cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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cvmx-spinlock.h (6385B)


      1/***********************license start***************
      2 * Author: Cavium Networks
      3 *
      4 * Contact: support@caviumnetworks.com
      5 * This file is part of the OCTEON SDK
      6 *
      7 * Copyright (c) 2003-2008 Cavium Networks
      8 *
      9 * This file is free software; you can redistribute it and/or modify
     10 * it under the terms of the GNU General Public License, Version 2, as
     11 * published by the Free Software Foundation.
     12 *
     13 * This file is distributed in the hope that it will be useful, but
     14 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty
     15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
     16 * NONINFRINGEMENT.  See the GNU General Public License for more
     17 * details.
     18 *
     19 * You should have received a copy of the GNU General Public License
     20 * along with this file; if not, write to the Free Software
     21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
     22 * or visit http://www.gnu.org/licenses/.
     23 *
     24 * This file may also be available under a different license from Cavium.
     25 * Contact Cavium Networks for more information
     26 ***********************license end**************************************/
     27
     28/**
     29 * Implementation of spinlocks for Octeon CVMX.	 Although similar in
     30 * function to Linux kernel spinlocks, they are not compatible.
     31 * Octeon CVMX spinlocks are only used to synchronize with the boot
     32 * monitor and other non-Linux programs running in the system.
     33 */
     34
     35#ifndef __CVMX_SPINLOCK_H__
     36#define __CVMX_SPINLOCK_H__
     37
     38#include <asm/octeon/cvmx-asm.h>
     39
     40/* Spinlocks for Octeon */
     41
     42/* define these to enable recursive spinlock debugging */
     43/*#define CVMX_SPINLOCK_DEBUG */
     44
     45/**
     46 * Spinlocks for Octeon CVMX
     47 */
     48typedef struct {
     49	volatile uint32_t value;
     50} cvmx_spinlock_t;
     51
     52/* note - macros not expanded in inline ASM, so values hardcoded */
     53#define	 CVMX_SPINLOCK_UNLOCKED_VAL  0
     54#define	 CVMX_SPINLOCK_LOCKED_VAL    1
     55
     56#define CVMX_SPINLOCK_UNLOCKED_INITIALIZER  {CVMX_SPINLOCK_UNLOCKED_VAL}
     57
     58/**
     59 * Initialize a spinlock
     60 *
     61 * @lock:   Lock to initialize
     62 */
     63static inline void cvmx_spinlock_init(cvmx_spinlock_t *lock)
     64{
     65	lock->value = CVMX_SPINLOCK_UNLOCKED_VAL;
     66}
     67
     68/**
     69 * Return non-zero if the spinlock is currently locked
     70 *
     71 * @lock:   Lock to check
     72 * Returns Non-zero if locked
     73 */
     74static inline int cvmx_spinlock_locked(cvmx_spinlock_t *lock)
     75{
     76	return lock->value != CVMX_SPINLOCK_UNLOCKED_VAL;
     77}
     78
     79/**
     80 * Releases lock
     81 *
     82 * @lock:   pointer to lock structure
     83 */
     84static inline void cvmx_spinlock_unlock(cvmx_spinlock_t *lock)
     85{
     86	CVMX_SYNCWS;
     87	lock->value = 0;
     88	CVMX_SYNCWS;
     89}
     90
     91/**
     92 * Attempts to take the lock, but does not spin if lock is not available.
     93 * May take some time to acquire the lock even if it is available
     94 * due to the ll/sc not succeeding.
     95 *
     96 * @lock:   pointer to lock structure
     97 *
     98 * Returns 0: lock successfully taken
     99 *	   1: lock not taken, held by someone else
    100 * These return values match the Linux semantics.
    101 */
    102
    103static inline unsigned int cvmx_spinlock_trylock(cvmx_spinlock_t *lock)
    104{
    105	unsigned int tmp;
    106
    107	__asm__ __volatile__(".set noreorder	     \n"
    108			     "1: ll   %[tmp], %[val] \n"
    109			/* if lock held, fail immediately */
    110			     "	 bnez %[tmp], 2f     \n"
    111			     "	 li   %[tmp], 1	     \n"
    112			     "	 sc   %[tmp], %[val] \n"
    113			     "	 beqz %[tmp], 1b     \n"
    114			     "	 li   %[tmp], 0	     \n"
    115			     "2:		     \n"
    116			     ".set reorder	     \n" :
    117			[val] "+m"(lock->value), [tmp] "=&r"(tmp)
    118			     : : "memory");
    119
    120	return tmp != 0;		/* normalize to 0 or 1 */
    121}
    122
    123/**
    124 * Gets lock, spins until lock is taken
    125 *
    126 * @lock:   pointer to lock structure
    127 */
    128static inline void cvmx_spinlock_lock(cvmx_spinlock_t *lock)
    129{
    130	unsigned int tmp;
    131
    132	__asm__ __volatile__(".set noreorder	     \n"
    133			     "1: ll   %[tmp], %[val]  \n"
    134			     "	 bnez %[tmp], 1b     \n"
    135			     "	 li   %[tmp], 1	     \n"
    136			     "	 sc   %[tmp], %[val] \n"
    137			     "	 beqz %[tmp], 1b     \n"
    138			     "	 nop		    \n"
    139			     ".set reorder	     \n" :
    140			[val] "+m"(lock->value), [tmp] "=&r"(tmp)
    141			: : "memory");
    142
    143}
    144
    145/** ********************************************************************
    146 * Bit spinlocks
    147 * These spinlocks use a single bit (bit 31) of a 32 bit word for locking.
    148 * The rest of the bits in the word are left undisturbed.  This enables more
    149 * compact data structures as only 1 bit is consumed for the lock.
    150 *
    151 */
    152
    153/**
    154 * Gets lock, spins until lock is taken
    155 * Preserves the low 31 bits of the 32 bit
    156 * word used for the lock.
    157 *
    158 *
    159 * @word:  word to lock bit 31 of
    160 */
    161static inline void cvmx_spinlock_bit_lock(uint32_t *word)
    162{
    163	unsigned int tmp;
    164	unsigned int sav;
    165
    166	__asm__ __volatile__(".set noreorder	     \n"
    167			     ".set noat		     \n"
    168			     "1: ll    %[tmp], %[val]  \n"
    169			     "	 bbit1 %[tmp], 31, 1b	 \n"
    170			     "	 li    $at, 1	   \n"
    171			     "	 ins   %[tmp], $at, 31, 1  \n"
    172			     "	 sc    %[tmp], %[val] \n"
    173			     "	 beqz  %[tmp], 1b     \n"
    174			     "	 nop		    \n"
    175			     ".set at		   \n"
    176			     ".set reorder	     \n" :
    177			[val] "+m"(*word), [tmp] "=&r"(tmp), [sav] "=&r"(sav)
    178			     : : "memory");
    179
    180}
    181
    182/**
    183 * Attempts to get lock, returns immediately with success/failure
    184 * Preserves the low 31 bits of the 32 bit
    185 * word used for the lock.
    186 *
    187 *
    188 * @word:  word to lock bit 31 of
    189 * Returns 0: lock successfully taken
    190 *	   1: lock not taken, held by someone else
    191 * These return values match the Linux semantics.
    192 */
    193static inline unsigned int cvmx_spinlock_bit_trylock(uint32_t *word)
    194{
    195	unsigned int tmp;
    196
    197	__asm__ __volatile__(".set noreorder\n\t"
    198			     ".set noat\n"
    199			     "1: ll    %[tmp], %[val] \n"
    200			/* if lock held, fail immediately */
    201			     "	 bbit1 %[tmp], 31, 2f	  \n"
    202			     "	 li    $at, 1	   \n"
    203			     "	 ins   %[tmp], $at, 31, 1  \n"
    204			     "	 sc    %[tmp], %[val] \n"
    205			     "	 beqz  %[tmp], 1b     \n"
    206			     "	 li    %[tmp], 0      \n"
    207			     "2:		     \n"
    208			     ".set at		   \n"
    209			     ".set reorder	     \n" :
    210			[val] "+m"(*word), [tmp] "=&r"(tmp)
    211			: : "memory");
    212
    213	return tmp != 0;		/* normalize to 0 or 1 */
    214}
    215
    216/**
    217 * Releases bit lock
    218 *
    219 * Unconditionally clears bit 31 of the lock word.  Note that this is
    220 * done non-atomically, as this implementation assumes that the rest
    221 * of the bits in the word are protected by the lock.
    222 *
    223 * @word:  word to unlock bit 31 in
    224 */
    225static inline void cvmx_spinlock_bit_unlock(uint32_t *word)
    226{
    227	CVMX_SYNCWS;
    228	*word &= ~(1UL << 31);
    229	CVMX_SYNCWS;
    230}
    231
    232#endif /* __CVMX_SPINLOCK_H__ */