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(fmt: "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, signr: 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, error_code: 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.l)) {
82 regs->orig_ax = regs->ax;
83 regs->ax = -ENOSYS;
84 do_syscall_64(regs, nr: regs->orig_ax);
85 return;
86 } else if (ia32_enabled() &&
87 likely(regs->fred_ss.vector == FRED_SYSENTER && !regs->fred_ss.l)) {
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 SYSVEC(POSTED_MSI_NOTIFICATION_VECTOR, posted_msi_notification),
122};
123
124static bool fred_setup_done __initdata;
125
126void __init fred_install_sysvec(unsigned int sysvec, idtentry_t handler)
127{
128 if (WARN_ON_ONCE(sysvec < FIRST_SYSTEM_VECTOR))
129 return;
130
131 if (WARN_ON_ONCE(fred_setup_done))
132 return;
133
134 if (!WARN_ON_ONCE(sysvec_table[sysvec - FIRST_SYSTEM_VECTOR]))
135 sysvec_table[sysvec - FIRST_SYSTEM_VECTOR] = handler;
136}
137
138static noinstr void fred_handle_spurious_interrupt(struct pt_regs *regs)
139{
140 spurious_interrupt(regs, error_code: regs->fred_ss.vector);
141}
142
143void __init fred_complete_exception_setup(void)
144{
145 unsigned int vector;
146
147 for (vector = 0; vector < FIRST_EXTERNAL_VECTOR; vector++)
148 set_bit(nr: vector, addr: system_vectors);
149
150 for (vector = 0; vector < NR_SYSTEM_VECTORS; vector++) {
151 if (sysvec_table[vector])
152 set_bit(nr: vector + FIRST_SYSTEM_VECTOR, addr: system_vectors);
153 else
154 sysvec_table[vector] = fred_handle_spurious_interrupt;
155 }
156 fred_setup_done = true;
157}
158
159static noinstr void fred_extint(struct pt_regs *regs)
160{
161 unsigned int vector = regs->fred_ss.vector;
162 unsigned int index = array_index_nospec(vector - FIRST_SYSTEM_VECTOR,
163 NR_SYSTEM_VECTORS);
164
165 if (WARN_ON_ONCE(vector < FIRST_EXTERNAL_VECTOR))
166 return;
167
168 if (likely(vector >= FIRST_SYSTEM_VECTOR)) {
169 irqentry_state_t state = irqentry_enter(regs);
170
171 instrumentation_begin();
172 sysvec_table[index](regs);
173 instrumentation_end();
174 irqentry_exit(regs, state);
175 } else {
176 common_interrupt(regs, error_code: vector);
177 }
178}
179
180static noinstr void fred_hwexc(struct pt_regs *regs, unsigned long error_code)
181{
182 /* Optimize for #PF. That's the only exception which matters performance wise */
183 if (likely(regs->fred_ss.vector == X86_TRAP_PF))
184 return exc_page_fault(regs, error_code);
185
186 switch (regs->fred_ss.vector) {
187 case X86_TRAP_DE: return exc_divide_error(regs);
188 case X86_TRAP_DB: return fred_exc_debug(regs);
189 case X86_TRAP_BR: return exc_bounds(regs);
190 case X86_TRAP_UD: return exc_invalid_op(regs);
191 case X86_TRAP_NM: return exc_device_not_available(regs);
192 case X86_TRAP_DF: return exc_double_fault(regs, error_code);
193 case X86_TRAP_TS: return exc_invalid_tss(regs, error_code);
194 case X86_TRAP_NP: return exc_segment_not_present(regs, error_code);
195 case X86_TRAP_SS: return exc_stack_segment(regs, error_code);
196 case X86_TRAP_GP: return exc_general_protection(regs, error_code);
197 case X86_TRAP_MF: return exc_coprocessor_error(regs);
198 case X86_TRAP_AC: return exc_alignment_check(regs, error_code);
199 case X86_TRAP_XF: return exc_simd_coprocessor_error(regs);
200
201#ifdef CONFIG_X86_MCE
202 case X86_TRAP_MC: return fred_exc_machine_check(regs);
203#endif
204#ifdef CONFIG_INTEL_TDX_GUEST
205 case X86_TRAP_VE: return exc_virtualization_exception(regs);
206#endif
207#ifdef CONFIG_X86_CET
208 case X86_TRAP_CP: return exc_control_protection(regs, error_code);
209#endif
210 default: return fred_bad_type(regs, error_code);
211 }
212
213}
214
215static noinstr void fred_swexc(struct pt_regs *regs, unsigned long error_code)
216{
217 switch (regs->fred_ss.vector) {
218 case X86_TRAP_BP: return exc_int3(regs);
219 case X86_TRAP_OF: return exc_overflow(regs);
220 default: return fred_bad_type(regs, error_code);
221 }
222}
223
224__visible noinstr void fred_entry_from_user(struct pt_regs *regs)
225{
226 unsigned long error_code = regs->orig_ax;
227
228 /* Invalidate orig_ax so that syscall_get_nr() works correctly */
229 regs->orig_ax = -1;
230
231 switch (regs->fred_ss.type) {
232 case EVENT_TYPE_EXTINT:
233 return fred_extint(regs);
234 case EVENT_TYPE_NMI:
235 if (likely(regs->fred_ss.vector == X86_TRAP_NMI))
236 return fred_exc_nmi(regs);
237 break;
238 case EVENT_TYPE_HWEXC:
239 return fred_hwexc(regs, error_code);
240 case EVENT_TYPE_SWINT:
241 return fred_intx(regs);
242 case EVENT_TYPE_PRIV_SWEXC:
243 if (likely(regs->fred_ss.vector == X86_TRAP_DB))
244 return fred_exc_debug(regs);
245 break;
246 case EVENT_TYPE_SWEXC:
247 return fred_swexc(regs, error_code);
248 case EVENT_TYPE_OTHER:
249 return fred_other(regs);
250 default: break;
251 }
252
253 return fred_bad_type(regs, error_code);
254}
255
256__visible noinstr void fred_entry_from_kernel(struct pt_regs *regs)
257{
258 unsigned long error_code = regs->orig_ax;
259
260 /* Invalidate orig_ax so that syscall_get_nr() works correctly */
261 regs->orig_ax = -1;
262
263 switch (regs->fred_ss.type) {
264 case EVENT_TYPE_EXTINT:
265 return fred_extint(regs);
266 case EVENT_TYPE_NMI:
267 if (likely(regs->fred_ss.vector == X86_TRAP_NMI))
268 return fred_exc_nmi(regs);
269 break;
270 case EVENT_TYPE_HWEXC:
271 return fred_hwexc(regs, error_code);
272 case EVENT_TYPE_PRIV_SWEXC:
273 if (likely(regs->fred_ss.vector == X86_TRAP_DB))
274 return fred_exc_debug(regs);
275 break;
276 case EVENT_TYPE_SWEXC:
277 return fred_swexc(regs, error_code);
278 default: break;
279 }
280
281 return fred_bad_type(regs, error_code);
282}
283
284#if IS_ENABLED(CONFIG_KVM_INTEL)
285__visible noinstr void __fred_entry_from_kvm(struct pt_regs *regs)
286{
287 switch (regs->fred_ss.type) {
288 case EVENT_TYPE_EXTINT:
289 return fred_extint(regs);
290 case EVENT_TYPE_NMI:
291 return fred_exc_nmi(regs);
292 default:
293 WARN_ON_ONCE(1);
294 }
295}
296#endif
297

source code of linux/arch/x86/entry/entry_fred.c