arch/loongarch/kernel/ptrace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Author: Hanlu Li <lihanlu@loongson.cn>
   4  *         Huacai Chen <chenhuacai@loongson.cn>
   5  *
   6  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
   7  *
   8  * Derived from MIPS:
   9  * Copyright (C) 1992 Ross Biro
  10  * Copyright (C) Linus Torvalds
  11  * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
  12  * Copyright (C) 1996 David S. Miller
  13  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
  14  * Copyright (C) 1999 MIPS Technologies, Inc.
  15  * Copyright (C) 2000 Ulf Carlsson
  16  */
  17 #include <linux/kernel.h>
  18 #include <linux/audit.h>
  19 #include <linux/compiler.h>
  20 #include <linux/context_tracking.h>
  21 #include <linux/elf.h>
  22 #include <linux/errno.h>
  23 #include <linux/mm.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/regset.h>
  26 #include <linux/sched.h>
  27 #include <linux/sched/task_stack.h>
  28 #include <linux/security.h>
  29 #include <linux/smp.h>
  30 #include <linux/stddef.h>
  31 #include <linux/seccomp.h>
  32 #include <linux/uaccess.h>
  33
  34 #include <asm/byteorder.h>
  35 #include <asm/cpu.h>
  36 #include <asm/cpu-info.h>
  37 #include <asm/fpu.h>
  38 #include <asm/loongarch.h>
  39 #include <asm/page.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/processor.h>
  42 #include <asm/reg.h>
  43 #include <asm/syscall.h>
  44
  45 static void init_fp_ctx(struct task_struct *target)
  46 {
  47         /* The target already has context */
  48         if (tsk_used_math(target))
  49                 return;
  50
  51         /* Begin with data registers set to all 1s... */
  52         memset(&target->thread.fpu.fpr, ~0, sizeof(target->thread.fpu.fpr));
  53         set_stopped_child_used_math(target);
  54 }
  55
  56 /*
  57  * Called by kernel/ptrace.c when detaching..
  58  *
  59  * Make sure single step bits etc are not set.
  60  */
  61 void ptrace_disable(struct task_struct *child)
  62 {
  63         /* Don't load the watchpoint registers for the ex-child. */
  64         clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
  65         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  66 }
  67
  68 /* regset get/set implementations */
  69
  70 static int gpr_get(struct task_struct *target,
  71                    const struct user_regset *regset,
  72                    struct membuf to)
  73 {
  74         int r;
  75         struct pt_regs *regs = task_pt_regs(target);
  76
  77         r = membuf_write(&to, &regs->regs, sizeof(u64) * GPR_NUM);
  78         r = membuf_write(&to, &regs->orig_a0, sizeof(u64));
  79         r = membuf_write(&to, &regs->csr_era, sizeof(u64));
  80         r = membuf_write(&to, &regs->csr_badvaddr, sizeof(u64));
  81
  82         return r;
  83 }
  84
  85 static int gpr_set(struct task_struct *target,
  86                    const struct user_regset *regset,
  87                    unsigned int pos, unsigned int count,
  88                    const void *kbuf, const void __user *ubuf)
  89 {
  90         int err;
  91         int a0_start = sizeof(u64) * GPR_NUM;
  92         int era_start = a0_start + sizeof(u64);
  93         int badvaddr_start = era_start + sizeof(u64);
  94         struct pt_regs *regs = task_pt_regs(target);
  95
  96         err = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  97                                  &regs->regs,
  98                                  0, a0_start);
  99         err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 100                                  &regs->orig_a0,
 101                                  a0_start, a0_start + sizeof(u64));
 102         err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 103                                  &regs->csr_era,
 104                                  era_start, era_start + sizeof(u64));
 105         err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 106                                  &regs->csr_badvaddr,
 107                                  badvaddr_start, badvaddr_start + sizeof(u64));
 108
 109         return err;
 110 }
 111
 112
 113 /*
 114  * Get the general floating-point registers.
 115  */
 116 static int gfpr_get(struct task_struct *target, struct membuf *to)
 117 {
 118         return membuf_write(to, &target->thread.fpu.fpr,
 119                             sizeof(elf_fpreg_t) * NUM_FPU_REGS);
 120 }
 121
 122 static int gfpr_get_simd(struct task_struct *target, struct membuf *to)
 123 {
 124         int i, r;
 125         u64 fpr_val;
 126
 127         BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
 128         for (i = 0; i < NUM_FPU_REGS; i++) {
 129                 fpr_val = get_fpr64(&target->thread.fpu.fpr[i], 0);
 130                 r = membuf_write(to, &fpr_val, sizeof(elf_fpreg_t));
 131         }
 132
 133         return r;
 134 }
 135
 136 /*
 137  * Choose the appropriate helper for general registers, and then copy
 138  * the FCC and FCSR registers separately.
 139  */
 140 static int fpr_get(struct task_struct *target,
 141                    const struct user_regset *regset,
 142                    struct membuf to)
 143 {
 144         int r;
 145
 146         if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
 147                 r = gfpr_get(target, &to);
 148         else
 149                 r = gfpr_get_simd(target, &to);
 150
 151         r = membuf_write(&to, &target->thread.fpu.fcc, sizeof(target->thread.fpu.fcc));
 152         r = membuf_write(&to, &target->thread.fpu.fcsr, sizeof(target->thread.fpu.fcsr));
 153
 154         return r;
 155 }
 156
 157 static int gfpr_set(struct task_struct *target,
 158                     unsigned int *pos, unsigned int *count,
 159                     const void **kbuf, const void __user **ubuf)
 160 {
 161         return user_regset_copyin(pos, count, kbuf, ubuf,
 162                                   &target->thread.fpu.fpr,
 163                                   0, NUM_FPU_REGS * sizeof(elf_fpreg_t));
 164 }
 165
 166 static int gfpr_set_simd(struct task_struct *target,
 167                        unsigned int *pos, unsigned int *count,
 168                        const void **kbuf, const void __user **ubuf)
 169 {
 170         int i, err;
 171         u64 fpr_val;
 172
 173         BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
 174         for (i = 0; i < NUM_FPU_REGS && *count > 0; i++) {
 175                 err = user_regset_copyin(pos, count, kbuf, ubuf,
 176                                          &fpr_val, i * sizeof(elf_fpreg_t),
 177                                          (i + 1) * sizeof(elf_fpreg_t));
 178                 if (err)
 179                         return err;
 180                 set_fpr64(&target->thread.fpu.fpr[i], 0, fpr_val);
 181         }
 182
 183         return 0;
 184 }
 185
 186 /*
 187  * Choose the appropriate helper for general registers, and then copy
 188  * the FCC register separately.
 189  */
 190 static int fpr_set(struct task_struct *target,
 191                    const struct user_regset *regset,
 192                    unsigned int pos, unsigned int count,
 193                    const void *kbuf, const void __user *ubuf)
 194 {
 195         const int fcc_start = NUM_FPU_REGS * sizeof(elf_fpreg_t);
 196         const int fcsr_start = fcc_start + sizeof(u64);
 197         int err;
 198
 199         BUG_ON(count % sizeof(elf_fpreg_t));
 200         if (pos + count > sizeof(elf_fpregset_t))
 201                 return -EIO;
 202
 203         init_fp_ctx(target);
 204
 205         if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
 206                 err = gfpr_set(target, &pos, &count, &kbuf, &ubuf);
 207         else
 208                 err = gfpr_set_simd(target, &pos, &count, &kbuf, &ubuf);
 209         if (err)
 210                 return err;
 211
 212         err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 213                                   &target->thread.fpu.fcc, fcc_start,
 214                                   fcc_start + sizeof(u64));
 215         err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 216                                   &target->thread.fpu.fcsr, fcsr_start,
 217                                   fcsr_start + sizeof(u32));
 218
 219         return err;
 220 }
 221
 222 static int cfg_get(struct task_struct *target,
 223                    const struct user_regset *regset,
 224                    struct membuf to)
 225 {
 226         int i, r;
 227         u32 cfg_val;
 228
 229         i = 0;
 230         while (to.left > 0) {
 231                 cfg_val = read_cpucfg(i++);
 232                 r = membuf_write(&to, &cfg_val, sizeof(u32));
 233         }
 234
 235         return r;
 236 }
 237
 238 /*
 239  * CFG registers are read-only.
 240  */
 241 static int cfg_set(struct task_struct *target,
 242                    const struct user_regset *regset,
 243                    unsigned int pos, unsigned int count,
 244                    const void *kbuf, const void __user *ubuf)
 245 {
 246         return 0;
 247 }
 248
 249 struct pt_regs_offset {
 250         const char *name;
 251         int offset;
 252 };
 253
 254 #define REG_OFFSET_NAME(n, r) {.name = #n, .offset = offsetof(struct pt_regs, r)}
 255 #define REG_OFFSET_END {.name = NULL, .offset = 0}
 256
 257 static const struct pt_regs_offset regoffset_table[] = {
 258         REG_OFFSET_NAME(r0, regs[0]),
 259         REG_OFFSET_NAME(r1, regs[1]),
 260         REG_OFFSET_NAME(r2, regs[2]),
 261         REG_OFFSET_NAME(r3, regs[3]),
 262         REG_OFFSET_NAME(r4, regs[4]),
 263         REG_OFFSET_NAME(r5, regs[5]),
 264         REG_OFFSET_NAME(r6, regs[6]),
 265         REG_OFFSET_NAME(r7, regs[7]),
 266         REG_OFFSET_NAME(r8, regs[8]),
 267         REG_OFFSET_NAME(r9, regs[9]),
 268         REG_OFFSET_NAME(r10, regs[10]),
 269         REG_OFFSET_NAME(r11, regs[11]),
 270         REG_OFFSET_NAME(r12, regs[12]),
 271         REG_OFFSET_NAME(r13, regs[13]),
 272         REG_OFFSET_NAME(r14, regs[14]),
 273         REG_OFFSET_NAME(r15, regs[15]),
 274         REG_OFFSET_NAME(r16, regs[16]),
 275         REG_OFFSET_NAME(r17, regs[17]),
 276         REG_OFFSET_NAME(r18, regs[18]),
 277         REG_OFFSET_NAME(r19, regs[19]),
 278         REG_OFFSET_NAME(r20, regs[20]),
 279         REG_OFFSET_NAME(r21, regs[21]),
 280         REG_OFFSET_NAME(r22, regs[22]),
 281         REG_OFFSET_NAME(r23, regs[23]),
 282         REG_OFFSET_NAME(r24, regs[24]),
 283         REG_OFFSET_NAME(r25, regs[25]),
 284         REG_OFFSET_NAME(r26, regs[26]),
 285         REG_OFFSET_NAME(r27, regs[27]),
 286         REG_OFFSET_NAME(r28, regs[28]),
 287         REG_OFFSET_NAME(r29, regs[29]),
 288         REG_OFFSET_NAME(r30, regs[30]),
 289         REG_OFFSET_NAME(r31, regs[31]),
 290         REG_OFFSET_NAME(orig_a0, orig_a0),
 291         REG_OFFSET_NAME(csr_era, csr_era),
 292         REG_OFFSET_NAME(csr_badvaddr, csr_badvaddr),
 293         REG_OFFSET_NAME(csr_crmd, csr_crmd),
 294         REG_OFFSET_NAME(csr_prmd, csr_prmd),
 295         REG_OFFSET_NAME(csr_euen, csr_euen),
 296         REG_OFFSET_NAME(csr_ecfg, csr_ecfg),
 297         REG_OFFSET_NAME(csr_estat, csr_estat),
 298         REG_OFFSET_END,
 299 };
 300
 301 /**
 302  * regs_query_register_offset() - query register offset from its name
 303  * @name:       the name of a register
 304  *
 305  * regs_query_register_offset() returns the offset of a register in struct
 306  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 307  */
 308 int regs_query_register_offset(const char *name)
 309 {
 310         const struct pt_regs_offset *roff;
 311
 312         for (roff = regoffset_table; roff->name != NULL; roff++)
 313                 if (!strcmp(roff->name, name))
 314                         return roff->offset;
 315         return -EINVAL;
 316 }
 317
 318 enum loongarch_regset {
 319         REGSET_GPR,
 320         REGSET_FPR,
 321         REGSET_CPUCFG,
 322 };
 323
 324 static const struct user_regset loongarch64_regsets[] = {
 325         [REGSET_GPR] = {
 326                 .core_note_type = NT_PRSTATUS,
 327                 .n              = ELF_NGREG,
 328                 .size           = sizeof(elf_greg_t),
 329                 .align          = sizeof(elf_greg_t),
 330                 .regset_get     = gpr_get,
 331                 .set            = gpr_set,
 332         },
 333         [REGSET_FPR] = {
 334                 .core_note_type = NT_PRFPREG,
 335                 .n              = ELF_NFPREG,
 336                 .size           = sizeof(elf_fpreg_t),
 337                 .align          = sizeof(elf_fpreg_t),
 338                 .regset_get     = fpr_get,
 339                 .set            = fpr_set,
 340         },
 341         [REGSET_CPUCFG] = {
 342                 .core_note_type = NT_LOONGARCH_CPUCFG,
 343                 .n              = 64,
 344                 .size           = sizeof(u32),
 345                 .align          = sizeof(u32),
 346                 .regset_get     = cfg_get,
 347                 .set            = cfg_set,
 348         },
 349 };
 350
 351 static const struct user_regset_view user_loongarch64_view = {
 352         .name           = "loongarch64",
 353         .e_machine      = ELF_ARCH,
 354         .regsets        = loongarch64_regsets,
 355         .n              = ARRAY_SIZE(loongarch64_regsets),
 356 };
 357
 358
 359 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 360 {
 361         return &user_loongarch64_view;
 362 }
 363
 364 static inline int read_user(struct task_struct *target, unsigned long addr,
 365                             unsigned long __user *data)
 366 {
 367         unsigned long tmp = 0;
 368
 369         switch (addr) {
 370         case 0 ... 31:
 371                 tmp = task_pt_regs(target)->regs[addr];
 372                 break;
 373         case ARG0:
 374                 tmp = task_pt_regs(target)->orig_a0;
 375                 break;
 376         case PC:
 377                 tmp = task_pt_regs(target)->csr_era;
 378                 break;
 379         case BADVADDR:
 380                 tmp = task_pt_regs(target)->csr_badvaddr;
 381                 break;
 382         default:
 383                 return -EIO;
 384         }
 385
 386         return put_user(tmp, data);
 387 }
 388
 389 static inline int write_user(struct task_struct *target, unsigned long addr,
 390                             unsigned long data)
 391 {
 392         switch (addr) {
 393         case 0 ... 31:
 394                 task_pt_regs(target)->regs[addr] = data;
 395                 break;
 396         case ARG0:
 397                 task_pt_regs(target)->orig_a0 = data;
 398                 break;
 399         case PC:
 400                 task_pt_regs(target)->csr_era = data;
 401                 break;
 402         case BADVADDR:
 403                 task_pt_regs(target)->csr_badvaddr = data;
 404                 break;
 405         default:
 406                 return -EIO;
 407         }
 408
 409         return 0;
 410 }
 411
 412 long arch_ptrace(struct task_struct *child, long request,
 413                  unsigned long addr, unsigned long data)
 414 {
 415         int ret;
 416         unsigned long __user *datap = (void __user *) data;
 417
 418         switch (request) {
 419         case PTRACE_PEEKUSR:
 420                 ret = read_user(child, addr, datap);
 421                 break;
 422
 423         case PTRACE_POKEUSR:
 424                 ret = write_user(child, addr, data);
 425                 break;
 426
 427         default:
 428                 ret = ptrace_request(child, request, addr, data);
 429                 break;
 430         }
 431
 432         return ret;
 433 }