1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_POWERPC_FUTEX_H 3 #define _ASM_POWERPC_FUTEX_H 4 5 #ifdef __KERNEL__ 6 7 #include <linux/futex.h> 8 #include <linux/uaccess.h> 9 #include <asm/errno.h> 10 #include <asm/synch.h> 11 #include <asm/asm-405.h> 12 13 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ 14 __asm__ __volatile ( \ 15 PPC_ATOMIC_ENTRY_BARRIER \ 16 "1: lwarx %0,0,%2\n" \ 17 insn \ 18 PPC405_ERR77(0, %2) \ 19 "2: stwcx. %1,0,%2\n" \ 20 "bne- 1b\n" \ 21 PPC_ATOMIC_EXIT_BARRIER \ 22 "li %1,0\n" \ 23 "3: .section .fixup,\"ax\"\n" \ 24 "4: li %1,%3\n" \ 25 "b 3b\n" \ 26 ".previous\n" \ 27 EX_TABLE(1b, 4b) \ 28 EX_TABLE(2b, 4b) \ 29 : "=&r" (oldval), "=&r" (ret) \ 30 : "b" (uaddr), "i" (-EFAULT), "r" (oparg) \ 31 : "cr0", "memory") 32 33 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 34 u32 __user *uaddr) 35 { 36 int oldval = 0, ret; 37 38 allow_write_to_user(uaddr, sizeof(*uaddr)); 39 pagefault_disable(); 40 41 switch (op) { 42 case FUTEX_OP_SET: 43 __futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg); 44 break; 45 case FUTEX_OP_ADD: 46 __futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg); 47 break; 48 case FUTEX_OP_OR: 49 __futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg); 50 break; 51 case FUTEX_OP_ANDN: 52 __futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg); 53 break; 54 case FUTEX_OP_XOR: 55 __futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg); 56 break; 57 default: 58 ret = -ENOSYS; 59 } 60 61 pagefault_enable(); 62 63 if (!ret) 64 *oval = oldval; 65 66 prevent_write_to_user(uaddr, sizeof(*uaddr)); 67 return ret; 68 } 69 70 static inline int 71 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 72 u32 oldval, u32 newval) 73 { 74 int ret = 0; 75 u32 prev; 76 77 if (!access_ok(uaddr, sizeof(u32))) 78 return -EFAULT; 79 80 allow_write_to_user(uaddr, sizeof(*uaddr)); 81 __asm__ __volatile__ ( 82 PPC_ATOMIC_ENTRY_BARRIER 83 "1: lwarx %1,0,%3 # futex_atomic_cmpxchg_inatomic\n\ 84 cmpw 0,%1,%4\n\ 85 bne- 3f\n" 86 PPC405_ERR77(0,%3) 87 "2: stwcx. %5,0,%3\n\ 88 bne- 1b\n" 89 PPC_ATOMIC_EXIT_BARRIER 90 "3: .section .fixup,\"ax\"\n\ 91 4: li %0,%6\n\ 92 b 3b\n\ 93 .previous\n" 94 EX_TABLE(1b, 4b) 95 EX_TABLE(2b, 4b) 96 : "+r" (ret), "=&r" (prev), "+m" (*uaddr) 97 : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT) 98 : "cc", "memory"); 99 100 *uval = prev; 101 prevent_write_to_user(uaddr, sizeof(*uaddr)); 102 return ret; 103 } 104 105 #endif /* __KERNEL__ */ 106 #endif /* _ASM_POWERPC_FUTEX_H */ 107