Commit e02718c9 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

x86/futex: Convert to scoped user access 



Replace the open coded implementation with the scoped user access
guards

No functional change intended.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20251027083745.799714344@linutronix.de
parent e4e28fd6

arch/x86/include/asm/futex.h

+33 −42
Original line number Diff line number Diff line
@@ -48,18 +48,13 @@ 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)))

		return -EFAULT;



	scoped_user_rw_access(uaddr, Efault) {

		switch (op) {

		case FUTEX_OP_SET:

			unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault);

			break;

		case FUTEX_OP_ADD:

		unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval,

				   uaddr, oparg, Efault);

			unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, uaddr, oparg, Efault);

			break;

		case FUTEX_OP_OR:

			unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault);
@@ -71,13 +66,11 @@ static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *o 
			unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault);

			break;

		default:

		user_access_end();

			return -ENOSYS;

		}

	user_access_end();

	}

	return 0;

Efault:

	user_access_end();

	return -EFAULT;

}
@@ -86,21 +79,19 @@ static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 
{

	int ret = 0;



	if (can_do_masked_user_access())

		uaddr = masked_user_access_begin(uaddr);

	else if (!user_access_begin(uaddr, sizeof(u32)))

		return -EFAULT;

	asm volatile("\n"

	scoped_user_rw_access(uaddr, Efault) {

		asm_inline volatile("\n"

				    "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"

				    "2:\n"

		_ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \

				    _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0)

				    : "+r" (ret), "=a" (oldval), "+m" (*uaddr)

				    : "r" (newval), "1" (oldval)

		: "memory"

	);

	user_access_end();

				    : "memory");

		*uval = oldval;

	}

	return ret;

Efault:

	return -EFAULT;

}



#endif