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 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 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 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 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 const struct user_regset_view *task_user_regset_view(struct task_struct *task) 115 { 116 return &riscv_user_native_view; 117 } 118 119 struct pt_regs_offset { 120 const char *name; 121 int offset; 122 }; 123 124 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)} 125 #define REG_OFFSET_END {.name = NULL, .offset = 0} 126 127 static const struct pt_regs_offset regoffset_table[] = { 128 REG_OFFSET_NAME(epc), 129 REG_OFFSET_NAME(ra), 130 REG_OFFSET_NAME(sp), 131 REG_OFFSET_NAME(gp), 132 REG_OFFSET_NAME(tp), 133 REG_OFFSET_NAME(t0), 134 REG_OFFSET_NAME(t1), 135 REG_OFFSET_NAME(t2), 136 REG_OFFSET_NAME(s0), 137 REG_OFFSET_NAME(s1), 138 REG_OFFSET_NAME(a0), 139 REG_OFFSET_NAME(a1), 140 REG_OFFSET_NAME(a2), 141 REG_OFFSET_NAME(a3), 142 REG_OFFSET_NAME(a4), 143 REG_OFFSET_NAME(a5), 144 REG_OFFSET_NAME(a6), 145 REG_OFFSET_NAME(a7), 146 REG_OFFSET_NAME(s2), 147 REG_OFFSET_NAME(s3), 148 REG_OFFSET_NAME(s4), 149 REG_OFFSET_NAME(s5), 150 REG_OFFSET_NAME(s6), 151 REG_OFFSET_NAME(s7), 152 REG_OFFSET_NAME(s8), 153 REG_OFFSET_NAME(s9), 154 REG_OFFSET_NAME(s10), 155 REG_OFFSET_NAME(s11), 156 REG_OFFSET_NAME(t3), 157 REG_OFFSET_NAME(t4), 158 REG_OFFSET_NAME(t5), 159 REG_OFFSET_NAME(t6), 160 REG_OFFSET_NAME(status), 161 REG_OFFSET_NAME(badaddr), 162 REG_OFFSET_NAME(cause), 163 REG_OFFSET_NAME(orig_a0), 164 REG_OFFSET_END, 165 }; 166 167 /** 168 * regs_query_register_offset() - query register offset from its name 169 * @name: the name of a register 170 * 171 * regs_query_register_offset() returns the offset of a register in struct 172 * pt_regs from its name. If the name is invalid, this returns -EINVAL; 173 */ 174 int regs_query_register_offset(const char *name) 175 { 176 const struct pt_regs_offset *roff; 177 178 for (roff = regoffset_table; roff->name != NULL; roff++) 179 if (!strcmp(roff->name, name)) 180 return roff->offset; 181 return -EINVAL; 182 } 183 184 /** 185 * regs_within_kernel_stack() - check the address in the stack 186 * @regs: pt_regs which contains kernel stack pointer. 187 * @addr: address which is checked. 188 * 189 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 190 * If @addr is within the kernel stack, it returns true. If not, returns false. 191 */ 192 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr) 193 { 194 return (addr & ~(THREAD_SIZE - 1)) == 195 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)); 196 } 197 198 /** 199 * regs_get_kernel_stack_nth() - get Nth entry of the stack 200 * @regs: pt_regs which contains kernel stack pointer. 201 * @n: stack entry number. 202 * 203 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 204 * is specified by @regs. If the @n th entry is NOT in the kernel stack, 205 * this returns 0. 206 */ 207 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n) 208 { 209 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs); 210 211 addr += n; 212 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 213 return *addr; 214 else 215 return 0; 216 } 217 218 void ptrace_disable(struct task_struct *child) 219 { 220 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 221 } 222 223 long arch_ptrace(struct task_struct *child, long request, 224 unsigned long addr, unsigned long data) 225 { 226 long ret = -EIO; 227 228 switch (request) { 229 default: 230 ret = ptrace_request(child, request, addr, data); 231 break; 232 } 233 234 return ret; 235 } 236 237 /* 238 * Allows PTRACE_SYSCALL to work. These are called from entry.S in 239 * {handle,ret_from}_syscall. 240 */ 241 __visible int do_syscall_trace_enter(struct pt_regs *regs) 242 { 243 if (test_thread_flag(TIF_SYSCALL_TRACE)) 244 if (tracehook_report_syscall_entry(regs)) 245 return -1; 246 247 /* 248 * Do the secure computing after ptrace; failures should be fast. 249 * If this fails we might have return value in a0 from seccomp 250 * (via SECCOMP_RET_ERRNO/TRACE). 251 */ 252 if (secure_computing() == -1) 253 return -1; 254 255 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS 256 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) 257 trace_sys_enter(regs, syscall_get_nr(current, regs)); 258 #endif 259 260 audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3); 261 return 0; 262 } 263 264 __visible void do_syscall_trace_exit(struct pt_regs *regs) 265 { 266 audit_syscall_exit(regs); 267 268 if (test_thread_flag(TIF_SYSCALL_TRACE)) 269 tracehook_report_syscall_exit(regs, 0); 270 271 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS 272 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) 273 trace_sys_exit(regs, regs_return_value(regs)); 274 #endif 275 } 276