1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2010 Tilera Corporation. All Rights Reserved.
4 * Copyright 2015 Regents of the University of California
5 * Copyright 2017 SiFive
6 *
7 * Copied from arch/tile/kernel/ptrace.c
8 */
9
10 #include <asm/ptrace.h>
11 #include <asm/syscall.h>
12 #include <asm/thread_info.h>
13 #include <asm/switch_to.h>
14 #include <linux/audit.h>
15 #include <linux/compat.h>
16 #include <linux/ptrace.h>
17 #include <linux/elf.h>
18 #include <linux/regset.h>
19 #include <linux/sched.h>
20 #include <linux/sched/task_stack.h>
21
22 #define CREATE_TRACE_POINTS
23 #include <trace/events/syscalls.h>
24
25 enum riscv_regset {
26 REGSET_X,
27 #ifdef CONFIG_FPU
28 REGSET_F,
29 #endif
30 };
31
riscv_gpr_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)32 static int riscv_gpr_get(struct task_struct *target,
33 const struct user_regset *regset,
34 struct membuf to)
35 {
36 return membuf_write(&to, task_pt_regs(target),
37 sizeof(struct user_regs_struct));
38 }
39
riscv_gpr_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)40 static int riscv_gpr_set(struct task_struct *target,
41 const struct user_regset *regset,
42 unsigned int pos, unsigned int count,
43 const void *kbuf, const void __user *ubuf)
44 {
45 struct pt_regs *regs;
46
47 regs = task_pt_regs(target);
48 return user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
49 }
50
51 #ifdef CONFIG_FPU
riscv_fpr_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)52 static int riscv_fpr_get(struct task_struct *target,
53 const struct user_regset *regset,
54 struct membuf to)
55 {
56 struct __riscv_d_ext_state *fstate = &target->thread.fstate;
57
58 if (target == current)
59 fstate_save(current, task_pt_regs(current));
60
61 membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
62 membuf_store(&to, fstate->fcsr);
63 return membuf_zero(&to, 4); // explicitly pad
64 }
65
riscv_fpr_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)66 static int riscv_fpr_set(struct task_struct *target,
67 const struct user_regset *regset,
68 unsigned int pos, unsigned int count,
69 const void *kbuf, const void __user *ubuf)
70 {
71 int ret;
72 struct __riscv_d_ext_state *fstate = &target->thread.fstate;
73
74 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
75 offsetof(struct __riscv_d_ext_state, fcsr));
76 if (!ret) {
77 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
78 offsetof(struct __riscv_d_ext_state, fcsr) +
79 sizeof(fstate->fcsr));
80 }
81
82 return ret;
83 }
84 #endif
85
86 static const struct user_regset riscv_user_regset[] = {
87 [REGSET_X] = {
88 .core_note_type = NT_PRSTATUS,
89 .n = ELF_NGREG,
90 .size = sizeof(elf_greg_t),
91 .align = sizeof(elf_greg_t),
92 .regset_get = riscv_gpr_get,
93 .set = riscv_gpr_set,
94 },
95 #ifdef CONFIG_FPU
96 [REGSET_F] = {
97 .core_note_type = NT_PRFPREG,
98 .n = ELF_NFPREG,
99 .size = sizeof(elf_fpreg_t),
100 .align = sizeof(elf_fpreg_t),
101 .regset_get = riscv_fpr_get,
102 .set = riscv_fpr_set,
103 },
104 #endif
105 };
106
107 static const struct user_regset_view riscv_user_native_view = {
108 .name = "riscv",
109 .e_machine = EM_RISCV,
110 .regsets = riscv_user_regset,
111 .n = ARRAY_SIZE(riscv_user_regset),
112 };
113
114 struct pt_regs_offset {
115 const char *name;
116 int offset;
117 };
118
119 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
120 #define REG_OFFSET_END {.name = NULL, .offset = 0}
121
122 static const struct pt_regs_offset regoffset_table[] = {
123 REG_OFFSET_NAME(epc),
124 REG_OFFSET_NAME(ra),
125 REG_OFFSET_NAME(sp),
126 REG_OFFSET_NAME(gp),
127 REG_OFFSET_NAME(tp),
128 REG_OFFSET_NAME(t0),
129 REG_OFFSET_NAME(t1),
130 REG_OFFSET_NAME(t2),
131 REG_OFFSET_NAME(s0),
132 REG_OFFSET_NAME(s1),
133 REG_OFFSET_NAME(a0),
134 REG_OFFSET_NAME(a1),
135 REG_OFFSET_NAME(a2),
136 REG_OFFSET_NAME(a3),
137 REG_OFFSET_NAME(a4),
138 REG_OFFSET_NAME(a5),
139 REG_OFFSET_NAME(a6),
140 REG_OFFSET_NAME(a7),
141 REG_OFFSET_NAME(s2),
142 REG_OFFSET_NAME(s3),
143 REG_OFFSET_NAME(s4),
144 REG_OFFSET_NAME(s5),
145 REG_OFFSET_NAME(s6),
146 REG_OFFSET_NAME(s7),
147 REG_OFFSET_NAME(s8),
148 REG_OFFSET_NAME(s9),
149 REG_OFFSET_NAME(s10),
150 REG_OFFSET_NAME(s11),
151 REG_OFFSET_NAME(t3),
152 REG_OFFSET_NAME(t4),
153 REG_OFFSET_NAME(t5),
154 REG_OFFSET_NAME(t6),
155 REG_OFFSET_NAME(status),
156 REG_OFFSET_NAME(badaddr),
157 REG_OFFSET_NAME(cause),
158 REG_OFFSET_NAME(orig_a0),
159 REG_OFFSET_END,
160 };
161
162 /**
163 * regs_query_register_offset() - query register offset from its name
164 * @name: the name of a register
165 *
166 * regs_query_register_offset() returns the offset of a register in struct
167 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
168 */
regs_query_register_offset(const char * name)169 int regs_query_register_offset(const char *name)
170 {
171 const struct pt_regs_offset *roff;
172
173 for (roff = regoffset_table; roff->name != NULL; roff++)
174 if (!strcmp(roff->name, name))
175 return roff->offset;
176 return -EINVAL;
177 }
178
179 /**
180 * regs_within_kernel_stack() - check the address in the stack
181 * @regs: pt_regs which contains kernel stack pointer.
182 * @addr: address which is checked.
183 *
184 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
185 * If @addr is within the kernel stack, it returns true. If not, returns false.
186 */
regs_within_kernel_stack(struct pt_regs * regs,unsigned long addr)187 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
188 {
189 return (addr & ~(THREAD_SIZE - 1)) ==
190 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
191 }
192
193 /**
194 * regs_get_kernel_stack_nth() - get Nth entry of the stack
195 * @regs: pt_regs which contains kernel stack pointer.
196 * @n: stack entry number.
197 *
198 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
199 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
200 * this returns 0.
201 */
regs_get_kernel_stack_nth(struct pt_regs * regs,unsigned int n)202 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
203 {
204 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
205
206 addr += n;
207 if (regs_within_kernel_stack(regs, (unsigned long)addr))
208 return *addr;
209 else
210 return 0;
211 }
212
ptrace_disable(struct task_struct * child)213 void ptrace_disable(struct task_struct *child)
214 {
215 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
216 }
217
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)218 long arch_ptrace(struct task_struct *child, long request,
219 unsigned long addr, unsigned long data)
220 {
221 long ret = -EIO;
222
223 switch (request) {
224 default:
225 ret = ptrace_request(child, request, addr, data);
226 break;
227 }
228
229 return ret;
230 }
231
232 /*
233 * Allows PTRACE_SYSCALL to work. These are called from entry.S in
234 * {handle,ret_from}_syscall.
235 */
do_syscall_trace_enter(struct pt_regs * regs)236 __visible int do_syscall_trace_enter(struct pt_regs *regs)
237 {
238 if (test_thread_flag(TIF_SYSCALL_TRACE))
239 if (ptrace_report_syscall_entry(regs))
240 return -1;
241
242 /*
243 * Do the secure computing after ptrace; failures should be fast.
244 * If this fails we might have return value in a0 from seccomp
245 * (via SECCOMP_RET_ERRNO/TRACE).
246 */
247 if (secure_computing() == -1)
248 return -1;
249
250 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
251 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
252 trace_sys_enter(regs, syscall_get_nr(current, regs));
253 #endif
254
255 audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
256 return 0;
257 }
258
do_syscall_trace_exit(struct pt_regs * regs)259 __visible void do_syscall_trace_exit(struct pt_regs *regs)
260 {
261 audit_syscall_exit(regs);
262
263 if (test_thread_flag(TIF_SYSCALL_TRACE))
264 ptrace_report_syscall_exit(regs, 0);
265
266 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
267 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
268 trace_sys_exit(regs, regs_return_value(regs));
269 #endif
270 }
271
272 #ifdef CONFIG_COMPAT
compat_riscv_gpr_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)273 static int compat_riscv_gpr_get(struct task_struct *target,
274 const struct user_regset *regset,
275 struct membuf to)
276 {
277 struct compat_user_regs_struct cregs;
278
279 regs_to_cregs(&cregs, task_pt_regs(target));
280
281 return membuf_write(&to, &cregs,
282 sizeof(struct compat_user_regs_struct));
283 }
284
compat_riscv_gpr_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)285 static int compat_riscv_gpr_set(struct task_struct *target,
286 const struct user_regset *regset,
287 unsigned int pos, unsigned int count,
288 const void *kbuf, const void __user *ubuf)
289 {
290 int ret;
291 struct compat_user_regs_struct cregs;
292
293 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &cregs, 0, -1);
294
295 cregs_to_regs(&cregs, task_pt_regs(target));
296
297 return ret;
298 }
299
300 static const struct user_regset compat_riscv_user_regset[] = {
301 [REGSET_X] = {
302 .core_note_type = NT_PRSTATUS,
303 .n = ELF_NGREG,
304 .size = sizeof(compat_elf_greg_t),
305 .align = sizeof(compat_elf_greg_t),
306 .regset_get = compat_riscv_gpr_get,
307 .set = compat_riscv_gpr_set,
308 },
309 #ifdef CONFIG_FPU
310 [REGSET_F] = {
311 .core_note_type = NT_PRFPREG,
312 .n = ELF_NFPREG,
313 .size = sizeof(elf_fpreg_t),
314 .align = sizeof(elf_fpreg_t),
315 .regset_get = riscv_fpr_get,
316 .set = riscv_fpr_set,
317 },
318 #endif
319 };
320
321 static const struct user_regset_view compat_riscv_user_native_view = {
322 .name = "riscv",
323 .e_machine = EM_RISCV,
324 .regsets = compat_riscv_user_regset,
325 .n = ARRAY_SIZE(compat_riscv_user_regset),
326 };
327
compat_arch_ptrace(struct task_struct * child,compat_long_t request,compat_ulong_t caddr,compat_ulong_t cdata)328 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
329 compat_ulong_t caddr, compat_ulong_t cdata)
330 {
331 long ret = -EIO;
332
333 switch (request) {
334 default:
335 ret = compat_ptrace_request(child, request, caddr, cdata);
336 break;
337 }
338
339 return ret;
340 }
341 #endif /* CONFIG_COMPAT */
342
task_user_regset_view(struct task_struct * task)343 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
344 {
345 #ifdef CONFIG_COMPAT
346 if (test_tsk_thread_flag(task, TIF_32BIT))
347 return &compat_riscv_user_native_view;
348 else
349 #endif
350 return &riscv_user_native_view;
351 }
352
