/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
#include <platforms.h>
#include <mach_ldebug.h>
#include <i386/asm.h>
+#include <i386/eflags.h>
+#include <i386/trap.h>
+#include <config_dtrace.h>
#include "assym.s"
#if BUILD_STACK_FRAMES
-/* STack-frame-relative: */
+/* Stack-frame-relative: */
#define L_PC B_PC
#define L_ARG0 B_ARG0
#define L_ARG1 B_ARG1
#endif /* MACH_LDEBUG */
+#define PREEMPTION_DISABLE \
+ incl %gs:CPU_PREEMPTION_LEVEL
+
+
+#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 ; \
+ 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 */
+#endif
+
+
/*
* void hw_lock_init(hw_lock_t)
*
*/
LEAF_ENTRY(hw_lock_init)
movl L_ARG0,%edx /* fetch lock pointer */
- movl $0,0(%edx) /* clear the lock */
+ movl $0,(%edx) /* clear the lock */
+ LEAF_RET
+
+
+/*
+ * void hw_lock_byte_init(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 */
LEAF_RET
/*
movl L_ARG0,%edx /* fetch lock pointer */
movl %gs:CPU_ACTIVE_THREAD,%ecx
- DISABLE_PREEMPTION
+ PREEMPTION_DISABLE
1:
- movl 0(%edx), %eax
+ movl (%edx), %eax
testl %eax,%eax /* lock locked? */
jne 3f /* branch if so */
- lock; cmpxchgl %ecx,0(%edx) /* try to acquire the HW lock */
+ 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 */
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.
+ */
+
+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 */
+ testb %al,%al /* lock locked? */
+ jne 3f /* branch if so */
+ lock; cmpxchgb %cl,(%edx) /* 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)
*
* Attempt to grab the lock immediately
* - fastpath without timeout nonsense.
*/
- DISABLE_PREEMPTION
- movl 0(%edx), %eax
+ PREEMPTION_DISABLE
+ movl (%edx), %eax
testl %eax,%eax /* lock locked? */
jne 2f /* branch if so */
- lock; cmpxchgl %ecx,0(%edx) /* try to acquire the HW lock */
+ lock; cmpxchgl %ecx,(%edx) /* try to acquire the HW lock */
jne 2f /* branch on failure */
movl $1,%eax
LEAF_RET
mov $(INNER_LOOP_COUNT),%edx
5:
PAUSE /* pause for hyper-threading */
- movl 0(%edi),%eax /* spin checking lock value in cache */
+ 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 */
* after contention.
*/
movl %gs:CPU_ACTIVE_THREAD,%edx
- lock; cmpxchgl %edx,0(%edi) /* try to acquire the HW lock */
+ lock; cmpxchgl %edx,(%edi) /* try to acquire the HW lock */
jne 4b /* no - spin again */
movl $1,%eax /* yes */
pop %ebx
*/
LEAF_ENTRY(hw_lock_unlock)
movl L_ARG0,%edx /* fetch lock pointer */
- movl $0,0(%edx) /* clear the lock */
- ENABLE_PREEMPTION
+ 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.
+ */
+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)
*
*/
LEAF_ENTRY(i386_lock_unlock_with_flush)
movl L_ARG0,%edx /* Fetch lock pointer */
- movl $0,0(%edx) /* Clear the lock */
+ movl $0,(%edx) /* Clear the lock */
mfence /* Serialize prior stores */
- clflush 0(%edx) /* Write back and invalidate line */
- ENABLE_PREEMPTION
+ clflush (%edx) /* Write back and invalidate line */
+ PREEMPTION_ENABLE
LEAF_RET
/*
movl L_ARG0,%edx /* fetch lock pointer */
movl %gs:CPU_ACTIVE_THREAD,%ecx
- DISABLE_PREEMPTION
- movl 0(%edx),%eax
+ PREEMPTION_DISABLE
+ movl (%edx),%eax
testl %eax,%eax
jne 1f
- lock; cmpxchgl %ecx,0(%edx) /* try to acquire the HW lock */
+ lock; cmpxchgl %ecx,(%edx) /* try to acquire the HW lock */
jne 1f
movl $1,%eax /* success */
LEAF_RET
1:
- ENABLE_PREEMPTION /* failure: release preemption... */
+ PREEMPTION_ENABLE /* failure: release preemption... */
xorl %eax,%eax /* ...and return failure */
LEAF_RET
LEAF_ENTRY(hw_lock_held)
movl L_ARG0,%edx /* fetch lock pointer */
- movl 0(%edx),%eax /* check lock value */
+ movl (%edx),%eax /* check lock value */
testl %eax,%eax
movl $1,%ecx
cmovne %ecx,%eax /* 0 => unlocked, 1 => locked */
LEAF_RET
-NONLEAF_ENTRY2(mutex_lock,_mutex_lock)
+/*
+ * 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()
- pushf /* save interrupt state */
+ movl M_ILK,%eax /* read interlock */
+ testl %eax,%eax /* unlocked? */
+ jne Lmls_ilk_loop /* no, go spin */
+Lmls_retry:
cli /* disable interrupts */
-Lml_retry:
movl %gs:CPU_ACTIVE_THREAD,%ecx
-Lml_get_hw:
+ /* 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? */
- jne Lml_ilk_fail /* no - take the slow path */
+ 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_get_hw /* branch on failure to retry */
+ jne Lml_ilk_fail /* branch on failure to spin loop */
movl M_LOCKED,%ecx /* get lock owner */
testl %ecx,%ecx /* is the mutex locked? */
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:
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
- NONLEAF_RET
-
+ /*
+ * We got the mutex, but there are waiters. Update information
+ * on waiters.
+ */
Lml_waiters:
pushl %edx /* save mutex address */
pushl %edx
popl %edx /* restore mutex address */
jmp Lml_return
+Lml_restart:
Lml_ilk_fail:
- /*
- * Slow path: call out to do the spinning.
- */
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Lml_retry /* try again */
+ 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:
/*
- n Check if the owner is on another processor and therefore
+ * Check if the owner is on another processor and therefore
* we should try to spin before blocking.
*/
testl $(OnProc),ACT_SPF(%ecx)
pushf /* restore interrupt state */
push %edx /* lock address */
- call EXT(lck_mtx_lock_spin) /* call out to do spinning */
+ call EXT(lck_mtx_lock_spinwait) /* call out to do spinning */
addl $4,%esp
movl B_ARG0,%edx /* refetch mutex address */
- /* Re-acquire interlock */
- cli /* disable interrupts */
+ /* 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
-Lml_reget_hw:
- movl M_ILK,%eax /* read interlock */
- testl %eax,%eax /* unlocked? */
- jne Lml_ilk_refail /* no - slow path */
-
+ /* eax == 0 at this point */
lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */
- jne Lml_reget_hw /* branch on failure to retry */
+ jne Lml_ilk_refail /* branch on failure to spin loop */
movl M_LOCKED,%ecx /* get lock owner */
testl %ecx,%ecx /* is the mutex free? */
pushl M_LOCKED
pushl %edx /* push mutex address */
call EXT(lck_mtx_lock_wait) /* wait for the lock */
- addl $8,%esp
+ addl $8,%esp /* returns with interlock dropped */
movl B_ARG0,%edx /* refetch mutex address */
- cli /* ensure interrupts disabled */
- jmp Lml_retry /* and try again */
+ jmp Lml_restart /* and start over */
Lml_ilk_refail:
- /*
- * Slow path: call out to do the spinning.
- */
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Lml_reget_retry /* try again */
+ popf /* restore interrupt state */
+ pushf /* resave interrupt state on stack */
-NONLEAF_ENTRY2(mutex_try,_mutex_try)
+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()
- pushf /* save interrupt state */
+ 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 */
-Lmt_retry:
movl %gs:CPU_ACTIVE_THREAD,%ecx
-Lmt_get_hw:
+ /* 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_fail /* no - slow path */
+ 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_get_hw /* branch on failure to retry */
+ 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
movl B_PC,%ecx
movl %ecx,M_PC
#endif
-
- cmpl $0,M_WAITERS /* are there any waiters? */
+ cmpw $0,M_WAITERS /* are there any waiters? */
jne Lmt_waiters /* yes, more work to do */
Lmt_return:
xorl %eax,%eax
popf /* restore interrupt state */
movl $1,%eax
-
- NONLEAF_RET
+ 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 */
jmp Lmt_return
Lmt_ilk_fail:
+ popf /* restore interrupt state */
+ pushf /* resave interrupt state on stack */
+
+Lmt_ilk_loop:
+ PAUSE
/*
- * Slow path: call out to do the spinning.
- */
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Lmt_retry /* try again */
+ * 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
- xorl %eax,%eax
- 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 */
- CHECK_MUTEX_TYPE()
- CHECK_THREAD(M_THREAD)
+ 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 */
- cli /* disable interrupts */
-Lmu_retry:
- movl %gs:CPU_ACTIVE_THREAD,%ecx
-Lmu_get_hw:
+ CHECK_MUTEX_TYPE()
+ CHECK_THREAD(M_THREAD)
+
movl M_ILK,%eax /* read interlock */
testl %eax,%eax /* unlocked? */
- jne Lmu_ilk_fail /* no - slow path */
+ 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_get_hw /* branch on failure to retry */
+ 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
-
+ movl %ecx,M_ILK /* release the interlock */
popf /* restore interrupt state */
-
- NONLEAF_RET
+ 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:
- /*
- * Slow path: call out to do the spinning.
- */
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Lmu_retry /* try again */
+ 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
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() and mutex_unlock() without
+ * 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)
+
+NONLEAF_ENTRY(lck_mtx_lock_spin)
movl B_ARG0,%edx /* fetch lock pointer */
- cmpl $(MUTEX_IND),M_ITAG /* is this indirect? */
- cmove M_PTR,%edx /* yes - take indirection */
+ pushf /* save interrupt state */
CHECK_NO_SIMPLELOCKS()
CHECK_PREEMPTION_LEVEL()
- pushf /* save interrupt state */
+ 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 */
-Llml_retry:
movl %gs:CPU_ACTIVE_THREAD,%ecx
-Llml_get_hw:
+ /* 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_ilk_fail /* no - slow path */
+ 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_get_hw /* branch on failure to retry */
+ jne Llml_ilk_fail /* branch on failure to spin loop */
movl M_LOCKED,%ecx /* get lock owner */
testl %ecx,%ecx /* is the mutex locked? */
movl %gs:CPU_ACTIVE_THREAD,%ecx
movl %ecx,M_LOCKED
- cmpl $0,M_WAITERS /* are there any waiters? */
- jne Llml_waiters /* yes, more work to do */
+ 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 */
-
- NONLEAF_RET
+ 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 */
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)
/*
- * Slow path: call out to do the spinning.
+ * shouldn't return from here, but just in case
*/
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Llml_retry /* try again */
+ popl %edx
+ jmp Llml_ilk_loop /* no - keep spinning */
Llml_fail:
/*
movl %eax,M_ILK /* zero interlock */
popf
pushf /* restore interrupt state */
-
pushl %edx /* save mutex address */
pushl %edx
- call EXT(lck_mtx_lock_spin)
+ call EXT(lck_mtx_lock_spinwait)
addl $4,%esp
popl %edx /* restore mutex address */
/* Re-acquire interlock */
- cli /* disable interrupts */
-Llml_reget_retry:
- movl %gs:CPU_ACTIVE_THREAD,%ecx
-
-Llml_reget_hw:
movl M_ILK,%eax /* read interlock */
testl %eax,%eax /* unlocked? */
- jne Llml_ilk_refail /* no - slow path */
+ 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_reget_hw /* branch on failure to retry */
+ jne Llml_ilk_refail /* branch on failure to retry */
movl M_LOCKED,%ecx /* get lock owner */
testl %ecx,%ecx /* is the mutex free? */
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 */
- cli /* ensure interrupts disabled */
- jmp Llml_retry /* and try again */
+ 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)
/*
- * Slow path: call out to do the spinning.
+ * shouldn't return from here, but just in case
*/
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Llml_reget_retry /* try again */
+ popl %edx
+ jmp Llml_ilk_reloop /* no - keep spinning */
-NONLEAF_ENTRY(lck_mtx_try_lock)
+
+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 */
- cmpl $(MUTEX_IND),M_ITAG /* is this indirect? */
- cmove M_PTR,%edx /* yes - take indirection */
+ pushf /* save interrupt state */
CHECK_NO_SIMPLELOCKS()
CHECK_PREEMPTION_LEVEL()
- pushf /* save interrupt state */
+ movl M_ILK,%eax /* read interlock */
+ testl %eax,%eax /* unlocked? */
+ jne Llmts_eval_ilk /* no, go see if indirect */
+Llmts_retry:
cli /* disable interrupts */
-Llmt_retry:
movl %gs:CPU_ACTIVE_THREAD,%ecx
-Llmt_get_hw:
+ /* 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_ilk_fail /* no - slow path */
+ 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_get_hw /* branch on failure to retry */
+ 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
- cmpl $0,M_WAITERS /* are there any waiters? */
+ cmpw $0,M_WAITERS /* are there any waiters? */
jne Llmt_waiters /* yes, more work to do */
Llmt_return:
xorl %eax,%eax
popf /* restore interrupt state */
movl $1,%eax /* return success */
- NONLEAF_RET
+ 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 */
jmp Llmt_return
Llmt_ilk_fail:
+ popf /* restore interrupt state */
+ pushf /* resave interrupt state */
+
+Llmt_ilk_loop:
+ PAUSE
/*
- * Slow path: call out to do the spinning.
+ * 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
*/
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Llmt_retry /* try again */
+ popl %edx
+ jmp Llmt_ilk_loop
Llmt_fail:
- xorl %eax,%eax
+ xorl %eax,%eax /* Zero interlock value */
movl %eax,M_ILK
+Llmt_fail_no_ilk:
popf /* restore interrupt state */
- xorl %eax,%eax /* return failure */
+ 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 */
+ 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 indirect? */
- cmove M_PTR,%edx /* yes - take indirection */
+ 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 */
- cli /* disable interrupts */
-Llmu_retry:
- movl %gs:CPU_ACTIVE_THREAD,%ecx
-Llmu_get_hw:
movl M_ILK,%eax /* read interlock */
testl %eax,%eax /* unlocked? */
- jne Llmu_ilk_fail /* no - slow path */
+ 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_get_hw /* branch on failure to retry */
+ 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 */
- movl %ecx,M_ILK
+ 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 */
- NONLEAF_RET
+ cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */
+ jne Llmu_ilk_loop /* no - keep spinning */
-Llmu_ilk_fail:
+ pushl %edx
+ call EXT(lck_mtx_interlock_panic)
/*
- * Slow path: call out to do the spinning.
+ * shouldn't return from here, but just in case
*/
- pushl %edx /* lock address */
- call EXT(lck_mtx_interlock_spin)
- popl %edx /* lock pointer */
- jmp Llmu_retry /* try again */
+ popl %edx
+ jmp Llmu_ilk_loop
Llmu_wakeup:
pushl %edx /* save mutex address */
call EXT(lck_mtx_unlock_wakeup)/* yes, wake a thread */
addl $8,%esp
popl %edx /* restore mutex pointer */
- jmp Llmu_doit
+ 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 */
movl %eax,M_ILK
LEAF_RET
-
+
+
LEAF_ENTRY(_disable_preemption)
#if MACH_RT
_DISABLE_PREEMPTION
btr %edx,(%eax)
LEAF_RET
+
LEAF_ENTRY(bit_lock)
movl L_ARG0,%ecx
movl L_ARG1,%eax
jb 1b
LEAF_RET
+
LEAF_ENTRY(bit_lock_try)
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
projects / apple / xnu.git / blobdiff