1
2
3#include <linux/kprobes.h>
4#include <linux/extable.h>
5#include <linux/slab.h>
6#include <linux/stop_machine.h>
7#include <asm/ptrace.h>
8#include <linux/uaccess.h>
9#include <asm/sections.h>
10#include <asm/cacheflush.h>
11#include <asm/bug.h>
12#include <asm/patch.h>
13
14#include "decode-insn.h"
15
16DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
17DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
18
19static void __kprobes
20post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
21
22static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
23{
24 unsigned long offset = GET_INSN_LENGTH(p->opcode);
25
26 p->ainsn.api.restore = (unsigned long)p->addr + offset;
27
28 patch_text(p->ainsn.api.insn, p->opcode);
29 patch_text((void *)((unsigned long)(p->ainsn.api.insn) + offset),
30 __BUG_INSN_32);
31}
32
33static void __kprobes arch_prepare_simulate(struct kprobe *p)
34{
35 p->ainsn.api.restore = 0;
36}
37
38static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
39{
40 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
41
42 if (p->ainsn.api.handler)
43 p->ainsn.api.handler((u32)p->opcode,
44 (unsigned long)p->addr, regs);
45
46 post_kprobe_handler(p, kcb, regs);
47}
48
49int __kprobes arch_prepare_kprobe(struct kprobe *p)
50{
51 unsigned long probe_addr = (unsigned long)p->addr;
52
53 if (probe_addr & 0x1) {
54 pr_warn("Address not aligned.\n");
55
56 return -EINVAL;
57 }
58
59
60 p->opcode = *p->addr;
61
62
63 switch (riscv_probe_decode_insn(p->addr, &p->ainsn.api)) {
64 case INSN_REJECTED:
65 return -EINVAL;
66
67 case INSN_GOOD_NO_SLOT:
68 p->ainsn.api.insn = NULL;
69 break;
70
71 case INSN_GOOD:
72 p->ainsn.api.insn = get_insn_slot();
73 if (!p->ainsn.api.insn)
74 return -ENOMEM;
75 break;
76 }
77
78
79 if (p->ainsn.api.insn)
80 arch_prepare_ss_slot(p);
81 else
82 arch_prepare_simulate(p);
83
84 return 0;
85}
86
87#ifdef CONFIG_MMU
88void *alloc_insn_page(void)
89{
90 return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
91 GFP_KERNEL, PAGE_KERNEL_READ_EXEC,
92 VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
93 __builtin_return_address(0));
94}
95#endif
96
97
98void __kprobes arch_arm_kprobe(struct kprobe *p)
99{
100 if ((p->opcode & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
101 patch_text(p->addr, __BUG_INSN_32);
102 else
103 patch_text(p->addr, __BUG_INSN_16);
104}
105
106
107void __kprobes arch_disarm_kprobe(struct kprobe *p)
108{
109 patch_text(p->addr, p->opcode);
110}
111
112void __kprobes arch_remove_kprobe(struct kprobe *p)
113{
114}
115
116static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
117{
118 kcb->prev_kprobe.kp = kprobe_running();
119 kcb->prev_kprobe.status = kcb->kprobe_status;
120}
121
122static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
123{
124 __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
125 kcb->kprobe_status = kcb->prev_kprobe.status;
126}
127
128static void __kprobes set_current_kprobe(struct kprobe *p)
129{
130 __this_cpu_write(current_kprobe, p);
131}
132
133
134
135
136
137
138
139
140
141static void __kprobes kprobes_save_local_irqflag(struct kprobe_ctlblk *kcb,
142 struct pt_regs *regs)
143{
144 kcb->saved_status = regs->status;
145 regs->status &= ~SR_SPIE;
146}
147
148static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb,
149 struct pt_regs *regs)
150{
151 regs->status = kcb->saved_status;
152}
153
154static void __kprobes setup_singlestep(struct kprobe *p,
155 struct pt_regs *regs,
156 struct kprobe_ctlblk *kcb, int reenter)
157{
158 unsigned long slot;
159
160 if (reenter) {
161 save_previous_kprobe(kcb);
162 set_current_kprobe(p);
163 kcb->kprobe_status = KPROBE_REENTER;
164 } else {
165 kcb->kprobe_status = KPROBE_HIT_SS;
166 }
167
168 if (p->ainsn.api.insn) {
169
170 slot = (unsigned long)p->ainsn.api.insn;
171
172
173 kprobes_save_local_irqflag(kcb, regs);
174
175 instruction_pointer_set(regs, slot);
176 } else {
177
178 arch_simulate_insn(p, regs);
179 }
180}
181
182static int __kprobes reenter_kprobe(struct kprobe *p,
183 struct pt_regs *regs,
184 struct kprobe_ctlblk *kcb)
185{
186 switch (kcb->kprobe_status) {
187 case KPROBE_HIT_SSDONE:
188 case KPROBE_HIT_ACTIVE:
189 kprobes_inc_nmissed_count(p);
190 setup_singlestep(p, regs, kcb, 1);
191 break;
192 case KPROBE_HIT_SS:
193 case KPROBE_REENTER:
194 pr_warn("Unrecoverable kprobe detected.\n");
195 dump_kprobe(p);
196 BUG();
197 break;
198 default:
199 WARN_ON(1);
200 return 0;
201 }
202
203 return 1;
204}
205
206static void __kprobes
207post_kprobe_handler(struct kprobe *cur, struct kprobe_ctlblk *kcb, struct pt_regs *regs)
208{
209
210 if (cur->ainsn.api.restore != 0)
211 regs->epc = cur->ainsn.api.restore;
212
213
214 if (kcb->kprobe_status == KPROBE_REENTER) {
215 restore_previous_kprobe(kcb);
216 return;
217 }
218
219
220 kcb->kprobe_status = KPROBE_HIT_SSDONE;
221 if (cur->post_handler) {
222
223
224
225 cur->post_handler(cur, regs, 0);
226 }
227
228 reset_current_kprobe();
229}
230
231int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr)
232{
233 struct kprobe *cur = kprobe_running();
234 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
235
236 switch (kcb->kprobe_status) {
237 case KPROBE_HIT_SS:
238 case KPROBE_REENTER:
239
240
241
242
243
244
245
246 regs->epc = (unsigned long) cur->addr;
247 BUG_ON(!instruction_pointer(regs));
248
249 if (kcb->kprobe_status == KPROBE_REENTER)
250 restore_previous_kprobe(kcb);
251 else {
252 kprobes_restore_local_irqflag(kcb, regs);
253 reset_current_kprobe();
254 }
255
256 break;
257 case KPROBE_HIT_ACTIVE:
258 case KPROBE_HIT_SSDONE:
259
260
261
262
263 if (fixup_exception(regs))
264 return 1;
265 }
266 return 0;
267}
268
269bool __kprobes
270kprobe_breakpoint_handler(struct pt_regs *regs)
271{
272 struct kprobe *p, *cur_kprobe;
273 struct kprobe_ctlblk *kcb;
274 unsigned long addr = instruction_pointer(regs);
275
276 kcb = get_kprobe_ctlblk();
277 cur_kprobe = kprobe_running();
278
279 p = get_kprobe((kprobe_opcode_t *) addr);
280
281 if (p) {
282 if (cur_kprobe) {
283 if (reenter_kprobe(p, regs, kcb))
284 return true;
285 } else {
286
287 set_current_kprobe(p);
288 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
289
290
291
292
293
294
295
296
297
298
299
300 if (!p->pre_handler || !p->pre_handler(p, regs))
301 setup_singlestep(p, regs, kcb, 0);
302 else
303 reset_current_kprobe();
304 }
305 return true;
306 }
307
308
309
310
311
312
313
314
315
316 return false;
317}
318
319bool __kprobes
320kprobe_single_step_handler(struct pt_regs *regs)
321{
322 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
323 unsigned long addr = instruction_pointer(regs);
324 struct kprobe *cur = kprobe_running();
325
326 if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) &&
327 ((unsigned long)&cur->ainsn.api.insn[0] + GET_INSN_LENGTH(cur->opcode) == addr)) {
328 kprobes_restore_local_irqflag(kcb, regs);
329 post_kprobe_handler(cur, kcb, regs);
330 return true;
331 }
332
333 return false;
334}
335
336
337
338
339
340int __init arch_populate_kprobe_blacklist(void)
341{
342 int ret;
343
344 ret = kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
345 (unsigned long)__irqentry_text_end);
346 return ret;
347}
348
349void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
350{
351 return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
352}
353
354void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
355 struct pt_regs *regs)
356{
357 ri->ret_addr = (kprobe_opcode_t *)regs->ra;
358 ri->fp = NULL;
359 regs->ra = (unsigned long) &kretprobe_trampoline;
360}
361
362int __kprobes arch_trampoline_kprobe(struct kprobe *p)
363{
364 return 0;
365}
366
367int __init arch_init_kprobes(void)
368{
369 return 0;
370}
371