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 <linux/audit.h> 14 #include <linux/ptrace.h> 15 #include <linux/elf.h> 16 #include <linux/regset.h> 17 #include <linux/sched.h> 18 #include <linux/sched/task_stack.h> 19 #include <linux/tracehook.h> 20 21 #define CREATE_TRACE_POINTS 22 #include <trace/events/syscalls.h> 23 24 enum riscv_regset { 25 REGSET_X, 26 #ifdef CONFIG_FPU 27 REGSET_F, 28 #endif 29 }; 30 31 static int riscv_gpr_get(struct task_struct *target, 32 const struct user_regset *regset, 33 struct membuf to) 34 { 35 return membuf_write(&to, task_pt_regs(target), 36 sizeof(struct user_regs_struct)); 37 } 38 39 static int riscv_gpr_set(struct task_struct *target, 40 const struct user_regset *regset, 41 unsigned int pos, unsigned int count, 42 const void *kbuf, const void __user *ubuf) 43 { 44 int ret; 45 struct pt_regs *regs; 46 47 regs = task_pt_regs(target); 48 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1); 49 return ret; 50 } 51 52 #ifdef CONFIG_FPU 53 static int riscv_fpr_get(struct task_struct *target, 54 const struct user_regset *regset, 55 struct membuf to) 56 { 57 struct __riscv_d_ext_state *fstate = &target->thread.fstate; 58 59 membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr)); 60 membuf_store(&to, fstate->fcsr); 61 return membuf_zero(&to, 4); // explicitly pad 62 } 63 64 static int riscv_fpr_set(struct task_struct *target, 65 const struct user_regset *regset, 66 unsigned int pos, unsigned int count, 67 const void *kbuf, const void __user *ubuf) 68 { 69 int ret; 70 struct __riscv_d_ext_state *fstate = &target->thread.fstate; 71 72 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0, 73 offsetof(struct __riscv_d_ext_state, fcsr)); 74 if (!ret) { 75 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0, 76 offsetof(struct __riscv_d_ext_state, fcsr) + 77 sizeof(fstate->fcsr)); 78 } 79 80 return ret; 81 } 82 #endif 83 84 static const struct user_regset riscv_user_regset[] = { 85 [REGSET_X] = { 86 .core_note_type = NT_PRSTATUS, 87 .n = ELF_NGREG, 88 .size = sizeof(elf_greg_t), 89 .align = sizeof(elf_greg_t), 90 .regset_get = riscv_gpr_get, 91 .set = riscv_gpr_set, 92 }, 93 #ifdef CONFIG_FPU 94 [REGSET_F] = { 95 .core_note_type = NT_PRFPREG, 96 .n = ELF_NFPREG, 97 .size = sizeof(elf_fpreg_t), 98 .align = sizeof(elf_fpreg_t), 99 .regset_get = riscv_fpr_get, 100 .set = riscv_fpr_set, 101 }, 102 #endif 103 }; 104 105 static const struct user_regset_view riscv_user_native_view = { 106 .name = "riscv", 107 .e_machine = EM_RISCV, 108 .regsets = riscv_user_regset, 109 .n = ARRAY_SIZE(riscv_user_regset), 110 }; 111 112 const struct user_regset_view *task_user_regset_view(struct task_struct *task) 113 { 114 return &riscv_user_native_view; 115 } 116 117 struct pt_regs_offset { 118 const char *name; 119 int offset; 120 }; 121 122 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)} 123 #define REG_OFFSET_END {.name = NULL, .offset = 0} 124 125 static const struct pt_regs_offset regoffset_table[] = { 126 REG_OFFSET_NAME(epc), 127 REG_OFFSET_NAME(ra), 128 REG_OFFSET_NAME(sp), 129 REG_OFFSET_NAME(gp), 130 REG_OFFSET_NAME(tp), 131 REG_OFFSET_NAME(t0), 132 REG_OFFSET_NAME(t1), 133 REG_OFFSET_NAME(t2), 134 REG_OFFSET_NAME(s0), 135 REG_OFFSET_NAME(s1), 136 REG_OFFSET_NAME(a0), 137 REG_OFFSET_NAME(a1), 138 REG_OFFSET_NAME(a2), 139 REG_OFFSET_NAME(a3), 140 REG_OFFSET_NAME(a4), 141 REG_OFFSET_NAME(a5), 142 REG_OFFSET_NAME(a6), 143 REG_OFFSET_NAME(a7), 144 REG_OFFSET_NAME(s2), 145 REG_OFFSET_NAME(s3), 146 REG_OFFSET_NAME(s4), 147 REG_OFFSET_NAME(s5), 148 REG_OFFSET_NAME(s6), 149 REG_OFFSET_NAME(s7), 150 REG_OFFSET_NAME(s8), 151 REG_OFFSET_NAME(s9), 152 REG_OFFSET_NAME(s10), 153 REG_OFFSET_NAME(s11), 154 REG_OFFSET_NAME(t3), 155 REG_OFFSET_NAME(t4), 156 REG_OFFSET_NAME(t5), 157 REG_OFFSET_NAME(t6), 158 REG_OFFSET_NAME(status), 159 REG_OFFSET_NAME(badaddr), 160 REG_OFFSET_NAME(cause), 161 REG_OFFSET_NAME(orig_a0), 162 REG_OFFSET_END, 163 }; 164 165 /** 166 * regs_query_register_offset() - query register offset from its name 167 * @name: the name of a register 168 * 169 * regs_query_register_offset() returns the offset of a register in struct 170 * pt_regs from its name. If the name is invalid, this returns -EINVAL; 171 */ 172 int regs_query_register_offset(const char *name) 173 { 174 const struct pt_regs_offset *roff; 175 176 for (roff = regoffset_table; roff->name != NULL; roff++) 177 if (!strcmp(roff->name, name)) 178 return roff->offset; 179 return -EINVAL; 180 } 181 182 /** 183 * regs_within_kernel_stack() - check the address in the stack 184 * @regs: pt_regs which contains kernel stack pointer. 185 * @addr: address which is checked. 186 * 187 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 188 * If @addr is within the kernel stack, it returns true. If not, returns false. 189 */ 190 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr) 191 { 192 return (addr & ~(THREAD_SIZE - 1)) == 193 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)); 194 } 195 196 /** 197 * regs_get_kernel_stack_nth() - get Nth entry of the stack 198 * @regs: pt_regs which contains kernel stack pointer. 199 * @n: stack entry number. 200 * 201 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 202 * is specified by @regs. If the @n th entry is NOT in the kernel stack, 203 * this returns 0. 204 */ 205 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n) 206 { 207 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs); 208 209 addr += n; 210 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 211 return *addr; 212 else 213 return 0; 214 } 215 216 void ptrace_disable(struct task_struct *child) 217 { 218 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 219 } 220 221 long arch_ptrace(struct task_struct *child, long request, 222 unsigned long addr, unsigned long data) 223 { 224 long ret = -EIO; 225 226 switch (request) { 227 default: 228 ret = ptrace_request(child, request, addr, data); 229 break; 230 } 231 232 return ret; 233 } 234 235 /* 236 * Allows PTRACE_SYSCALL to work. These are called from entry.S in 237 * {handle,ret_from}_syscall. 238 */ 239 __visible int do_syscall_trace_enter(struct pt_regs *regs) 240 { 241 if (test_thread_flag(TIF_SYSCALL_TRACE)) 242 if (tracehook_report_syscall_entry(regs)) 243 return -1; 244 245 /* 246 * Do the secure computing after ptrace; failures should be fast. 247 * If this fails we might have return value in a0 from seccomp 248 * (via SECCOMP_RET_ERRNO/TRACE). 249 */ 250 if (secure_computing() == -1) 251 return -1; 252 253 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS 254 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) 255 trace_sys_enter(regs, syscall_get_nr(current, regs)); 256 #endif 257 258 audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3); 259 return 0; 260 } 261 262 __visible void do_syscall_trace_exit(struct pt_regs *regs) 263 { 264 audit_syscall_exit(regs); 265 266 if (test_thread_flag(TIF_SYSCALL_TRACE)) 267 tracehook_report_syscall_exit(regs, 0); 268 269 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS 270 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) 271 trace_sys_exit(regs, regs_return_value(regs)); 272 #endif 273 } 274