From bc4adda7297b07a764b42f2c30e80f9bbee6a25d Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Sun, 21 Apr 2024 17:15:38 -0400 Subject: libc: impl: Add spinlocks Signed-off-by: Ian Moffett --- lib/libc/impl/libc_lock.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 lib/libc/impl/libc_lock.h (limited to 'lib/libc/impl') diff --git a/lib/libc/impl/libc_lock.h b/lib/libc/impl/libc_lock.h new file mode 100644 index 0000000..c6fdcbc --- /dev/null +++ b/lib/libc/impl/libc_lock.h @@ -0,0 +1,62 @@ +/* + * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _LIBC_LOCK_H +#define _LIBC_LOCK_H + +#include + +typedef struct { + volatile __uint8_t lock; +} __libc_spinlock_t; + +#if defined(__x86_64__) +__attribute__((__always_inline__, __weak__)) inline int +__test_and_set(__libc_spinlock_t *lock) +{ + int tmp = 0; + + __asm__ __volatile__( + "lock; cmpxchgb %b2, %0" + : "+m" (lock->lock), "+a" (tmp) + : "r" (1) + : "cc" + ); + + return tmp; +} +#else +#warn "Unimplemented arch" +#endif + +#define __spinlock_def(NAME) __libc_spinlock_t NAME = {0}; +#define __spinlock_acquire(LOCKPTR) while (__test_and_set(LOCKPTR)) +#define __spinlock_release(LOCKPTR) ((LOCKPTR)->lock = 0) + +#endif /* _LIBC_LOCK_H */ -- cgit v1.2.3