| 1 |
|
| 2 | |
| 3 | * User-mode machine state access
|
| 4 | *
|
| 5 | * Copyright (C) 2007 Red Hat, Inc. All rights reserved.
|
| 6 | *
|
| 7 | * Red Hat Author: Roland McGrath.
|
| 8 |
|
| 9 |
|
| 10 | #ifndef _LINUX_REGSET_H
|
| 11 | #define _LINUX_REGSET_H 1
|
| 12 |
|
| 13 | #include <linux/compiler.h>
|
| 14 | #include <linux/types.h>
|
| 15 | #include <linux/bug.h>
|
| 16 | #include <linux/uaccess.h>
|
| 17 | struct task_struct;
|
| 18 | struct user_regset;
|
| 19 |
|
| 20 | struct membuf {
|
| 21 | void *p;
|
| 22 | size_t left;
|
| 23 | };
|
| 24 |
|
| 25 | static inline int membuf_zero(struct membuf *s, size_t size)
|
| 26 | {
|
| 27 | if (s->left) {
|
| 28 | if (size > s->left)
|
| 29 | size = s->left;
|
| 30 | memset(s->p, 0, size);
|
| 31 | s->p += size;
|
| 32 | s->left -= size;
|
| 33 | }
|
| 34 | return s->left;
|
| 35 | }
|
| 36 |
|
| 37 | static inline int membuf_write(struct membuf *s, const void *v, size_t size)
|
| 38 | {
|
| 39 | if (s->left) {
|
| 40 | if (size > s->left)
|
| 41 | size = s->left;
|
| 42 | memcpy(s->p, v, size);
|
| 43 | s->p += size;
|
| 44 | s->left -= size;
|
| 45 | }
|
| 46 | return s->left;
|
| 47 | }
|
| 48 |
|
| 49 | static inline struct membuf membuf_at(const struct membuf *s, size_t offs)
|
| 50 | {
|
| 51 | struct membuf n = *s;
|
| 52 |
|
| 53 | if (offs > n.left)
|
| 54 | offs = n.left;
|
| 55 | n.p += offs;
|
| 56 | n.left -= offs;
|
| 57 |
|
| 58 | return n;
|
| 59 | }
|
| 60 |
|
| 61 |
|
| 62 | #define membuf_store(s, v) \
|
| 63 | ({ \
|
| 64 | struct membuf *__s = (s); \
|
| 65 | if (__s->left) { \
|
| 66 | typeof(v) __v = (v); \
|
| 67 | size_t __size = sizeof(__v); \
|
| 68 | if (unlikely(__size > __s->left)) { \
|
| 69 | __size = __s->left; \
|
| 70 | memcpy(__s->p, &__v, __size); \
|
| 71 | } else { \
|
| 72 | *(typeof(__v + 0) *)__s->p = __v; \
|
| 73 | } \
|
| 74 | __s->p += __size; \
|
| 75 | __s->left -= __size; \
|
| 76 | } \
|
| 77 | __s->left;})
|
| 78 |
|
| 79 | |
| 80 | * user_regset_active_fn - type of @active function in &struct user_regset
|
| 81 | * @target: thread being examined
|
| 82 | * @regset: regset being examined
|
| 83 | *
|
| 84 | * Return -%ENODEV if not available on the hardware found.
|
| 85 | * Return %0 if no interesting state in this thread.
|
| 86 | * Return >%0 number of @size units of interesting state.
|
| 87 | * Any get call fetching state beyond that number will
|
| 88 | * see the default initialization state for this data,
|
| 89 | * so a caller that knows what the default state is need
|
| 90 | * not copy it all out.
|
| 91 | * This call is optional; the pointer is %NULL if there
|
| 92 | * is no inexpensive check to yield a value < @n.
|
| 93 |
|
| 94 | typedef int user_regset_active_fn(struct task_struct *target,
|
| 95 | const struct user_regset *regset);
|
| 96 |
|
| 97 | typedef int user_regset_get2_fn(struct task_struct *target,
|
| 98 | const struct user_regset *regset,
|
| 99 | struct membuf to);
|
| 100 |
|
| 101 | |
| 102 | * user_regset_set_fn - type of @set function in &struct user_regset
|
| 103 | * @target: thread being examined
|
| 104 | * @regset: regset being examined
|
| 105 | * @pos: offset into the regset data to access, in bytes
|
| 106 | * @count: amount of data to copy, in bytes
|
| 107 | * @kbuf: if not %NULL, a kernel-space pointer to copy from
|
| 108 | * @ubuf: if @kbuf is %NULL, a user-space pointer to copy from
|
| 109 | *
|
| 110 | * Store register values. Return %0 on success; -%EIO or -%ENODEV
|
| 111 | * are usual failure returns. The @pos and @count values are in
|
| 112 | * bytes, but must be properly aligned. If @kbuf is non-null, that
|
| 113 | * buffer is used and @ubuf is ignored. If @kbuf is %NULL, then
|
| 114 | * ubuf gives a userland pointer to access directly, and an -%EFAULT
|
| 115 | * return value is possible.
|
| 116 |
|
| 117 | typedef int user_regset_set_fn(struct task_struct *target,
|
| 118 | const struct user_regset *regset,
|
| 119 | unsigned int pos, unsigned int count,
|
| 120 | const void *kbuf, const void __user *ubuf);
|
| 121 |
|
| 122 | |
| 123 | * user_regset_writeback_fn - type of @writeback function in &struct user_regset
|
| 124 | * @target: thread being examined
|
| 125 | * @regset: regset being examined
|
| 126 | * @immediate: zero if writeback at completion of next context switch is OK
|
| 127 | *
|
| 128 | * This call is optional; usually the pointer is %NULL. When
|
| 129 | * provided, there is some user memory associated with this regset's
|
| 130 | * hardware, such as memory backing cached register data on register
|
| 131 | * window machines; the regset's data controls what user memory is
|
| 132 | * used (e.g. via the stack pointer value).
|
| 133 | *
|
| 134 | * Write register data back to user memory. If the @immediate flag
|
| 135 | * is nonzero, it must be written to the user memory so uaccess or
|
| 136 | * access_process_vm() can see it when this call returns; if zero,
|
| 137 | * then it must be written back by the time the task completes a
|
| 138 | * context switch (as synchronized with wait_task_inactive()).
|
| 139 | * Return %0 on success or if there was nothing to do, -%EFAULT for
|
| 140 | * a memory problem (bad stack pointer or whatever), or -%EIO for a
|
| 141 | * hardware problem.
|
| 142 |
|
| 143 | typedef int user_regset_writeback_fn(struct task_struct *target,
|
| 144 | const struct user_regset *regset,
|
| 145 | int immediate);
|
| 146 |
|
| 147 | |
| 148 | * struct user_regset - accessible thread CPU state
|
| 149 | * @n: Number of slots (registers).
|
| 150 | * @size: Size in bytes of a slot (register).
|
| 151 | * @align: Required alignment, in bytes.
|
| 152 | * @bias: Bias from natural indexing.
|
| 153 | * @core_note_type: ELF note @n_type value used in core dumps.
|
| 154 | * @get: Function to fetch values.
|
| 155 | * @set: Function to store values.
|
| 156 | * @active: Function to report if regset is active, or %NULL.
|
| 157 | * @writeback: Function to write data back to user memory, or %NULL.
|
| 158 | *
|
| 159 | * This data structure describes a machine resource we call a register set.
|
| 160 | * This is part of the state of an individual thread, not necessarily
|
| 161 | * actual CPU registers per se. A register set consists of a number of
|
| 162 | * similar slots, given by @n. Each slot is @size bytes, and aligned to
|
| 163 | * @align bytes (which is at least @size). For dynamically-sized
|
| 164 | * regsets, @n must contain the maximum possible number of slots for the
|
| 165 | * regset.
|
| 166 | *
|
| 167 | * For backward compatibility, the @get and @set methods must pad to, or
|
| 168 | * accept, @n * @size bytes, even if the current regset size is smaller.
|
| 169 | * The precise semantics of these operations depend on the regset being
|
| 170 | * accessed.
|
| 171 | *
|
| 172 | * The functions to which &struct user_regset members point must be
|
| 173 | * called only on the current thread or on a thread that is in
|
| 174 | * %TASK_STOPPED or %TASK_TRACED state, that we are guaranteed will not
|
| 175 | * be woken up and return to user mode, and that we have called
|
| 176 | * wait_task_inactive() on. (The target thread always might wake up for
|
| 177 | * SIGKILL while these functions are working, in which case that
|
| 178 | * thread's user_regset state might be scrambled.)
|
| 179 | *
|
| 180 | * The @pos argument must be aligned according to @align; the @count
|
| 181 | * argument must be a multiple of @size. These functions are not
|
| 182 | * responsible for checking for invalid arguments.
|
| 183 | *
|
| 184 | * When there is a natural value to use as an index, @bias gives the
|
| 185 | * difference between the natural index and the slot index for the
|
| 186 | * register set. For example, x86 GDT segment descriptors form a regset;
|
| 187 | * the segment selector produces a natural index, but only a subset of
|
| 188 | * that index space is available as a regset (the TLS slots); subtracting
|
| 189 | * @bias from a segment selector index value computes the regset slot.
|
| 190 | *
|
| 191 | * If nonzero, @core_note_type gives the n_type field (NT_* value)
|
| 192 | * of the core file note in which this regset's data appears.
|
| 193 | * NT_PRSTATUS is a special case in that the regset data starts at
|
| 194 | * offsetof(struct elf_prstatus, pr_reg) into the note data; that is
|
| 195 | * part of the per-machine ELF formats userland knows about. In
|
| 196 | * other cases, the core file note contains exactly the whole regset
|
| 197 | * (@n * @size) and nothing else. The core file note is normally
|
| 198 | * omitted when there is an @active function and it returns zero.
|
| 199 |
|
| 200 | struct user_regset {
|
| 201 | user_regset_get2_fn *regset_get;
|
| 202 | user_regset_set_fn *set;
|
| 203 | user_regset_active_fn *active;
|
| 204 | user_regset_writeback_fn *writeback;
|
| 205 | unsigned int n;
|
| 206 | unsigned int size;
|
| 207 | unsigned int align;
|
| 208 | unsigned int bias;
|
| 209 | unsigned int core_note_type;
|
| 210 | };
|
| 211 |
|
| 212 | |
| 213 | * struct user_regset_view - available regsets
|
| 214 | * @name: Identifier, e.g. UTS_MACHINE string.
|
| 215 | * @regsets: Array of @n regsets available in this view.
|
| 216 | * @n: Number of elements in @regsets.
|
| 217 | * @e_machine: ELF header @e_machine %EM_* value written in core dumps.
|
| 218 | * @e_flags: ELF header @e_flags value written in core dumps.
|
| 219 | * @ei_osabi: ELF header @e_ident[%EI_OSABI] value written in core dumps.
|
| 220 | *
|
| 221 | * A regset view is a collection of regsets (&struct user_regset,
|
| 222 | * above). This describes all the state of a thread that can be seen
|
| 223 | * from a given architecture/ABI environment. More than one view might
|
| 224 | * refer to the same &struct user_regset, or more than one regset
|
| 225 | * might refer to the same machine-specific state in the thread. For
|
| 226 | * example, a 32-bit thread's state could be examined from the 32-bit
|
| 227 | * view or from the 64-bit view. Either method reaches the same thread
|
| 228 | * register state, doing appropriate widening or truncation.
|
| 229 |
|
| 230 | struct user_regset_view {
|
| 231 | const char *name;
|
| 232 | const struct user_regset *regsets;
|
| 233 | unsigned int n;
|
| 234 | u32 e_flags;
|
| 235 | u16 e_machine;
|
| 236 | u8 ei_osabi;
|
| 237 | };
|
| 238 |
|
| 239 | |
| 240 | * This is documented here rather than at the definition sites because its
|
| 241 | * implementation is machine-dependent but its interface is universal.
|
| 242 |
|
| 243 | |
| 244 | * task_user_regset_view - Return the process's native regset view.
|
| 245 | * @tsk: a thread of the process in question
|
| 246 | *
|
| 247 | * Return the &struct user_regset_view that is native for the given process.
|
| 248 | * For example, what it would access when it called ptrace().
|
| 249 | * Throughout the life of the process, this only changes at exec.
|
| 250 |
|
| 251 | const struct user_regset_view *task_user_regset_view(struct task_struct *tsk);
|
| 252 |
|
| 253 | static inline int user_regset_copyin(unsigned int *pos, unsigned int *count,
|
| 254 | const void **kbuf,
|
| 255 | const void __user **ubuf, void *data,
|
| 256 | const int start_pos, const int end_pos)
|
| 257 | {
|
| 258 | if (*count == 0)
|
| 259 | return 0;
|
| 260 | BUG_ON(*pos < start_pos);
|
| 261 | if (end_pos < 0 || *pos < end_pos) {
|
| 262 | unsigned int copy = (end_pos < 0 ? *count
|
| 263 | : min(*count, end_pos - *pos));
|
| 264 | data += *pos - start_pos;
|
| 265 | if (*kbuf) {
|
| 266 | memcpy(data, *kbuf, copy);
|
| 267 | *kbuf += copy;
|
| 268 | } else if (__copy_from_user(data, *ubuf, copy))
|
| 269 | return -EFAULT;
|
| 270 | else
|
| 271 | *ubuf += copy;
|
| 272 | *pos += copy;
|
| 273 | *count -= copy;
|
| 274 | }
|
| 275 | return 0;
|
| 276 | }
|
| 277 |
|
| 278 | static inline void user_regset_copyin_ignore(unsigned int *pos,
|
| 279 | unsigned int *count,
|
| 280 | const void **kbuf,
|
| 281 | const void __user **ubuf,
|
| 282 | const int start_pos,
|
| 283 | const int end_pos)
|
| 284 | {
|
| 285 | if (*count == 0)
|
| 286 | return;
|
| 287 | BUG_ON(*pos < start_pos);
|
| 288 | if (end_pos < 0 || *pos < end_pos) {
|
| 289 | unsigned int copy = (end_pos < 0 ? *count
|
| 290 | : min(*count, end_pos - *pos));
|
| 291 | if (*kbuf)
|
| 292 | *kbuf += copy;
|
| 293 | else
|
| 294 | *ubuf += copy;
|
| 295 | *pos += copy;
|
| 296 | *count -= copy;
|
| 297 | }
|
| 298 | }
|
| 299 |
|
| 300 | extern int regset_get(struct task_struct *target,
|
| 301 | const struct user_regset *regset,
|
| 302 | unsigned int size, void *data);
|
| 303 |
|
| 304 | extern int regset_get_alloc(struct task_struct *target,
|
| 305 | const struct user_regset *regset,
|
| 306 | unsigned int size,
|
| 307 | void **data);
|
| 308 |
|
| 309 | extern int copy_regset_to_user(struct task_struct *target,
|
| 310 | const struct user_regset_view *view,
|
| 311 | unsigned int setno, unsigned int offset,
|
| 312 | unsigned int size, void __user *data);
|
| 313 |
|
| 314 | |
| 315 | * copy_regset_from_user - store into thread's user_regset data from user memory
|
| 316 | * @target: thread to be examined
|
| 317 | * @view: &struct user_regset_view describing user thread machine state
|
| 318 | * @setno: index in @view->regsets
|
| 319 | * @offset: offset into the regset data, in bytes
|
| 320 | * @size: amount of data to copy, in bytes
|
| 321 | * @data: user-mode pointer to copy from
|
| 322 |
|
| 323 | static inline int copy_regset_from_user(struct task_struct *target,
|
| 324 | const struct user_regset_view *view,
|
| 325 | unsigned int setno,
|
| 326 | unsigned int offset, unsigned int size,
|
| 327 | const void __user *data)
|
| 328 | {
|
| 329 | const struct user_regset *regset = &view->regsets[setno];
|
| 330 |
|
| 331 | if (!regset->set)
|
| 332 | return -EOPNOTSUPP;
|
| 333 |
|
| 334 | if (!access_ok(data, size))
|
| 335 | return -EFAULT;
|
| 336 |
|
| 337 | return regset->set(target, regset, offset, size, NULL, data);
|
| 338 | }
|
| 339 |
|
| 340 | #endif
|