arch/riscv/kernel/ptrace.c

   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/vector.h>
  11 #include <asm/ptrace.h>
  12 #include <asm/syscall.h>
  13 #include <asm/thread_info.h>
  14 #include <asm/switch_to.h>
  15 #include <linux/audit.h>
  16 #include <linux/compat.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/elf.h>
  19 #include <linux/regset.h>
  20 #include <linux/sched.h>
  21 #include <linux/sched/task_stack.h>
  22
  23 enum riscv_regset {
  24         REGSET_X,
  25 #ifdef CONFIG_FPU
  26         REGSET_F,
  27 #endif
  28 #ifdef CONFIG_RISCV_ISA_V
  29         REGSET_V,
  30 #endif
  31 };
  32
  33 static int riscv_gpr_get(struct task_struct *target,
  34                          const struct user_regset *regset,
  35                          struct membuf to)
  36 {
  37         return membuf_write(&to, task_pt_regs(target),
  38                             sizeof(struct user_regs_struct));
  39 }
  40
  41 static int riscv_gpr_set(struct task_struct *target,
  42                          const struct user_regset *regset,
  43                          unsigned int pos, unsigned int count,
  44                          const void *kbuf, const void __user *ubuf)
  45 {
  46         struct pt_regs *regs;
  47
  48         regs = task_pt_regs(target);
  49         return user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
  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         if (target == current)
  60                 fstate_save(current, task_pt_regs(current));
  61
  62         membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
  63         membuf_store(&to, fstate->fcsr);
  64         return membuf_zero(&to, 4);     // explicitly pad
  65 }
  66
  67 static int riscv_fpr_set(struct task_struct *target,
  68                          const struct user_regset *regset,
  69                          unsigned int pos, unsigned int count,
  70                          const void *kbuf, const void __user *ubuf)
  71 {
  72         int ret;
  73         struct __riscv_d_ext_state *fstate = &target->thread.fstate;
  74
  75         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  76                                  offsetof(struct __riscv_d_ext_state, fcsr));
  77         if (!ret) {
  78                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  79                                          offsetof(struct __riscv_d_ext_state, fcsr) +
  80                                          sizeof(fstate->fcsr));
  81         }
  82
  83         return ret;
  84 }
  85 #endif
  86
  87 #ifdef CONFIG_RISCV_ISA_V
  88 static int riscv_vr_get(struct task_struct *target,
  89                         const struct user_regset *regset,
  90                         struct membuf to)
  91 {
  92         struct __riscv_v_ext_state *vstate = &target->thread.vstate;
  93         struct __riscv_v_regset_state ptrace_vstate;
  94
  95         if (!riscv_v_vstate_query(task_pt_regs(target)))
  96                 return -EINVAL;
  97
  98         /*
  99          * Ensure the vector registers have been saved to the memory before
 100          * copying them to membuf.
 101          */
 102         if (target == current) {
 103                 get_cpu_vector_context();
 104                 riscv_v_vstate_save(&current->thread.vstate, task_pt_regs(current));
 105                 put_cpu_vector_context();
 106         }
 107
 108         ptrace_vstate.vstart = vstate->vstart;
 109         ptrace_vstate.vl = vstate->vl;
 110         ptrace_vstate.vtype = vstate->vtype;
 111         ptrace_vstate.vcsr = vstate->vcsr;
 112         ptrace_vstate.vlenb = vstate->vlenb;
 113
 114         /* Copy vector header from vstate. */
 115         membuf_write(&to, &ptrace_vstate, sizeof(struct __riscv_v_regset_state));
 116
 117         /* Copy all the vector registers from vstate. */
 118         return membuf_write(&to, vstate->datap, riscv_v_vsize);
 119 }
 120
 121 static int riscv_vr_set(struct task_struct *target,
 122                         const struct user_regset *regset,
 123                         unsigned int pos, unsigned int count,
 124                         const void *kbuf, const void __user *ubuf)
 125 {
 126         int ret;
 127         struct __riscv_v_ext_state *vstate = &target->thread.vstate;
 128         struct __riscv_v_regset_state ptrace_vstate;
 129
 130         if (!riscv_v_vstate_query(task_pt_regs(target)))
 131                 return -EINVAL;
 132
 133         /* Copy rest of the vstate except datap */
 134         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ptrace_vstate, 0,
 135                                  sizeof(struct __riscv_v_regset_state));
 136         if (unlikely(ret))
 137                 return ret;
 138
 139         if (vstate->vlenb != ptrace_vstate.vlenb)
 140                 return -EINVAL;
 141
 142         vstate->vstart = ptrace_vstate.vstart;
 143         vstate->vl = ptrace_vstate.vl;
 144         vstate->vtype = ptrace_vstate.vtype;
 145         vstate->vcsr = ptrace_vstate.vcsr;
 146
 147         /* Copy all the vector registers. */
 148         pos = 0;
 149         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vstate->datap,
 150                                  0, riscv_v_vsize);
 151         return ret;
 152 }
 153 #endif
 154
 155 static const struct user_regset riscv_user_regset[] = {
 156         [REGSET_X] = {
 157                 .core_note_type = NT_PRSTATUS,
 158                 .n = ELF_NGREG,
 159                 .size = sizeof(elf_greg_t),
 160                 .align = sizeof(elf_greg_t),
 161                 .regset_get = riscv_gpr_get,
 162                 .set = riscv_gpr_set,
 163         },
 164 #ifdef CONFIG_FPU
 165         [REGSET_F] = {
 166                 .core_note_type = NT_PRFPREG,
 167                 .n = ELF_NFPREG,
 168                 .size = sizeof(elf_fpreg_t),
 169                 .align = sizeof(elf_fpreg_t),
 170                 .regset_get = riscv_fpr_get,
 171                 .set = riscv_fpr_set,
 172         },
 173 #endif
 174 #ifdef CONFIG_RISCV_ISA_V
 175         [REGSET_V] = {
 176                 .core_note_type = NT_RISCV_VECTOR,
 177                 .align = 16,
 178                 .n = ((32 * RISCV_MAX_VLENB) +
 179                       sizeof(struct __riscv_v_regset_state)) / sizeof(__u32),
 180                 .size = sizeof(__u32),
 181                 .regset_get = riscv_vr_get,
 182                 .set = riscv_vr_set,
 183         },
 184 #endif
 185 };
 186
 187 static const struct user_regset_view riscv_user_native_view = {
 188         .name = "riscv",
 189         .e_machine = EM_RISCV,
 190         .regsets = riscv_user_regset,
 191         .n = ARRAY_SIZE(riscv_user_regset),
 192 };
 193
 194 struct pt_regs_offset {
 195         const char *name;
 196         int offset;
 197 };
 198
 199 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
 200 #define REG_OFFSET_END {.name = NULL, .offset = 0}
 201
 202 static const struct pt_regs_offset regoffset_table[] = {
 203         REG_OFFSET_NAME(epc),
 204         REG_OFFSET_NAME(ra),
 205         REG_OFFSET_NAME(sp),
 206         REG_OFFSET_NAME(gp),
 207         REG_OFFSET_NAME(tp),
 208         REG_OFFSET_NAME(t0),
 209         REG_OFFSET_NAME(t1),
 210         REG_OFFSET_NAME(t2),
 211         REG_OFFSET_NAME(s0),
 212         REG_OFFSET_NAME(s1),
 213         REG_OFFSET_NAME(a0),
 214         REG_OFFSET_NAME(a1),
 215         REG_OFFSET_NAME(a2),
 216         REG_OFFSET_NAME(a3),
 217         REG_OFFSET_NAME(a4),
 218         REG_OFFSET_NAME(a5),
 219         REG_OFFSET_NAME(a6),
 220         REG_OFFSET_NAME(a7),
 221         REG_OFFSET_NAME(s2),
 222         REG_OFFSET_NAME(s3),
 223         REG_OFFSET_NAME(s4),
 224         REG_OFFSET_NAME(s5),
 225         REG_OFFSET_NAME(s6),
 226         REG_OFFSET_NAME(s7),
 227         REG_OFFSET_NAME(s8),
 228         REG_OFFSET_NAME(s9),
 229         REG_OFFSET_NAME(s10),
 230         REG_OFFSET_NAME(s11),
 231         REG_OFFSET_NAME(t3),
 232         REG_OFFSET_NAME(t4),
 233         REG_OFFSET_NAME(t5),
 234         REG_OFFSET_NAME(t6),
 235         REG_OFFSET_NAME(status),
 236         REG_OFFSET_NAME(badaddr),
 237         REG_OFFSET_NAME(cause),
 238         REG_OFFSET_NAME(orig_a0),
 239         REG_OFFSET_END,
 240 };
 241
 242 /**
 243  * regs_query_register_offset() - query register offset from its name
 244  * @name:       the name of a register
 245  *
 246  * regs_query_register_offset() returns the offset of a register in struct
 247  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 248  */
 249 int regs_query_register_offset(const char *name)
 250 {
 251         const struct pt_regs_offset *roff;
 252
 253         for (roff = regoffset_table; roff->name != NULL; roff++)
 254                 if (!strcmp(roff->name, name))
 255                         return roff->offset;
 256         return -EINVAL;
 257 }
 258
 259 /**
 260  * regs_within_kernel_stack() - check the address in the stack
 261  * @regs:      pt_regs which contains kernel stack pointer.
 262  * @addr:      address which is checked.
 263  *
 264  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 265  * If @addr is within the kernel stack, it returns true. If not, returns false.
 266  */
 267 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 268 {
 269         return (addr & ~(THREAD_SIZE - 1))  ==
 270                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
 271 }
 272
 273 /**
 274  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 275  * @regs:       pt_regs which contains kernel stack pointer.
 276  * @n:          stack entry number.
 277  *
 278  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 279  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 280  * this returns 0.
 281  */
 282 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 283 {
 284         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 285
 286         addr += n;
 287         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 288                 return *addr;
 289         else
 290                 return 0;
 291 }
 292
 293 void ptrace_disable(struct task_struct *child)
 294 {
 295 }
 296
 297 long arch_ptrace(struct task_struct *child, long request,
 298                  unsigned long addr, unsigned long data)
 299 {
 300         long ret = -EIO;
 301
 302         switch (request) {
 303         default:
 304                 ret = ptrace_request(child, request, addr, data);
 305                 break;
 306         }
 307
 308         return ret;
 309 }
 310
 311 #ifdef CONFIG_COMPAT
 312 static int compat_riscv_gpr_get(struct task_struct *target,
 313                                 const struct user_regset *regset,
 314                                 struct membuf to)
 315 {
 316         struct compat_user_regs_struct cregs;
 317
 318         regs_to_cregs(&cregs, task_pt_regs(target));
 319
 320         return membuf_write(&to, &cregs,
 321                             sizeof(struct compat_user_regs_struct));
 322 }
 323
 324 static int compat_riscv_gpr_set(struct task_struct *target,
 325                                 const struct user_regset *regset,
 326                                 unsigned int pos, unsigned int count,
 327                                 const void *kbuf, const void __user *ubuf)
 328 {
 329         int ret;
 330         struct compat_user_regs_struct cregs;
 331
 332         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &cregs, 0, -1);
 333
 334         cregs_to_regs(&cregs, task_pt_regs(target));
 335
 336         return ret;
 337 }
 338
 339 static const struct user_regset compat_riscv_user_regset[] = {
 340         [REGSET_X] = {
 341                 .core_note_type = NT_PRSTATUS,
 342                 .n = ELF_NGREG,
 343                 .size = sizeof(compat_elf_greg_t),
 344                 .align = sizeof(compat_elf_greg_t),
 345                 .regset_get = compat_riscv_gpr_get,
 346                 .set = compat_riscv_gpr_set,
 347         },
 348 #ifdef CONFIG_FPU
 349         [REGSET_F] = {
 350                 .core_note_type = NT_PRFPREG,
 351                 .n = ELF_NFPREG,
 352                 .size = sizeof(elf_fpreg_t),
 353                 .align = sizeof(elf_fpreg_t),
 354                 .regset_get = riscv_fpr_get,
 355                 .set = riscv_fpr_set,
 356         },
 357 #endif
 358 };
 359
 360 static const struct user_regset_view compat_riscv_user_native_view = {
 361         .name = "riscv",
 362         .e_machine = EM_RISCV,
 363         .regsets = compat_riscv_user_regset,
 364         .n = ARRAY_SIZE(compat_riscv_user_regset),
 365 };
 366
 367 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 368                         compat_ulong_t caddr, compat_ulong_t cdata)
 369 {
 370         long ret = -EIO;
 371
 372         switch (request) {
 373         default:
 374                 ret = compat_ptrace_request(child, request, caddr, cdata);
 375                 break;
 376         }
 377
 378         return ret;
 379 }
 380 #else
 381 static const struct user_regset_view compat_riscv_user_native_view = {};
 382 #endif /* CONFIG_COMPAT */
 383
 384 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 385 {
 386         if (is_compat_thread(&task->thread_info))
 387                 return &compat_riscv_user_native_view;
 388         else
 389                 return &riscv_user_native_view;
 390 }