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 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 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 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 }; 115 116 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 */ 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 */ 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 */ 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 } 219 220 void ptrace_disable(struct task_struct *child) 221 { 222 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 223 } 224 225 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 */ 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 } 265 266 __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