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Diffstat (limited to '')
| -rw-r--r-- | arch/xtensa/include/asm/futex.h | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/futex.h b/arch/xtensa/include/asm/futex.h new file mode 100644 index 000000000..a1a27b2ea --- /dev/null +++ b/arch/xtensa/include/asm/futex.h @@ -0,0 +1,163 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Atomic futex routines + * + * Based on the PowerPC implementataion + * + * Copyright (C) 2013 TangoTec Ltd. + * + * Baruch Siach <baruch@tkos.co.il> + */ + +#ifndef _ASM_XTENSA_FUTEX_H +#define _ASM_XTENSA_FUTEX_H + +#include <linux/futex.h> +#include <linux/uaccess.h> +#include <linux/errno.h> + +#if XCHAL_HAVE_EXCLUSIVE +#define __futex_atomic_op(insn, ret, old, uaddr, arg) \ + __asm__ __volatile( \ + "1: l32ex %[oldval], %[addr]\n" \ + insn "\n" \ + "2: s32ex %[newval], %[addr]\n" \ + " getex %[newval]\n" \ + " beqz %[newval], 1b\n" \ + " movi %[newval], 0\n" \ + "3:\n" \ + " .section .fixup,\"ax\"\n" \ + " .align 4\n" \ + " .literal_position\n" \ + "5: movi %[oldval], 3b\n" \ + " movi %[newval], %[fault]\n" \ + " jx %[oldval]\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .long 1b, 5b, 2b, 5b\n" \ + " .previous\n" \ + : [oldval] "=&r" (old), [newval] "=&r" (ret) \ + : [addr] "r" (uaddr), [oparg] "r" (arg), \ + [fault] "I" (-EFAULT) \ + : "memory") +#elif XCHAL_HAVE_S32C1I +#define __futex_atomic_op(insn, ret, old, uaddr, arg) \ + __asm__ __volatile( \ + "1: l32i %[oldval], %[mem]\n" \ + insn "\n" \ + " wsr %[oldval], scompare1\n" \ + "2: s32c1i %[newval], %[mem]\n" \ + " bne %[newval], %[oldval], 1b\n" \ + " movi %[newval], 0\n" \ + "3:\n" \ + " .section .fixup,\"ax\"\n" \ + " .align 4\n" \ + " .literal_position\n" \ + "5: movi %[oldval], 3b\n" \ + " movi %[newval], %[fault]\n" \ + " jx %[oldval]\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .long 1b, 5b, 2b, 5b\n" \ + " .previous\n" \ + : [oldval] "=&r" (old), [newval] "=&r" (ret), \ + [mem] "+m" (*(uaddr)) \ + : [oparg] "r" (arg), [fault] "I" (-EFAULT) \ + : "memory") +#endif + +static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, + u32 __user *uaddr) +{ +#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE + int oldval = 0, ret; + + if (!access_ok(uaddr, sizeof(u32))) + return -EFAULT; + + switch (op) { + case FUTEX_OP_SET: + __futex_atomic_op("mov %[newval], %[oparg]", + ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_ADD: + __futex_atomic_op("add %[newval], %[oldval], %[oparg]", + ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_OR: + __futex_atomic_op("or %[newval], %[oldval], %[oparg]", + ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_ANDN: + __futex_atomic_op("and %[newval], %[oldval], %[oparg]", + ret, oldval, uaddr, ~oparg); + break; + case FUTEX_OP_XOR: + __futex_atomic_op("xor %[newval], %[oldval], %[oparg]", + ret, oldval, uaddr, oparg); + break; + default: + ret = -ENOSYS; + } + + if (!ret) + *oval = oldval; + + return ret; +#else + return -ENOSYS; +#endif +} + +static inline int +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, + u32 oldval, u32 newval) +{ +#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE + unsigned long tmp; + int ret = 0; + + if (!access_ok(uaddr, sizeof(u32))) + return -EFAULT; + + __asm__ __volatile__ ( + " # futex_atomic_cmpxchg_inatomic\n" +#if XCHAL_HAVE_EXCLUSIVE + "1: l32ex %[tmp], %[addr]\n" + " s32i %[tmp], %[uval], 0\n" + " bne %[tmp], %[oldval], 2f\n" + " mov %[tmp], %[newval]\n" + "3: s32ex %[tmp], %[addr]\n" + " getex %[tmp]\n" + " beqz %[tmp], 1b\n" +#elif XCHAL_HAVE_S32C1I + " wsr %[oldval], scompare1\n" + "1: s32c1i %[newval], %[addr], 0\n" + " s32i %[newval], %[uval], 0\n" +#endif + "2:\n" + " .section .fixup,\"ax\"\n" + " .align 4\n" + " .literal_position\n" + "4: movi %[tmp], 2b\n" + " movi %[ret], %[fault]\n" + " jx %[tmp]\n" + " .previous\n" + " .section __ex_table,\"a\"\n" + " .long 1b, 4b\n" +#if XCHAL_HAVE_EXCLUSIVE + " .long 3b, 4b\n" +#endif + " .previous\n" + : [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp) + : [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval), + [fault] "I" (-EFAULT) + : "memory"); + + return ret; +#else + return -ENOSYS; +#endif +} + +#endif /* _ASM_XTENSA_FUTEX_H */ |