| /* |
| * Copyright (C) 2012 ARM Ltd. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| #ifndef __ASM_FUTEX_H |
| #define __ASM_FUTEX_H |
| |
| #ifdef __KERNEL__ |
| |
| #include <linux/futex.h> |
| #include <linux/uaccess.h> |
| |
| #include <asm/errno.h> |
| |
| #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \ |
| do { \ |
| uaccess_enable(); \ |
| asm volatile( \ |
| " prfm pstl1strm, %2\n" \ |
| "1: ldxr %w1, %2\n" \ |
| insn "\n" \ |
| "2: stlxr %w3, %w0, %2\n" \ |
| " cbnz %w3, 1b\n" \ |
| " dmb ish\n" \ |
| "3:\n" \ |
| " .pushsection .fixup,\"ax\"\n" \ |
| " .align 2\n" \ |
| "4: mov %w0, %w5\n" \ |
| " b 3b\n" \ |
| " .popsection\n" \ |
| _ASM_EXTABLE(1b, 4b) \ |
| _ASM_EXTABLE(2b, 4b) \ |
| : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp) \ |
| : "r" (oparg), "Ir" (-EFAULT) \ |
| : "memory"); \ |
| uaccess_disable(); \ |
| } while (0) |
| |
| static inline int |
| arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr) |
| { |
| int oldval = 0, ret, tmp; |
| u32 __user *uaddr = __uaccess_mask_ptr(_uaddr); |
| |
| pagefault_disable(); |
| |
| switch (op) { |
| case FUTEX_OP_SET: |
| __futex_atomic_op("mov %w0, %w4", |
| ret, oldval, uaddr, tmp, oparg); |
| break; |
| case FUTEX_OP_ADD: |
| __futex_atomic_op("add %w0, %w1, %w4", |
| ret, oldval, uaddr, tmp, oparg); |
| break; |
| case FUTEX_OP_OR: |
| __futex_atomic_op("orr %w0, %w1, %w4", |
| ret, oldval, uaddr, tmp, oparg); |
| break; |
| case FUTEX_OP_ANDN: |
| __futex_atomic_op("and %w0, %w1, %w4", |
| ret, oldval, uaddr, tmp, ~oparg); |
| break; |
| case FUTEX_OP_XOR: |
| __futex_atomic_op("eor %w0, %w1, %w4", |
| ret, oldval, uaddr, tmp, oparg); |
| break; |
| default: |
| ret = -ENOSYS; |
| } |
| |
| pagefault_enable(); |
| |
| if (!ret) |
| *oval = oldval; |
| |
| return ret; |
| } |
| |
| static inline int |
| futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, |
| u32 oldval, u32 newval) |
| { |
| int ret = 0; |
| u32 val, tmp; |
| u32 __user *uaddr; |
| |
| if (!access_ok(VERIFY_WRITE, _uaddr, sizeof(u32))) |
| return -EFAULT; |
| |
| uaddr = __uaccess_mask_ptr(_uaddr); |
| uaccess_enable(); |
| asm volatile("// futex_atomic_cmpxchg_inatomic\n" |
| " prfm pstl1strm, %2\n" |
| "1: ldxr %w1, %2\n" |
| " sub %w3, %w1, %w4\n" |
| " cbnz %w3, 3f\n" |
| "2: stlxr %w3, %w5, %2\n" |
| " cbnz %w3, 1b\n" |
| " dmb ish\n" |
| "3:\n" |
| " .pushsection .fixup,\"ax\"\n" |
| "4: mov %w0, %w6\n" |
| " b 3b\n" |
| " .popsection\n" |
| _ASM_EXTABLE(1b, 4b) |
| _ASM_EXTABLE(2b, 4b) |
| : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp) |
| : "r" (oldval), "r" (newval), "Ir" (-EFAULT) |
| : "memory"); |
| uaccess_disable(); |
| |
| *uval = val; |
| return ret; |
| } |
| |
| #endif /* __KERNEL__ */ |
| #endif /* __ASM_FUTEX_H */ |