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Diffstat (limited to 'arch/tile/include/asm/futex.h')
| -rw-r--r-- | arch/tile/include/asm/futex.h | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/arch/tile/include/asm/futex.h b/arch/tile/include/asm/futex.h new file mode 100644 index 000000000..1a6ef1b69 --- /dev/null +++ b/arch/tile/include/asm/futex.h @@ -0,0 +1,196 @@ +/* + * 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 futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) +{ + int op = (encoded_op >> 28) & 7; + int cmp = (encoded_op >> 24) & 15; + int oparg = (encoded_op << 8) >> 20; + int cmparg = (encoded_op << 20) >> 20; + 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)); + + if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) + oparg = 1 << oparg; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; + + 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) { + switch (cmp) { + case FUTEX_OP_CMP_EQ: + ret = (val == cmparg); + break; + case FUTEX_OP_CMP_NE: + ret = (val != cmparg); + break; + case FUTEX_OP_CMP_LT: + ret = (val < cmparg); + break; + case FUTEX_OP_CMP_GE: + ret = (val >= cmparg); + break; + case FUTEX_OP_CMP_LE: + ret = (val <= cmparg); + break; + case FUTEX_OP_CMP_GT: + ret = (val > cmparg); + break; + default: + ret = -ENOSYS; + } + } + 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 */ |