426 lines
15 KiB
C
426 lines
15 KiB
C
/* 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;
|
|
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* user_regset_get_fn - type of @get 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 into
|
|
* @ubuf: if @kbuf is %NULL, a user-space pointer to copy into
|
|
*
|
|
* Fetch 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_get_fn(struct task_struct *target,
|
|
const struct user_regset *regset,
|
|
unsigned int pos, unsigned int count,
|
|
void *kbuf, void __user *ubuf);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* user_regset_get_size_fn - type of @get_size function in &struct user_regset
|
|
* @target: thread being examined
|
|
* @regset: regset being examined
|
|
*
|
|
* This call is optional; usually the pointer is %NULL.
|
|
*
|
|
* When provided, this function must return the current size of regset
|
|
* data, as observed by the @get function in &struct user_regset. The
|
|
* value returned must be a multiple of @size. The returned size is
|
|
* required to be valid only until the next time (if any) @regset is
|
|
* modified for @target.
|
|
*
|
|
* This function is intended for dynamically sized regsets. A regset
|
|
* that is statically sized does not need to implement it.
|
|
*
|
|
* This function should not be called directly: instead, callers should
|
|
* call regset_size() to determine the current size of a regset.
|
|
*/
|
|
typedef unsigned int user_regset_get_size_fn(struct task_struct *target,
|
|
const struct user_regset *regset);
|
|
|
|
/**
|
|
* 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.
|
|
* @get_size: Function to return the regset's size, 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, and @get_size must point to a function that returns the
|
|
* current regset size.
|
|
*
|
|
* Callers that need to know only the current size of the regset and do
|
|
* not care about its internal structure should call regset_size()
|
|
* instead of inspecting @n or calling @get_size.
|
|
*
|
|
* 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_get_fn *get;
|
|
user_regset_set_fn *set;
|
|
user_regset_active_fn *active;
|
|
user_regset_writeback_fn *writeback;
|
|
user_regset_get_size_fn *get_size;
|
|
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);
|
|
|
|
|
|
/*
|
|
* These are helpers for writing regset get/set functions in arch code.
|
|
* Because @start_pos and @end_pos are always compile-time constants,
|
|
* these are inlined into very little code though they look large.
|
|
*
|
|
* Use one or more calls sequentially for each chunk of regset data stored
|
|
* contiguously in memory. Call with constants for @start_pos and @end_pos,
|
|
* giving the range of byte positions in the regset that data corresponds
|
|
* to; @end_pos can be -1 if this chunk is at the end of the regset layout.
|
|
* Each call updates the arguments to point past its chunk.
|
|
*/
|
|
|
|
static inline int user_regset_copyout(unsigned int *pos, unsigned int *count,
|
|
void **kbuf,
|
|
void __user **ubuf, const 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(*kbuf, data, copy);
|
|
*kbuf += copy;
|
|
} else if (__copy_to_user(*ubuf, data, copy))
|
|
return -EFAULT;
|
|
else
|
|
*ubuf += copy;
|
|
*pos += copy;
|
|
*count -= copy;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* These two parallel the two above, but for portions of a regset layout
|
|
* that always read as all-zero or for which writes are ignored.
|
|
*/
|
|
static inline int user_regset_copyout_zero(unsigned int *pos,
|
|
unsigned int *count,
|
|
void **kbuf, 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) {
|
|
memset(*kbuf, 0, copy);
|
|
*kbuf += copy;
|
|
} else if (clear_user(*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;
|
|
}
|
|
|
|
/**
|
|
* copy_regset_to_user - fetch a thread's user_regset data into 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 into
|
|
*/
|
|
static inline 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)
|
|
{
|
|
const struct user_regset *regset = &view->regsets[setno];
|
|
|
|
if (!regset->get)
|
|
return -EOPNOTSUPP;
|
|
|
|
if (!access_ok(data, size))
|
|
return -EFAULT;
|
|
|
|
return regset->get(target, regset, offset, size, NULL, 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);
|
|
}
|
|
|
|
/**
|
|
* regset_size - determine the current size of a regset
|
|
* @target: thread to be examined
|
|
* @regset: regset to be examined
|
|
*
|
|
* Note that the returned size is valid only until the next time
|
|
* (if any) @regset is modified for @target.
|
|
*/
|
|
static inline unsigned int regset_size(struct task_struct *target,
|
|
const struct user_regset *regset)
|
|
{
|
|
if (!regset->get_size)
|
|
return regset->n * regset->size;
|
|
else
|
|
return regset->get_size(target, regset);
|
|
}
|
|
|
|
#endif /* <linux/regset.h> */
|