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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>
126 lines
2.6 KiB
C
126 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_PARISC_FUTEX_H
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#define _ASM_PARISC_FUTEX_H
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#ifdef __KERNEL__
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#include <linux/futex.h>
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#include <linux/uaccess.h>
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#include <asm/atomic.h>
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#include <asm/errno.h>
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/* The following has to match the LWS code in syscall.S. We have
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sixteen four-word locks. */
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static inline void
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_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
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{
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extern u32 lws_lock_start[];
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long index = ((long)uaddr & 0xf0) >> 2;
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arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
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local_irq_save(*flags);
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arch_spin_lock(s);
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}
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static inline void
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_futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags)
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{
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extern u32 lws_lock_start[];
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long index = ((long)uaddr & 0xf0) >> 2;
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arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
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arch_spin_unlock(s);
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local_irq_restore(*flags);
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}
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static inline int
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arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
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{
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unsigned long int flags;
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int oldval, ret;
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u32 tmp;
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_futex_spin_lock_irqsave(uaddr, &flags);
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pagefault_disable();
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ret = -EFAULT;
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if (unlikely(get_user(oldval, uaddr) != 0))
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goto out_pagefault_enable;
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ret = 0;
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tmp = oldval;
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switch (op) {
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case FUTEX_OP_SET:
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tmp = oparg;
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break;
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case FUTEX_OP_ADD:
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tmp += oparg;
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break;
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case FUTEX_OP_OR:
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tmp |= oparg;
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break;
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case FUTEX_OP_ANDN:
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tmp &= ~oparg;
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break;
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case FUTEX_OP_XOR:
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tmp ^= oparg;
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break;
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default:
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ret = -ENOSYS;
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}
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if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
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ret = -EFAULT;
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out_pagefault_enable:
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pagefault_enable();
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_futex_spin_unlock_irqrestore(uaddr, &flags);
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if (!ret)
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*oval = oldval;
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return ret;
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}
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static inline int
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futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
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u32 oldval, u32 newval)
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{
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u32 val;
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unsigned long flags;
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/* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
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* our gateway page, and causes no end of trouble...
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*/
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if (uaccess_kernel() && !uaddr)
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return -EFAULT;
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if (!access_ok(uaddr, sizeof(u32)))
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return -EFAULT;
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/* HPPA has no cmpxchg in hardware and therefore the
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* best we can do here is use an array of locks. The
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* lock selected is based on a hash of the userspace
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* address. This should scale to a couple of CPUs.
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*/
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_futex_spin_lock_irqsave(uaddr, &flags);
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if (unlikely(get_user(val, uaddr) != 0)) {
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_futex_spin_unlock_irqrestore(uaddr, &flags);
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return -EFAULT;
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}
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if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
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_futex_spin_unlock_irqrestore(uaddr, &flags);
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return -EFAULT;
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}
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*uval = val;
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_futex_spin_unlock_irqrestore(uaddr, &flags);
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return 0;
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}
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#endif /*__KERNEL__*/
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#endif /*_ASM_PARISC_FUTEX_H*/
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