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/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/compat.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/elf.h>
  18 #include <linux/regset.h>
  19 #include <linux/sched.h>
  20 #include <linux/sched/task_stack.h>
  21
  22 enum riscv_regset {
  23         REGSET_X,
  24 #ifdef CONFIG_FPU
  25         REGSET_F,
  26 #endif
  27 };
  28
  29 static int riscv_gpr_get(struct task_struct *target,
  30                          const struct user_regset *regset,
  31                          struct membuf to)
  32 {
  33         return membuf_write(&to, task_pt_regs(target),
  34                             sizeof(struct user_regs_struct));
  35 }
  36
  37 static int riscv_gpr_set(struct task_struct *target,
  38                          const struct user_regset *regset,
  39                          unsigned int pos, unsigned int count,
  40                          const void *kbuf, const void __user *ubuf)
  41 {
  42         struct pt_regs *regs;
  43
  44         regs = task_pt_regs(target);
  45         return user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
  46 }
  47
  48 #ifdef CONFIG_FPU
  49 static int riscv_fpr_get(struct task_struct *target,
  50                          const struct user_regset *regset,
  51                          struct membuf to)
  52 {
  53         struct __riscv_d_ext_state *fstate = &target->thread.fstate;
  54
  55         if (target == current)
  56                 fstate_save(current, task_pt_regs(current));
  57
  58         membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
  59         membuf_store(&to, fstate->fcsr);
  60         return membuf_zero(&to, 4);     // explicitly pad
  61 }
  62
  63 static int riscv_fpr_set(struct task_struct *target,
  64                          const struct user_regset *regset,
  65                          unsigned int pos, unsigned int count,
  66                          const void *kbuf, const void __user *ubuf)
  67 {
  68         int ret;
  69         struct __riscv_d_ext_state *fstate = &target->thread.fstate;
  70
  71         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  72                                  offsetof(struct __riscv_d_ext_state, fcsr));
  73         if (!ret) {
  74                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  75                                          offsetof(struct __riscv_d_ext_state, fcsr) +
  76                                          sizeof(fstate->fcsr));
  77         }
  78
  79         return ret;
  80 }
  81 #endif
  82
  83 static const struct user_regset riscv_user_regset[] = {
  84         [REGSET_X] = {
  85                 .core_note_type = NT_PRSTATUS,
  86                 .n = ELF_NGREG,
  87                 .size = sizeof(elf_greg_t),
  88                 .align = sizeof(elf_greg_t),
  89                 .regset_get = riscv_gpr_get,
  90                 .set = riscv_gpr_set,
  91         },
  92 #ifdef CONFIG_FPU
  93         [REGSET_F] = {
  94                 .core_note_type = NT_PRFPREG,
  95                 .n = ELF_NFPREG,
  96                 .size = sizeof(elf_fpreg_t),
  97                 .align = sizeof(elf_fpreg_t),
  98                 .regset_get = riscv_fpr_get,
  99                 .set = riscv_fpr_set,
 100         },
 101 #endif
 102 };
 103
 104 static const struct user_regset_view riscv_user_native_view = {
 105         .name = "riscv",
 106         .e_machine = EM_RISCV,
 107         .regsets = riscv_user_regset,
 108         .n = ARRAY_SIZE(riscv_user_regset),
 109 };
 110
 111 struct pt_regs_offset {
 112         const char *name;
 113         int offset;
 114 };
 115
 116 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
 117 #define REG_OFFSET_END {.name = NULL, .offset = 0}
 118
 119 static const struct pt_regs_offset regoffset_table[] = {
 120         REG_OFFSET_NAME(epc),
 121         REG_OFFSET_NAME(ra),
 122         REG_OFFSET_NAME(sp),
 123         REG_OFFSET_NAME(gp),
 124         REG_OFFSET_NAME(tp),
 125         REG_OFFSET_NAME(t0),
 126         REG_OFFSET_NAME(t1),
 127         REG_OFFSET_NAME(t2),
 128         REG_OFFSET_NAME(s0),
 129         REG_OFFSET_NAME(s1),
 130         REG_OFFSET_NAME(a0),
 131         REG_OFFSET_NAME(a1),
 132         REG_OFFSET_NAME(a2),
 133         REG_OFFSET_NAME(a3),
 134         REG_OFFSET_NAME(a4),
 135         REG_OFFSET_NAME(a5),
 136         REG_OFFSET_NAME(a6),
 137         REG_OFFSET_NAME(a7),
 138         REG_OFFSET_NAME(s2),
 139         REG_OFFSET_NAME(s3),
 140         REG_OFFSET_NAME(s4),
 141         REG_OFFSET_NAME(s5),
 142         REG_OFFSET_NAME(s6),
 143         REG_OFFSET_NAME(s7),
 144         REG_OFFSET_NAME(s8),
 145         REG_OFFSET_NAME(s9),
 146         REG_OFFSET_NAME(s10),
 147         REG_OFFSET_NAME(s11),
 148         REG_OFFSET_NAME(t3),
 149         REG_OFFSET_NAME(t4),
 150         REG_OFFSET_NAME(t5),
 151         REG_OFFSET_NAME(t6),
 152         REG_OFFSET_NAME(status),
 153         REG_OFFSET_NAME(badaddr),
 154         REG_OFFSET_NAME(cause),
 155         REG_OFFSET_NAME(orig_a0),
 156         REG_OFFSET_END,
 157 };
 158
 159 /**
 160  * regs_query_register_offset() - query register offset from its name
 161  * @name:       the name of a register
 162  *
 163  * regs_query_register_offset() returns the offset of a register in struct
 164  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 165  */
 166 int regs_query_register_offset(const char *name)
 167 {
 168         const struct pt_regs_offset *roff;
 169
 170         for (roff = regoffset_table; roff->name != NULL; roff++)
 171                 if (!strcmp(roff->name, name))
 172                         return roff->offset;
 173         return -EINVAL;
 174 }
 175
 176 /**
 177  * regs_within_kernel_stack() - check the address in the stack
 178  * @regs:      pt_regs which contains kernel stack pointer.
 179  * @addr:      address which is checked.
 180  *
 181  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 182  * If @addr is within the kernel stack, it returns true. If not, returns false.
 183  */
 184 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 185 {
 186         return (addr & ~(THREAD_SIZE - 1))  ==
 187                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
 188 }
 189
 190 /**
 191  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 192  * @regs:       pt_regs which contains kernel stack pointer.
 193  * @n:          stack entry number.
 194  *
 195  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 196  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 197  * this returns 0.
 198  */
 199 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 200 {
 201         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 202
 203         addr += n;
 204         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 205                 return *addr;
 206         else
 207                 return 0;
 208 }
 209
 210 void ptrace_disable(struct task_struct *child)
 211 {
 212 }
 213
 214 long arch_ptrace(struct task_struct *child, long request,
 215                  unsigned long addr, unsigned long data)
 216 {
 217         long ret = -EIO;
 218
 219         switch (request) {
 220         default:
 221                 ret = ptrace_request(child, request, addr, data);
 222                 break;
 223         }
 224
 225         return ret;
 226 }
 227
 228 #ifdef CONFIG_COMPAT
 229 static int compat_riscv_gpr_get(struct task_struct *target,
 230                                 const struct user_regset *regset,
 231                                 struct membuf to)
 232 {
 233         struct compat_user_regs_struct cregs;
 234
 235         regs_to_cregs(&cregs, task_pt_regs(target));
 236
 237         return membuf_write(&to, &cregs,
 238                             sizeof(struct compat_user_regs_struct));
 239 }
 240
 241 static int compat_riscv_gpr_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         int ret;
 247         struct compat_user_regs_struct cregs;
 248
 249         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &cregs, 0, -1);
 250
 251         cregs_to_regs(&cregs, task_pt_regs(target));
 252
 253         return ret;
 254 }
 255
 256 static const struct user_regset compat_riscv_user_regset[] = {
 257         [REGSET_X] = {
 258                 .core_note_type = NT_PRSTATUS,
 259                 .n = ELF_NGREG,
 260                 .size = sizeof(compat_elf_greg_t),
 261                 .align = sizeof(compat_elf_greg_t),
 262                 .regset_get = compat_riscv_gpr_get,
 263                 .set = compat_riscv_gpr_set,
 264         },
 265 #ifdef CONFIG_FPU
 266         [REGSET_F] = {
 267                 .core_note_type = NT_PRFPREG,
 268                 .n = ELF_NFPREG,
 269                 .size = sizeof(elf_fpreg_t),
 270                 .align = sizeof(elf_fpreg_t),
 271                 .regset_get = riscv_fpr_get,
 272                 .set = riscv_fpr_set,
 273         },
 274 #endif
 275 };
 276
 277 static const struct user_regset_view compat_riscv_user_native_view = {
 278         .name = "riscv",
 279         .e_machine = EM_RISCV,
 280         .regsets = compat_riscv_user_regset,
 281         .n = ARRAY_SIZE(compat_riscv_user_regset),
 282 };
 283
 284 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 285                         compat_ulong_t caddr, compat_ulong_t cdata)
 286 {
 287         long ret = -EIO;
 288
 289         switch (request) {
 290         default:
 291                 ret = compat_ptrace_request(child, request, caddr, cdata);
 292                 break;
 293         }
 294
 295         return ret;
 296 }
 297 #endif /* CONFIG_COMPAT */
 298
 299 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 300 {
 301 #ifdef CONFIG_COMPAT
 302         if (test_tsk_thread_flag(task, TIF_32BIT))
 303                 return &compat_riscv_user_native_view;
 304         else
 305 #endif
 306                 return &riscv_user_native_view;
 307 }