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![Linus Torvalds](/assets/img/avatar_default.png)
"[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 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAABAgAGBQJPbNwpAAoJEOvOhAQsB9HWrqYP/A0t9VB0nK6e42F0OR2P14MZ GJFtf1B++wwioIrx+KSWSRfSur1C5FKhDbxLR3I/pvkAYl4+T4JvRdMG6xJwxyip CC1kVQQNDjWVVqzjz2x6rYkOffx6dUlw/ERyIyk+OzP+1HzRIsIrugMqbzGLlX0X y0v2Tbd0G6xg1DV8lcRdp95eIzcGuUvdb2iY2LGadWZczEOeSXx64Jz3QCFxg3aL LFU4oovsg8Nb7MRJmqDvHK/oQf5vaTm9WSrS0pvVte0msSQRn8LStYdWC0G9BPCS GwL86h/eLXlUXQlC5GpgWg1QQt5i2QpjBFcVBIG0IT5SgEPMx+gXyiqZva2KwbHu LKicjKtfnzPitQnyEV/N6JyV1fb1U6/MsB7ebU5nCCzt9Gr7MYbjZ44peNeprAtu HMvJ/BNnRr4Ha6nPQNu952AdASPKkxmeXFUwBL1zUbLkOX/bK/vy1ujlcdkFxCD7 fP3t7hghYa737IHk0ehUOhrE4H67hvxTSCKioLUAy/YeN1IcfH/iOQiCBQVLWmoS AqYV6ou9cqgdYoyila2UeAqegb+8xyubPIHt+lebcaKxs5aGsTg+r3vq5juMDAPs iwSVYUDcIw9dHer1lJfo7QCy3QUTRDTxh+LB9VlHXQICgeCK02sLBOi9hbEr4/H8 Ko9g8J3BMxcMkXLHT9ud =PYQT -----END PGP SIGNATURE----- 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.
375 lines
13 KiB
C
375 lines
13 KiB
C
/*
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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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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License v.2.
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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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/**
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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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/**
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* user_regset_get_fn - type of @get 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 into
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* @ubuf: if @kbuf is %NULL, a user-space pointer to copy into
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*
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* Fetch 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_get_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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void *kbuf, void __user *ubuf);
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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).
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*
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* These functions must be called only on the current thread or on a
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* thread that is in %TASK_STOPPED or %TASK_TRACED state, that we are
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* guaranteed will not be woken up and return to user mode, and that we
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* have called wait_task_inactive() on. (The target thread always might
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* wake up for SIGKILL while these functions are working, in which case
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* that 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_get_fn *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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/*
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* These are helpers for writing regset get/set functions in arch code.
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* Because @start_pos and @end_pos are always compile-time constants,
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* these are inlined into very little code though they look large.
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*
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* Use one or more calls sequentially for each chunk of regset data stored
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* contiguously in memory. Call with constants for @start_pos and @end_pos,
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* giving the range of byte positions in the regset that data corresponds
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* to; @end_pos can be -1 if this chunk is at the end of the regset layout.
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* Each call updates the arguments to point past its chunk.
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*/
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static inline int user_regset_copyout(unsigned int *pos, unsigned int *count,
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void **kbuf,
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void __user **ubuf, const 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(*kbuf, data, copy);
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*kbuf += copy;
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} else if (__copy_to_user(*ubuf, data, 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(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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/*
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* These two parallel the two above, but for portions of a regset layout
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* that always read as all-zero or for which writes are ignored.
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*/
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static inline int user_regset_copyout_zero(unsigned int *pos,
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unsigned int *count,
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void **kbuf, 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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memset(*kbuf, 0, copy);
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*kbuf += copy;
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} else if (__clear_user(*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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/**
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* copy_regset_to_user - fetch a thread's user_regset data into 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 into
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*/
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static inline 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,
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unsigned int offset, unsigned int size,
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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->get)
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return -EOPNOTSUPP;
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if (!access_ok(VERIFY_WRITE, data, size))
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return -EFAULT;
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return regset->get(target, regset, offset, size, NULL, data);
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}
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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];
|
|
|
|
if (!regset->set)
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return -EOPNOTSUPP;
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|
|
|
if (!access_ok(VERIFY_READ, data, size))
|
|
return -EFAULT;
|
|
|
|
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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