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/ptrace.h>
16 #include <linux/elf.h>
17 #include <linux/regset.h>
18 #include <linux/sched.h>
19 #include <linux/sched/task_stack.h>
20 #include <linux/tracehook.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 int ret;
46 struct pt_regs *regs;
47
48 regs = task_pt_regs(target);
49 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
50 return ret;
51 }
52
53 #ifdef CONFIG_FPU
riscv_fpr_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)54 static int riscv_fpr_get(struct task_struct *target,
55 const struct user_regset *regset,
56 struct membuf to)
57 {
58 struct __riscv_d_ext_state *fstate = &target->thread.fstate;
59
60 if (target == current)
61 fstate_save(current, task_pt_regs(current));
62
63 membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
64 membuf_store(&to, fstate->fcsr);
65 return membuf_zero(&to, 4); // explicitly pad
66 }
67
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)68 static int riscv_fpr_set(struct task_struct *target,
69 const struct user_regset *regset,
70 unsigned int pos, unsigned int count,
71 const void *kbuf, const void __user *ubuf)
72 {
73 int ret;
74 struct __riscv_d_ext_state *fstate = &target->thread.fstate;
75
76 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
77 offsetof(struct __riscv_d_ext_state, fcsr));
78 if (!ret) {
79 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
80 offsetof(struct __riscv_d_ext_state, fcsr) +
81 sizeof(fstate->fcsr));
82 }
83
84 return ret;
85 }
86 #endif
87
88 static const struct user_regset riscv_user_regset[] = {
89 [REGSET_X] = {
90 .core_note_type = NT_PRSTATUS,
91 .n = ELF_NGREG,
92 .size = sizeof(elf_greg_t),
93 .align = sizeof(elf_greg_t),
94 .regset_get = riscv_gpr_get,
95 .set = riscv_gpr_set,
96 },
97 #ifdef CONFIG_FPU
98 [REGSET_F] = {
99 .core_note_type = NT_PRFPREG,
100 .n = ELF_NFPREG,
101 .size = sizeof(elf_fpreg_t),
102 .align = sizeof(elf_fpreg_t),
103 .regset_get = riscv_fpr_get,
104 .set = riscv_fpr_set,
105 },
106 #endif
107 };
108
109 static const struct user_regset_view riscv_user_native_view = {
110 .name = "riscv",
111 .e_machine = EM_RISCV,
112 .regsets = riscv_user_regset,
113 .n = ARRAY_SIZE(riscv_user_regset),
114 };
115
task_user_regset_view(struct task_struct * task)116 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
117 {
118 return &riscv_user_native_view;
119 }
120
121 struct pt_regs_offset {
122 const char *name;
123 int offset;
124 };
125
126 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
127 #define REG_OFFSET_END {.name = NULL, .offset = 0}
128
129 static const struct pt_regs_offset regoffset_table[] = {
130 REG_OFFSET_NAME(epc),
131 REG_OFFSET_NAME(ra),
132 REG_OFFSET_NAME(sp),
133 REG_OFFSET_NAME(gp),
134 REG_OFFSET_NAME(tp),
135 REG_OFFSET_NAME(t0),
136 REG_OFFSET_NAME(t1),
137 REG_OFFSET_NAME(t2),
138 REG_OFFSET_NAME(s0),
139 REG_OFFSET_NAME(s1),
140 REG_OFFSET_NAME(a0),
141 REG_OFFSET_NAME(a1),
142 REG_OFFSET_NAME(a2),
143 REG_OFFSET_NAME(a3),
144 REG_OFFSET_NAME(a4),
145 REG_OFFSET_NAME(a5),
146 REG_OFFSET_NAME(a6),
147 REG_OFFSET_NAME(a7),
148 REG_OFFSET_NAME(s2),
149 REG_OFFSET_NAME(s3),
150 REG_OFFSET_NAME(s4),
151 REG_OFFSET_NAME(s5),
152 REG_OFFSET_NAME(s6),
153 REG_OFFSET_NAME(s7),
154 REG_OFFSET_NAME(s8),
155 REG_OFFSET_NAME(s9),
156 REG_OFFSET_NAME(s10),
157 REG_OFFSET_NAME(s11),
158 REG_OFFSET_NAME(t3),
159 REG_OFFSET_NAME(t4),
160 REG_OFFSET_NAME(t5),
161 REG_OFFSET_NAME(t6),
162 REG_OFFSET_NAME(status),
163 REG_OFFSET_NAME(badaddr),
164 REG_OFFSET_NAME(cause),
165 REG_OFFSET_NAME(orig_a0),
166 REG_OFFSET_END,
167 };
168
169 /**
170 * regs_query_register_offset() - query register offset from its name
171 * @name: the name of a register
172 *
173 * regs_query_register_offset() returns the offset of a register in struct
174 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
175 */
regs_query_register_offset(const char * name)176 int regs_query_register_offset(const char *name)
177 {
178 const struct pt_regs_offset *roff;
179
180 for (roff = regoffset_table; roff->name != NULL; roff++)
181 if (!strcmp(roff->name, name))
182 return roff->offset;
183 return -EINVAL;
184 }
185
186 /**
187 * regs_within_kernel_stack() - check the address in the stack
188 * @regs: pt_regs which contains kernel stack pointer.
189 * @addr: address which is checked.
190 *
191 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
192 * If @addr is within the kernel stack, it returns true. If not, returns false.
193 */
regs_within_kernel_stack(struct pt_regs * regs,unsigned long addr)194 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
195 {
196 return (addr & ~(THREAD_SIZE - 1)) ==
197 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
198 }
199
200 /**
201 * regs_get_kernel_stack_nth() - get Nth entry of the stack
202 * @regs: pt_regs which contains kernel stack pointer.
203 * @n: stack entry number.
204 *
205 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
206 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
207 * this returns 0.
208 */
regs_get_kernel_stack_nth(struct pt_regs * regs,unsigned int n)209 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
210 {
211 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
212
213 addr += n;
214 if (regs_within_kernel_stack(regs, (unsigned long)addr))
215 return *addr;
216 else
217 return 0;
218 }
219
ptrace_disable(struct task_struct * child)220 void ptrace_disable(struct task_struct *child)
221 {
222 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
223 }
224
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)225 long arch_ptrace(struct task_struct *child, long request,
226 unsigned long addr, unsigned long data)
227 {
228 long ret = -EIO;
229
230 switch (request) {
231 default:
232 ret = ptrace_request(child, request, addr, data);
233 break;
234 }
235
236 return ret;
237 }
238
239 /*
240 * Allows PTRACE_SYSCALL to work. These are called from entry.S in
241 * {handle,ret_from}_syscall.
242 */
do_syscall_trace_enter(struct pt_regs * regs)243 __visible int do_syscall_trace_enter(struct pt_regs *regs)
244 {
245 if (test_thread_flag(TIF_SYSCALL_TRACE))
246 if (tracehook_report_syscall_entry(regs))
247 return -1;
248
249 /*
250 * Do the secure computing after ptrace; failures should be fast.
251 * If this fails we might have return value in a0 from seccomp
252 * (via SECCOMP_RET_ERRNO/TRACE).
253 */
254 if (secure_computing() == -1)
255 return -1;
256
257 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
258 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
259 trace_sys_enter(regs, syscall_get_nr(current, regs));
260 #endif
261
262 audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
263 return 0;
264 }
265
do_syscall_trace_exit(struct pt_regs * regs)266 __visible void do_syscall_trace_exit(struct pt_regs *regs)
267 {
268 audit_syscall_exit(regs);
269
270 if (test_thread_flag(TIF_SYSCALL_TRACE))
271 tracehook_report_syscall_exit(regs, 0);
272
273 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
274 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
275 trace_sys_exit(regs, regs_return_value(regs));
276 #endif
277 }
278