1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_PARISC_FUTEX_H 3 #define _ASM_PARISC_FUTEX_H 4 5 #ifdef __KERNEL__ 6 7 #include <linux/futex.h> 8 #include <linux/uaccess.h> 9 #include <asm/atomic.h> 10 #include <asm/errno.h> 11 12 /* The following has to match the LWS code in syscall.S. We have 13 sixteen four-word locks. */ 14 15 static inline void 16 _futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags) 17 { 18 extern u32 lws_lock_start[]; 19 long index = ((long)uaddr & 0xf0) >> 2; 20 arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index]; 21 local_irq_save(*flags); 22 arch_spin_lock(s); 23 } 24 25 static inline void 26 _futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags) 27 { 28 extern u32 lws_lock_start[]; 29 long index = ((long)uaddr & 0xf0) >> 2; 30 arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index]; 31 arch_spin_unlock(s); 32 local_irq_restore(*flags); 33 } 34 35 static inline int 36 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) 37 { 38 unsigned long int flags; 39 int oldval, ret; 40 u32 tmp; 41 42 _futex_spin_lock_irqsave(uaddr, &flags); 43 44 ret = -EFAULT; 45 if (unlikely(get_user(oldval, uaddr) != 0)) 46 goto out_pagefault_enable; 47 48 ret = 0; 49 tmp = oldval; 50 51 switch (op) { 52 case FUTEX_OP_SET: 53 tmp = oparg; 54 break; 55 case FUTEX_OP_ADD: 56 tmp += oparg; 57 break; 58 case FUTEX_OP_OR: 59 tmp |= oparg; 60 break; 61 case FUTEX_OP_ANDN: 62 tmp &= ~oparg; 63 break; 64 case FUTEX_OP_XOR: 65 tmp ^= oparg; 66 break; 67 default: 68 ret = -ENOSYS; 69 } 70 71 if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) 72 ret = -EFAULT; 73 74 out_pagefault_enable: 75 _futex_spin_unlock_irqrestore(uaddr, &flags); 76 77 if (!ret) 78 *oval = oldval; 79 80 return ret; 81 } 82 83 static inline int 84 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 85 u32 oldval, u32 newval) 86 { 87 u32 val; 88 unsigned long flags; 89 90 /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is 91 * our gateway page, and causes no end of trouble... 92 */ 93 if (uaccess_kernel() && !uaddr) 94 return -EFAULT; 95 96 if (!access_ok(uaddr, sizeof(u32))) 97 return -EFAULT; 98 99 /* HPPA has no cmpxchg in hardware and therefore the 100 * best we can do here is use an array of locks. The 101 * lock selected is based on a hash of the userspace 102 * address. This should scale to a couple of CPUs. 103 */ 104 105 _futex_spin_lock_irqsave(uaddr, &flags); 106 if (unlikely(get_user(val, uaddr) != 0)) { 107 _futex_spin_unlock_irqrestore(uaddr, &flags); 108 return -EFAULT; 109 } 110 111 if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) { 112 _futex_spin_unlock_irqrestore(uaddr, &flags); 113 return -EFAULT; 114 } 115 116 *uval = val; 117 _futex_spin_unlock_irqrestore(uaddr, &flags); 118 119 return 0; 120 } 121 122 #endif /*__KERNEL__*/ 123 #endif /*_ASM_PARISC_FUTEX_H*/ 124