYSTEM_VECTOR] = handler;
134}
135
136static noinstr void fred_handle_spurious_interrupt(struct pt_regs *regs)
137{
138 spurious_interrupt(regs, regs->fred_ss.vector);
139}
140
141void __init fred_complete_exception_setup(void)
142{
143 unsigned int vector;
144
145 for (vector = 0; vector < FIRST_EXTERNAL_VECTOR; vector++)
146 set_bit(vector, system_vectors);
147
148 for (vector = 0; vector < NR_SYSTEM_VECTORS; vector++) {
149 if (sysvec_table[vector])
150 set_bit(vector + FIRST_SYSTEM_VECTOR, system_vectors);
151 else
152 sysvec_table[vector] = fred_handle_spurious_interrupt;
153 }
154 fred_setup_done = true;
155}
156
157static noinstr void fred_extint(struct pt_regs *regs)
158{
159 unsigned int vector = regs->fred_ss.vector;
160 unsigned int index = array_index_nospec(vector - FIRST_SYSTEM_VECTOR,
161 NR_SYSTEM_VECTORS);
162
163 if (WARN_ON_ONCE(vector < FIRST_EXTERNAL_VECTOR))
164 return;
165
166 if (likely(vector >= FIRST_SYSTEM_VECTOR)) {
167 irqentry_state_t state = irqentry_enter(regs);
168
169 instrumentation_begin();
170 sysvec_table[index](regs);
171 instrumentation_end();
172 irqentry_exit(regs, state);
173 } else {
174 common_interrupt(regs, vector);
175 }
176}
177
178static noinstr void fred_hwexc(struct pt_regs *regs, unsigned long error_code)
179{
180 /* Optimize for #PF. That's the only exception which matters performance wise */
181 if (likely(regs->fred_ss.vector == X86_TRAP_PF))
182 return exc_page_fault(regs, error_code);
183
184 switch (regs->fred_ss.vector) {
185 case X86_TRAP_DE: return exc_divide_error(regs);
186 case X86_TRAP_DB: return fred_exc_debug(regs);
187 case X86_TRAP_BR: return exc_bounds(regs);
188 case X86_TRAP_UD: return exc_invalid_op(regs);
189 case X86_TRAP_NM: return exc_device_not_available(regs);
190 case X86_TRAP_DF: return exc_double_fault(regs, error_code);
191 case X86_TRAP_TS: return exc_invalid_tss(regs, error_code);
192 case X86_TRAP_NP: return exc_segment_not_present(regs, error_code);
193 case X86_TRAP_SS: return exc_stack_segment(regs, error_code);
194 case X86_TRAP_GP: return exc_general_protection(regs, error_code);
195 case X86_TRAP_MF: return exc_coprocessor_error(regs);
196 case X86_TRAP_AC: return exc_alignment_check(regs, error_code);
197 case X86_TRAP_XF: return exc_simd_coprocessor_error(regs);
198
199#ifdef CONFIG_X86_MCE
200 case X86_TRAP_MC: return fred_exc_machine_check(regs);
201#endif
202#ifdef CONFIG_INTEL_TDX_GUEST
203 case X86_TRAP_VE: return exc_virtualization_exception(regs);
204#endif
205#ifdef CONFIG_X86_CET
206 case X86_TRAP_CP: return exc_control_protection(regs, error_code);
207#endif
208 default: return fred_bad_type(regs, error_code);
209 }
210
211}
212
213static noinstr void fred_swexc(struct pt_regs *regs, unsigned long error_code)
214{
215 switch (regs->fred_ss.vector) {
216 case X86_TRAP_BP: return exc_int3(regs);
217 case X86_TRAP_OF: return exc_overflow(regs);
218 default: return fred_bad_type(regs, error_code);
219 }
220}
221
222__visible noinstr void fred_entry_from_user(struct pt_regs *regs)
223{
224 unsigned long error_code = regs->orig_ax;
225
226 /* Invalidate orig_ax so that syscall_get_nr() works correctly */
227 regs->orig_ax = -1;
228
229 switch (regs->fred_ss.type) {
230 case EVENT_TYPE_EXTINT:
231 return fred_extint(regs);
232 case EVENT_TYPE_NMI:
233 if (likely(regs->fred_ss.vector == X86_TRAP_NMI))
234 return fred_exc_nmi(regs);
235 break;
236 case EVENT_TYPE_HWEXC:
237 return fred_hwexc(regs, error_code);
238 case EVENT_TYPE_SWINT:
239 return fred_intx(regs);
240 case EVENT_TYPE_PRIV_SWEXC:
241 if (likely(regs->fred_ss.vector == X86_TRAP_DB))
242 return fred_exc_debug(regs);
243 break;
244 case EVENT_TYPE_SWEXC:
245 return fred_swexc(regs, error_code);
246 case EVENT_TYPE_OTHER:
247 return fred_other(regs);
248 default: break;
249 }
250
251 return fred_bad_type(regs, error_code);
252}
253
254__visible noinstr void fred_entry_from_kernel(struct pt_regs *regs)
255{
256 unsigned long error_code = regs->orig_ax;
257
258 /* Invalidate orig_ax so that syscall_get_nr() works correctly */
259 regs->orig_ax = -1;
260
261 switch (regs->fred_ss.type) {
262 case EVENT_TYPE_EXTINT:
263 return fred_extint(regs);
264 case EVENT_TYPE_NMI:
265 if (likely(regs->fred_ss.vector == X86_TRAP_NMI))
266 return fred_exc_nmi(regs);
267 break;
268 case EVENT_TYPE_HWEXC:
269 return fred_hwexc(regs, error_code);
270 case EVENT_TYPE_PRIV_SWEXC:
271 if (likely(regs->fred_ss.vector == X86_TRAP_DB))
272 return fred_exc_debug(regs);
273 break;
274 case EVENT_TYPE_SWEXC:
275 return fred_swexc(regs, error_code);
276 default: break;
277 }
278
279 return fred_bad_type(regs, error_code);
280}
281
282#if IS_ENABLED(CONFIG_KVM_INTEL)
283__visible noinstr void __fred_entry_from_kvm(struct pt_regs *regs)
284{
285 switch (regs->fred_ss.type) {
286 case EVENT_TYPE_EXTINT:
287 return fred_extint(regs);
288 case EVENT_TYPE_NMI:
289 return fred_exc_nmi(regs);
290 default:
291 WARN_ON_ONCE(1);
292 }
293}
294#endif