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