X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/91447636331957f3d9b5ca5b508f07c526b0074d..f427ee49d309d8fc33ebf3042c3a775f2f530ded:/osfmk/i386/i386_lock.s diff --git a/osfmk/i386/i386_lock.s b/osfmk/i386/i386_lock.s index d8d36ebbd..ac0726918 100644 --- a/osfmk/i386/i386_lock.s +++ b/osfmk/i386/i386_lock.s @@ -1,23 +1,29 @@ /* - * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2012 Apple Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ @@ -29,850 +35,128 @@ * the terms and conditions for use and redistribution. */ -#include -#include #include #include +#include +#include +#include +#include #include "assym.s" #define PAUSE rep; nop -/* - * When performance isn't the only concern, it's - * nice to build stack frames... - */ -#define BUILD_STACK_FRAMES (GPROF || \ - ((MACH_LDEBUG || ETAP_LOCK_TRACE) && MACH_KDB)) - -#if BUILD_STACK_FRAMES - -/* STack-frame-relative: */ -#define L_PC B_PC -#define L_ARG0 B_ARG0 -#define L_ARG1 B_ARG1 - -#define LEAF_ENTRY(name) \ - Entry(name); \ - FRAME; \ - MCOUNT - -#define LEAF_ENTRY2(n1,n2) \ - Entry(n1); \ - Entry(n2); \ - FRAME; \ - MCOUNT - -#define LEAF_RET \ - EMARF; \ - ret - -#else /* BUILD_STACK_FRAMES */ - -/* Stack-pointer-relative: */ -#define L_PC S_PC -#define L_ARG0 S_ARG0 -#define L_ARG1 S_ARG1 +#include #define LEAF_ENTRY(name) \ Entry(name) -#define LEAF_ENTRY2(n1,n2) \ - Entry(n1); \ - Entry(n2) - #define LEAF_RET \ ret -#endif /* BUILD_STACK_FRAMES */ - - -/* Non-leaf routines always have a stack frame: */ - -#define NONLEAF_ENTRY(name) \ - Entry(name); \ - FRAME; \ - MCOUNT - -#define NONLEAF_ENTRY2(n1,n2) \ - Entry(n1); \ - Entry(n2); \ - FRAME; \ - MCOUNT - -#define NONLEAF_RET \ - EMARF; \ - ret - - -#define M_ILK (%edx) -#define M_LOCKED MUTEX_LOCKED(%edx) -#define M_WAITERS MUTEX_WAITERS(%edx) -#define M_PROMOTED_PRI MUTEX_PROMOTED_PRI(%edx) -#define M_ITAG MUTEX_ITAG(%edx) -#define M_PTR MUTEX_PTR(%edx) -#if MACH_LDEBUG -#define M_TYPE MUTEX_TYPE(%edx) -#define M_PC MUTEX_PC(%edx) -#define M_THREAD MUTEX_THREAD(%edx) -#endif /* MACH_LDEBUG */ - -#include -#define CX(addr,reg) addr(,reg,4) - -#if MACH_LDEBUG -/* - * Routines for general lock debugging. - */ -#define S_TYPE SLOCK_TYPE(%edx) -#define S_PC SLOCK_PC(%edx) -#define S_THREAD SLOCK_THREAD(%edx) -#define S_DURATIONH SLOCK_DURATIONH(%edx) -#define S_DURATIONL SLOCK_DURATIONL(%edx) - -/* - * Checks for expected lock types and calls "panic" on - * mismatch. Detects calls to Mutex functions with - * type simplelock and vice versa. - */ -#define CHECK_MUTEX_TYPE() \ - cmpl $ MUTEX_TAG,M_TYPE ; \ - je 1f ; \ - pushl $2f ; \ - call EXT(panic) ; \ - hlt ; \ - .data ; \ -2: String "not a mutex!" ; \ - .text ; \ -1: - -#define CHECK_SIMPLE_LOCK_TYPE() \ - cmpl $ USLOCK_TAG,S_TYPE ; \ - je 1f ; \ - pushl $2f ; \ - call EXT(panic) ; \ - hlt ; \ - .data ; \ -2: String "not a simple lock!" ; \ - .text ; \ -1: +/* For x86_64, the varargs ABI requires that %al indicate + * how many SSE register contain arguments. In our case, 0 */ +#define ALIGN_STACK() and $0xFFFFFFFFFFFFFFF0, %rsp ; +#define LOAD_STRING_ARG0(label) leaq label(%rip), %rdi ; +#define LOAD_ARG1(x) mov x, %esi ; +#define LOAD_PTR_ARG1(x) mov x, %rsi ; +#define CALL_PANIC() xorb %al,%al ; call EXT(panic) ; + +#define PREEMPTION_DISABLE \ + incl %gs:CPU_PREEMPTION_LEVEL + +#define PREEMPTION_LEVEL_DEBUG 1 +#if PREEMPTION_LEVEL_DEBUG +#define PREEMPTION_ENABLE \ + decl %gs:CPU_PREEMPTION_LEVEL ; \ + js 17f ; \ + jnz 19f ; \ + testl $AST_URGENT,%gs:CPU_PENDING_AST ; \ + jz 19f ; \ + PUSHF ; \ + testl $EFL_IF, S_PC ; \ + jz 18f ; \ + POPF ; \ + int $(T_PREEMPT) ; \ + jmp 19f ; \ +17: \ + call _preemption_underflow_panic ; \ +18: \ + POPF ; \ +19: +#else +#define PREEMPTION_ENABLE \ + decl %gs:CPU_PREEMPTION_LEVEL ; \ + jnz 19f ; \ + testl $AST_URGENT,%gs:CPU_PENDING_AST ; \ + jz 19f ; \ + PUSHF ; \ + testl $EFL_IF, S_PC ; \ + jz 18f ; \ + POPF ; \ + int $(T_PREEMPT) ; \ + jmp 19f ; \ +18: \ + POPF ; \ +19: +#endif /* - * If one or more simplelocks are currently held by a thread, - * an attempt to acquire a mutex will cause this check to fail - * (since a mutex lock may context switch, holding a simplelock - * is not a good thing). - */ -#if MACH_RT -#define CHECK_PREEMPTION_LEVEL() \ - cmpl $0,%gs:CPU_PREEMPTION_LEVEL ; \ - je 1f ; \ - pushl $2f ; \ - call EXT(panic) ; \ - hlt ; \ - .data ; \ -2: String "preemption_level != 0!" ; \ - .text ; \ -1: -#else /* MACH_RT */ -#define CHECK_PREEMPTION_LEVEL() -#endif /* MACH_RT */ - -#define CHECK_NO_SIMPLELOCKS() \ - cmpl $0,%gs:CPU_SIMPLE_LOCK_COUNT ; \ - je 1f ; \ - pushl $2f ; \ - call EXT(panic) ; \ - hlt ; \ - .data ; \ -2: String "simple_locks_held!" ; \ - .text ; \ -1: - -/* - * Verifies return to the correct thread in "unlock" situations. + * For most routines, the hw_lock_t pointer is loaded into a + * register initially, and then either a byte or register-sized + * word is loaded/stored to the pointer */ -#define CHECK_THREAD(thd) \ - movl %gs:CPU_ACTIVE_THREAD,%ecx ; \ - testl %ecx,%ecx ; \ - je 1f ; \ - cmpl %ecx,thd ; \ - je 1f ; \ - pushl $2f ; \ - call EXT(panic) ; \ - hlt ; \ - .data ; \ -2: String "wrong thread!" ; \ - .text ; \ -1: - -#define CHECK_MYLOCK(thd) \ - movl %gs:CPU_ACTIVE_THREAD,%ecx ; \ - testl %ecx,%ecx ; \ - je 1f ; \ - cmpl %ecx,thd ; \ - jne 1f ; \ - pushl $2f ; \ - call EXT(panic) ; \ - hlt ; \ - .data ; \ -2: String "mylock attempt!" ; \ - .text ; \ -1: - -#define METER_SIMPLE_LOCK_LOCK(reg) \ - pushl reg ; \ - call EXT(meter_simple_lock) ; \ - popl reg - -#define METER_SIMPLE_LOCK_UNLOCK(reg) \ - pushl reg ; \ - call EXT(meter_simple_unlock) ; \ - popl reg - -#else /* MACH_LDEBUG */ -#define CHECK_MUTEX_TYPE() -#define CHECK_SIMPLE_LOCK_TYPE -#define CHECK_THREAD(thd) -#define CHECK_PREEMPTION_LEVEL() -#define CHECK_NO_SIMPLELOCKS() -#define CHECK_MYLOCK(thd) -#define METER_SIMPLE_LOCK_LOCK(reg) -#define METER_SIMPLE_LOCK_UNLOCK(reg) -#endif /* MACH_LDEBUG */ - /* - * void hw_lock_init(hw_lock_t) + * void hw_lock_byte_init(volatile uint8_t *) * - * Initialize a hardware lock. + * Initialize a hardware byte lock. */ -LEAF_ENTRY(hw_lock_init) - movl L_ARG0,%edx /* fetch lock pointer */ - movl $0,0(%edx) /* clear the lock */ +LEAF_ENTRY(hw_lock_byte_init) + movb $0, (%rdi) /* clear the lock */ LEAF_RET /* - * void hw_lock_lock(hw_lock_t) + * void hw_lock_byte_lock(uint8_t *lock_byte) * - * Acquire lock, spinning until it becomes available. - * MACH_RT: also return with preemption disabled. + * Acquire byte sized lock operand, spinning until it becomes available. + * return with preemption disabled. */ -LEAF_ENTRY(hw_lock_lock) - movl L_ARG0,%edx /* fetch lock pointer */ - movl L_PC,%ecx -1: DISABLE_PREEMPTION - movl 0(%edx), %eax - testl %eax,%eax /* lock locked? */ +LEAF_ENTRY(hw_lock_byte_lock) + PREEMPTION_DISABLE + movl $1, %ecx /* Set lock value */ +1: + movb (%rdi), %al /* Load byte at address */ + testb %al,%al /* lock locked? */ jne 3f /* branch if so */ - lock; cmpxchgl %ecx,0(%edx) /* try to acquire the HW lock */ + lock; cmpxchg %cl,(%rdi) /* attempt atomic compare exchange */ jne 3f - movl $1,%eax /* In case this was a timeout call */ LEAF_RET /* if yes, then nothing left to do */ - -3: ENABLE_PREEMPTION /* no reason we can't be preemptable */ - PAUSE /* pause for hyper-threading */ - jmp 1b /* try again */ - -/* - * unsigned int hw_lock_to(hw_lock_t, unsigned int) - * - * Acquire lock, spinning until it becomes available or timeout. - * MACH_RT: also return with preemption disabled. - */ -LEAF_ENTRY(hw_lock_to) -1: - movl L_ARG0,%edx /* fetch lock pointer */ - movl L_PC,%ecx - /* - * Attempt to grab the lock immediately - * - fastpath without timeout nonsense. - */ - DISABLE_PREEMPTION - movl 0(%edx), %eax - testl %eax,%eax /* lock locked? */ - jne 2f /* branch if so */ - lock; cmpxchgl %ecx,0(%edx) /* try to acquire the HW lock */ - jne 2f /* branch on failure */ - movl $1,%eax - LEAF_RET - -2: -#define INNER_LOOP_COUNT 1000 - /* - * Failed to get the lock so set the timeout - * and then spin re-checking the lock but pausing - * every so many (INNER_LOOP_COUNT) spins to check for timeout. - */ - movl L_ARG1,%ecx /* fetch timeout */ - push %edi - push %ebx - mov %edx,%edi - - rdtsc /* read cyclecount into %edx:%eax */ - addl %ecx,%eax /* fetch and timeout */ - adcl $0,%edx /* add carry */ - mov %edx,%ecx - mov %eax,%ebx /* %ecx:%ebx is the timeout expiry */ 3: - ENABLE_PREEMPTION /* no reason not to be preempted now */ -4: - /* - * The inner-loop spin to look for the lock being freed. - */ - mov $(INNER_LOOP_COUNT),%edx -5: PAUSE /* pause for hyper-threading */ - movl 0(%edi),%eax /* spin checking lock value in cache */ - testl %eax,%eax - je 6f /* zero => unlocked, try to grab it */ - decl %edx /* decrement inner loop count */ - jnz 5b /* time to check for timeout? */ - - /* - * Here after spinning INNER_LOOP_COUNT times, check for timeout - */ - rdtsc /* cyclecount into %edx:%eax */ - cmpl %ecx,%edx /* compare high-order 32-bits */ - jb 4b /* continue spinning if less, or */ - cmpl %ebx,%eax /* compare low-order 32-bits */ - jb 5b /* continue if less, else bail */ - xor %eax,%eax /* with 0 return value */ - pop %ebx - pop %edi - LEAF_RET - -6: - /* - * Here to try to grab the lock that now appears to be free - * after contention. - */ - movl 8+L_PC,%edx /* calling pc (8+ for pushed regs) */ - DISABLE_PREEMPTION - lock; cmpxchgl %edx,0(%edi) /* try to acquire the HW lock */ - jne 3b /* no - spin again */ - movl $1,%eax /* yes */ - pop %ebx - pop %edi - LEAF_RET - -/* - * void hw_lock_unlock(hw_lock_t) - * - * Unconditionally release lock. - * MACH_RT: release preemption level. - */ -LEAF_ENTRY(hw_lock_unlock) - movl L_ARG0,%edx /* fetch lock pointer */ - movl $0,0(%edx) /* clear the lock */ - ENABLE_PREEMPTION - LEAF_RET - -/* - * unsigned int hw_lock_try(hw_lock_t) - * MACH_RT: returns with preemption disabled on success. - */ -LEAF_ENTRY(hw_lock_try) - movl L_ARG0,%edx /* fetch lock pointer */ - - movl L_PC,%ecx - DISABLE_PREEMPTION - movl 0(%edx),%eax - testl %eax,%eax - jne 1f - lock; cmpxchgl %ecx,0(%edx) /* try to acquire the HW lock */ - jne 1f - - movl $1,%eax /* success */ - LEAF_RET - -1: ENABLE_PREEMPTION /* failure: release preemption... */ - xorl %eax,%eax /* ...and return failure */ - LEAF_RET - -/* - * unsigned int hw_lock_held(hw_lock_t) - * MACH_RT: doesn't change preemption state. - * N.B. Racy, of course. - */ -LEAF_ENTRY(hw_lock_held) - movl L_ARG0,%edx /* fetch lock pointer */ - - movl 0(%edx),%eax /* check lock value */ - testl %eax,%eax - movl $1,%ecx - cmovne %ecx,%eax /* 0 => unlocked, 1 => locked */ - LEAF_RET - -LEAF_ENTRY(mutex_init) - movl L_ARG0,%edx /* fetch lock pointer */ - xorl %eax,%eax - movl %eax,M_ILK /* clear interlock */ - movl %eax,M_LOCKED /* clear locked flag */ - movw %ax,M_WAITERS /* init waiter count */ - movw %ax,M_PROMOTED_PRI - -#if MACH_LDEBUG - movl $ MUTEX_TAG,M_TYPE /* set lock type */ - movl %eax,M_PC /* init caller pc */ - movl %eax,M_THREAD /* and owning thread */ -#endif - - LEAF_RET - -NONLEAF_ENTRY2(mutex_lock,_mutex_lock) - - movl B_ARG0,%edx /* fetch lock pointer */ - - CHECK_MUTEX_TYPE() - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - pushf /* save interrupt state */ - cli /* disable interrupts */ - -ml_retry: - movl B_PC,%ecx - -ml_get_hw: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je 1f /* yes - attempt to lock it */ - PAUSE /* no - pause */ - jmp ml_get_hw /* try again */ -1: - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne ml_get_hw /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne ml_fail /* yes, we lose */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_LOCKED - -#if MACH_LDEBUG - movl %ecx,M_THREAD - movl B_PC,%ecx - movl %ecx,M_PC -#endif - - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - - NONLEAF_RET - -ml_fail: -ml_block: - CHECK_MYLOCK(M_THREAD) - pushl M_LOCKED - pushl %edx /* push mutex address */ - call EXT(lck_mtx_lock_wait) /* wait for the lock */ - addl $8,%esp - movl B_ARG0,%edx /* refetch mutex address */ - jmp ml_retry /* and try again */ - -NONLEAF_ENTRY2(mutex_try,_mutex_try) - - movl B_ARG0,%edx /* fetch lock pointer */ - - CHECK_MUTEX_TYPE() - CHECK_NO_SIMPLELOCKS() - - movl B_PC,%ecx - - pushf /* save interrupt state */ - cli /* disable interrupts */ - -mt_get_hw: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je 1f /* yes - attempt to lock it */ - PAUSE /* no - pause */ - jmp mt_get_hw /* try again */ -1: - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne mt_get_hw /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne mt_fail /* yes, we lose */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_LOCKED - -#if MACH_LDEBUG - movl %ecx,M_THREAD - movl B_PC,%ecx - movl %ecx,M_PC -#endif - - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - - movl $1,%eax - - NONLEAF_RET - -mt_fail: - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - - xorl %eax,%eax - - NONLEAF_RET - -NONLEAF_ENTRY(mutex_unlock) - movl B_ARG0,%edx /* fetch lock pointer */ - - CHECK_MUTEX_TYPE() - CHECK_THREAD(M_THREAD) - - movl B_PC,%ecx - - pushf /* save interrupt state */ - cli /* disable interrupts */ - -mu_get_hw: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je 1f /* yes - attempt to lock it */ - PAUSE /* no - pause */ - jmp mu_get_hw /* try again */ -1: - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne mu_get_hw /* branch on failure to retry */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne mu_wakeup /* yes, more work to do */ - -mu_doit: - -#if MACH_LDEBUG - movl $0,M_THREAD /* disown thread */ -#endif - - xorl %ecx,%ecx - movl %ecx,M_LOCKED /* unlock the mutex */ - - movl %ecx,M_ILK - - popf /* restore interrupt state */ - - NONLEAF_RET - -mu_wakeup: - pushl M_LOCKED - pushl %edx /* push mutex address */ - call EXT(lck_mtx_unlock_wakeup)/* yes, wake a thread */ - addl $8,%esp - movl B_ARG0,%edx /* restore lock pointer */ - jmp mu_doit + jmp 1b /* try again */ /* - * lck_mtx_lock() - * lck_mtx_try_lock() - * lck_mutex_unlock() + * void hw_lock_byte_unlock(uint8_t *lock_byte) * - * These are variants of mutex_lock(), mutex_try() and mutex_unlock() without - * DEBUG checks (which require fields not present in lck_mtx_t's). + * Unconditionally release byte sized lock operand, + * release preemption level. */ -NONLEAF_ENTRY(lck_mtx_lock) - - movl B_ARG0,%edx /* fetch lock pointer */ - cmpl $(MUTEX_IND),M_ITAG /* is this indirect? */ - cmove M_PTR,%edx /* yes - take indirection */ - - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - pushf /* save interrupt state */ - cli /* disable interrupts */ - -lml_retry: - movl B_PC,%ecx - -lml_get_hw: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je 1f /* yes - attempt to lock it */ - PAUSE /* no - pause */ - jmp lml_get_hw /* try again */ -1: - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne lml_get_hw /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne lml_fail /* yes, we lose */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_LOCKED - - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - - NONLEAF_RET - -lml_fail: - CHECK_MYLOCK(M_THREAD) - pushl %edx /* save mutex address */ - pushl M_LOCKED - pushl %edx /* push mutex address */ - call EXT(lck_mtx_lock_wait) /* wait for the lock */ - addl $8,%esp - popl %edx /* restore mutex address */ - jmp lml_retry /* and try again */ - -NONLEAF_ENTRY(lck_mtx_try_lock) - - movl B_ARG0,%edx /* fetch lock pointer */ - cmpl $(MUTEX_IND),M_ITAG /* is this indirect? */ - cmove M_PTR,%edx /* yes - take indirection */ - - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - movl B_PC,%ecx - - pushf /* save interrupt state */ - cli /* disable interrupts */ - -lmt_get_hw: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je 1f /* yes - attempt to lock it */ - PAUSE /* no - pause */ - jmp lmt_get_hw /* try again */ -1: - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne lmt_get_hw /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne lmt_fail /* yes, we lose */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_LOCKED - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - - movl $1,%eax /* return success */ - NONLEAF_RET - -lmt_fail: - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - - xorl %eax,%eax /* return failure */ - NONLEAF_RET - -NONLEAF_ENTRY(lck_mtx_unlock) - - movl B_ARG0,%edx /* fetch lock pointer */ - cmpl $(MUTEX_IND),M_ITAG /* is this indirect? */ - cmove M_PTR,%edx /* yes - take indirection */ - - movl B_PC,%ecx - - pushf /* save interrupt state */ - cli /* disable interrupts */ - -lmu_get_hw: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je 1f /* yes - attempt to lock it */ - PAUSE /* no - pause */ - jmp lmu_get_hw /* try again */ -1: - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne lmu_get_hw /* branch on failure to retry */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne lmu_wakeup /* yes, more work to do */ - -lmu_doit: - xorl %ecx,%ecx - movl %ecx,M_LOCKED /* unlock the mutex */ - - movl %ecx,M_ILK - - popf /* restore interrupt state */ - - NONLEAF_RET - -lmu_wakeup: - pushl %edx /* save mutex address */ - pushl M_LOCKED - pushl %edx /* push mutex address */ - call EXT(lck_mtx_unlock_wakeup)/* yes, wake a thread */ - addl $8,%esp - popl %edx /* restore mutex pointer */ - jmp lmu_doit - -LEAF_ENTRY(lck_mtx_ilk_unlock) - movl L_ARG0,%edx /* no indirection here */ - - xorl %eax,%eax - movl %eax,M_ILK - - LEAF_RET - -LEAF_ENTRY(_disable_preemption) -#if MACH_RT - _DISABLE_PREEMPTION -#endif /* MACH_RT */ - LEAF_RET - -LEAF_ENTRY(_enable_preemption) -#if MACH_RT -#if MACH_ASSERT - cmpl $0,%gs:CPU_PREEMPTION_LEVEL - jg 1f - pushl %gs:CPU_PREEMPTION_LEVEL - pushl $2f - call EXT(panic) - hlt - .data -2: String "_enable_preemption: preemption_level(%d) < 0!" - .text -1: -#endif /* MACH_ASSERT */ - _ENABLE_PREEMPTION -#endif /* MACH_RT */ - LEAF_RET - -LEAF_ENTRY(_enable_preemption_no_check) -#if MACH_RT -#if MACH_ASSERT - cmpl $0,%gs:CPU_PREEMPTION_LEVEL - jg 1f - pushl $2f - call EXT(panic) - hlt - .data -2: String "_enable_preemption_no_check: preemption_level <= 0!" - .text -1: -#endif /* MACH_ASSERT */ - _ENABLE_PREEMPTION_NO_CHECK -#endif /* MACH_RT */ - LEAF_RET - - -LEAF_ENTRY(_mp_disable_preemption) -#if MACH_RT - _DISABLE_PREEMPTION -#endif /* MACH_RT */ - LEAF_RET - -LEAF_ENTRY(_mp_enable_preemption) -#if MACH_RT -#if MACH_ASSERT - cmpl $0,%gs:CPU_PREEMPTION_LEVEL - jg 1f - pushl %gs:CPU_PREEMPTION_LEVEL - pushl $2f - call EXT(panic) - hlt - .data -2: String "_mp_enable_preemption: preemption_level (%d) <= 0!" - .text -1: -#endif /* MACH_ASSERT */ - _ENABLE_PREEMPTION -#endif /* MACH_RT */ +LEAF_ENTRY(hw_lock_byte_unlock) + movb $0, (%rdi) /* Clear the lock byte */ + PREEMPTION_ENABLE LEAF_RET -LEAF_ENTRY(_mp_enable_preemption_no_check) -#if MACH_RT -#if MACH_ASSERT - cmpl $0,%gs:CPU_PREEMPTION_LEVEL - jg 1f - pushl $2f - call EXT(panic) +LEAF_ENTRY(preemption_underflow_panic) + FRAME + incl %gs:CPU_PREEMPTION_LEVEL + ALIGN_STACK() + LOAD_STRING_ARG0(16f) + CALL_PANIC() hlt .data -2: String "_mp_enable_preemption_no_check: preemption_level <= 0!" +16: String "Preemption level underflow, possible cause unlocking an unlocked mutex or spinlock" .text -1: -#endif /* MACH_ASSERT */ - _ENABLE_PREEMPTION_NO_CHECK -#endif /* MACH_RT */ - LEAF_RET - - -LEAF_ENTRY(i_bit_set) - movl L_ARG0,%edx - movl L_ARG1,%eax - lock - bts %dl,(%eax) - LEAF_RET - -LEAF_ENTRY(i_bit_clear) - movl L_ARG0,%edx - movl L_ARG1,%eax - lock - btr %dl,(%eax) - LEAF_RET -LEAF_ENTRY(bit_lock) - movl L_ARG0,%ecx - movl L_ARG1,%eax -1: - lock - bts %ecx,(%eax) - jb 1b - LEAF_RET - -LEAF_ENTRY(bit_lock_try) - movl L_ARG0,%ecx - movl L_ARG1,%eax - lock - bts %ecx,(%eax) - jb bit_lock_failed - LEAF_RET /* %eax better not be null ! */ -bit_lock_failed: - xorl %eax,%eax - LEAF_RET - -LEAF_ENTRY(bit_unlock) - movl L_ARG0,%ecx - movl L_ARG1,%eax - lock - btr %ecx,(%eax) - LEAF_RET