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- /*
- * Copyright 2010 Tilera Corporation. All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation, version 2.
- *
- * 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, GOOD TITLE or
- * NON INFRINGEMENT. See the GNU General Public License for
- * more details.
- *
- * These routines make two important assumptions:
- *
- * 1. atomic_t is really an int and can be freely cast back and forth
- * (validated in __init_atomic_per_cpu).
- *
- * 2. userspace uses sys_cmpxchg() for all atomic operations, thus using
- * the same locking convention that all the kernel atomic routines use.
- */
- #ifndef _ASM_TILE_FUTEX_H
- #define _ASM_TILE_FUTEX_H
- #ifndef __ASSEMBLY__
- #include <linux/futex.h>
- #include <linux/uaccess.h>
- #include <linux/errno.h>
- #include <asm/atomic.h>
- /*
- * Support macros for futex operations. Do not use these macros directly.
- * They assume "ret", "val", "oparg", and "uaddr" in the lexical context.
- * __futex_cmpxchg() additionally assumes "oldval".
- */
- #ifdef __tilegx__
- #define __futex_asm(OP) \
- asm("1: {" #OP " %1, %3, %4; movei %0, 0 }\n" \
- ".pushsection .fixup,\"ax\"\n" \
- "0: { movei %0, %5; j 9f }\n" \
- ".section __ex_table,\"a\"\n" \
- ".align 8\n" \
- ".quad 1b, 0b\n" \
- ".popsection\n" \
- "9:" \
- : "=r" (ret), "=r" (val), "+m" (*(uaddr)) \
- : "r" (uaddr), "r" (oparg), "i" (-EFAULT))
- #define __futex_set() __futex_asm(exch4)
- #define __futex_add() __futex_asm(fetchadd4)
- #define __futex_or() __futex_asm(fetchor4)
- #define __futex_andn() ({ oparg = ~oparg; __futex_asm(fetchand4); })
- #define __futex_cmpxchg() \
- ({ __insn_mtspr(SPR_CMPEXCH_VALUE, oldval); __futex_asm(cmpexch4); })
- #define __futex_xor() \
- ({ \
- u32 oldval, n = oparg; \
- if ((ret = __get_user(oldval, uaddr)) == 0) { \
- do { \
- oparg = oldval ^ n; \
- __futex_cmpxchg(); \
- } while (ret == 0 && oldval != val); \
- } \
- })
- /* No need to prefetch, since the atomic ops go to the home cache anyway. */
- #define __futex_prolog()
- #else
- #define __futex_call(FN) \
- { \
- struct __get_user gu = FN((u32 __force *)uaddr, lock, oparg); \
- val = gu.val; \
- ret = gu.err; \
- }
- #define __futex_set() __futex_call(__atomic_xchg)
- #define __futex_add() __futex_call(__atomic_xchg_add)
- #define __futex_or() __futex_call(__atomic_or)
- #define __futex_andn() __futex_call(__atomic_andn)
- #define __futex_xor() __futex_call(__atomic_xor)
- #define __futex_cmpxchg() \
- { \
- struct __get_user gu = __atomic_cmpxchg((u32 __force *)uaddr, \
- lock, oldval, oparg); \
- val = gu.val; \
- ret = gu.err; \
- }
- /*
- * Find the lock pointer for the atomic calls to use, and issue a
- * prefetch to the user address to bring it into cache. Similar to
- * __atomic_setup(), but we can't do a read into the L1 since it might
- * fault; instead we do a prefetch into the L2.
- */
- #define __futex_prolog() \
- int *lock; \
- __insn_prefetch(uaddr); \
- lock = __atomic_hashed_lock((int __force *)uaddr)
- #endif
- static inline int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval,
- u32 __user *uaddr)
- {
- int uninitialized_var(val), ret;
- __futex_prolog();
- /* The 32-bit futex code makes this assumption, so validate it here. */
- BUILD_BUG_ON(sizeof(atomic_t) != sizeof(int));
- pagefault_disable();
- switch (op) {
- case FUTEX_OP_SET:
- __futex_set();
- break;
- case FUTEX_OP_ADD:
- __futex_add();
- break;
- case FUTEX_OP_OR:
- __futex_or();
- break;
- case FUTEX_OP_ANDN:
- __futex_andn();
- break;
- case FUTEX_OP_XOR:
- __futex_xor();
- break;
- default:
- ret = -ENOSYS;
- break;
- }
- pagefault_enable();
- if (!ret)
- *oval = val;
- return ret;
- }
- static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
- u32 oldval, u32 oparg)
- {
- int ret, val;
- __futex_prolog();
- if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
- return -EFAULT;
- __futex_cmpxchg();
- *uval = val;
- return ret;
- }
- #endif /* !__ASSEMBLY__ */
- #endif /* _ASM_TILE_FUTEX_H */
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