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powerpc/futex: Switch to user_access block

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Use user_access_begin() instead of the access_ok/allow_access sequence.

This brings the missing might_fault() check.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6cd202cdc4f939d47822e4ddd3c0856210431a58.1615398498.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-03-10 17:57:06 +00:00 committed by Michael Ellerman
parent 164dc6ce36
commit 870779f40e
1 changed files with 5 additions and 7 deletions
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12
arch/powerpc/include/asm/futex.h
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@ -33,9 +33,8 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
{
int oldval = 0, ret;
if (!access_ok(uaddr, sizeof(u32)))
if (!user_access_begin(uaddr, sizeof(u32)))
return -EFAULT;
allow_read_write_user(uaddr, uaddr, sizeof(*uaddr));
switch (op) {
case FUTEX_OP_SET:
@ -56,10 +55,10 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
default:
ret = -ENOSYS;
}
user_access_end();
*oval = oldval;
prevent_read_write_user(uaddr, uaddr, sizeof(*uaddr));
return ret;
}
@ -70,11 +69,9 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
int ret = 0;
u32 prev;
if (!access_ok(uaddr, sizeof(u32)))
if (!user_access_begin(uaddr, sizeof(u32)))
return -EFAULT;
allow_read_write_user(uaddr, uaddr, sizeof(*uaddr));
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %1,0,%3 # futex_atomic_cmpxchg_inatomic\n\
@ -93,8 +90,9 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
: "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
: "cc", "memory");
user_access_end();
*uval = prev;
prevent_read_write_user(uaddr, uaddr, sizeof(*uaddr));
return ret;
}