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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Regents of the University of California
4 */
5
6#include <linux/cpu.h>
7#include <linux/kernel.h>
8#include <linux/init.h>
9#include <linux/sched.h>
10#include <linux/sched/debug.h>
11#include <linux/sched/signal.h>
12#include <linux/signal.h>
13#include <linux/kdebug.h>
14#include <linux/uaccess.h>
15#include <linux/kprobes.h>
16#include <linux/uprobes.h>
17#include <asm/uprobes.h>
18#include <linux/mm.h>
19#include <linux/module.h>
20#include <linux/irq.h>
21#include <linux/kexec.h>
22#include <linux/entry-common.h>
23
24#include <asm/asm-prototypes.h>
25#include <asm/bug.h>
26#include <asm/cfi.h>
27#include <asm/csr.h>
28#include <asm/processor.h>
29#include <asm/ptrace.h>
30#include <asm/syscall.h>
31#include <asm/thread_info.h>
32#include <asm/vector.h>
33#include <asm/irq_stack.h>
34
35int show_unhandled_signals = 1;
36
37static DEFINE_SPINLOCK(die_lock);
38
39static int copy_code(struct pt_regs *regs, u16 *val, const u16 *insns)
40{
41 const void __user *uaddr = (__force const void __user *)insns;
42
43 if (!user_mode(regs))
44 return get_kernel_nofault(*val, insns);
45
46 /* The user space code from other tasks cannot be accessed. */
47 if (regs != task_pt_regs(current))
48 return -EPERM;
49
50 return copy_from_user_nofault(val, uaddr, sizeof(*val));
51}
52
53static void dump_instr(const char *loglvl, struct pt_regs *regs)
54{
55 char str[sizeof("0000 ") * 12 + 2 + 1], *p = str;
56 const u16 *insns = (u16 *)instruction_pointer(regs);
57 long bad;
58 u16 val;
59 int i;
60
61 for (i = -10; i < 2; i++) {
62 bad = copy_code(regs, &val, &insns[i]);
63 if (!bad) {
64 p += sprintf(p, i == 0 ? "(%04hx) " : "%04hx ", val);
65 } else {
66 printk("%sCode: Unable to access instruction at 0x%px.\n",
67 loglvl, &insns[i]);
68 return;
69 }
70 }
71 printk("%sCode: %s\n", loglvl, str);
72}
73
74void die(struct pt_regs *regs, const char *str)
75{
76 static int die_counter;
77 int ret;
78 long cause;
79 unsigned long flags;
80
81 oops_enter();
82
83 spin_lock_irqsave(&die_lock, flags);
84 console_verbose();
85 bust_spinlocks(1);
86
87 pr_emerg("%s [#%d]\n", str, ++die_counter);
88 print_modules();
89 if (regs) {
90 show_regs(regs);
91 dump_instr(KERN_EMERG, regs);
92 }
93
94 cause = regs ? regs->cause : -1;
95 ret = notify_die(DIE_OOPS, str, regs, 0, cause, SIGSEGV);
96
97 if (kexec_should_crash(current))
98 crash_kexec(regs);
99
100 bust_spinlocks(0);
101 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
102 spin_unlock_irqrestore(&die_lock, flags);
103 oops_exit();
104
105 if (in_interrupt())
106 panic("Fatal exception in interrupt");
107 if (panic_on_oops)
108 panic("Fatal exception");
109 if (ret != NOTIFY_STOP)
110 make_task_dead(SIGSEGV);
111}
112
113void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
114{
115 struct task_struct *tsk = current;
116
117 if (show_unhandled_signals && unhandled_signal(tsk, signo)
118 && printk_ratelimit()) {
119 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
120 tsk->comm, task_pid_nr(tsk), signo, code, addr);
121 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
122 pr_cont("\n");
123 __show_regs(regs);
124 dump_instr(KERN_EMERG, regs);
125 }
126
127 force_sig_fault(signo, code, (void __user *)addr);
128}
129
130static void do_trap_error(struct pt_regs *regs, int signo, int code,
131 unsigned long addr, const char *str)
132{
133 current->thread.bad_cause = regs->cause;
134
135 if (user_mode(regs)) {
136 do_trap(regs, signo, code, addr);
137 } else {
138 if (!fixup_exception(regs))
139 die(regs, str);
140 }
141}
142
143#if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_RISCV_ALTERNATIVE)
144#define __trap_section __noinstr_section(".xip.traps")
145#else
146#define __trap_section noinstr
147#endif
148#define DO_ERROR_INFO(name, signo, code, str) \
149asmlinkage __visible __trap_section void name(struct pt_regs *regs) \
150{ \
151 if (user_mode(regs)) { \
152 irqentry_enter_from_user_mode(regs); \
153 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
154 irqentry_exit_to_user_mode(regs); \
155 } else { \
156 irqentry_state_t state = irqentry_nmi_enter(regs); \
157 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
158 irqentry_nmi_exit(regs, state); \
159 } \
160}
161
162DO_ERROR_INFO(do_trap_unknown,
163 SIGILL, ILL_ILLTRP, "unknown exception");
164DO_ERROR_INFO(do_trap_insn_misaligned,
165 SIGBUS, BUS_ADRALN, "instruction address misaligned");
166DO_ERROR_INFO(do_trap_insn_fault,
167 SIGSEGV, SEGV_ACCERR, "instruction access fault");
168
169asmlinkage __visible __trap_section void do_trap_insn_illegal(struct pt_regs *regs)
170{
171 bool handled;
172
173 if (user_mode(regs)) {
174 irqentry_enter_from_user_mode(regs);
175
176 local_irq_enable();
177
178 handled = riscv_v_first_use_handler(regs);
179
180 local_irq_disable();
181
182 if (!handled)
183 do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->epc,
184 "Oops - illegal instruction");
185
186 irqentry_exit_to_user_mode(regs);
187 } else {
188 irqentry_state_t state = irqentry_nmi_enter(regs);
189
190 do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->epc,
191 "Oops - illegal instruction");
192
193 irqentry_nmi_exit(regs, state);
194 }
195}
196
197DO_ERROR_INFO(do_trap_load_fault,
198 SIGSEGV, SEGV_ACCERR, "load access fault");
199
200asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
201{
202 if (user_mode(regs)) {
203 irqentry_enter_from_user_mode(regs);
204
205 if (handle_misaligned_load(regs))
206 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
207 "Oops - load address misaligned");
208
209 irqentry_exit_to_user_mode(regs);
210 } else {
211 irqentry_state_t state = irqentry_nmi_enter(regs);
212
213 if (handle_misaligned_load(regs))
214 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
215 "Oops - load address misaligned");
216
217 irqentry_nmi_exit(regs, state);
218 }
219}
220
221asmlinkage __visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs)
222{
223 if (user_mode(regs)) {
224 irqentry_enter_from_user_mode(regs);
225
226 if (handle_misaligned_store(regs))
227 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
228 "Oops - store (or AMO) address misaligned");
229
230 irqentry_exit_to_user_mode(regs);
231 } else {
232 irqentry_state_t state = irqentry_nmi_enter(regs);
233
234 if (handle_misaligned_store(regs))
235 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
236 "Oops - store (or AMO) address misaligned");
237
238 irqentry_nmi_exit(regs, state);
239 }
240}
241DO_ERROR_INFO(do_trap_store_fault,
242 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
243DO_ERROR_INFO(do_trap_ecall_s,
244 SIGILL, ILL_ILLTRP, "environment call from S-mode");
245DO_ERROR_INFO(do_trap_ecall_m,
246 SIGILL, ILL_ILLTRP, "environment call from M-mode");
247
248static inline unsigned long get_break_insn_length(unsigned long pc)
249{
250 bug_insn_t insn;
251
252 if (get_kernel_nofault(insn, (bug_insn_t *)pc))
253 return 0;
254
255 return GET_INSN_LENGTH(insn);
256}
257
258static bool probe_single_step_handler(struct pt_regs *regs)
259{
260 bool user = user_mode(regs);
261
262 return user ? uprobe_single_step_handler(regs) : kprobe_single_step_handler(regs);
263}
264
265static bool probe_breakpoint_handler(struct pt_regs *regs)
266{
267 bool user = user_mode(regs);
268
269 return user ? uprobe_breakpoint_handler(regs) : kprobe_breakpoint_handler(regs);
270}
271
272void handle_break(struct pt_regs *regs)
273{
274 if (probe_single_step_handler(regs))
275 return;
276
277 if (probe_breakpoint_handler(regs))
278 return;
279
280 current->thread.bad_cause = regs->cause;
281
282 if (user_mode(regs))
283 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc);
284#ifdef CONFIG_KGDB
285 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP)
286 == NOTIFY_STOP)
287 return;
288#endif
289 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN ||
290 handle_cfi_failure(regs) == BUG_TRAP_TYPE_WARN)
291 regs->epc += get_break_insn_length(regs->epc);
292 else
293 die(regs, "Kernel BUG");
294}
295
296asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
297{
298 if (user_mode(regs)) {
299 irqentry_enter_from_user_mode(regs);
300
301 handle_break(regs);
302
303 irqentry_exit_to_user_mode(regs);
304 } else {
305 irqentry_state_t state = irqentry_nmi_enter(regs);
306
307 handle_break(regs);
308
309 irqentry_nmi_exit(regs, state);
310 }
311}
312
313asmlinkage __visible __trap_section void do_trap_ecall_u(struct pt_regs *regs)
314{
315 if (user_mode(regs)) {
316 long syscall = regs->a7;
317
318 regs->epc += 4;
319 regs->orig_a0 = regs->a0;
320
321 riscv_v_vstate_discard(regs);
322
323 syscall = syscall_enter_from_user_mode(regs, syscall);
324
325 if (syscall >= 0 && syscall < NR_syscalls)
326 syscall_handler(regs, syscall);
327 else if (syscall != -1)
328 regs->a0 = -ENOSYS;
329
330 syscall_exit_to_user_mode(regs);
331 } else {
332 irqentry_state_t state = irqentry_nmi_enter(regs);
333
334 do_trap_error(regs, SIGILL, ILL_ILLTRP, regs->epc,
335 "Oops - environment call from U-mode");
336
337 irqentry_nmi_exit(regs, state);
338 }
339
340}
341
342#ifdef CONFIG_MMU
343asmlinkage __visible noinstr void do_page_fault(struct pt_regs *regs)
344{
345 irqentry_state_t state = irqentry_enter(regs);
346
347 handle_page_fault(regs);
348
349 local_irq_disable();
350
351 irqentry_exit(regs, state);
352}
353#endif
354
355static void noinstr handle_riscv_irq(struct pt_regs *regs)
356{
357 struct pt_regs *old_regs;
358
359 irq_enter_rcu();
360 old_regs = set_irq_regs(regs);
361 handle_arch_irq(regs);
362 set_irq_regs(old_regs);
363 irq_exit_rcu();
364}
365
366asmlinkage void noinstr do_irq(struct pt_regs *regs)
367{
368 irqentry_state_t state = irqentry_enter(regs);
369
370 if (IS_ENABLED(CONFIG_IRQ_STACKS) && on_thread_stack())
371 call_on_irq_stack(regs, handle_riscv_irq);
372 else
373 handle_riscv_irq(regs);
374
375 irqentry_exit(regs, state);
376}
377
378#ifdef CONFIG_GENERIC_BUG
379int is_valid_bugaddr(unsigned long pc)
380{
381 bug_insn_t insn;
382
383 if (pc < VMALLOC_START)
384 return 0;
385 if (get_kernel_nofault(insn, (bug_insn_t *)pc))
386 return 0;
387 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
388 return (insn == __BUG_INSN_32);
389 else
390 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
391}
392#endif /* CONFIG_GENERIC_BUG */
393
394#ifdef CONFIG_VMAP_STACK
395DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)],
396 overflow_stack)__aligned(16);
397
398asmlinkage void handle_bad_stack(struct pt_regs *regs)
399{
400 unsigned long tsk_stk = (unsigned long)current->stack;
401 unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
402
403 console_verbose();
404
405 pr_emerg("Insufficient stack space to handle exception!\n");
406 pr_emerg("Task stack: [0x%016lx..0x%016lx]\n",
407 tsk_stk, tsk_stk + THREAD_SIZE);
408 pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
409 ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
410
411 __show_regs(regs);
412 panic("Kernel stack overflow");
413
414 for (;;)
415 wait_for_interrupt();
416}
417#endif
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Regents of the University of California
4 */
5
6#include <linux/cpu.h>
7#include <linux/kernel.h>
8#include <linux/init.h>
9#include <linux/sched.h>
10#include <linux/sched/debug.h>
11#include <linux/sched/signal.h>
12#include <linux/signal.h>
13#include <linux/kdebug.h>
14#include <linux/uaccess.h>
15#include <linux/kprobes.h>
16#include <linux/mm.h>
17#include <linux/module.h>
18#include <linux/irq.h>
19
20#include <asm/asm-prototypes.h>
21#include <asm/bug.h>
22#include <asm/processor.h>
23#include <asm/ptrace.h>
24#include <asm/csr.h>
25
26int show_unhandled_signals = 1;
27
28static DEFINE_SPINLOCK(die_lock);
29
30void die(struct pt_regs *regs, const char *str)
31{
32 static int die_counter;
33 int ret;
34
35 oops_enter();
36
37 spin_lock_irq(&die_lock);
38 console_verbose();
39 bust_spinlocks(1);
40
41 pr_emerg("%s [#%d]\n", str, ++die_counter);
42 print_modules();
43 show_regs(regs);
44
45 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV);
46
47 bust_spinlocks(0);
48 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
49 spin_unlock_irq(&die_lock);
50 oops_exit();
51
52 if (in_interrupt())
53 panic("Fatal exception in interrupt");
54 if (panic_on_oops)
55 panic("Fatal exception");
56 if (ret != NOTIFY_STOP)
57 do_exit(SIGSEGV);
58}
59
60void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
61{
62 struct task_struct *tsk = current;
63
64 if (show_unhandled_signals && unhandled_signal(tsk, signo)
65 && printk_ratelimit()) {
66 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
67 tsk->comm, task_pid_nr(tsk), signo, code, addr);
68 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
69 pr_cont("\n");
70 __show_regs(regs);
71 }
72
73 force_sig_fault(signo, code, (void __user *)addr);
74}
75
76static void do_trap_error(struct pt_regs *regs, int signo, int code,
77 unsigned long addr, const char *str)
78{
79 current->thread.bad_cause = regs->cause;
80
81 if (user_mode(regs)) {
82 do_trap(regs, signo, code, addr);
83 } else {
84 if (!fixup_exception(regs))
85 die(regs, str);
86 }
87}
88
89#if defined (CONFIG_XIP_KERNEL) && defined (CONFIG_RISCV_ERRATA_ALTERNATIVE)
90#define __trap_section __section(".xip.traps")
91#else
92#define __trap_section
93#endif
94#define DO_ERROR_INFO(name, signo, code, str) \
95asmlinkage __visible __trap_section void name(struct pt_regs *regs) \
96{ \
97 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
98}
99
100DO_ERROR_INFO(do_trap_unknown,
101 SIGILL, ILL_ILLTRP, "unknown exception");
102DO_ERROR_INFO(do_trap_insn_misaligned,
103 SIGBUS, BUS_ADRALN, "instruction address misaligned");
104DO_ERROR_INFO(do_trap_insn_fault,
105 SIGSEGV, SEGV_ACCERR, "instruction access fault");
106DO_ERROR_INFO(do_trap_insn_illegal,
107 SIGILL, ILL_ILLOPC, "illegal instruction");
108DO_ERROR_INFO(do_trap_load_fault,
109 SIGSEGV, SEGV_ACCERR, "load access fault");
110#ifndef CONFIG_RISCV_M_MODE
111DO_ERROR_INFO(do_trap_load_misaligned,
112 SIGBUS, BUS_ADRALN, "Oops - load address misaligned");
113DO_ERROR_INFO(do_trap_store_misaligned,
114 SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned");
115#else
116int handle_misaligned_load(struct pt_regs *regs);
117int handle_misaligned_store(struct pt_regs *regs);
118
119asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs)
120{
121 if (!handle_misaligned_load(regs))
122 return;
123 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
124 "Oops - load address misaligned");
125}
126
127asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs)
128{
129 if (!handle_misaligned_store(regs))
130 return;
131 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
132 "Oops - store (or AMO) address misaligned");
133}
134#endif
135DO_ERROR_INFO(do_trap_store_fault,
136 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
137DO_ERROR_INFO(do_trap_ecall_u,
138 SIGILL, ILL_ILLTRP, "environment call from U-mode");
139DO_ERROR_INFO(do_trap_ecall_s,
140 SIGILL, ILL_ILLTRP, "environment call from S-mode");
141DO_ERROR_INFO(do_trap_ecall_m,
142 SIGILL, ILL_ILLTRP, "environment call from M-mode");
143
144static inline unsigned long get_break_insn_length(unsigned long pc)
145{
146 bug_insn_t insn;
147
148 if (get_kernel_nofault(insn, (bug_insn_t *)pc))
149 return 0;
150
151 return GET_INSN_LENGTH(insn);
152}
153
154asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
155{
156#ifdef CONFIG_KPROBES
157 if (kprobe_single_step_handler(regs))
158 return;
159
160 if (kprobe_breakpoint_handler(regs))
161 return;
162#endif
163#ifdef CONFIG_UPROBES
164 if (uprobe_single_step_handler(regs))
165 return;
166
167 if (uprobe_breakpoint_handler(regs))
168 return;
169#endif
170 current->thread.bad_cause = regs->cause;
171
172 if (user_mode(regs))
173 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc);
174#ifdef CONFIG_KGDB
175 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP)
176 == NOTIFY_STOP)
177 return;
178#endif
179 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN)
180 regs->epc += get_break_insn_length(regs->epc);
181 else
182 die(regs, "Kernel BUG");
183}
184NOKPROBE_SYMBOL(do_trap_break);
185
186#ifdef CONFIG_GENERIC_BUG
187int is_valid_bugaddr(unsigned long pc)
188{
189 bug_insn_t insn;
190
191 if (pc < VMALLOC_START)
192 return 0;
193 if (get_kernel_nofault(insn, (bug_insn_t *)pc))
194 return 0;
195 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
196 return (insn == __BUG_INSN_32);
197 else
198 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
199}
200#endif /* CONFIG_GENERIC_BUG */
201
202/* stvec & scratch is already set from head.S */
203void __init trap_init(void)
204{
205}
206
207#ifdef CONFIG_VMAP_STACK
208static DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)],
209 overflow_stack)__aligned(16);
210/*
211 * shadow stack, handled_ kernel_ stack_ overflow(in kernel/entry.S) is used
212 * to get per-cpu overflow stack(get_overflow_stack).
213 */
214long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE/sizeof(long)];
215asmlinkage unsigned long get_overflow_stack(void)
216{
217 return (unsigned long)this_cpu_ptr(overflow_stack) +
218 OVERFLOW_STACK_SIZE;
219}
220
221asmlinkage void handle_bad_stack(struct pt_regs *regs)
222{
223 unsigned long tsk_stk = (unsigned long)current->stack;
224 unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
225
226 console_verbose();
227
228 pr_emerg("Insufficient stack space to handle exception!\n");
229 pr_emerg("Task stack: [0x%016lx..0x%016lx]\n",
230 tsk_stk, tsk_stk + THREAD_SIZE);
231 pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
232 ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
233
234 __show_regs(regs);
235 panic("Kernel stack overflow");
236
237 for (;;)
238 wait_for_interrupt();
239}
240#endif