* the terms and conditions for use and redistribution.
*/
-#include <mach_rt.h>
#include <mach_ldebug.h>
#include <i386/asm.h>
#include <i386/eflags.h>
.text ; \
1:
+#define CHECK_MYLOCK(current, owner) \
+ cmp current, owner ; \
+ jne 1f ; \
+ ALIGN_STACK() ; \
+ LOAD_STRING_ARG0(2f) ; \
+ CALL_PANIC() ; \
+ hlt ; \
+ .data ; \
+2: String "Attempt to recursively lock a non-recursive lock"; \
+ .text ; \
+1:
+
+#else /* MACH_LDEBUG */
+#define CHECK_MUTEX_TYPE()
+#define CHECK_MYLOCK(thd)
+#endif /* MACH_LDEBUG */
+
+#if DEVELOPMENT || DEBUG
/*
* If one or more simplelocks are currently held by a thread,
* an attempt to acquire a mutex will cause this check to fail
* (since a mutex lock may context switch, holding a simplelock
* is not a good thing).
*/
-#if MACH_RT
#define CHECK_PREEMPTION_LEVEL() \
- cmpl $0,%gs:CPU_HIBERNATE ; \
- jne 1f ; \
cmpl $0,%gs:CPU_PREEMPTION_LEVEL ; \
je 1f ; \
+ cmpl $0,EXT(LckDisablePreemptCheck)(%rip) ; \
+ jne 1f ; \
+ cmpl $0,%gs:CPU_HIBERNATE ; \
+ jne 1f ; \
ALIGN_STACK() ; \
movl %gs:CPU_PREEMPTION_LEVEL, %eax ; \
LOAD_ARG1(%eax) ; \
2: String "preemption_level(%d) != 0!" ; \
.text ; \
1:
-#else /* MACH_RT */
-#define CHECK_PREEMPTION_LEVEL()
-#endif /* MACH_RT */
-
-#define CHECK_MYLOCK(current, owner) \
- cmp current, owner ; \
- jne 1f ; \
- ALIGN_STACK() ; \
- LOAD_STRING_ARG0(2f) ; \
- CALL_PANIC() ; \
- hlt ; \
- .data ; \
-2: String "Attempt to recursively lock a non-recursive lock"; \
- .text ; \
-1:
-
-#else /* MACH_LDEBUG */
-#define CHECK_MUTEX_TYPE()
+#else /* DEVELOPMENT || DEBUG */
#define CHECK_PREEMPTION_LEVEL()
-#define CHECK_MYLOCK(thd)
-#endif /* MACH_LDEBUG */
+#endif /* DEVELOPMENT || DEBUG */
#define PREEMPTION_DISABLE \
incl %gs:CPU_PREEMPTION_LEVEL
* register initially, and then either a byte or register-sized
* word is loaded/stored to the pointer
*/
-
-/*
- * void hw_lock_init(hw_lock_t)
- *
- * Initialize a hardware lock.
- */
-LEAF_ENTRY(hw_lock_init)
- movq $0, (%rdi) /* clear the lock */
- LEAF_RET
-
/*
* void hw_lock_byte_init(volatile uint8_t *)
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)
- mov %gs:CPU_ACTIVE_THREAD, %rcx /* get thread pointer */
-
- PREEMPTION_DISABLE
-1:
- mov (%rdi), %rax
- test %rax,%rax /* lock locked? */
- jne 3f /* branch if so */
- lock; cmpxchg %rcx,(%rdi) /* try to acquire the HW lock */
- jne 3f
- movl $1,%eax /* In case this was a timeout call */
- LEAF_RET /* if yes, then nothing left to do */
-3:
- PAUSE /* pause for hyper-threading */
- jmp 1b /* try again */
-
/*
* void hw_lock_byte_lock(uint8_t *lock_byte)
*
* Acquire byte sized lock operand, spinning until it becomes available.
- * MACH_RT: also return with preemption disabled.
+ * return with preemption disabled.
*/
LEAF_ENTRY(hw_lock_byte_lock)
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:
- mov %gs:CPU_ACTIVE_THREAD, %rcx
-
- /*
- * Attempt to grab the lock immediately
- * - fastpath without timeout nonsense.
- */
- PREEMPTION_DISABLE
-
- mov (%rdi), %rax
- test %rax,%rax /* lock locked? */
- jne 2f /* branch if so */
- lock; cmpxchg %rcx,(%rdi) /* 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.
- */
- push %r9
- lfence
- rdtsc /* read cyclecount into %edx:%eax */
- shlq $32, %rdx
- orq %rdx, %rax /* load 64-bit quantity into %rax */
- addq %rax, %rsi /* %rsi is the timeout expiry */
-
-4:
- /*
- * The inner-loop spin to look for the lock being freed.
- */
- mov $(INNER_LOOP_COUNT),%r9
-5:
- PAUSE /* pause for hyper-threading */
- mov (%rdi),%rax /* spin checking lock value in cache */
- test %rax,%rax
- je 6f /* zero => unlocked, try to grab it */
- decq %r9 /* decrement inner loop count */
- jnz 5b /* time to check for timeout? */
-
- /*
- * Here after spinning INNER_LOOP_COUNT times, check for timeout
- */
- lfence
- rdtsc /* cyclecount into %edx:%eax */
- shlq $32, %rdx
- orq %rdx, %rax /* load 64-bit quantity into %rax */
- cmpq %rsi, %rax /* compare to timeout */
- jb 4b /* continue spinning if less, or */
- xor %rax,%rax /* with 0 return value */
- pop %r9
- LEAF_RET
-
-6:
- /*
- * Here to try to grab the lock that now appears to be free
- * after contention.
- */
- mov %gs:CPU_ACTIVE_THREAD, %rcx
- lock; cmpxchg %rcx,(%rdi) /* try to acquire the HW lock */
- jne 4b /* no - spin again */
- movl $1,%eax /* yes */
- pop %r9
- LEAF_RET
-
-/*
- * void hw_lock_unlock(hw_lock_t)
- *
- * Unconditionally release lock.
- * MACH_RT: release preemption level.
- */
-LEAF_ENTRY(hw_lock_unlock)
- movq $0, (%rdi) /* clear the lock */
- PREEMPTION_ENABLE
- LEAF_RET
-
/*
* void hw_lock_byte_unlock(uint8_t *lock_byte)
*
- * Unconditionally release byte sized lock operand.
- * MACH_RT: release preemption level.
+ * Unconditionally release byte sized lock operand,
+ * release preemption level.
*/
LEAF_ENTRY(hw_lock_byte_unlock)
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)
- mov %gs:CPU_ACTIVE_THREAD, %rcx
- PREEMPTION_DISABLE
-
- mov (%rdi),%rax
- test %rax,%rax
- jne 1f
- lock; cmpxchg %rcx,(%rdi) /* try to acquire the HW lock */
- jne 1f
-
- movl $1,%eax /* success */
- LEAF_RET
-
-1:
- PREEMPTION_ENABLE /* failure: release preemption... */
- xorl %eax,%eax /* ...and return failure */
- LEAF_RET
-
-/*
- * unsigned int hw_lock_held(hw_lock_t)
- * MACH_RT: doesn't change preemption state.
- * N.B. Racy, of course.
- */
-LEAF_ENTRY(hw_lock_held)
- mov (%rdi),%rax /* check lock value */
- test %rax,%rax
- movl $1,%ecx
- cmovne %ecx,%eax /* 0 => unlocked, 1 => locked */
- LEAF_RET
-
-
-/*
- * 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).
- */
-#define LCK_RW_INTERLOCK (0x1 << 16)
-
-#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)
-
-#define LCK_RW_SHARED_MASK (0xffff)
-
-/*
- * 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 RW_LOCK_SHARED_MASK (LCK_RW_INTERLOCK | LCK_RW_WANT_UPGRADE | LCK_RW_WANT_WRITE)
-/*
- * void lck_rw_lock_shared(lck_rw_t *)
- *
- */
-Entry(lck_rw_lock_shared)
- 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 and interlock */
- testl $(RW_LOCK_SHARED_MASK), %eax /* Eligible for fastpath? */
- jne 3f
-
- movl %eax, %ecx /* original value in %eax for cmpxchgl */
- incl %ecx /* Increment reader refcount */
- lock
- cmpxchgl %ecx, (%rdi) /* 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 %rdi
- */
- LOCKSTAT_RECORD(LS_LCK_RW_LOCK_SHARED_ACQUIRE, %rdi)
-#endif
- ret
-2:
- PAUSE
- jmp 1b
-3:
- jmp EXT(lck_rw_lock_shared_gen)
-
-
-
-#define RW_TRY_LOCK_SHARED_MASK (LCK_RW_WANT_UPGRADE | LCK_RW_WANT_WRITE)
-/*
- * void lck_rw_try_lock_shared(lck_rw_t *)
- *
- */
-Entry(lck_rw_try_lock_shared)
-1:
- 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, (%rdi) /* Attempt atomic exchange */
- jne 2f
-
- 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
- movl $1, %eax
- /*
- * 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_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:
- xorl %eax, %eax
- ret
-
-
-#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
-3:
- testl $(LCK_RW_SHARED_MASK), %eax
- je 4f
- testl $(LCK_RW_PRIV_EXCL), %eax
- je 2b
-4:
- xorl %eax, %eax /* return failure */
- ret
-5:
- PAUSE
- jmp 1b
-
-
-
-#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 */
-
- movl %eax, %ecx /* original value in %eax for cmpxchgl */
- orl $(LCK_RW_WANT_WRITE), %ecx
- lock
- cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
- jne 2f
-
-#if CONFIG_DTRACE
- /*
- * 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
- /* Fall thru when patched, counting on lock pointer in %rdi */
- LOCKSTAT_RECORD(LS_LCK_RW_LOCK_EXCL_ACQUIRE, %rdi)
-#endif
- ret
-2:
- PAUSE
- jmp 1b
-3:
- jmp EXT(lck_rw_lock_exclusive_gen)
-
-
-
-#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 */
-
- movl %eax, %ecx /* original value in %eax for cmpxchgl */
- orl $(LCK_RW_WANT_WRITE), %ecx
- lock
- cmpxchgl %ecx, (%rdi) /* Attempt atomic exchange */
- jne 2f
-
- 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
- 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
- /* 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
-2:
- PAUSE
- jmp 1b
-3:
- xorl %eax, %eax /* return FALSE */
- ret
-
-
-
-/*
- * 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 %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 CONFIG_DTRACE
- 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
- /* 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)
-
-
-
- .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
-
- mov %eax,%esi /* old flags in %rsi */
- /* lock is in %rdi already */
- call EXT(lck_rw_done_gen)
- ret
-7:
- PAUSE
- 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
-
-
-
-/*
- * 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 */
-
- 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
-2:
- xorl %eax, %eax /* return failure */
- ret
-3:
- PAUSE
- jmp 1b
-
-
-#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
-
-
/*
* N.B.: On x86, statistics are currently recorded for all indirect mutexes.
.text
-LEAF_ENTRY(_disable_preemption)
-#if MACH_RT
- PREEMPTION_DISABLE
-#endif /* MACH_RT */
- LEAF_RET
-
-LEAF_ENTRY(_enable_preemption)
-#if MACH_RT
-#if MACH_ASSERT
- cmpl $0,%gs:CPU_PREEMPTION_LEVEL
- jg 1f
- movl %gs:CPU_PREEMPTION_LEVEL,%esi
- ALIGN_STACK()
- LOAD_STRING_ARG0(_enable_preemption_less_than_zero)
- CALL_PANIC()
- hlt
- .cstring
-_enable_preemption_less_than_zero:
- .asciz "_enable_preemption: preemption_level(%d) < 0!"
- .text
-1:
-#endif /* MACH_ASSERT */
- PREEMPTION_ENABLE
-#endif /* MACH_RT */
- LEAF_RET
-
-LEAF_ENTRY(_enable_preemption_no_check)
-#if MACH_RT
-#if MACH_ASSERT
- cmpl $0,%gs:CPU_PREEMPTION_LEVEL
- jg 1f
- ALIGN_STACK()
- LOAD_STRING_ARG0(_enable_preemption_no_check_less_than_zero)
- CALL_PANIC()
- hlt
- .cstring
-_enable_preemption_no_check_less_than_zero:
- .asciz "_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
- PREEMPTION_DISABLE
-#endif /* MACH_RT */
- LEAF_RET
-
-LEAF_ENTRY(_mp_enable_preemption)
-#if MACH_RT
-#if MACH_ASSERT
- cmpl $0,%gs:CPU_PREEMPTION_LEVEL
- jg 1f
- movl %gs:CPU_PREEMPTION_LEVEL,%esi
- ALIGN_PANIC()
- LOAD_STRING_ARG0(_mp_enable_preemption_less_than_zero)
- CALL_PANIC()
- hlt
- .cstring
-_mp_enable_preemption_less_than_zero:
- .asciz "_mp_enable_preemption: preemption_level (%d) <= 0!"
- .text
-1:
-#endif /* MACH_ASSERT */
- PREEMPTION_ENABLE
-#endif /* MACH_RT */
- LEAF_RET
-
-LEAF_ENTRY(_mp_enable_preemption_no_check)
-#if MACH_RT
-#if MACH_ASSERT
- cmpl $0,%gs:CPU_PREEMPTION_LEVEL
- jg 1f
- ALIGN_STACK()
- LOAD_STRING_ARG0(_mp_enable_preemption_no_check_less_than_zero)
- CALL_PANIC()
- hlt
- .cstring
-_mp_enable_preemption_no_check_less_than_zero:
- .asciz "_mp_enable_preemption_no_check: preemption_level <= 0!"
- .text
-1:
-#endif /* MACH_ASSERT */
- _ENABLE_PREEMPTION_NO_CHECK
-#endif /* MACH_RT */
- LEAF_RET
-
-/*
- * Atomic primitives, prototyped in kern/simple_lock.h
- */
-LEAF_ENTRY(hw_atomic_add)
-#if MACH_LDEBUG
- test $3, %rdi
- jz 1f
- ud2
-1:
-#endif
- movl %esi, %eax /* Load addend */
- lock xaddl %eax, (%rdi) /* Atomic exchange and add */
- addl %esi, %eax /* Calculate result */
- LEAF_RET
-
-LEAF_ENTRY(hw_atomic_sub)
-#if MACH_LDEBUG
- test $3, %rdi
- jz 1f
- ud2
-1:
-#endif
- negl %esi
- movl %esi, %eax
- lock xaddl %eax, (%rdi) /* Atomic exchange and add */
- addl %esi, %eax /* Calculate result */
- LEAF_RET
-
-LEAF_ENTRY(hw_atomic_or)
-#if MACH_LDEBUG
- test $3, %rdi
- jz 1f
- ud2
-1:
-#endif
- movl (%rdi), %eax
-1:
- movl %esi, %edx /* Load mask */
- orl %eax, %edx
- lock cmpxchgl %edx, (%rdi) /* 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)
-#if MACH_LDEBUG
- test $3, %rdi
- jz 1f
- ud2
-1:
-#endif
- lock
- orl %esi, (%rdi) /* Atomic OR */
- LEAF_RET
-
-
-LEAF_ENTRY(hw_atomic_and)
-#if MACH_LDEBUG
- test $3, %rdi
- jz 1f
- ud2
-1:
-#endif
- movl (%rdi), %eax
-1:
- movl %esi, %edx /* Load mask */
- andl %eax, %edx
- lock cmpxchgl %edx, (%rdi) /* 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)
-#if MACH_LDEBUG
- test $3, %rdi
- jz 1f
- ud2
-1:
-#endif
- lock andl %esi, (%rdi) /* Atomic OR */
- LEAF_RET
-
projects / apple / xnu.git / blobdiff