Le 13/08/2025 à 17:57, Thomas Gleixner a écrit :
Replace the can_do_masked_user_access() conditional with the generic macro.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
---
arch/x86/include/asm/futex.h | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
--- a/arch/x86/include/asm/futex.h
+++ b/arch/x86/include/asm/futex.h
@@ -48,9 +48,7 @@ do { \
static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
u32 __user *uaddr)
{
- if (can_do_masked_user_access())
- uaddr = masked_user_access_begin(uaddr);
- else if (!user_access_begin(uaddr, sizeof(u32)))
+ if (!user_write_masked_begin(uaddr))
You are replacing a user_access_begin() by a macro that calls
user_write_access_begin(). I means that reads will not be allowed,
allthough arch_futex_atomic_op_inuser() performs read-then-write, so it
requires a full read-write user access.
return -EFAULT;
switch (op) {
@@ -74,7 +72,7 @@ static __always_inline int arch_futex_at
user_access_end();
return -ENOSYS;
}
- user_access_end();
+ user_write_access_end();
Same, can't be changed to write-only, read permission is required as well.
return 0;
Efault:
user_access_end();
@@ -86,9 +84,7 @@ static inline int futex_atomic_cmpxchg_i
{
int ret = 0;
- if (can_do_masked_user_access())
- uaddr = masked_user_access_begin(uaddr);
- else if (!user_access_begin(uaddr, sizeof(u32)))
+ if (!user_write_masked_begin(uaddr))
Same, read access is also needed.
return -EFAULT;
asm volatile("\n"
"1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"
@@ -98,7 +94,7 @@ static inline int futex_atomic_cmpxchg_i
: "r" (newval), "1" (oldval)
: "memory"
);
- user_access_end();
+ user_write_access_end();
Same, read access is also needed.
*uval = oldval;
return ret;
}
