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96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
129 lines
4.3 KiB
C
129 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*---------------------------------------------------------------------------+
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| fpu_system.h |
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| Copyright (C) 1992,1994,1997 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@suburbia.net |
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+---------------------------------------------------------------------------*/
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#ifndef _FPU_SYSTEM_H
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#define _FPU_SYSTEM_H
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/* system dependent definitions */
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <asm/desc.h>
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#include <asm/mmu_context.h>
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static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)
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{
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static struct desc_struct zero_desc;
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struct desc_struct ret = zero_desc;
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#ifdef CONFIG_MODIFY_LDT_SYSCALL
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seg >>= 3;
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mutex_lock(¤t->mm->context.lock);
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if (current->mm->context.ldt && seg < current->mm->context.ldt->nr_entries)
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ret = current->mm->context.ldt->entries[seg];
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mutex_unlock(¤t->mm->context.lock);
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#endif
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return ret;
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}
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#define SEG_TYPE_WRITABLE (1U << 1)
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#define SEG_TYPE_EXPANDS_DOWN (1U << 2)
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#define SEG_TYPE_EXECUTE (1U << 3)
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#define SEG_TYPE_EXPAND_MASK (SEG_TYPE_EXPANDS_DOWN | SEG_TYPE_EXECUTE)
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#define SEG_TYPE_EXECUTE_MASK (SEG_TYPE_WRITABLE | SEG_TYPE_EXECUTE)
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static inline unsigned long seg_get_base(struct desc_struct *d)
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{
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unsigned long base = (unsigned long)d->base2 << 24;
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return base | ((unsigned long)d->base1 << 16) | d->base0;
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}
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static inline unsigned long seg_get_limit(struct desc_struct *d)
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{
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return ((unsigned long)d->limit1 << 16) | d->limit0;
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}
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static inline unsigned long seg_get_granularity(struct desc_struct *d)
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{
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return d->g ? 4096 : 1;
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}
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static inline bool seg_expands_down(struct desc_struct *d)
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{
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return (d->type & SEG_TYPE_EXPAND_MASK) == SEG_TYPE_EXPANDS_DOWN;
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}
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static inline bool seg_execute_only(struct desc_struct *d)
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{
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return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_EXECUTE;
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}
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static inline bool seg_writable(struct desc_struct *d)
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{
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return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_WRITABLE;
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}
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#define I387 (¤t->thread.fpu.state)
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#define FPU_info (I387->soft.info)
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#define FPU_CS (*(unsigned short *) &(FPU_info->regs->cs))
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#define FPU_SS (*(unsigned short *) &(FPU_info->regs->ss))
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#define FPU_DS (*(unsigned short *) &(FPU_info->regs->ds))
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#define FPU_EAX (FPU_info->regs->ax)
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#define FPU_EFLAGS (FPU_info->regs->flags)
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#define FPU_EIP (FPU_info->regs->ip)
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#define FPU_ORIG_EIP (FPU_info->___orig_eip)
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#define FPU_lookahead (I387->soft.lookahead)
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/* nz if ip_offset and cs_selector are not to be set for the current
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instruction. */
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#define no_ip_update (*(u_char *)&(I387->soft.no_update))
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#define FPU_rm (*(u_char *)&(I387->soft.rm))
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/* Number of bytes of data which can be legally accessed by the current
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instruction. This only needs to hold a number <= 108, so a byte will do. */
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#define access_limit (*(u_char *)&(I387->soft.alimit))
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#define partial_status (I387->soft.swd)
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#define control_word (I387->soft.cwd)
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#define fpu_tag_word (I387->soft.twd)
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#define registers (I387->soft.st_space)
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#define top (I387->soft.ftop)
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#define instruction_address (*(struct address *)&I387->soft.fip)
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#define operand_address (*(struct address *)&I387->soft.foo)
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#define FPU_access_ok(y,z) if ( !access_ok(y,z) ) \
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math_abort(FPU_info,SIGSEGV)
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#define FPU_abort math_abort(FPU_info, SIGSEGV)
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#undef FPU_IGNORE_CODE_SEGV
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#ifdef FPU_IGNORE_CODE_SEGV
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/* access_ok() is very expensive, and causes the emulator to run
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about 20% slower if applied to the code. Anyway, errors due to bad
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code addresses should be much rarer than errors due to bad data
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addresses. */
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#define FPU_code_access_ok(z)
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#else
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/* A simpler test than access_ok() can probably be done for
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FPU_code_access_ok() because the only possible error is to step
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past the upper boundary of a legal code area. */
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#define FPU_code_access_ok(z) FPU_access_ok((void __user *)FPU_EIP,z)
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#endif
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#define FPU_get_user(x,y) get_user((x),(y))
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#define FPU_put_user(x,y) put_user((x),(y))
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#endif
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