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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 13:43:55 +08:00
linux-next/include/linux/regset.h
Linus Torvalds ed2d265d12 The following text was taken from the original review request:
"[RFC - PATCH 0/7] consolidation of BUG support code."
 		https://lkml.org/lkml/2012/1/26/525
 --
 
 The changes shown here are to unify linux's BUG support under
 the one <linux/bug.h> file.  Due to historical reasons, we have
 some BUG code in bug.h and some in kernel.h -- i.e. the support for
 BUILD_BUG in linux/kernel.h predates the addition of linux/bug.h,
 but old code in kernel.h wasn't moved to bug.h at that time.  As
 a band-aid, kernel.h was including <asm/bug.h> to pseudo link them.
 
 This has caused confusion[1] and general yuck/WTF[2] reactions.
 Here is an example that violates the principle of least surprise:
 
       CC      lib/string.o
       lib/string.c: In function 'strlcat':
       lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON'
       make[2]: *** [lib/string.o] Error 1
       $
       $ grep linux/bug.h lib/string.c
       #include <linux/bug.h>
       $
 
 We've included <linux/bug.h> for the BUG infrastructure and yet we
 still get a compile fail!  [We've not kernel.h for BUILD_BUG_ON.]
 Ugh - very confusing for someone who is new to kernel development.
 
 With the above in mind, the goals of this changeset are:
 
 1) find and fix any include/*.h files that were relying on the
    implicit presence of BUG code.
 2) find and fix any C files that were consuming kernel.h and
    hence relying on implicitly getting some/all BUG code.
 3) Move the BUG related code living in kernel.h to <linux/bug.h>
 4) remove the asm/bug.h from kernel.h to finally break the chain.
 
 During development, the order was more like 3-4, build-test, 1-2.
 But to ensure that git history for bisect doesn't get needless
 build failures introduced, the commits have been reorderd to fix
 the problem areas in advance.
 
 [1]  https://lkml.org/lkml/2012/1/3/90
 [2]  https://lkml.org/lkml/2012/1/17/414
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Merge tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

Pull <linux/bug.h> cleanup from Paul Gortmaker:
 "The changes shown here are to unify linux's BUG support under the one
  <linux/bug.h> file.  Due to historical reasons, we have some BUG code
  in bug.h and some in kernel.h -- i.e.  the support for BUILD_BUG in
  linux/kernel.h predates the addition of linux/bug.h, but old code in
  kernel.h wasn't moved to bug.h at that time.  As a band-aid, kernel.h
  was including <asm/bug.h> to pseudo link them.

  This has caused confusion[1] and general yuck/WTF[2] reactions.  Here
  is an example that violates the principle of least surprise:

      CC      lib/string.o
      lib/string.c: In function 'strlcat':
      lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON'
      make[2]: *** [lib/string.o] Error 1
      $
      $ grep linux/bug.h lib/string.c
      #include <linux/bug.h>
      $

  We've included <linux/bug.h> for the BUG infrastructure and yet we
  still get a compile fail! [We've not kernel.h for BUILD_BUG_ON.] Ugh -
  very confusing for someone who is new to kernel development.

  With the above in mind, the goals of this changeset are:

  1) find and fix any include/*.h files that were relying on the
     implicit presence of BUG code.
  2) find and fix any C files that were consuming kernel.h and hence
     relying on implicitly getting some/all BUG code.
  3) Move the BUG related code living in kernel.h to <linux/bug.h>
  4) remove the asm/bug.h from kernel.h to finally break the chain.

  During development, the order was more like 3-4, build-test, 1-2.  But
  to ensure that git history for bisect doesn't get needless build
  failures introduced, the commits have been reorderd to fix the problem
  areas in advance.

	[1]  https://lkml.org/lkml/2012/1/3/90
	[2]  https://lkml.org/lkml/2012/1/17/414"

Fix up conflicts (new radeon file, reiserfs header cleanups) as per Paul
and linux-next.

* tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
  kernel.h: doesn't explicitly use bug.h, so don't include it.
  bug: consolidate BUILD_BUG_ON with other bug code
  BUG: headers with BUG/BUG_ON etc. need linux/bug.h
  bug.h: add include of it to various implicit C users
  lib: fix implicit users of kernel.h for TAINT_WARN
  spinlock: macroize assert_spin_locked to avoid bug.h dependency
  x86: relocate get/set debugreg fcns to include/asm/debugreg.
2012-03-24 10:08:39 -07:00

376 lines
13 KiB
C

/*
* User-mode machine state access
*
* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* 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);
/**
* 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).
*
* These functions 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;
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(VERIFY_WRITE, 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(VERIFY_READ, data, size))
return -EFAULT;
return regset->set(target, regset, offset, size, NULL, data);
}
#endif /* <linux/regset.h> */