X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/593a1d5fd87cdf5b46dd5fcb84467b432cea0f91..d9a64523371fa019c4575bb400cbbc3a50ac9903:/osfmk/i386/i386_lock.s?ds=sidebyside diff --git a/osfmk/i386/i386_lock.s b/osfmk/i386/i386_lock.s index b5153c73d..ac0726918 100644 --- a/osfmk/i386/i386_lock.s +++ b/osfmk/i386/i386_lock.s @@ -1,5 +1,5 @@ /* - * Copyright (c) 2000-2007 Apple Inc. All rights reserved. + * Copyright (c) 2000-2012 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * @@ -35,2229 +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. - */ - -/* - * 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: - -/* - * 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. - */ -#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 */ - +/* 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 ; \ - jne 9f ; \ - pushf ; \ - testl $ EFL_IF,(%esp) ; \ - je 8f ; \ - cli ; \ - movl %gs:CPU_PENDING_AST,%eax ; \ - testl $ AST_URGENT,%eax ; \ - je 8f ; \ - movl %gs:CPU_INTERRUPT_LEVEL,%eax ; \ - testl %eax,%eax ; \ - jne 8f ; \ - popf ; \ + 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 9f ; \ -8: \ - popf ; \ -9: - - - -#if CONFIG_DTRACE -#define LOCKSTAT_LABEL(lab) \ - .data ;\ - .globl lab ;\ - lab: ;\ - .long 9f ;\ - .text ;\ - 9: - - .globl _lockstat_probe - .globl _lockstat_probemap - -#define LOCKSTAT_RECORD(id, lck) \ - push %ebp ; \ - mov %esp,%ebp ; \ - sub $0x38,%esp /* size of dtrace_probe args */ ; \ - movl _lockstat_probemap + (id * 4),%eax ; \ - test %eax,%eax ; \ - je 9f ; \ - movl $0,36(%esp) ; \ - movl $0,40(%esp) ; \ - movl $0,28(%esp) ; \ - movl $0,32(%esp) ; \ - movl $0,20(%esp) ; \ - movl $0,24(%esp) ; \ - movl $0,12(%esp) ; \ - movl $0,16(%esp) ; \ - movl lck,4(%esp) /* copy lock pointer to arg 1 */ ; \ - movl $0,8(%esp) ; \ - movl %eax,(%esp) ; \ - call *_lockstat_probe ; \ -9: leave - /* ret - left to subsequent code, e.g. return values */ - -#define LOCKSTAT_RECORD2(id, lck, arg) \ - push %ebp ; \ - mov %esp,%ebp ; \ - sub $0x38,%esp /* size of dtrace_probe args */ ; \ - movl _lockstat_probemap + (id * 4),%eax ; \ - test %eax,%eax ; \ - je 9f ; \ - movl $0,36(%esp) ; \ - movl $0,40(%esp) ; \ - movl $0,28(%esp) ; \ - movl $0,32(%esp) ; \ - movl $0,20(%esp) ; \ - movl $0,24(%esp) ; \ - movl $0,12(%esp) ; \ - movl $0,16(%esp) ; \ - movl lck,4(%esp) /* copy lock pointer to arg 1 */ ; \ - movl arg,8(%esp) ; \ - movl %eax,(%esp) ; \ - call *_lockstat_probe ; \ -9: leave - /* ret - left to subsequent code, e.g. return values */ + 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 - /* - * void hw_lock_init(hw_lock_t) - * - * Initialize a hardware lock. + * 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 */ -LEAF_ENTRY(hw_lock_init) - movl L_ARG0,%edx /* fetch lock pointer */ - movl $0,(%edx) /* clear the lock */ - LEAF_RET - /* - * void hw_lock_byte_init(uint8_t *) + * void hw_lock_byte_init(volatile uint8_t *) * * Initialize a hardware byte lock. */ LEAF_ENTRY(hw_lock_byte_init) - movl L_ARG0,%edx /* fetch lock pointer */ - movb $0,(%edx) /* clear the lock */ + movb $0, (%rdi) /* clear the lock */ LEAF_RET -/* - * void hw_lock_lock(hw_lock_t) - * - * Acquire lock, spinning until it becomes available. - * MACH_RT: also return with preemption disabled. - */ -LEAF_ENTRY(hw_lock_lock) - movl L_ARG0,%edx /* fetch lock pointer */ - - movl %gs:CPU_ACTIVE_THREAD,%ecx - PREEMPTION_DISABLE -1: - movl (%edx), %eax - testl %eax,%eax /* lock locked? */ - jne 3f /* branch if so */ - lock; cmpxchgl %ecx,(%edx) /* try to acquire the HW lock */ - jne 3f - movl $1,%eax /* In case this was a timeout call */ - LEAF_RET /* if yes, then nothing left to do */ -3: - PAUSE /* pause for hyper-threading */ - jmp 1b /* try again */ - /* * void hw_lock_byte_lock(uint8_t *lock_byte) * * Acquire byte sized lock operand, spinning until it becomes available. - * MACH_RT: also return with preemption disabled. + * return with preemption disabled. */ LEAF_ENTRY(hw_lock_byte_lock) - movl L_ARG0,%edx /* Load lock pointer */ PREEMPTION_DISABLE movl $1, %ecx /* Set lock value */ 1: - movb (%edx), %al /* Load byte at address */ + movb (%rdi), %al /* Load byte at address */ testb %al,%al /* lock locked? */ jne 3f /* branch if so */ - lock; cmpxchgb %cl,(%edx) /* attempt atomic compare exchange */ + lock; cmpxchg %cl,(%rdi) /* attempt atomic compare exchange */ jne 3f LEAF_RET /* if yes, then nothing left to do */ 3: 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 %gs:CPU_ACTIVE_THREAD,%ecx - /* - * Attempt to grab the lock immediately - * - fastpath without timeout nonsense. - */ - PREEMPTION_DISABLE - movl (%edx), %eax - testl %eax,%eax /* lock locked? */ - jne 2f /* branch if so */ - lock; cmpxchgl %ecx,(%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 */ - lfence - addl %ecx,%eax /* fetch and timeout */ - adcl $0,%edx /* add carry */ - mov %edx,%ecx - mov %eax,%ebx /* %ecx:%ebx is the timeout expiry */ -4: - /* - * The inner-loop spin to look for the lock being freed. - */ - mov $(INNER_LOOP_COUNT),%edx -5: - PAUSE /* pause for hyper-threading */ - movl (%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 */ - lfence - cmpl %ecx,%edx /* compare high-order 32-bits */ - jb 4b /* continue spinning if less, or */ - cmpl %ebx,%eax /* compare low-order 32-bits */ - jb 4b /* 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 %gs:CPU_ACTIVE_THREAD,%edx - lock; cmpxchgl %edx,(%edi) /* try to acquire the HW lock */ - jne 4b /* 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,(%edx) /* clear the lock */ - PREEMPTION_ENABLE - LEAF_RET /* * void hw_lock_byte_unlock(uint8_t *lock_byte) * - * Unconditionally release byte sized lock operand. - * MACH_RT: release preemption level. + * Unconditionally release byte sized lock operand, + * release preemption level. */ LEAF_ENTRY(hw_lock_byte_unlock) - movl L_ARG0,%edx /* Load lock pointer */ - movb $0,(%edx) /* Clear the lock byte */ - PREEMPTION_ENABLE - LEAF_RET - -/* - * void i386_lock_unlock_with_flush(hw_lock_t) - * - * Unconditionally release lock, followed by a cacheline flush of - * the line corresponding to the lock dword. This routine is currently - * used with certain locks which are susceptible to lock starvation, - * minimizing cache affinity for lock acquisitions. A queued spinlock - * or other mechanism that ensures fairness would obviate the need - * for this routine, but ideally few or no spinlocks should exhibit - * enough contention to require such measures. - * MACH_RT: release preemption level. - */ -LEAF_ENTRY(i386_lock_unlock_with_flush) - movl L_ARG0,%edx /* Fetch lock pointer */ - movl $0,(%edx) /* Clear the lock */ - mfence /* Serialize prior stores */ - clflush (%edx) /* Write back and invalidate line */ - PREEMPTION_ENABLE - 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 %gs:CPU_ACTIVE_THREAD,%ecx - PREEMPTION_DISABLE - movl (%edx),%eax - testl %eax,%eax - jne 1f - lock; cmpxchgl %ecx,(%edx) /* try to acquire the HW lock */ - jne 1f - - movl $1,%eax /* success */ - LEAF_RET - -1: - PREEMPTION_ENABLE /* 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 (%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 - -/* - * Reader-writer lock fastpaths. These currently exist for the - * shared lock acquire and release paths (where they reduce overhead - * considerably)--more can be added as necessary (DRK). - */ - -/* - * These should reflect the layout of the bitfield embedded within - * the lck_rw_t structure (see i386/locks.h). - */ -#define LCK_RW_INTERLOCK 0x1 -#define LCK_RW_WANT_UPGRADE 0x2 -#define LCK_RW_WANT_WRITE 0x4 -#define LCK_R_WAITING 0x8 -#define LCK_W_WAITING 0x10 - -#define RW_LOCK_SHARED_MASK ((LCK_RW_INTERLOCK<<16) | \ - ((LCK_RW_WANT_UPGRADE|LCK_RW_WANT_WRITE) << 24)) -/* - * void lck_rw_lock_shared(lck_rw_t*) - * - */ - -Entry(lck_rw_lock_shared) - movl S_ARG0, %edx -1: - movl (%edx), %eax /* Load state bitfield and interlock */ - testl $(RW_LOCK_SHARED_MASK), %eax /* Eligible for fastpath? */ - jne 3f - movl %eax, %ecx - incl %ecx /* Increment reader refcount */ - lock - cmpxchgl %ecx, (%edx) /* Attempt atomic exchange */ - jne 2f - -#if CONFIG_DTRACE - /* - * Dtrace lockstat event: LS_LCK_RW_LOCK_SHARED_ACQUIRE - * Implemented by swapping between return and no-op instructions. - * See bsd/dev/dtrace/lockstat.c. - */ - LOCKSTAT_LABEL(_lck_rw_lock_shared_lockstat_patch_point) - ret - /* Fall thru when patched, counting on lock pointer in %edx */ - LOCKSTAT_RECORD(LS_LCK_RW_LOCK_SHARED_ACQUIRE, %edx) -#endif - ret - -2: - PAUSE - jmp 1b -3: - jmp EXT(lck_rw_lock_shared_gen) - - -/* - * lck_rw_type_t lck_rw_done(lck_rw_t*) - * - */ - -.data -rwl_release_error_str: - .asciz "Releasing non-exclusive RW lock without a reader refcount!" -.text - -#define RW_LOCK_RELEASE_MASK ((LCK_RW_INTERLOCK<<16) | \ - ((LCK_RW_WANT_UPGRADE|LCK_RW_WANT_WRITE|LCK_R_WAITING|LCK_W_WAITING) << 24)) -Entry(lck_rw_done) - movl S_ARG0, %edx -1: - movl (%edx), %eax /* Load state bitfield and interlock */ - testl $(RW_LOCK_RELEASE_MASK), %eax /* Eligible for fastpath? */ - jne 3f - movl %eax, %ecx - /* Assert refcount */ - testl $(0xFFFF), %ecx - jne 5f - movl $(rwl_release_error_str), S_ARG0 - jmp EXT(panic) -5: - decl %ecx /* Decrement reader count */ - lock - cmpxchgl %ecx, (%edx) - jne 2f - movl $(RW_SHARED), %eax /* Indicate that the lock was shared */ -#if CONFIG_DTRACE - /* Dtrace lockstat probe: LS_RW_DONE_RELEASE as reader */ - LOCKSTAT_LABEL(_lck_rw_done_lockstat_patch_point) - ret - /* - * Note: Dtrace's convention is 0 ==> reader, which is - * a different absolute value than $(RW_SHARED) - * %edx contains the lock address already from the above - */ - LOCKSTAT_RECORD2(LS_LCK_RW_DONE_RELEASE, %edx, $0) - movl $(RW_SHARED), %eax /* Indicate that the lock was shared */ -#endif - ret - -2: - PAUSE - jmp 1b -3: - jmp EXT(lck_rw_done_gen) - - -NONLEAF_ENTRY2(mutex_lock_spin,_mutex_lock_spin) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_MUTEX_TYPE() - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Lmls_ilk_loop /* no, go spin */ -Lmls_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Lmls_ilk_fail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Lml_fail /* yes, fall back to a normal mutex lock */ - movl $(MUTEX_LOCKED_AS_SPIN),M_LOCKED /* indicate ownership as a spin lock */ - -#if MACH_LDEBUG - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_THREAD - movl B_PC,%ecx - movl %ecx,M_PC -#endif - PREEMPTION_DISABLE - popf /* restore interrupt state */ - leave /* return with the interlock held */ -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_mutex_lock_spin_lockstat_patch_point) - ret - /* %edx contains the lock address from above */ - LOCKSTAT_RECORD(LS_MUTEX_LOCK_SPIN_ACQUIRE, %edx) -#endif - ret - -Lmls_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Lmls_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Lmls_retry /* yes, go for it */ - jmp Lmls_ilk_loop /* no, keep spinning */ - - -NONLEAF_ENTRY2(mutex_lock,_mutex_lock) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_MUTEX_TYPE() - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - movl M_ILK,%eax /* is interlock held */ - testl %eax,%eax - jne Lml_ilk_loop /* yes, go do the spin loop */ -Lml_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Lml_ilk_fail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Lml_fail /* yes, we lose */ -Lml_acquire: - 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 - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Lml_waiters /* yes, more work to do */ -Lml_return: - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_mutex_lock_lockstat_patch_point) - ret - /* %edx still contains the lock pointer */ - LOCKSTAT_RECORD(LS_MUTEX_LOCK_ACQUIRE, %edx) -#endif - ret - - /* - * We got the mutex, but there are waiters. Update information - * on waiters. - */ -Lml_waiters: - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - jmp Lml_return - -Lml_restart: -Lml_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Lml_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Lml_retry /* yes, go try to grab it */ - jmp Lml_ilk_loop /* no - keep spinning */ - -Lml_fail: - /* - * Check if the owner is on another processor and therefore - * we should try to spin before blocking. - */ - testl $(OnProc),ACT_SPF(%ecx) - jz Lml_block - - /* - * Here if owner is on another processor: - * - release the interlock - * - spin on the holder until release or timeout - * - in either case re-acquire the interlock - * - if released, acquire it - * - otherwise drop thru to block. - */ - xorl %eax,%eax - movl %eax,M_ILK /* zero interlock */ - popf - pushf /* restore interrupt state */ - - push %edx /* lock address */ - call EXT(lck_mtx_lock_spinwait) /* call out to do spinning */ - addl $4,%esp - movl B_ARG0,%edx /* refetch mutex address */ - - /* Re-acquire interlock - interrupts currently enabled */ - movl M_ILK,%eax /* is interlock held */ - testl %eax,%eax - jne Lml_ilk_reloop /* yes, go do the spin loop */ -Lml_reget_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Lml_ilk_refail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex free? */ - je Lml_acquire /* yes, acquire */ - -Lml_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 /* returns with interlock dropped */ - movl B_ARG0,%edx /* refetch mutex address */ - jmp Lml_restart /* and start over */ - -Lml_ilk_refail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Lml_ilk_reloop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Lml_reget_retry /* yes, go try to grab it */ - jmp Lml_ilk_reloop /* no - keep spinning */ - - - -NONLEAF_ENTRY2(mutex_try_spin,_mutex_try_spin) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_MUTEX_TYPE() - CHECK_NO_SIMPLELOCKS() - - movl M_ILK,%eax - testl %eax,%eax /* is the interlock held? */ - jne Lmts_ilk_loop /* yes, go to spin loop */ -Lmts_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Lmts_ilk_fail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Lmt_fail /* yes, we lose */ -Lmts_acquire: - movl $(MUTEX_LOCKED_AS_SPIN),M_LOCKED /* indicate ownership as a spin lock */ - -#if MACH_LDEBUG - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_THREAD - movl B_PC,%ecx - movl %ecx,M_PC -#endif - PREEMPTION_DISABLE /* no, return with interlock held */ - popf /* restore interrupt state */ - movl $1,%eax - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_mutex_try_spin_lockstat_patch_point) - ret - /* %edx inherits the lock pointer from above */ - LOCKSTAT_RECORD(LS_MUTEX_TRY_SPIN_ACQUIRE, %edx) - movl $1,%eax -#endif - ret - -Lmts_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Lmts_ilk_loop: - PAUSE - /* - * need to do this check outside of the interlock in - * case this lock is held as a simple lock which means - * we won't be able to take the interlock - */ - movl M_LOCKED,%eax - testl %eax,%eax /* is the mutex locked? */ - jne Lmt_fail_no_ilk /* yes, go return failure */ - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Lmts_retry /* yes, go try to grab it */ - jmp Lmts_ilk_loop /* keep spinning */ - - - -NONLEAF_ENTRY2(mutex_try,_mutex_try) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_MUTEX_TYPE() - CHECK_NO_SIMPLELOCKS() - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Lmt_ilk_loop /* yes, go try to grab it */ -Lmt_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Lmt_ilk_fail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Lmt_fail /* yes, we lose */ -Lmt_acquire: - 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 - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Lmt_waiters /* yes, more work to do */ -Lmt_return: - xorl %eax,%eax - movl %eax,M_ILK - popf /* restore interrupt state */ - - movl $1,%eax - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_mutex_try_lockstat_patch_point) - ret - /* inherit the lock pointer in %edx from above */ - LOCKSTAT_RECORD(LS_MUTEX_TRY_LOCK_ACQUIRE, %edx) - movl $1,%eax -#endif - ret - -Lmt_waiters: - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - jmp Lmt_return - -Lmt_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Lmt_ilk_loop: - PAUSE - /* - * need to do this check outside of the interlock in - * case this lock is held as a simple lock which means - * we won't be able to take the interlock - */ - movl M_LOCKED,%eax /* get lock owner */ - testl %eax,%eax /* is the mutex locked? */ - jne Lmt_fail_no_ilk /* yes, go return failure */ - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Lmt_retry /* yes, go try to grab it */ - jmp Lmt_ilk_loop /* no - keep spinning */ - -Lmt_fail: - xorl %eax,%eax - movl %eax,M_ILK - -Lmt_fail_no_ilk: - xorl %eax,%eax - popf /* restore interrupt state */ - NONLEAF_RET - - - -LEAF_ENTRY(mutex_convert_spin) - movl L_ARG0,%edx /* fetch lock pointer */ - - movl M_LOCKED,%ecx /* is this the spin variant of the mutex */ - cmpl $(MUTEX_LOCKED_AS_SPIN),%ecx - jne Lmcs_exit /* already owned as a mutex, just return */ - - movl M_ILK,%ecx /* convert from spin version to mutex */ - movl %ecx,M_LOCKED /* take control of the mutex */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Lmcs_waiters /* yes, more work to do */ - -Lmcs_return: - xorl %ecx,%ecx - movl %ecx,M_ILK /* clear interlock */ - PREEMPTION_ENABLE -Lmcs_exit: -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_mutex_convert_spin_lockstat_patch_point) - ret - /* inherit %edx from above */ - LOCKSTAT_RECORD(LS_MUTEX_CONVERT_SPIN_ACQUIRE, %edx) -#endif - ret - - -Lmcs_waiters: - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - jmp Lmcs_return - - - -NONLEAF_ENTRY(mutex_unlock) - movl B_ARG0,%edx /* fetch lock pointer */ - - movl M_LOCKED,%ecx /* is this the spin variant of the mutex */ - cmpl $(MUTEX_LOCKED_AS_SPIN),%ecx - jne Lmu_enter /* no, go treat like a real mutex */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Lmus_wakeup /* yes, more work to do */ - -Lmus_drop_ilk: - xorl %ecx,%ecx - movl %ecx,M_LOCKED /* yes, clear the spin indicator */ - movl %ecx,M_ILK /* release the interlock */ - PREEMPTION_ENABLE /* and re-enable preemption */ - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_mutex_unlock_lockstat_patch_point) - ret - /* inherit lock pointer in %edx from above */ - LOCKSTAT_RECORD(LS_MUTEX_UNLOCK_RELEASE, %edx) -#endif - ret - -Lmus_wakeup: - pushl %edx /* save mutex address */ - pushl %edx /* push mutex address */ - call EXT(lck_mtx_unlockspin_wakeup) /* yes, wake a thread */ - addl $4,%esp - popl %edx /* restore mutex pointer */ - jmp Lmus_drop_ilk - -Lmu_enter: - pushf /* save interrupt state */ - - CHECK_MUTEX_TYPE() - CHECK_THREAD(M_THREAD) - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Lmu_ilk_loop /* yes, go try to grab it */ -Lmu_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Lmu_ilk_fail /* branch on failure to spin loop */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Lmu_wakeup /* yes, more work to do */ - -Lmu_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 /* release the interlock */ - popf /* restore interrupt state */ - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_mutex_unlock2_lockstat_patch_point) - ret - /* inherit %edx from above */ - LOCKSTAT_RECORD(LS_MUTEX_UNLOCK_RELEASE, %edx) -#endif - ret - -Lmu_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Lmu_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Lmu_retry /* yes, go try to grab it */ - jmp Lmu_ilk_loop /* no - keep spinning */ - -Lmu_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 Lmu_doit - -/* - * void lck_mtx_assert(lck_mtx_t* l, unsigned int) - * void _mutex_assert(mutex_t, unsigned int) - * Takes the address of a lock, and an assertion type as parameters. - * The assertion can take one of two forms determine by the type - * parameter: either the lock is held by the current thread, and the - * type is LCK_MTX_ASSERT_OWNED, or it isn't and the type is - * LCK_MTX_ASSERT_NOT_OWNED. Calls panic on assertion failure. - * - */ - -Entry(lck_mtx_assert) -Entry(_mutex_assert) - movl S_ARG0,%edx /* Load lock address */ - movl %gs:CPU_ACTIVE_THREAD,%ecx /* Load current thread */ - - cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */ - cmove M_PTR,%edx /* If so, take indirection */ - - movl M_LOCKED,%eax /* Load lock word */ - cmpl $(MUTEX_LOCKED_AS_SPIN),%eax /* check for spin variant */ - cmove M_ILK,%eax /* yes, spin lock owner is in the interlock */ - - cmpl $(MUTEX_ASSERT_OWNED),S_ARG1 /* Determine assert type */ - jne 2f /* Assert ownership? */ - cmpl %eax,%ecx /* Current thread match? */ - jne 3f /* no, go panic */ -1: /* yes, we own it */ - ret /* just return */ -2: - cmpl %eax,%ecx /* Current thread match? */ - jne 1b /* No, return */ - movl %edx,S_ARG1 /* Prep assertion failure */ - movl $(mutex_assert_owned_str),S_ARG0 - jmp 4f -3: - movl %edx,S_ARG1 /* Prep assertion failure */ - movl $(mutex_assert_not_owned_str),S_ARG0 -4: - jmp EXT(panic) - -.data -mutex_assert_not_owned_str: - .asciz "mutex (%p) not owned\n" -mutex_assert_owned_str: - .asciz "mutex (%p) owned\n" -.text - -/* This preprocessor define controls whether the R-M-W update of the - * per-group statistics elements are atomic (LOCK-prefixed) - * Enabled by default. - */ -#define ATOMIC_STAT_UPDATES 1 - -#if defined(ATOMIC_STAT_UPDATES) -#define LOCK_IF_ATOMIC_STAT_UPDATES lock -#else -#define LOCK_IF_ATOMIC_STAT_UPDATES -#endif /* ATOMIC_STAT_UPDATES */ - - -/* - * lck_mtx_lock() - * lck_mtx_try_lock() - * lck_mutex_unlock() - * lck_mtx_lock_spin() - * lck_mtx_convert_spin() - * - * These are variants of mutex_lock(), mutex_try(), mutex_unlock() - * mutex_lock_spin and mutex_convert_spin without - * DEBUG checks (which require fields not present in lck_mtx_t's). - */ - -NONLEAF_ENTRY(lck_mtx_lock_spin) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llmls_eval_ilk /* no, go see if indirect */ -Llmls_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llmls_ilk_fail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Llml_fail /* yes, fall back to a normal mutex */ - -Llmls_acquire: - movl $(MUTEX_LOCKED_AS_SPIN),M_LOCKED /* indicate ownership as a spin lock */ - PREEMPTION_DISABLE - popf /* restore interrupt state */ - NONLEAF_RET /* return with the interlock held */ - -Llmls_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Llmls_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llmls_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llmls_ilk_loop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llmls_ilk_loop - - -Llmls_eval_ilk: - cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */ - cmove M_PTR,%edx /* If so, take indirection */ - jne Llmls_ilk_loop /* If not, go to spin loop */ - -Llmls_lck_ext: - pushl %esi /* Used to hold the lock group ptr */ - pushl %edi /* Used for stat update records */ - movl MUTEX_GRP(%edx),%esi /* Load lock group */ - xorl %edi,%edi /* Clear stat update records */ - /* 64-bit increment of acquire attempt statistic (per-group) */ - LOCK_IF_ATOMIC_STAT_UPDATES - addl $1, GRP_MTX_STAT_UTIL(%esi) - jnc 1f - incl GRP_MTX_STAT_UTIL+4(%esi) -1: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llmls_ext_ilk_loop /* no, go to spin loop */ -Llmls_ext_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llmls_ext_ilk_fail /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Llml_ext_fail /* yes, we lose */ - - popl %edi - popl %esi - jmp Llmls_acquire - -Llmls_ext_ilk_fail: - /* - * Slow path: call out to do the spinning. - */ - movl 8(%esp),%ecx - pushl %ecx - popf /* restore interrupt state */ - -Llmls_ext_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llmls_ext_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llmls_ext_ilk_loop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llmls_ext_ilk_loop /* no - keep spinning */ - - - -NONLEAF_ENTRY(lck_mtx_lock) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llml_eval_ilk /* no, go see if indirect */ -Llml_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llml_ilk_fail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Llml_fail /* yes, we lose */ -Llml_acquire: - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_LOCKED - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Lml_waiters /* yes, more work to do */ -Llml_return: - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_lck_mtx_lock_lockstat_patch_point) - ret - /* inherit lock pointer in %edx above */ - LOCKSTAT_RECORD(LS_LCK_MTX_LOCK_ACQUIRE, %edx) -#endif - ret - -Llml_waiters: - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - jmp Llml_return - -Llml_restart: -Llml_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Llml_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llml_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llml_ilk_loop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llml_ilk_loop /* no - keep spinning */ - -Llml_fail: - /* - * Check if the owner is on another processor and therefore - * we should try to spin before blocking. - */ - testl $(OnProc),ACT_SPF(%ecx) - jz Llml_block - - /* - * Here if owner is on another processor: - * - release the interlock - * - spin on the holder until release or timeout - * - in either case re-acquire the interlock - * - if released, acquire it - * - otherwise drop thru to block. - */ - xorl %eax,%eax - movl %eax,M_ILK /* zero interlock */ - popf - pushf /* restore interrupt state */ - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_spinwait) - addl $4,%esp - popl %edx /* restore mutex address */ - - /* Re-acquire interlock */ - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llml_ilk_refail /* no, go to spin loop */ -Llml_reget_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llml_ilk_refail /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex free? */ - je Llml_acquire /* yes, acquire */ - -Llml_block: - CHECK_MYLOCK(M_THREAD) - pushl %edx /* save mutex address */ - pushl M_LOCKED - pushl %edx /* push mutex address */ - /* - * N.B.: lck_mtx_lock_wait is called here with interrupts disabled - * Consider reworking. - */ - call EXT(lck_mtx_lock_wait) /* wait for the lock */ - addl $8,%esp - popl %edx /* restore mutex address */ - jmp Llml_restart /* and start over */ - -Llml_ilk_refail: - popf /* restore interrupt state */ - pushf /* resave interrupt state on stack */ - -Llml_ilk_reloop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llml_reget_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llml_ilk_reloop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llml_ilk_reloop /* no - keep spinning */ - - -Llml_eval_ilk: - cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */ - cmove M_PTR,%edx /* If so, take indirection */ - jne Llml_ilk_loop /* If not, go to spin loop */ - -/* - * Entry into statistics codepath for lck_mtx_lock: - * EDX: real lock pointer - * first dword on stack contains flags - */ - -/* Enable this preprocessor define to record the first miss alone - * By default, we count every miss, hence multiple misses may be - * recorded for a single lock acquire attempt via lck_mtx_lock - */ -#undef LOG_FIRST_MISS_ALONE - -/* - * N.B.: On x86, statistics are currently recorded for all indirect mutexes. - * Also, only the acquire attempt count (GRP_MTX_STAT_UTIL) is maintained - * as a 64-bit quantity (this matches the existing PowerPC implementation, - * and the new x86 specific statistics are also maintained as 32-bit - * quantities). - */ - -Llml_lck_ext: - pushl %esi /* Used to hold the lock group ptr */ - pushl %edi /* Used for stat update records */ - movl MUTEX_GRP(%edx),%esi /* Load lock group */ - xorl %edi,%edi /* Clear stat update records */ - /* 64-bit increment of acquire attempt statistic (per-group) */ - LOCK_IF_ATOMIC_STAT_UPDATES - addl $1, GRP_MTX_STAT_UTIL(%esi) - jnc 1f - incl GRP_MTX_STAT_UTIL+4(%esi) -1: - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llml_ext_ilk_loop /* no, go to spin loop */ -Llml_ext_get_hw: - cli - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llml_ext_ilk_fail /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Llml_ext_fail /* yes, we lose */ - -Llml_ext_acquire: - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_LOCKED - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Llml_ext_waiters /* yes, more work to do */ -Llml_ext_return: - xorl %eax,%eax - movl %eax,M_ILK - - popl %edi - popl %esi - popf /* restore interrupt state */ - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_lck_mtx_lock_ext_lockstat_patch_point) - ret - /* inherit lock pointer in %edx above */ - LOCKSTAT_RECORD(LS_LCK_MTX_EXT_LOCK_ACQUIRE, %edx) -#endif - ret - -Llml_ext_waiters: - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - jmp Llml_ext_return - -Llml_ext_restart: -Llml_ext_ilk_fail: - movl 8(%esp),%ecx - pushl %ecx - popf /* restore interrupt state */ - -Llml_ext_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llml_ext_get_hw /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llml_ext_ilk_loop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llml_ext_ilk_loop - - -Llml_ext_fail: -#ifdef LOG_FIRST_MISS_ALONE - testl $1, %edi - jnz 1f -#endif /* LOG_FIRST_MISS_ALONE */ - /* Record that a lock acquire attempt missed (per-group statistic) */ - LOCK_IF_ATOMIC_STAT_UPDATES - incl GRP_MTX_STAT_MISS(%esi) -#ifdef LOG_FIRST_MISS_ALONE - orl $1, %edi -#endif /* LOG_FIRST_MISS_ALONE */ -1: - /* - * Check if the owner is on another processor and therefore - * we should try to spin before blocking. - */ - testl $(OnProc),ACT_SPF(%ecx) - jnz 2f - /* - * Record the "direct wait" statistic, which indicates if a - * miss proceeded to block directly without spinning--occurs - * if the owner of the mutex isn't running on another processor - * at the time of the check. - */ - LOCK_IF_ATOMIC_STAT_UPDATES - incl GRP_MTX_STAT_DIRECT_WAIT(%esi) - jmp Llml_ext_block -2: - /* - * Here if owner is on another processor: - * - release the interlock - * - spin on the holder until release or timeout - * - in either case re-acquire the interlock - * - if released, acquire it - * - otherwise drop thru to block. - */ - xorl %eax,%eax - movl %eax,M_ILK /* zero interlock */ - - pushl 8(%esp) /* Make another copy of EFLAGS image */ - popf /* Restore interrupt state */ - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_spinwait) - addl $4,%esp - popl %edx /* restore mutex address */ - - /* Re-acquire interlock */ - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llml_ext_ilk_refail /* no, go to spin loop */ -Llml_ext_reget_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llml_ext_ilk_refail /* branch on failure to spin loop */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex free? */ - je Llml_ext_acquire /* yes, acquire */ - -Llml_ext_block: - /* If we wanted to count waits just once per lock acquire, we'd - * skip over the stat update here - */ - LOCK_IF_ATOMIC_STAT_UPDATES - /* Record that a lock miss proceeded to block */ - incl GRP_MTX_STAT_WAIT(%esi) -1: - CHECK_MYLOCK(M_THREAD) - pushl %edx /* save mutex address */ - pushl M_LOCKED - pushl %edx /* push mutex address */ - /* - * N.B.: lck_mtx_lock_wait is called here with interrupts disabled - * Consider reworking. - */ - call EXT(lck_mtx_lock_wait) /* wait for the lock */ - addl $8,%esp - popl %edx /* restore mutex address */ - jmp Llml_ext_restart /* and start over */ - -Llml_ext_ilk_refail: - movl 8(%esp),%ecx - pushl %ecx - popf /* restore interrupt state */ - -Llml_ext_ilk_reloop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llml_ext_reget_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llml_ext_ilk_reloop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llml_ext_ilk_reloop - - - -NONLEAF_ENTRY(lck_mtx_try_lock_spin) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llmts_eval_ilk /* no, go see if indirect */ -Llmts_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llmts_ilk_fail /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Llmt_fail /* yes, we lose */ - - movl $(MUTEX_LOCKED_AS_SPIN),M_LOCKED /* no, indicate ownership as a spin lock */ - PREEMPTION_DISABLE /* and return with interlock held */ - - movl $1,%eax /* return success */ - popf /* restore interrupt state */ - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_lck_mtx_try_lock_spin_lockstat_patch_point) - ret - /* inherit lock pointer in %edx above */ - LOCKSTAT_RECORD(LS_LCK_MTX_TRY_SPIN_LOCK_ACQUIRE, %edx) - movl $1,%eax /* return success */ -#endif - ret - -Llmts_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state */ - -Llmts_ilk_loop: - PAUSE - /* - * need to do this check outside of the interlock in - * case this lock is held as a simple lock which means - * we won't be able to take the interlock - */ - movl M_LOCKED,%eax /* get lock owner */ - testl %eax,%eax /* is the mutex locked? */ - jne Llmt_fail_no_ilk /* yes, go return failure */ - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llmts_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llmts_ilk_loop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llmts_ilk_loop - -Llmts_eval_ilk: - cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */ - cmove M_PTR,%edx /* If so, take indirection */ - jne Llmts_ilk_loop /* If not, go to spin loop */ - - /* - * bump counter on indirect lock - */ - pushl %esi /* Used to hold the lock group ptr */ - movl MUTEX_GRP(%edx),%esi /* Load lock group */ - /* 64-bit increment of acquire attempt statistic (per-group) */ - LOCK_IF_ATOMIC_STAT_UPDATES - addl $1, GRP_MTX_STAT_UTIL(%esi) - jnc 1f - incl GRP_MTX_STAT_UTIL+4(%esi) -1: - popl %esi - jmp Llmts_ilk_loop - - - -NONLEAF_ENTRY(lck_mtx_try_lock) - - movl B_ARG0,%edx /* fetch lock pointer */ - pushf /* save interrupt state */ - - CHECK_NO_SIMPLELOCKS() - CHECK_PREEMPTION_LEVEL() - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llmt_eval_ilk /* no, go see if indirect */ -Llmt_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llmt_ilk_fail /* branch on failure to retry */ - - movl M_LOCKED,%ecx /* get lock owner */ - testl %ecx,%ecx /* is the mutex locked? */ - jne Llmt_fail /* yes, we lose */ -Llmt_acquire: - movl %gs:CPU_ACTIVE_THREAD,%ecx - movl %ecx,M_LOCKED - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Llmt_waiters /* yes, more work to do */ -Llmt_return: - xorl %eax,%eax - movl %eax,M_ILK - - popf /* restore interrupt state */ - - movl $1,%eax /* return success */ - leave -#if CONFIG_DTRACE - /* Dtrace probe: LS_LCK_MTX_TRY_LOCK_ACQUIRE */ - LOCKSTAT_LABEL(_lck_mtx_try_lock_lockstat_patch_point) - ret - /* inherit lock pointer in %edx from above */ - LOCKSTAT_RECORD(LS_LCK_MTX_TRY_LOCK_ACQUIRE, %edx) - movl $1,%eax /* return success */ -#endif - ret - -Llmt_waiters: - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - jmp Llmt_return - -Llmt_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state */ - -Llmt_ilk_loop: - PAUSE - /* - * need to do this check outside of the interlock in - * case this lock is held as a simple lock which means - * we won't be able to take the interlock - */ - movl M_LOCKED,%eax /* get lock owner */ - testl %eax,%eax /* is the mutex locked? */ - jne Llmt_fail_no_ilk /* yes, go return failure */ - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llmt_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llmt_ilk_loop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llmt_ilk_loop - -Llmt_fail: - xorl %eax,%eax /* Zero interlock value */ - movl %eax,M_ILK - -Llmt_fail_no_ilk: - popf /* restore interrupt state */ - - cmpl %edx,B_ARG0 - jne Llmt_fail_indirect - - xorl %eax,%eax - /* Note that we don't record a dtrace event for trying and missing */ - NONLEAF_RET - -Llmt_fail_indirect: - pushl %esi /* Used to hold the lock group ptr */ - movl MUTEX_GRP(%edx),%esi /* Load lock group */ - - /* Record mutex acquire attempt miss statistic */ - LOCK_IF_ATOMIC_STAT_UPDATES - incl GRP_MTX_STAT_MISS(%esi) - - popl %esi - xorl %eax,%eax - NONLEAF_RET - -Llmt_eval_ilk: - cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */ - cmove M_PTR,%edx /* If so, take indirection */ - jne Llmt_ilk_loop /* If not, go to spin loop */ - - /* - * bump counter for indirect lock - */ - pushl %esi /* Used to hold the lock group ptr */ - movl MUTEX_GRP(%edx),%esi /* Load lock group */ - - /* 64-bit increment of acquire attempt statistic (per-group) */ - LOCK_IF_ATOMIC_STAT_UPDATES - addl $1, GRP_MTX_STAT_UTIL(%esi) - jnc 1f - incl GRP_MTX_STAT_UTIL+4(%esi) -1: - pop %esi - jmp Llmt_ilk_loop - - - -LEAF_ENTRY(lck_mtx_convert_spin) - movl L_ARG0,%edx /* fetch lock pointer */ - - cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */ - cmove M_PTR,%edx /* If so, take indirection */ - - movl M_LOCKED,%ecx /* is this the spin variant of the mutex */ - cmpl $(MUTEX_LOCKED_AS_SPIN),%ecx - jne Llmcs_exit /* already owned as a mutex, just return */ - - movl M_ILK,%ecx /* convert from spin version to mutex */ - movl %ecx,M_LOCKED /* take control of the mutex */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Llmcs_waiters /* yes, more work to do */ - -Llmcs_return: - xorl %ecx,%ecx - movl %ecx,M_ILK /* clear interlock */ + movb $0, (%rdi) /* Clear the lock byte */ PREEMPTION_ENABLE -Llmcs_exit: LEAF_RET -Llmcs_waiters: - pushl %edx /* save mutex address */ - pushl %edx - call EXT(lck_mtx_lock_acquire) - addl $4,%esp - popl %edx /* restore mutex address */ - jmp Llmcs_return - - - -NONLEAF_ENTRY(lck_mtx_unlock) - - movl B_ARG0,%edx /* fetch lock pointer */ - - cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */ - cmove M_PTR,%edx /* If so, take indirection */ - - movl M_LOCKED,%ecx /* is this the spin variant of the mutex */ - cmpl $(MUTEX_LOCKED_AS_SPIN),%ecx - jne Llmu_enter /* no, go treat like a real mutex */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Llmus_wakeup /* yes, more work to do */ - -Llmu_drop_ilk: - xorl %eax,%eax - movl %eax,M_LOCKED /* clear spin indicator */ - movl %eax,M_ILK /* release the interlock */ - - PREEMPTION_ENABLE /* and re-enable preemption */ - leave -#if CONFIG_DTRACE - /* Dtrace: LS_LCK_MTX_UNLOCK_RELEASE */ - LOCKSTAT_LABEL(_lck_mtx_unlock_lockstat_patch_point) - ret - /* inherit lock pointer in %edx from above */ - LOCKSTAT_RECORD(LS_LCK_MTX_UNLOCK_RELEASE, %edx) -#endif - ret - -Llmus_wakeup: - pushl %edx /* save mutex address */ - pushl %edx /* push mutex address */ - call EXT(lck_mtx_unlockspin_wakeup) /* yes, wake a thread */ - addl $4,%esp - popl %edx /* restore mutex pointer */ - jmp Llmu_drop_ilk - - -Llmu_enter: - pushf /* save interrupt state */ - - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - jne Llmu_ilk_loop /* no - go to spin loop */ -Llmu_retry: - cli /* disable interrupts */ - movl %gs:CPU_ACTIVE_THREAD,%ecx - - /* eax == 0 at this point */ - lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */ - jne Llmu_ilk_fail /* branch on failure to spin loop */ - - cmpw $0,M_WAITERS /* are there any waiters? */ - jne Llmu_wakeup /* yes, more work to do */ - -Llmu_doit: - xorl %ecx,%ecx - movl %ecx,M_LOCKED /* unlock the mutex */ - movl %ecx,M_ILK /* clear the interlock */ - - popf /* restore interrupt state */ - leave -#if CONFIG_DTRACE - LOCKSTAT_LABEL(_lck_mtx_unlock2_lockstat_patch_point) - ret - /* inherit lock pointer in %edx above */ - LOCKSTAT_RECORD(LS_LCK_MTX_UNLOCK_RELEASE, %edx) -#endif - ret - -Llmu_ilk_fail: - popf /* restore interrupt state */ - pushf /* resave interrupt state */ - -Llmu_ilk_loop: - PAUSE - movl M_ILK,%eax /* read interlock */ - testl %eax,%eax /* unlocked? */ - je Llmu_retry /* yes - go try to grab it */ - - cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */ - jne Llmu_ilk_loop /* no - keep spinning */ - - pushl %edx - call EXT(lck_mtx_interlock_panic) - /* - * shouldn't return from here, but just in case - */ - popl %edx - jmp Llmu_ilk_loop - -Llmu_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 */ - xorl %ecx,%ecx - movl %ecx,M_LOCKED /* unlock the mutex */ - - movl %ecx,M_ILK - - popf /* restore interrupt state */ - - leave -#if CONFIG_DTRACE - /* Dtrace: LS_LCK_MTX_EXT_UNLOCK_RELEASE */ - LOCKSTAT_LABEL(_lck_mtx_ext_unlock_lockstat_patch_point) - ret - /* inherit lock pointer in %edx from above */ - LOCKSTAT_RECORD(LS_LCK_MTX_EXT_UNLOCK_RELEASE, %edx) -#endif - ret - - -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) +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: preemption_level (%d) <= 0!" +16: String "Preemption level underflow, possible cause unlocking an unlocked mutex or spinlock" .text -1: -#endif /* MACH_ASSERT */ - _ENABLE_PREEMPTION -#endif /* MACH_RT */ - 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) - hlt - .data -2: String "_mp_enable_preemption_no_check: preemption_level <= 0!" - .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 %edx,(%eax) - LEAF_RET - -LEAF_ENTRY(i_bit_clear) - movl L_ARG0,%edx - movl L_ARG1,%eax - lock - btr %edx,(%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 - -/* - * Atomic primitives, prototyped in kern/simple_lock.h - */ -LEAF_ENTRY(hw_atomic_add) - movl L_ARG0, %ecx /* Load address of operand */ - movl L_ARG1, %eax /* Load addend */ - movl %eax, %edx - lock - xaddl %eax, (%ecx) /* Atomic exchange and add */ - addl %edx, %eax /* Calculate result */ - LEAF_RET - -LEAF_ENTRY(hw_atomic_sub) - movl L_ARG0, %ecx /* Load address of operand */ - movl L_ARG1, %eax /* Load subtrahend */ - negl %eax - movl %eax, %edx - lock - xaddl %eax, (%ecx) /* Atomic exchange and add */ - addl %edx, %eax /* Calculate result */ - LEAF_RET - -LEAF_ENTRY(hw_atomic_or) - movl L_ARG0, %ecx /* Load address of operand */ - movl (%ecx), %eax -1: - movl L_ARG1, %edx /* Load mask */ - orl %eax, %edx - lock - cmpxchgl %edx, (%ecx) /* Atomic CAS */ - jne 1b - movl %edx, %eax /* Result */ - LEAF_RET -/* - * A variant of hw_atomic_or which doesn't return a value. - * The implementation is thus comparatively more efficient. - */ - -LEAF_ENTRY(hw_atomic_or_noret) - movl L_ARG0, %ecx /* Load address of operand */ - movl L_ARG1, %edx /* Load mask */ - lock - orl %edx, (%ecx) /* Atomic OR */ - LEAF_RET - -LEAF_ENTRY(hw_atomic_and) - movl L_ARG0, %ecx /* Load address of operand */ - movl (%ecx), %eax -1: - movl L_ARG1, %edx /* Load mask */ - andl %eax, %edx - lock - cmpxchgl %edx, (%ecx) /* Atomic CAS */ - jne 1b - movl %edx, %eax /* Result */ - LEAF_RET -/* - * A variant of hw_atomic_and which doesn't return a value. - * The implementation is thus comparatively more efficient. - */ - -LEAF_ENTRY(hw_atomic_and_noret) - movl L_ARG0, %ecx /* Load address of operand */ - movl L_ARG1, %edx /* Load mask */ - lock - andl %edx, (%ecx) /* Atomic OR */ - LEAF_RET