| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * User-mode machine state access |
| * |
| * Copyright (C) 2007 Red Hat, Inc. All rights reserved. |
| * |
| * Red Hat Author: Roland McGrath. |
| */ |
| |
| #ifndef _LINUX_REGSET_H |
| #define _LINUX_REGSET_H 1 |
| |
| #include <linux/compiler.h> |
| #include <linux/types.h> |
| #include <linux/bug.h> |
| #include <linux/uaccess.h> |
| struct task_struct; |
| struct user_regset; |
| |
| struct membuf { |
| void *p; |
| size_t left; |
| }; |
| |
| static inline int membuf_zero(struct membuf *s, size_t size) |
| { |
| if (s->left) { |
| if (size > s->left) |
| size = s->left; |
| memset(s->p, 0, size); |
| s->p += size; |
| s->left -= size; |
| } |
| return s->left; |
| } |
| |
| static inline int membuf_write(struct membuf *s, const void *v, size_t size) |
| { |
| if (s->left) { |
| if (size > s->left) |
| size = s->left; |
| memcpy(s->p, v, size); |
| s->p += size; |
| s->left -= size; |
| } |
| return s->left; |
| } |
| |
| static inline struct membuf membuf_at(const struct membuf *s, size_t offs) |
| { |
| struct membuf n = *s; |
| |
| if (offs > n.left) |
| offs = n.left; |
| n.p += offs; |
| n.left -= offs; |
| |
| return n; |
| } |
| |
| /* current s->p must be aligned for v; v must be a scalar */ |
| #define membuf_store(s, v) \ |
| ({ \ |
| struct membuf *__s = (s); \ |
| if (__s->left) { \ |
| typeof(v) __v = (v); \ |
| size_t __size = sizeof(__v); \ |
| if (unlikely(__size > __s->left)) { \ |
| __size = __s->left; \ |
| memcpy(__s->p, &__v, __size); \ |
| } else { \ |
| *(typeof(__v + 0) *)__s->p = __v; \ |
| } \ |
| __s->p += __size; \ |
| __s->left -= __size; \ |
| } \ |
| __s->left;}) |
| |
| /** |
| * user_regset_active_fn - type of @active function in &struct user_regset |
| * @target: thread being examined |
| * @regset: regset being examined |
| * |
| * Return -%ENODEV if not available on the hardware found. |
| * Return %0 if no interesting state in this thread. |
| * Return >%0 number of @size units of interesting state. |
| * Any get call fetching state beyond that number will |
| * see the default initialization state for this data, |
| * so a caller that knows what the default state is need |
| * not copy it all out. |
| * This call is optional; the pointer is %NULL if there |
| * is no inexpensive check to yield a value < @n. |
| */ |
| typedef int user_regset_active_fn(struct task_struct *target, |
| const struct user_regset *regset); |
| |
| typedef int user_regset_get2_fn(struct task_struct *target, |
| const struct user_regset *regset, |
| struct membuf to); |
| |
| /** |
| * user_regset_set_fn - type of @set function in &struct user_regset |
| * @target: thread being examined |
| * @regset: regset being examined |
| * @pos: offset into the regset data to access, in bytes |
| * @count: amount of data to copy, in bytes |
| * @kbuf: if not %NULL, a kernel-space pointer to copy from |
| * @ubuf: if @kbuf is %NULL, a user-space pointer to copy from |
| * |
| * Store register values. Return %0 on success; -%EIO or -%ENODEV |
| * are usual failure returns. The @pos and @count values are in |
| * bytes, but must be properly aligned. If @kbuf is non-null, that |
| * buffer is used and @ubuf is ignored. If @kbuf is %NULL, then |
| * ubuf gives a userland pointer to access directly, and an -%EFAULT |
| * return value is possible. |
| */ |
| typedef int user_regset_set_fn(struct task_struct *target, |
| const struct user_regset *regset, |
| unsigned int pos, unsigned int count, |
| const void *kbuf, const void __user *ubuf); |
| |
| /** |
| * user_regset_writeback_fn - type of @writeback function in &struct user_regset |
| * @target: thread being examined |
| * @regset: regset being examined |
| * @immediate: zero if writeback at completion of next context switch is OK |
| * |
| * This call is optional; usually the pointer is %NULL. When |
| * provided, there is some user memory associated with this regset's |
| * hardware, such as memory backing cached register data on register |
| * window machines; the regset's data controls what user memory is |
| * used (e.g. via the stack pointer value). |
| * |
| * Write register data back to user memory. If the @immediate flag |
| * is nonzero, it must be written to the user memory so uaccess or |
| * access_process_vm() can see it when this call returns; if zero, |
| * then it must be written back by the time the task completes a |
| * context switch (as synchronized with wait_task_inactive()). |
| * Return %0 on success or if there was nothing to do, -%EFAULT for |
| * a memory problem (bad stack pointer or whatever), or -%EIO for a |
| * hardware problem. |
| */ |
| typedef int user_regset_writeback_fn(struct task_struct *target, |
| const struct user_regset *regset, |
| int immediate); |
| |
| /** |
| * struct user_regset - accessible thread CPU state |
| * @n: Number of slots (registers). |
| * @size: Size in bytes of a slot (register). |
| * @align: Required alignment, in bytes. |
| * @bias: Bias from natural indexing. |
| * @core_note_type: ELF note @n_type value used in core dumps. |
| * @get: Function to fetch values. |
| * @set: Function to store values. |
| * @active: Function to report if regset is active, or %NULL. |
| * @writeback: Function to write data back to user memory, or %NULL. |
| * |
| * This data structure describes a machine resource we call a register set. |
| * This is part of the state of an individual thread, not necessarily |
| * actual CPU registers per se. A register set consists of a number of |
| * similar slots, given by @n. Each slot is @size bytes, and aligned to |
| * @align bytes (which is at least @size). For dynamically-sized |
| * regsets, @n must contain the maximum possible number of slots for the |
| * regset. |
| * |
| * For backward compatibility, the @get and @set methods must pad to, or |
| * accept, @n * @size bytes, even if the current regset size is smaller. |
| * The precise semantics of these operations depend on the regset being |
| * accessed. |
| * |
| * The functions to which &struct user_regset members point must be |
| * called only on the current thread or on a thread that is in |
| * %TASK_STOPPED or %TASK_TRACED state, that we are guaranteed will not |
| * be woken up and return to user mode, and that we have called |
| * wait_task_inactive() on. (The target thread always might wake up for |
| * SIGKILL while these functions are working, in which case that |
| * thread's user_regset state might be scrambled.) |
| * |
| * The @pos argument must be aligned according to @align; the @count |
| * argument must be a multiple of @size. These functions are not |
| * responsible for checking for invalid arguments. |
| * |
| * When there is a natural value to use as an index, @bias gives the |
| * difference between the natural index and the slot index for the |
| * register set. For example, x86 GDT segment descriptors form a regset; |
| * the segment selector produces a natural index, but only a subset of |
| * that index space is available as a regset (the TLS slots); subtracting |
| * @bias from a segment selector index value computes the regset slot. |
| * |
| * If nonzero, @core_note_type gives the n_type field (NT_* value) |
| * of the core file note in which this regset's data appears. |
| * NT_PRSTATUS is a special case in that the regset data starts at |
| * offsetof(struct elf_prstatus, pr_reg) into the note data; that is |
| * part of the per-machine ELF formats userland knows about. In |
| * other cases, the core file note contains exactly the whole regset |
| * (@n * @size) and nothing else. The core file note is normally |
| * omitted when there is an @active function and it returns zero. |
| */ |
| struct user_regset { |
| user_regset_get2_fn *regset_get; |
| user_regset_set_fn *set; |
| user_regset_active_fn *active; |
| user_regset_writeback_fn *writeback; |
| unsigned int n; |
| unsigned int size; |
| unsigned int align; |
| unsigned int bias; |
| unsigned int core_note_type; |
| }; |
| |
| /** |
| * struct user_regset_view - available regsets |
| * @name: Identifier, e.g. UTS_MACHINE string. |
| * @regsets: Array of @n regsets available in this view. |
| * @n: Number of elements in @regsets. |
| * @e_machine: ELF header @e_machine %EM_* value written in core dumps. |
| * @e_flags: ELF header @e_flags value written in core dumps. |
| * @ei_osabi: ELF header @e_ident[%EI_OSABI] value written in core dumps. |
| * |
| * A regset view is a collection of regsets (&struct user_regset, |
| * above). This describes all the state of a thread that can be seen |
| * from a given architecture/ABI environment. More than one view might |
| * refer to the same &struct user_regset, or more than one regset |
| * might refer to the same machine-specific state in the thread. For |
| * example, a 32-bit thread's state could be examined from the 32-bit |
| * view or from the 64-bit view. Either method reaches the same thread |
| * register state, doing appropriate widening or truncation. |
| */ |
| struct user_regset_view { |
| const char *name; |
| const struct user_regset *regsets; |
| unsigned int n; |
| u32 e_flags; |
| u16 e_machine; |
| u8 ei_osabi; |
| }; |
| |
| /* |
| * This is documented here rather than at the definition sites because its |
| * implementation is machine-dependent but its interface is universal. |
| */ |
| /** |
| * task_user_regset_view - Return the process's native regset view. |
| * @tsk: a thread of the process in question |
| * |
| * Return the &struct user_regset_view that is native for the given process. |
| * For example, what it would access when it called ptrace(). |
| * Throughout the life of the process, this only changes at exec. |
| */ |
| const struct user_regset_view *task_user_regset_view(struct task_struct *tsk); |
| |
| static inline int user_regset_copyin(unsigned int *pos, unsigned int *count, |
| const void **kbuf, |
| const void __user **ubuf, void *data, |
| const int start_pos, const int end_pos) |
| { |
| if (*count == 0) |
| return 0; |
| BUG_ON(*pos < start_pos); |
| if (end_pos < 0 || *pos < end_pos) { |
| unsigned int copy = (end_pos < 0 ? *count |
| : min(*count, end_pos - *pos)); |
| data += *pos - start_pos; |
| if (*kbuf) { |
| memcpy(data, *kbuf, copy); |
| *kbuf += copy; |
| } else if (__copy_from_user(data, *ubuf, copy)) |
| return -EFAULT; |
| else |
| *ubuf += copy; |
| *pos += copy; |
| *count -= copy; |
| } |
| return 0; |
| } |
| |
| static inline int user_regset_copyin_ignore(unsigned int *pos, |
| unsigned int *count, |
| const void **kbuf, |
| const void __user **ubuf, |
| const int start_pos, |
| const int end_pos) |
| { |
| if (*count == 0) |
| return 0; |
| BUG_ON(*pos < start_pos); |
| if (end_pos < 0 || *pos < end_pos) { |
| unsigned int copy = (end_pos < 0 ? *count |
| : min(*count, end_pos - *pos)); |
| if (*kbuf) |
| *kbuf += copy; |
| else |
| *ubuf += copy; |
| *pos += copy; |
| *count -= copy; |
| } |
| return 0; |
| } |
| |
| extern int regset_get(struct task_struct *target, |
| const struct user_regset *regset, |
| unsigned int size, void *data); |
| |
| extern int regset_get_alloc(struct task_struct *target, |
| const struct user_regset *regset, |
| unsigned int size, |
| void **data); |
| |
| extern int copy_regset_to_user(struct task_struct *target, |
| const struct user_regset_view *view, |
| unsigned int setno, unsigned int offset, |
| unsigned int size, void __user *data); |
| |
| /** |
| * copy_regset_from_user - store into thread's user_regset data from user memory |
| * @target: thread to be examined |
| * @view: &struct user_regset_view describing user thread machine state |
| * @setno: index in @view->regsets |
| * @offset: offset into the regset data, in bytes |
| * @size: amount of data to copy, in bytes |
| * @data: user-mode pointer to copy from |
| */ |
| static inline int copy_regset_from_user(struct task_struct *target, |
| const struct user_regset_view *view, |
| unsigned int setno, |
| unsigned int offset, unsigned int size, |
| const void __user *data) |
| { |
| const struct user_regset *regset = &view->regsets[setno]; |
| |
| if (!regset->set) |
| return -EOPNOTSUPP; |
| |
| if (!access_ok(data, size)) |
| return -EFAULT; |
| |
| return regset->set(target, regset, offset, size, NULL, data); |
| } |
| |
| #endif /* <linux/regset.h> */ |