Commit 870779f4 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/futex: Switch to user_access block 



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

This brings the missing might_fault() check.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6cd202cdc4f939d47822e4ddd3c0856210431a58.1615398498.git.christophe.leroy@csgroup.eu
parent 164dc6ce

arch/powerpc/include/asm/futex.h

+5 −7
Original line number Diff line number Diff line
@@ -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;

}