From 870779f40e99c795ddfafa0dfc43318e51f15127 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Wed, 10 Mar 2021 17:57:06 +0000 Subject: [PATCH] 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: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/6cd202cdc4f939d47822e4ddd3c0856210431a58.1615398498.git.christophe.leroy@csgroup.eu --- arch/powerpc/include/asm/futex.h | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/include/asm/futex.h b/arch/powerpc/include/asm/futex.h index e93ee3202e4c..b3001f8b2c1e 100644 --- a/arch/powerpc/include/asm/futex.h +++ b/arch/powerpc/include/asm/futex.h @@ -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; }