/*
- * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
*/
#include <mach_rt.h>
-#include <platforms.h>
#include <mach_ldebug.h>
#include <i386/asm.h>
#include <i386/eflags.h>
#include <i386/trap.h>
#include <config_dtrace.h>
-
+#include <i386/mp.h>
+
#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 <i386/pal_lock_asm.h>
#define LEAF_ENTRY(name) \
Entry(name)
#define LEAF_RET \
ret
-#endif /* BUILD_STACK_FRAMES */
-
-
/* Non-leaf routines always have a stack frame: */
#define NONLEAF_ENTRY(name) \
Entry(name); \
- FRAME; \
- MCOUNT
+ FRAME
#define NONLEAF_ENTRY2(n1,n2) \
Entry(n1); \
Entry(n2); \
- FRAME; \
- MCOUNT
+ FRAME
#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 */
+/* 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) ;
-#include <i386/mp.h>
-#define CX(addr,reg) addr(,reg,4)
+#define CHECK_UNLOCK(current, owner) \
+ cmp current, owner ; \
+ je 1f ; \
+ ALIGN_STACK() ; \
+ LOAD_STRING_ARG0(2f) ; \
+ CALL_PANIC() ; \
+ hlt ; \
+ .data ; \
+2: String "Mutex unlock attempted from non-owner thread"; \
+ .text ; \
+1:
#if MACH_LDEBUG
/*
#define CHECK_MUTEX_TYPE() \
cmpl $ MUTEX_TAG,M_TYPE ; \
je 1f ; \
- pushl $2f ; \
- call EXT(panic) ; \
+ ALIGN_STACK() ; \
+ LOAD_STRING_ARG0(2f) ; \
+ CALL_PANIC() ; \
hlt ; \
.data ; \
2: String "not a mutex!" ; \
*/
#if MACH_RT
#define CHECK_PREEMPTION_LEVEL() \
+ cmpl $0,%gs:CPU_HIBERNATE ; \
+ jne 1f ; \
cmpl $0,%gs:CPU_PREEMPTION_LEVEL ; \
je 1f ; \
- pushl $2f ; \
- call EXT(panic) ; \
+ ALIGN_STACK() ; \
+ movl %gs:CPU_PREEMPTION_LEVEL, %eax ; \
+ LOAD_ARG1(%eax) ; \
+ LOAD_STRING_ARG0(2f) ; \
+ CALL_PANIC() ; \
hlt ; \
.data ; \
-2: String "preemption_level != 0!" ; \
+2: String "preemption_level(%d) != 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 ; \
+#define CHECK_MYLOCK(current, owner) \
+ cmp current, owner ; \
jne 1f ; \
- pushl $2f ; \
- call EXT(panic) ; \
+ ALIGN_STACK() ; \
+ LOAD_STRING_ARG0(2f) ; \
+ CALL_PANIC() ; \
hlt ; \
.data ; \
-2: String "mylock attempt!" ; \
+2: String "Attempt to recursively lock a non-recursive lock"; \
.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 */
-
#define PREEMPTION_DISABLE \
incl %gs:CPU_PREEMPTION_LEVEL
-
-
+
+#define PREEMPTION_LEVEL_DEBUG 1
+#if PREEMPTION_LEVEL_DEBUG
+#define PREEMPTION_ENABLE \
+ decl %gs:CPU_PREEMPTION_LEVEL ; \
+ js 17f ; \
+ jnz 19f ; \
+ testl $AST_URGENT,%gs:CPU_PENDING_AST ; \
+ jz 19f ; \
+ PUSHF ; \
+ testl $EFL_IF, S_PC ; \
+ jz 18f ; \
+ POPF ; \
+ int $(T_PREEMPT) ; \
+ jmp 19f ; \
+17: \
+ call _preemption_underflow_panic ; \
+18: \
+ POPF ; \
+19:
+#else
#define PREEMPTION_ENABLE \
decl %gs:CPU_PREEMPTION_LEVEL ; \
- 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 ; \
+ 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:
+ jmp 19f ; \
+18: \
+ POPF ; \
+19:
+#endif
-
#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 ; \
+ .globl _lockstat_probe
+ .globl _lockstat_probemap
+
+/*
+ * LOCKSTAT_LABEL creates a dtrace symbol which contains
+ * a pointer into the lock code function body. At that
+ * point is a "ret" instruction that can be patched into
+ * a "nop"
+ */
+
+#define LOCKSTAT_LABEL(lab) \
+ .data ;\
+ .globl lab ;\
+ lab: ;\
+ .quad 9f ;\
+ .text ;\
+ 9:
+
+#define LOCKSTAT_RECORD(id, lck) \
+ push %rbp ; \
+ mov %rsp,%rbp ; \
+ movl _lockstat_probemap + (id * 4)(%rip),%eax ; \
+ test %eax,%eax ; \
+ je 9f ; \
+ mov lck, %rsi ; \
+ mov %rax, %rdi ; \
+ mov $0, %rdx ; \
+ mov $0, %rcx ; \
+ mov $0, %r8 ; \
+ mov $0, %r9 ; \
+ call *_lockstat_probe(%rip) ; \
9: leave
/* ret - left to subsequent code, e.g. return values */
-#endif
+#endif /* CONFIG_DTRACE */
/*
- * 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)
*
*/
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 */
- 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 */
- 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)
*
*/
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 */
+ movb $0, (%rdi) /* Clear the lock byte */
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.
+ * Reader-writer lock fastpaths. These currently exist for the
+ * shared lock acquire, the exclusive lock acquire, the shared to
+ * exclusive upgrade and the release paths (where they reduce overhead
+ * considerably) -- these are by far the most frequently used routines
+ *
+ * The following should reflect the layout of the bitfield embedded within
+ * the lck_rw_t structure (see i386/locks.h).
*/
-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
+#define LCK_RW_INTERLOCK (0x1 << 16)
-#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
+#define LCK_RW_PRIV_EXCL (0x1 << 24)
+#define LCK_RW_WANT_UPGRADE (0x2 << 24)
+#define LCK_RW_WANT_WRITE (0x4 << 24)
+#define LCK_R_WAITING (0x8 << 24)
+#define LCK_W_WAITING (0x10 << 24)
-/*
- * 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).
- */
+#define LCK_RW_SHARED_MASK (0xffff)
/*
- * These should reflect the layout of the bitfield embedded within
- * the lck_rw_t structure (see i386/locks.h).
+ * For most routines, the lck_rw_t pointer is loaded into a
+ * register initially, and the flags bitfield loaded into another
+ * register and examined
*/
-#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))
+
+#define RW_LOCK_SHARED_MASK (LCK_RW_INTERLOCK | LCK_RW_WANT_UPGRADE | LCK_RW_WANT_WRITE)
/*
- * void lck_rw_lock_shared(lck_rw_t*)
+ * void lck_rw_lock_shared(lck_rw_t *)
*
*/
-
Entry(lck_rw_lock_shared)
- movl S_ARG0, %edx
+ mov %gs:CPU_ACTIVE_THREAD, %rcx /* Load thread pointer */
+ incl TH_RWLOCK_COUNT(%rcx) /* Increment count before atomic CAS */
1:
- movl (%edx), %eax /* Load state bitfield and interlock */
+ mov (%rdi), %eax /* Load state bitfield and interlock */
testl $(RW_LOCK_SHARED_MASK), %eax /* Eligible for fastpath? */
jne 3f
- movl %eax, %ecx
+
+ movl %eax, %ecx /* original value in %eax for cmpxchgl */
incl %ecx /* Increment reader refcount */
lock
- cmpxchgl %ecx, (%edx) /* Attempt atomic exchange */
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
jne 2f
#if CONFIG_DTRACE
*/
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)
+ /*
+ Fall thru when patched, counting on lock pointer in %rdi
+ */
+ LOCKSTAT_RECORD(LS_LCK_RW_LOCK_SHARED_ACQUIRE, %rdi)
#endif
ret
-
2:
PAUSE
jmp 1b
jmp EXT(lck_rw_lock_shared_gen)
+
+#define RW_TRY_LOCK_SHARED_MASK (LCK_RW_WANT_UPGRADE | LCK_RW_WANT_WRITE)
/*
- * lck_rw_type_t lck_rw_done(lck_rw_t*)
+ * void lck_rw_try_lock_shared(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
+Entry(lck_rw_try_lock_shared)
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 */
+ mov (%rdi), %eax /* Load state bitfield and interlock */
+ testl $(LCK_RW_INTERLOCK), %eax
+ jne 2f
+ testl $(RW_TRY_LOCK_SHARED_MASK), %eax
+ jne 3f /* lock is busy */
+
+ movl %eax, %ecx /* original value in %eax for cmpxchgl */
+ incl %ecx /* Increment reader refcount */
lock
- cmpxchgl %ecx, (%edx)
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
jne 2f
- movl $(RW_SHARED), %eax /* Indicate that the lock was shared */
+
+ mov %gs:CPU_ACTIVE_THREAD, %rcx /* Load thread pointer */
+ incl TH_RWLOCK_COUNT(%rcx) /* Increment count on success. */
+ /* There is a 3 instr window where preemption may not notice rwlock_count after cmpxchg */
+
#if CONFIG_DTRACE
- /* Dtrace lockstat probe: LS_RW_DONE_RELEASE as reader */
- LOCKSTAT_LABEL(_lck_rw_done_lockstat_patch_point)
- ret
+ movl $1, %eax
/*
- * 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
+ * Dtrace lockstat event: LS_LCK_RW_TRY_LOCK_SHARED_ACQUIRE
+ * Implemented by swapping between return and no-op instructions.
+ * See bsd/dev/dtrace/lockstat.c.
*/
- LOCKSTAT_RECORD2(LS_LCK_RW_DONE_RELEASE, %edx, $0)
- movl $(RW_SHARED), %eax /* Indicate that the lock was shared */
+ LOCKSTAT_LABEL(_lck_rw_try_lock_shared_lockstat_patch_point)
+ ret
+ /* Fall thru when patched, counting on lock pointer in %rdi */
+ LOCKSTAT_RECORD(LS_LCK_RW_TRY_LOCK_SHARED_ACQUIRE, %rdi)
#endif
+ movl $1, %eax /* return TRUE */
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()
+ xorl %eax, %eax
+ ret
- 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)
+#define RW_LOCK_EXCLUSIVE_HELD (LCK_RW_WANT_WRITE | LCK_RW_WANT_UPGRADE)
+/*
+ * int lck_rw_grab_shared(lck_rw_t *)
+ *
+ */
+Entry(lck_rw_grab_shared)
+1:
+ mov (%rdi), %eax /* Load state bitfield and interlock */
+ testl $(LCK_RW_INTERLOCK), %eax
+ jne 5f
+ testl $(RW_LOCK_EXCLUSIVE_HELD), %eax
+ jne 3f
+2:
+ movl %eax, %ecx /* original value in %eax for cmpxchgl */
+ incl %ecx /* Increment reader refcount */
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 4f
+
+ movl $1, %eax /* return success */
ret
- /* %edx contains the lock address from above */
- LOCKSTAT_RECORD(LS_MUTEX_LOCK_SPIN_ACQUIRE, %edx)
-#endif
+3:
+ testl $(LCK_RW_SHARED_MASK), %eax
+ je 4f
+ testl $(LCK_RW_PRIV_EXCL), %eax
+ je 2b
+4:
+ xorl %eax, %eax /* return failure */
ret
-
-Lmls_ilk_fail:
- popf /* restore interrupt state */
- pushf /* resave interrupt state on stack */
-
-Lmls_ilk_loop:
+5:
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
+ jmp 1b
- /* 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
+
+#define RW_LOCK_EXCLUSIVE_MASK (LCK_RW_SHARED_MASK | LCK_RW_INTERLOCK | \
+ LCK_RW_WANT_UPGRADE | LCK_RW_WANT_WRITE)
+/*
+ * void lck_rw_lock_exclusive(lck_rw_t*)
+ *
+ */
+Entry(lck_rw_lock_exclusive)
+ mov %gs:CPU_ACTIVE_THREAD, %rcx /* Load thread pointer */
+ incl TH_RWLOCK_COUNT(%rcx) /* Increment count before atomic CAS */
+1:
+ mov (%rdi), %eax /* Load state bitfield, interlock and shared count */
+ testl $(RW_LOCK_EXCLUSIVE_MASK), %eax /* Eligible for fastpath? */
+ jne 3f /* no, go slow */
-#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
+ movl %eax, %ecx /* original value in %eax for cmpxchgl */
+ orl $(LCK_RW_WANT_WRITE), %ecx
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 2f
- popf /* restore interrupt state */
- leave
#if CONFIG_DTRACE
- LOCKSTAT_LABEL(_mutex_lock_lockstat_patch_point)
+ /*
+ * Dtrace lockstat event: LS_LCK_RW_LOCK_EXCL_ACQUIRE
+ * Implemented by swapping between return and no-op instructions.
+ * See bsd/dev/dtrace/lockstat.c.
+ */
+ LOCKSTAT_LABEL(_lck_rw_lock_exclusive_lockstat_patch_point)
ret
- /* %edx still contains the lock pointer */
- LOCKSTAT_RECORD(LS_MUTEX_LOCK_ACQUIRE, %edx)
+ /* Fall thru when patched, counting on lock pointer in %rdi */
+ LOCKSTAT_RECORD(LS_LCK_RW_LOCK_EXCL_ACQUIRE, %rdi)
#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:
+2:
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
+ jmp 1b
+3:
+ jmp EXT(lck_rw_lock_exclusive_gen)
- /*
- * 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 */
+#define RW_TRY_LOCK_EXCLUSIVE_MASK (LCK_RW_SHARED_MASK | LCK_RW_WANT_UPGRADE | LCK_RW_WANT_WRITE)
+/*
+ * void lck_rw_try_lock_exclusive(lck_rw_t *)
+ *
+ * Tries to get a write lock.
+ *
+ * Returns FALSE if the lock is not held on return.
+ */
+Entry(lck_rw_try_lock_exclusive)
+1:
+ mov (%rdi), %eax /* Load state bitfield, interlock and shared count */
+ testl $(LCK_RW_INTERLOCK), %eax
+ jne 2f
+ testl $(RW_TRY_LOCK_EXCLUSIVE_MASK), %eax
+ jne 3f /* can't get it */
-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 %eax, %ecx /* original value in %eax for cmpxchgl */
+ orl $(LCK_RW_WANT_WRITE), %ecx
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 2f
- 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 */
+ mov %gs:CPU_ACTIVE_THREAD, %rcx /* Load thread pointer */
+ incl TH_RWLOCK_COUNT(%rcx) /* Increment count on success. */
+ /* There is a 3 instr window where preemption may not notice rwlock_count after cmpxchg */
-#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)
+ movl $1, %eax
+ /*
+ * Dtrace lockstat event: LS_LCK_RW_TRY_LOCK_EXCL_ACQUIRE
+ * Implemented by swapping between return and no-op instructions.
+ * See bsd/dev/dtrace/lockstat.c.
+ */
+ LOCKSTAT_LABEL(_lck_rw_try_lock_exclusive_lockstat_patch_point)
ret
- /* %edx inherits the lock pointer from above */
- LOCKSTAT_RECORD(LS_MUTEX_TRY_SPIN_ACQUIRE, %edx)
- movl $1,%eax
+ /* Fall thru when patched, counting on lock pointer in %rdi */
+ LOCKSTAT_RECORD(LS_LCK_RW_TRY_LOCK_EXCL_ACQUIRE, %rdi)
#endif
+ movl $1, %eax /* return TRUE */
ret
-
-Lmts_ilk_fail:
- popf /* restore interrupt state */
- pushf /* resave interrupt state on stack */
-
-Lmts_ilk_loop:
+2:
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 */
+ jmp 1b
+3:
+ xorl %eax, %eax /* return FALSE */
+ ret
-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 */
+/*
+ * void lck_rw_lock_shared_to_exclusive(lck_rw_t*)
+ *
+ * fastpath can be taken if
+ * the current rw_shared_count == 1
+ * AND the interlock is clear
+ * AND RW_WANT_UPGRADE is not set
+ *
+ * note that RW_WANT_WRITE could be set, but will not
+ * be indicative of an exclusive hold since we have
+ * a read count on the lock that we have not yet released
+ * we can blow by that state since the lck_rw_lock_exclusive
+ * function will block until rw_shared_count == 0 and
+ * RW_WANT_UPGRADE is clear... it does this check behind
+ * the interlock which we are also checking for
+ *
+ * to make the transition we must be able to atomically
+ * set RW_WANT_UPGRADE and get rid of the read count we hold
+ */
+Entry(lck_rw_lock_shared_to_exclusive)
+1:
+ mov (%rdi), %eax /* Load state bitfield, interlock and shared count */
+ testl $(LCK_RW_INTERLOCK), %eax
+ jne 7f
+ testl $(LCK_RW_WANT_UPGRADE), %eax
+ jne 2f
- 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 %eax, %ecx /* original value in %eax for cmpxchgl */
+ orl $(LCK_RW_WANT_UPGRADE), %ecx /* ask for WANT_UPGRADE */
+ decl %ecx /* and shed our read count */
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 7f
+ /* we now own the WANT_UPGRADE */
+ testl $(LCK_RW_SHARED_MASK), %ecx /* check to see if all of the readers are drained */
+ jne 8f /* if not, we need to go wait */
-#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)
+ movl $1, %eax
+ /*
+ * Dtrace lockstat event: LS_LCK_RW_LOCK_SHARED_TO_EXCL_UPGRADE
+ * Implemented by swapping between return and no-op instructions.
+ * See bsd/dev/dtrace/lockstat.c.
+ */
+ LOCKSTAT_LABEL(_lck_rw_lock_shared_to_exclusive_lockstat_patch_point)
ret
- /* inherit the lock pointer in %edx from above */
- LOCKSTAT_RECORD(LS_MUTEX_TRY_LOCK_ACQUIRE, %edx)
- movl $1,%eax
+ /* Fall thru when patched, counting on lock pointer in %rdi */
+ LOCKSTAT_RECORD(LS_LCK_RW_LOCK_SHARED_TO_EXCL_UPGRADE, %rdi)
#endif
+ movl $1, %eax /* return success */
ret
+
+2: /* someone else already holds WANT_UPGRADE */
+ movl %eax, %ecx /* original value in %eax for cmpxchgl */
+ decl %ecx /* shed our read count */
+ testl $(LCK_RW_SHARED_MASK), %ecx
+ jne 3f /* we were the last reader */
+ andl $(~LCK_W_WAITING), %ecx /* so clear the wait indicator */
+3:
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 7f
+
+ mov %eax, %esi /* put old flags as second arg */
+ /* lock is alread in %rdi */
+ call EXT(lck_rw_lock_shared_to_exclusive_failure)
+ ret /* and pass the failure return along */
+7:
+ PAUSE
+ jmp 1b
+8:
+ jmp EXT(lck_rw_lock_shared_to_exclusive_success)
-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 */
+
+ .cstring
+rwl_release_error_str:
+ .asciz "Releasing non-exclusive RW lock without a reader refcount!"
+ .text
+
+/*
+ * lck_rw_type_t lck_rw_done(lck_rw_t *)
+ *
+ */
+Entry(lck_rw_done)
+1:
+ mov (%rdi), %eax /* Load state bitfield, interlock and reader count */
+ testl $(LCK_RW_INTERLOCK), %eax
+ jne 7f /* wait for interlock to clear */
+
+ movl %eax, %ecx /* keep original value in %eax for cmpxchgl */
+ testl $(LCK_RW_SHARED_MASK), %ecx /* if reader count == 0, must be exclusive lock */
+ je 2f
+ decl %ecx /* Decrement reader count */
+ testl $(LCK_RW_SHARED_MASK), %ecx /* if reader count has now gone to 0, check for waiters */
+ je 4f
+ jmp 6f
+2:
+ testl $(LCK_RW_WANT_UPGRADE), %ecx
+ je 3f
+ andl $(~LCK_RW_WANT_UPGRADE), %ecx
+ jmp 4f
+3:
+ testl $(LCK_RW_WANT_WRITE), %ecx
+ je 8f /* lock is not 'owned', go panic */
+ andl $(~LCK_RW_WANT_WRITE), %ecx
+4:
+ /*
+ * test the original values to match what
+ * lck_rw_done_gen is going to do to determine
+ * which wakeups need to happen...
+ *
+ * if !(fake_lck->lck_rw_priv_excl && fake_lck->lck_w_waiting)
+ */
+ testl $(LCK_W_WAITING), %eax
+ je 5f
+ andl $(~LCK_W_WAITING), %ecx
+
+ testl $(LCK_RW_PRIV_EXCL), %eax
+ jne 6f
+5:
+ andl $(~LCK_R_WAITING), %ecx
+6:
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 7f
-Lmt_ilk_loop:
+ mov %eax,%esi /* old flags in %rsi */
+ /* lock is in %rdi already */
+ call EXT(lck_rw_done_gen)
+ ret
+7:
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
+ jmp 1b
+8:
+ ALIGN_STACK()
+ LOAD_STRING_ARG0(rwl_release_error_str)
+ CALL_PANIC()
+
+
+/*
+ * lck_rw_type_t lck_rw_lock_exclusive_to_shared(lck_rw_t *)
+ *
+ */
+Entry(lck_rw_lock_exclusive_to_shared)
+1:
+ mov (%rdi), %eax /* Load state bitfield, interlock and reader count */
+ testl $(LCK_RW_INTERLOCK), %eax
+ jne 6f /* wait for interlock to clear */
+
+ movl %eax, %ecx /* keep original value in %eax for cmpxchgl */
+ incl %ecx /* Increment reader count */
+
+ testl $(LCK_RW_WANT_UPGRADE), %ecx
+ je 2f
+ andl $(~LCK_RW_WANT_UPGRADE), %ecx
+ jmp 3f
+2:
+ andl $(~LCK_RW_WANT_WRITE), %ecx
+3:
+ /*
+ * test the original values to match what
+ * lck_rw_lock_exclusive_to_shared_gen is going to do to determine
+ * which wakeups need to happen...
+ *
+ * if !(fake_lck->lck_rw_priv_excl && fake_lck->lck_w_waiting)
+ */
+ testl $(LCK_W_WAITING), %eax
+ je 4f
+ testl $(LCK_RW_PRIV_EXCL), %eax
+ jne 5f
+4:
+ andl $(~LCK_R_WAITING), %ecx
+5:
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 6f
+ mov %eax,%esi
+ call EXT(lck_rw_lock_exclusive_to_shared_gen)
+ ret
+6:
+ PAUSE
+ jmp 1b
-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 */
+/*
+ * int lck_rw_grab_want(lck_rw_t *)
+ *
+ */
+Entry(lck_rw_grab_want)
+1:
+ mov (%rdi), %eax /* Load state bitfield, interlock and reader count */
+ testl $(LCK_RW_INTERLOCK), %eax
+ jne 3f /* wait for interlock to clear */
+ testl $(LCK_RW_WANT_WRITE), %eax /* want_write has been grabbed by someone else */
+ jne 2f /* go return failure */
- 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)
+ movl %eax, %ecx /* original value in %eax for cmpxchgl */
+ orl $(LCK_RW_WANT_WRITE), %ecx
+ lock
+ cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
+ jne 2f
+ /* we now own want_write */
+ movl $1, %eax /* return success */
ret
- /* inherit %edx from above */
- LOCKSTAT_RECORD(LS_MUTEX_CONVERT_SPIN_ACQUIRE, %edx)
-#endif
+2:
+ xorl %eax, %eax /* return failure */
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
+3:
+ PAUSE
+ jmp 1b
-
-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
+#define RW_LOCK_SHARED_OR_UPGRADE_MASK (LCK_RW_SHARED_MASK | LCK_RW_INTERLOCK | LCK_RW_WANT_UPGRADE)
+/*
+ * int lck_rw_held_read_or_upgrade(lck_rw_t *)
+ *
+ */
+Entry(lck_rw_held_read_or_upgrade)
+ mov (%rdi), %eax
+ andl $(RW_LOCK_SHARED_OR_UPGRADE_MASK), %eax
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 */
+
+/*
+ * 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).
+ *
+ *
+ * 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
- CHECK_MUTEX_TYPE()
- CHECK_THREAD(M_THREAD)
+/*
+ * 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
- 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
+#if defined(ATOMIC_STAT_UPDATES)
+#define LOCK_IF_ATOMIC_STAT_UPDATES lock
+#else
+#define LOCK_IF_ATOMIC_STAT_UPDATES
+#endif /* ATOMIC_STAT_UPDATES */
- /* 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 */
+/*
+ * For most routines, the lck_mtx_t pointer is loaded into a
+ * register initially, and the owner field checked for indirection.
+ * Eventually the lock owner is loaded into a register and examined.
+ */
-Lmu_doit:
-#if MACH_LDEBUG
- movl $0,M_THREAD /* disown thread */
+#define M_OWNER MUTEX_OWNER
+#define M_PTR MUTEX_PTR
+#define M_STATE MUTEX_STATE
+
+
+#define LMTX_ENTER_EXTENDED \
+ mov M_PTR(%rdx), %rdx ; \
+ xor %r11, %r11 ; \
+ mov MUTEX_GRP(%rdx), %r10 ; \
+ LOCK_IF_ATOMIC_STAT_UPDATES ; \
+ incq GRP_MTX_STAT_UTIL(%r10)
+
+
+#if LOG_FIRST_MISS_ALONE
+#define LMTX_UPDATE_MISS \
+ test $1, %r11 ; \
+ jnz 11f ; \
+ LOCK_IF_ATOMIC_STAT_UPDATES ; \
+ incl GRP_MTX_STAT_MISS(%r10) ; \
+ or $1, %r11 ; \
+11:
+#else
+#define LMTX_UPDATE_MISS \
+ LOCK_IF_ATOMIC_STAT_UPDATES ; \
+ incl GRP_MTX_STAT_MISS(%r10)
#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)
+
+
+#if LOG_FIRST_MISS_ALONE
+#define LMTX_UPDATE_WAIT \
+ test $2, %r11 ; \
+ jnz 11f ; \
+ LOCK_IF_ATOMIC_STAT_UPDATES ; \
+ incl GRP_MTX_STAT_WAIT(%r10) ; \
+ or $2, %r11 ; \
+11:
+#else
+#define LMTX_UPDATE_WAIT \
+ LOCK_IF_ATOMIC_STAT_UPDATES ; \
+ incl GRP_MTX_STAT_WAIT(%r10)
#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
+/*
+ * 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.
+ */
+#define LMTX_UPDATE_DIRECT_WAIT \
+ LOCK_IF_ATOMIC_STAT_UPDATES ; \
+ incl GRP_MTX_STAT_DIRECT_WAIT(%r10)
+
+
+#define LMTX_CALLEXT1(func_name) \
+ cmp %rdx, %rdi ; \
+ je 12f ; \
+ push %r10 ; \
+ push %r11 ; \
+12: push %rdi ; \
+ push %rdx ; \
+ mov %rdx, %rdi ; \
+ call EXT(func_name) ; \
+ pop %rdx ; \
+ pop %rdi ; \
+ cmp %rdx, %rdi ; \
+ je 12f ; \
+ pop %r11 ; \
+ pop %r10 ; \
+12:
+
+#define LMTX_CALLEXT2(func_name, reg) \
+ cmp %rdx, %rdi ; \
+ je 12f ; \
+ push %r10 ; \
+ push %r11 ; \
+12: push %rdi ; \
+ push %rdx ; \
+ mov reg, %rsi ; \
+ mov %rdx, %rdi ; \
+ call EXT(func_name) ; \
+ pop %rdx ; \
+ pop %rdi ; \
+ cmp %rdx, %rdi ; \
+ je 12f ; \
+ pop %r11 ; \
+ pop %r10 ; \
+12:
+
+
+#define M_WAITERS_MSK 0x0000ffff
+#define M_PRIORITY_MSK 0x00ff0000
+#define M_ILOCKED_MSK 0x01000000
+#define M_MLOCKED_MSK 0x02000000
+#define M_PROMOTED_MSK 0x04000000
+#define M_SPIN_MSK 0x08000000
/*
* 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.
+ * LCK_MTX_ASSERT_NOTOWNED. 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 */
+NONLEAF_ENTRY(lck_mtx_assert)
+ mov %rdi, %rdx /* Load lock address */
+ mov %gs:CPU_ACTIVE_THREAD, %rax /* Load current thread */
+
+ mov M_STATE(%rdx), %ecx
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex? */
+ jne 0f
+ mov M_PTR(%rdx), %rdx /* If so, take indirection */
+0:
+ mov M_OWNER(%rdx), %rcx /* Load owner */
+ cmp $(MUTEX_ASSERT_OWNED), %rsi
jne 2f /* Assert ownership? */
- cmpl %eax,%ecx /* Current thread match? */
+ cmp %rax, %rcx /* Current thread match? */
jne 3f /* no, go panic */
+ testl $(M_ILOCKED_MSK | M_MLOCKED_MSK), M_STATE(%rdx)
+ je 3f
1: /* yes, we own it */
- ret /* just return */
+ NONLEAF_RET
2:
- cmpl %eax,%ecx /* Current thread match? */
+ cmp %rax, %rcx /* Current thread match? */
jne 1b /* No, return */
- movl %edx,S_ARG1 /* Prep assertion failure */
- movl $(mutex_assert_owned_str),S_ARG0
+ ALIGN_STACK()
+ LOAD_PTR_ARG1(%rdx)
+ LOAD_STRING_ARG0(mutex_assert_owned_str)
jmp 4f
3:
- movl %edx,S_ARG1 /* Prep assertion failure */
- movl $(mutex_assert_not_owned_str),S_ARG0
+ ALIGN_STACK()
+ LOAD_PTR_ARG1(%rdx)
+ LOAD_STRING_ARG0(mutex_assert_not_owned_str)
4:
- jmp EXT(panic)
+ CALL_PANIC()
+
+
+lck_mtx_destroyed:
+ ALIGN_STACK()
+ LOAD_PTR_ARG1(%rdx)
+ LOAD_STRING_ARG0(mutex_interlock_destroyed_str)
+ CALL_PANIC()
+
.data
mutex_assert_not_owned_str:
.asciz "mutex (%p) not owned\n"
mutex_assert_owned_str:
.asciz "mutex (%p) owned\n"
+mutex_interlock_destroyed_str:
+ .asciz "trying to interlock destroyed mutex (%p)"
.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_unlock()
* lck_mtx_lock_spin()
+ * lck_mtx_lock_spin_always()
+ * lck_mtx_try_lock_spin()
+ * lck_mtx_try_lock_spin_always()
* 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_always)
+ mov %rdi, %rdx /* fetch lock pointer */
+ jmp Llmls_avoid_check
+
NONLEAF_ENTRY(lck_mtx_lock_spin)
+ mov %rdi, %rdx /* fetch lock pointer */
- movl B_ARG0,%edx /* fetch lock pointer */
- pushf /* save interrupt state */
-
- CHECK_NO_SIMPLELOCKS()
CHECK_PREEMPTION_LEVEL()
+Llmls_avoid_check:
+ mov M_STATE(%rdx), %ecx
+ test $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx /* is the interlock or mutex held */
+ jnz Llmls_slow
+Llmls_try: /* no - can't be INDIRECT, DESTROYED or locked */
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK | M_SPIN_MSK), %ecx
- 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 */
+ lock
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne Llmls_busy_disabled
- CHECK_NO_SIMPLELOCKS()
- CHECK_PREEMPTION_LEVEL()
+ mov %gs:CPU_ACTIVE_THREAD, %rax
+ mov %rax, M_OWNER(%rdx) /* record owner of interlock */
+#if MACH_LDEBUG
+ test %rax, %rax
+ jz 1f
+ incl TH_MUTEX_COUNT(%rax) /* lock statistic */
+1:
+#endif /* MACH_LDEBUG */
- 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 */
+ /* return with the interlock held and preemption disabled */
leave
#if CONFIG_DTRACE
- LOCKSTAT_LABEL(_lck_mtx_lock_lockstat_patch_point)
+ LOCKSTAT_LABEL(_lck_mtx_lock_spin_lockstat_patch_point)
ret
- /* inherit lock pointer in %edx above */
- LOCKSTAT_RECORD(LS_LCK_MTX_LOCK_ACQUIRE, %edx)
+ /* inherit lock pointer in %rdx above */
+ LOCKSTAT_RECORD(LS_LCK_MTX_LOCK_SPIN_ACQUIRE, %rdx)
#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
+Llmls_slow:
+ test $M_ILOCKED_MSK, %ecx /* is the interlock held */
+ jz Llml_contended /* no, must have been the mutex */
-Llml_restart:
-Llml_ilk_fail:
- popf /* restore interrupt state */
- pushf /* resave interrupt state on stack */
+ cmp $(MUTEX_DESTROYED), %ecx /* check to see if its marked destroyed */
+ je lck_mtx_destroyed
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex */
+ jne Llmls_loop /* no... must be interlocked */
-Llml_ilk_loop:
- PAUSE
- movl M_ILK,%eax /* read interlock */
- testl %eax,%eax /* unlocked? */
- je Llml_retry /* yes - go try to grab it */
+ LMTX_ENTER_EXTENDED
- cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */
- jne Llml_ilk_loop /* no - keep spinning */
+ mov M_STATE(%rdx), %ecx
+ test $(M_SPIN_MSK), %ecx
+ jz Llmls_loop1
- 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 */
+ LMTX_UPDATE_MISS /* M_SPIN_MSK was set, so M_ILOCKED_MSK must also be present */
+Llmls_loop:
+ PAUSE
+ mov M_STATE(%rdx), %ecx
+Llmls_loop1:
+ test $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx
+ jz Llmls_try
+ test $(M_MLOCKED_MSK), %ecx
+ jnz Llml_contended /* mutex owned by someone else, go contend for it */
+ jmp Llmls_loop
+
+Llmls_busy_disabled:
+ PREEMPTION_ENABLE
+ jmp Llmls_loop
-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 */
+NONLEAF_ENTRY(lck_mtx_lock)
+ mov %rdi, %rdx /* fetch lock pointer */
-Llml_ilk_reloop:
- PAUSE
- movl M_ILK,%eax /* read interlock */
- testl %eax,%eax /* unlocked? */
- je Llml_reget_retry /* yes - go try to grab it */
+ CHECK_PREEMPTION_LEVEL()
- cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */
- jne Llml_ilk_reloop /* no - keep spinning */
+ mov M_STATE(%rdx), %ecx
+ test $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx /* is the interlock or mutex held */
+ jnz Llml_slow
+Llml_try: /* no - can't be INDIRECT, DESTROYED or locked */
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx
- 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 */
+ PREEMPTION_DISABLE
+ lock
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne Llml_busy_disabled
+ mov %gs:CPU_ACTIVE_THREAD, %rax
+ mov %rax, M_OWNER(%rdx) /* record owner of mutex */
+#if MACH_LDEBUG
+ test %rax, %rax
+ jz 1f
+ incl TH_MUTEX_COUNT(%rax) /* lock statistic */
+1:
+#endif /* MACH_LDEBUG */
-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 */
+ testl $(M_WAITERS_MSK), M_STATE(%rdx)
+ jz Llml_finish
-/*
- * 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
+ LMTX_CALLEXT1(lck_mtx_lock_acquire_x86)
-/*
- * 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_finish:
+ andl $(~M_ILOCKED_MSK), M_STATE(%rdx)
+ PREEMPTION_ENABLE
-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 */
+ cmp %rdx, %rdi /* is this an extended mutex */
+ jne 2f
+
+ leave
+#if CONFIG_DTRACE
+ LOCKSTAT_LABEL(_lck_mtx_lock_lockstat_patch_point)
+ ret
+ /* inherit lock pointer in %rdx above */
+ LOCKSTAT_RECORD(LS_LCK_MTX_LOCK_ACQUIRE, %rdx)
+#endif
+ ret
+2:
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)
+ /* inherit lock pointer in %rdx above */
+ LOCKSTAT_RECORD(LS_LCK_MTX_EXT_LOCK_ACQUIRE, %rdx)
#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 */
+
+Llml_slow:
+ test $M_ILOCKED_MSK, %ecx /* is the interlock held */
+ jz Llml_contended /* no, must have been the mutex */
+
+ cmp $(MUTEX_DESTROYED), %ecx /* check to see if its marked destroyed */
+ je lck_mtx_destroyed
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex? */
+ jne Llml_loop /* no... must be interlocked */
- pushl %edx
- call EXT(lck_mtx_interlock_panic)
- /*
- * shouldn't return from here, but just in case
- */
- popl %edx
- jmp Llml_ext_ilk_loop
+ LMTX_ENTER_EXTENDED
+ mov M_STATE(%rdx), %ecx
+ test $(M_SPIN_MSK), %ecx
+ jz Llml_loop1
-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:
+ LMTX_UPDATE_MISS /* M_SPIN_MSK was set, so M_ILOCKED_MSK must also be present */
+Llml_loop:
PAUSE
- movl M_ILK,%eax /* read interlock */
- testl %eax,%eax /* unlocked? */
- je Llml_ext_reget_retry /* yes - go try to grab it */
+ mov M_STATE(%rdx), %ecx
+Llml_loop1:
+ test $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx
+ jz Llml_try
+ test $(M_MLOCKED_MSK), %ecx
+ jnz Llml_contended /* mutex owned by someone else, go contend for it */
+ jmp Llml_loop
+
+Llml_busy_disabled:
+ PREEMPTION_ENABLE
+ jmp Llml_loop
- cmpl $(MUTEX_DESTROYED),%eax /* check to see if its marked destroyed */
- jne Llml_ext_ilk_reloop /* no - keep spinning */
+
+Llml_contended:
+ cmp %rdx, %rdi /* is this an extended mutex */
+ je 0f
+ LMTX_UPDATE_MISS
+0:
+ LMTX_CALLEXT1(lck_mtx_lock_spinwait_x86)
+
+ test %rax, %rax
+ jz Llml_acquired /* acquired mutex, interlock held and preemption disabled */
+
+ cmp $1, %rax /* check for direct wait status */
+ je 2f
+ cmp %rdx, %rdi /* is this an extended mutex */
+ je 2f
+ LMTX_UPDATE_DIRECT_WAIT
+2:
+ mov M_STATE(%rdx), %ecx
+ test $(M_ILOCKED_MSK), %ecx
+ jnz 6f
+
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK), %ecx /* try to take the interlock */
- pushl %edx
- call EXT(lck_mtx_interlock_panic)
- /*
- * shouldn't return from here, but just in case
- */
- popl %edx
- jmp Llml_ext_ilk_reloop
+ PREEMPTION_DISABLE
+ lock
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne 5f
+ test $(M_MLOCKED_MSK), %ecx /* we've got the interlock and */
+ jnz 3f
+ or $(M_MLOCKED_MSK), %ecx /* the mutex is free... grab it directly */
+ mov %ecx, M_STATE(%rdx)
+ mov %gs:CPU_ACTIVE_THREAD, %rax
+ mov %rax, M_OWNER(%rdx) /* record owner of mutex */
+#if MACH_LDEBUG
+ test %rax, %rax
+ jz 1f
+ incl TH_MUTEX_COUNT(%rax) /* lock statistic */
+1:
+#endif /* MACH_LDEBUG */
-NONLEAF_ENTRY(lck_mtx_try_lock_spin)
-
- movl B_ARG0,%edx /* fetch lock pointer */
- pushf /* save interrupt state */
+Llml_acquired:
+ testl $(M_WAITERS_MSK), M_STATE(%rdx)
+ jnz 1f
+ mov M_OWNER(%rdx), %rax
+ mov TH_WAS_PROMOTED_ON_WAKEUP(%rax), %eax
+ test %eax, %eax
+ jz Llml_finish
+1:
+ LMTX_CALLEXT1(lck_mtx_lock_acquire_x86)
+ jmp Llml_finish
+
+3: /* interlock held, mutex busy */
+ cmp %rdx, %rdi /* is this an extended mutex */
+ je 4f
+ LMTX_UPDATE_WAIT
+4:
+ LMTX_CALLEXT1(lck_mtx_lock_wait_x86)
+ jmp Llml_contended
+5:
+ PREEMPTION_ENABLE
+6:
+ PAUSE
+ jmp 2b
+
- CHECK_NO_SIMPLELOCKS()
- CHECK_PREEMPTION_LEVEL()
+NONLEAF_ENTRY(lck_mtx_try_lock_spin_always)
+ mov %rdi, %rdx /* fetch lock pointer */
+ jmp Llmts_avoid_check
- 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
+NONLEAF_ENTRY(lck_mtx_try_lock_spin)
+ mov %rdi, %rdx /* fetch lock pointer */
- /* eax == 0 at this point */
- lock; cmpxchgl %ecx,M_ILK /* atomic compare and exchange */
- jne Llmts_ilk_fail /* branch on failure to retry */
+Llmts_avoid_check:
+ mov M_STATE(%rdx), %ecx
+ test $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx /* is the interlock or mutex held */
+ jnz Llmts_slow
+Llmts_try: /* no - can't be INDIRECT, DESTROYED or locked */
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK | M_SPIN_MSK), %rcx
- movl M_LOCKED,%ecx /* get lock owner */
- testl %ecx,%ecx /* is the mutex locked? */
- jne Llmt_fail /* yes, we lose */
+ PREEMPTION_DISABLE
+ lock
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne Llmts_busy_disabled
- movl $(MUTEX_LOCKED_AS_SPIN),M_LOCKED /* no, indicate ownership as a spin lock */
- PREEMPTION_DISABLE /* and return with interlock held */
+ mov %gs:CPU_ACTIVE_THREAD, %rax
+ mov %rax, M_OWNER(%rdx) /* record owner of mutex */
+#if MACH_LDEBUG
+ test %rax, %rax
+ jz 1f
+ incl TH_MUTEX_COUNT(%rax) /* lock statistic */
+1:
+#endif /* MACH_LDEBUG */
- movl $1,%eax /* return success */
- popf /* restore interrupt state */
leave
+
#if CONFIG_DTRACE
+ mov $1, %rax /* return success */
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 */
+ /* inherit lock pointer in %rdx above */
+ LOCKSTAT_RECORD(LS_LCK_MTX_TRY_SPIN_LOCK_ACQUIRE, %rdx)
#endif
+ mov $1, %rax /* return success */
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_slow:
+ test $(M_ILOCKED_MSK), %ecx /* is the interlock held */
+ jz Llmts_fail /* no, must be held as a mutex */
-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 */
+ cmp $(MUTEX_DESTROYED), %ecx /* check to see if its marked destroyed */
+ je lck_mtx_destroyed
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex? */
+ jne Llmts_loop1
- /*
- * 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
+ LMTX_ENTER_EXTENDED
+Llmts_loop:
+ PAUSE
+ mov M_STATE(%rdx), %ecx
+Llmts_loop1:
+ test $(M_MLOCKED_MSK | M_SPIN_MSK), %ecx
+ jnz Llmts_fail
+ test $(M_ILOCKED_MSK), %ecx
+ jz Llmts_try
+ jmp Llmts_loop
+
+Llmts_busy_disabled:
+ PREEMPTION_ENABLE
+ jmp Llmts_loop
NONLEAF_ENTRY(lck_mtx_try_lock)
+ mov %rdi, %rdx /* fetch lock pointer */
+
+ mov M_STATE(%rdx), %ecx
+ test $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx /* is the interlock or mutex held */
+ jnz Llmt_slow
+Llmt_try: /* no - can't be INDIRECT, DESTROYED or locked */
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx
+
+ PREEMPTION_DISABLE
+ lock
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne Llmt_busy_disabled
- movl B_ARG0,%edx /* fetch lock pointer */
- pushf /* save interrupt state */
+ mov %gs:CPU_ACTIVE_THREAD, %rax
+ mov %rax, M_OWNER(%rdx) /* record owner of mutex */
+#if MACH_LDEBUG
+ test %rax, %rax
+ jz 1f
+ incl TH_MUTEX_COUNT(%rax) /* lock statistic */
+1:
+#endif /* MACH_LDEBUG */
- CHECK_NO_SIMPLELOCKS()
- CHECK_PREEMPTION_LEVEL()
+ test $(M_WAITERS_MSK), %ecx
+ jz 0f
+
+ LMTX_CALLEXT1(lck_mtx_lock_acquire_x86)
+0:
+ andl $(~M_ILOCKED_MSK), M_STATE(%rdx)
+ PREEMPTION_ENABLE
- 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
+ mov $1, %rax /* return success */
/* 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
+ /* inherit lock pointer in %rdx from above */
+ LOCKSTAT_RECORD(LS_LCK_MTX_TRY_LOCK_ACQUIRE, %rdx)
+#endif
+ mov $1, %rax /* return success */
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
+Llmt_slow:
+ test $(M_ILOCKED_MSK), %ecx /* is the interlock held */
+ jz Llmt_fail /* no, must be held as a mutex */
- xorl %eax,%eax
- /* Note that we don't record a dtrace event for trying and missing */
- NONLEAF_RET
+ cmp $(MUTEX_DESTROYED), %ecx /* check to see if its marked destroyed */
+ je lck_mtx_destroyed
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex? */
+ jne Llmt_loop
-Llmt_fail_indirect:
- pushl %esi /* Used to hold the lock group ptr */
- movl MUTEX_GRP(%edx),%esi /* Load lock group */
+ LMTX_ENTER_EXTENDED
+Llmt_loop:
+ PAUSE
+ mov M_STATE(%rdx), %ecx
+Llmt_loop1:
+ test $(M_MLOCKED_MSK | M_SPIN_MSK), %ecx
+ jnz Llmt_fail
+ test $(M_ILOCKED_MSK), %ecx
+ jz Llmt_try
+ jmp Llmt_loop
+
+Llmt_busy_disabled:
+ PREEMPTION_ENABLE
+ jmp Llmt_loop
- /* Record mutex acquire attempt miss statistic */
- LOCK_IF_ATOMIC_STAT_UPDATES
- incl GRP_MTX_STAT_MISS(%esi)
- popl %esi
- xorl %eax,%eax
+Llmt_fail:
+Llmts_fail:
+ cmp %rdx, %rdi /* is this an extended mutex */
+ je 0f
+ LMTX_UPDATE_MISS
+0:
+ xor %rax, %rax
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 */
+NONLEAF_ENTRY(lck_mtx_convert_spin)
+ mov %rdi, %rdx /* fetch lock pointer */
- 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 */
+ mov M_STATE(%rdx), %ecx
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex? */
+ jne 0f
+ mov M_PTR(%rdx), %rdx /* If so, take indirection */
+ mov M_STATE(%rdx), %ecx
+0:
+ test $(M_MLOCKED_MSK), %ecx /* already owned as a mutex, just return */
+ jnz 2f
+ test $(M_WAITERS_MSK), %ecx /* are there any waiters? */
+ jz 1f
- cmpw $0,M_WAITERS /* are there any waiters? */
- jne Llmcs_waiters /* yes, more work to do */
+ LMTX_CALLEXT1(lck_mtx_lock_acquire_x86)
+ mov M_STATE(%rdx), %ecx
+1:
+ and $(~(M_ILOCKED_MSK | M_SPIN_MSK)), %ecx /* convert from spin version to mutex */
+ or $(M_MLOCKED_MSK), %ecx
+ mov %ecx, M_STATE(%rdx) /* since I own the interlock, I don't need an atomic update */
-Llmcs_return:
- xorl %ecx,%ecx
- movl %ecx,M_ILK /* clear interlock */
PREEMPTION_ENABLE
-Llmcs_exit:
- LEAF_RET
+2:
+ NONLEAF_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)
+ mov %rdi, %rdx /* fetch lock pointer */
+Llmu_entry:
+ mov M_STATE(%rdx), %ecx
+Llmu_prim:
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex? */
+ je Llmu_ext
+
+Llmu_chktype:
+ test $(M_MLOCKED_MSK), %ecx /* check for full mutex */
+ jz Llmu_unlock
+Llmu_mutex:
+ test $(M_ILOCKED_MSK), %rcx /* have to wait for interlock to clear */
+ jnz Llmu_busy
+
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ and $(~M_MLOCKED_MSK), %ecx /* drop mutex */
+ or $(M_ILOCKED_MSK), %ecx /* pick up interlock */
- movl B_ARG0,%edx /* fetch lock pointer */
+ PREEMPTION_DISABLE
+ lock
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne Llmu_busy_disabled /* branch on failure to spin loop */
- cmpl $(MUTEX_IND),M_ITAG /* Is this an indirect mutex? */
- cmove M_PTR,%edx /* If so, take indirection */
+Llmu_unlock:
+ xor %rax, %rax
+ mov %rax, M_OWNER(%rdx)
+ mov %rcx, %rax /* keep original state in %ecx for later evaluation */
+ and $(~(M_ILOCKED_MSK | M_SPIN_MSK | M_PROMOTED_MSK)), %rax
- 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 */
+ test $(M_WAITERS_MSK), %eax
+ jz 2f
+ dec %eax /* decrement waiter count */
+2:
+ mov %eax, M_STATE(%rdx) /* since I own the interlock, I don't need an atomic update */
- cmpw $0,M_WAITERS /* are there any waiters? */
- jne Llmus_wakeup /* yes, more work to do */
+#if MACH_LDEBUG
+ /* perform lock statistics after drop to prevent delay */
+ mov %gs:CPU_ACTIVE_THREAD, %rax
+ test %rax, %rax
+ jz 1f
+ decl TH_MUTEX_COUNT(%rax) /* lock statistic */
+1:
+#endif /* MACH_LDEBUG */
+
+ test $(M_PROMOTED_MSK | M_WAITERS_MSK), %ecx
+ jz 3f
-Llmu_drop_ilk:
- xorl %eax,%eax
- movl %eax,M_LOCKED /* clear spin indicator */
- movl %eax,M_ILK /* release the interlock */
+ LMTX_CALLEXT2(lck_mtx_unlock_wakeup_x86, %rcx)
+3:
+ PREEMPTION_ENABLE
+
+ cmp %rdx, %rdi
+ jne 4f
- 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)
+ /* inherit lock pointer in %rdx from above */
+ LOCKSTAT_RECORD(LS_LCK_MTX_UNLOCK_RELEASE, %rdx)
#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 */
+4:
leave
#if CONFIG_DTRACE
- LOCKSTAT_LABEL(_lck_mtx_unlock2_lockstat_patch_point)
+ /* Dtrace: LS_LCK_MTX_EXT_UNLOCK_RELEASE */
+ LOCKSTAT_LABEL(_lck_mtx_ext_unlock_lockstat_patch_point)
ret
- /* inherit lock pointer in %edx above */
- LOCKSTAT_RECORD(LS_LCK_MTX_UNLOCK_RELEASE, %edx)
+ /* inherit lock pointer in %rdx from above */
+ LOCKSTAT_RECORD(LS_LCK_MTX_EXT_UNLOCK_RELEASE, %rdx)
#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_busy_disabled:
+ PREEMPTION_ENABLE
+Llmu_busy:
+ PAUSE
+ mov M_STATE(%rdx), %ecx
+ jmp Llmu_mutex
-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 */
+Llmu_ext:
+ mov M_PTR(%rdx), %rdx
+ mov M_OWNER(%rdx), %rax
+ mov %gs:CPU_ACTIVE_THREAD, %rcx
+ CHECK_UNLOCK(%rcx, %rax)
+ mov M_STATE(%rdx), %ecx
+ jmp Llmu_chktype
- movl %ecx,M_ILK
- popf /* restore interrupt state */
+
+LEAF_ENTRY(lck_mtx_ilk_try_lock)
+ mov %rdi, %rdx /* fetch lock pointer - no indirection here */
- 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
+ mov M_STATE(%rdx), %ecx
+ test $(M_ILOCKED_MSK), %ecx /* can't have the interlock yet */
+ jnz 3f
-LEAF_ENTRY(lck_mtx_ilk_unlock)
- movl L_ARG0,%edx /* no indirection here */
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK), %ecx
- xorl %eax,%eax
- movl %eax,M_ILK
+ PREEMPTION_DISABLE
+ lock
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne 2f /* return failure after re-enabling preemption */
+ mov $1, %rax /* return success with preemption disabled */
LEAF_RET
-
-
-LEAF_ENTRY(_disable_preemption)
-#if MACH_RT
- _DISABLE_PREEMPTION
-#endif /* MACH_RT */
+2:
+ PREEMPTION_ENABLE /* need to re-enable preemption */
+3:
+ xor %rax, %rax /* return failure */
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(lck_mtx_ilk_unlock)
+ mov %rdi, %rdx /* fetch lock pointer - no indirection here */
-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
+ andl $(~M_ILOCKED_MSK), M_STATE(%rdx)
-LEAF_ENTRY(_mp_enable_preemption)
-#if MACH_RT
-#if MACH_ASSERT
- cmpl $0,%gs:CPU_PREEMPTION_LEVEL
- jg 1f
- pushl %gs:CPU_PREEMPTION_LEVEL
- pushl $2f
- call EXT(panic)
- hlt
- .data
-2: String "_mp_enable_preemption: preemption_level (%d) <= 0!"
- .text
-1:
-#endif /* MACH_ASSERT */
- _ENABLE_PREEMPTION
-#endif /* MACH_RT */
- LEAF_RET
+ PREEMPTION_ENABLE /* need to re-enable preemption */
-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(lck_mtx_lock_grab_mutex)
+ mov %rdi, %rdx /* fetch lock pointer - no indirection here */
+ mov M_STATE(%rdx), %ecx
-LEAF_ENTRY(bit_lock)
- movl L_ARG0,%ecx
- movl L_ARG1,%eax
-1:
- lock
- bts %ecx,(%eax)
- jb 1b
- LEAF_RET
+ test $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx /* can't have the mutex yet */
+ jnz 3f
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK | M_MLOCKED_MSK), %ecx
-LEAF_ENTRY(bit_lock_try)
- movl L_ARG0,%ecx
- movl L_ARG1,%eax
+ PREEMPTION_DISABLE
lock
- bts %ecx,(%eax)
- jb bit_lock_failed
- LEAF_RET /* %eax better not be null ! */
-bit_lock_failed:
- xorl %eax,%eax
- LEAF_RET
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne 2f /* branch on failure to spin loop */
-LEAF_ENTRY(bit_unlock)
- movl L_ARG0,%ecx
- movl L_ARG1,%eax
- lock
- btr %ecx,(%eax)
- LEAF_RET
+ mov %gs:CPU_ACTIVE_THREAD, %rax
+ mov %rax, M_OWNER(%rdx) /* record owner of mutex */
+#if MACH_LDEBUG
+ test %rax, %rax
+ jz 1f
+ incl TH_MUTEX_COUNT(%rax) /* lock statistic */
+1:
+#endif /* MACH_LDEBUG */
-/*
- * 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 */
+ mov $1, %rax /* return success */
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 */
+2:
+ PREEMPTION_ENABLE
+3:
+ xor %rax, %rax /* return failure */
LEAF_RET
+
+
-LEAF_ENTRY(hw_atomic_or)
- movl L_ARG0, %ecx /* Load address of operand */
- movl (%ecx), %eax
+LEAF_ENTRY(lck_mtx_lock_mark_destroyed)
+ mov %rdi, %rdx
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.
- */
+ mov M_STATE(%rdx), %ecx
+ cmp $(MUTEX_IND), %ecx /* Is this an indirect mutex? */
+ jne 2f
-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
+ movl $(MUTEX_DESTROYED), M_STATE(%rdx) /* convert to destroyed state */
+ jmp 3f
+2:
+ test $(M_ILOCKED_MSK), %rcx /* have to wait for interlock to clear */
+ jnz 5f
-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
+ PREEMPTION_DISABLE
+ mov %rcx, %rax /* eax contains snapshot for cmpxchgl */
+ or $(M_ILOCKED_MSK), %ecx
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.
- */
+ cmpxchg %ecx, M_STATE(%rdx) /* atomic compare and exchange */
+ jne 4f /* branch on failure to spin loop */
+ movl $(MUTEX_DESTROYED), M_STATE(%rdx) /* convert to destroyed state */
+ PREEMPTION_ENABLE
+3:
+ LEAF_RET /* return with M_ILOCKED set */
+4:
+ PREEMPTION_ENABLE
+5:
+ PAUSE
+ jmp 1b
+
+LEAF_ENTRY(preemption_underflow_panic)
+ FRAME
+ incl %gs:CPU_PREEMPTION_LEVEL
+ ALIGN_STACK()
+ LOAD_STRING_ARG0(16f)
+ CALL_PANIC()
+ hlt
+ .data
+16: String "Preemption level underflow, possible cause unlocking an unlocked mutex or spinlock"
+ .text
+
-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