diff options
Diffstat (limited to 'runtime/arch/x86_64/quick_entrypoints_x86_64.S')
| -rw-r--r-- | runtime/arch/x86_64/quick_entrypoints_x86_64.S | 55 |
1 files changed, 41 insertions, 14 deletions
diff --git a/runtime/arch/x86_64/quick_entrypoints_x86_64.S b/runtime/arch/x86_64/quick_entrypoints_x86_64.S index c865541..9b6b367 100644 --- a/runtime/arch/x86_64/quick_entrypoints_x86_64.S +++ b/runtime/arch/x86_64/quick_entrypoints_x86_64.S @@ -955,24 +955,33 @@ DEFINE_FUNCTION art_quick_lock_object jz .Lslow_lock .Lretry_lock: movl MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi), %ecx // ecx := lock word. - test LITERAL(0xC0000000), %ecx // Test the 2 high bits. + test LITERAL(LOCK_WORD_STATE_MASK), %ecx // Test the 2 high bits. jne .Lslow_lock // Slow path if either of the two high bits are set. - movl %gs:THREAD_ID_OFFSET, %edx // edx := thread id + movl %ecx, %edx // save lock word (edx) to keep read barrier bits. + andl LITERAL(LOCK_WORD_READ_BARRIER_STATE_MASK_TOGGLED), %ecx // zero the read barrier bits. test %ecx, %ecx jnz .Lalready_thin // Lock word contains a thin lock. - // unlocked case - %edx holds thread id with count of 0 - xor %eax, %eax // eax == 0 for comparison with lock word in cmpxchg + // unlocked case - edx: original lock word, edi: obj. + movl %edx, %eax // eax: lock word zero except for read barrier bits. + movl %gs:THREAD_ID_OFFSET, %edx // edx := thread id + or %eax, %edx // edx: thread id with count of 0 + read barrier bits. lock cmpxchg %edx, MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) jnz .Lretry_lock // cmpxchg failed retry ret -.Lalready_thin: +.Lalready_thin: // edx: lock word (with high 2 bits zero and original rb bits), edi: obj. + movl %gs:THREAD_ID_OFFSET, %ecx // ecx := thread id cmpw %cx, %dx // do we hold the lock already? jne .Lslow_lock - addl LITERAL(65536), %ecx // increment recursion count - test LITERAL(0xC0000000), %ecx // overflowed if either of top two bits are set + movl %edx, %ecx // copy the lock word to check count overflow. + andl LITERAL(LOCK_WORD_READ_BARRIER_STATE_MASK_TOGGLED), %ecx // zero the read barrier bits. + addl LITERAL(LOCK_WORD_THIN_LOCK_COUNT_ONE), %ecx // increment recursion count + test LITERAL(LOCK_WORD_READ_BARRIER_STATE_MASK), %ecx // overflowed if either of the upper two bits (28-29) are set jne .Lslow_lock // count overflowed so go slow - // update lockword, cmpxchg not necessary as we hold lock - movl %ecx, MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) + movl %edx, %eax // copy the lock word as the old val for cmpxchg. + addl LITERAL(LOCK_WORD_THIN_LOCK_COUNT_ONE), %edx // increment recursion count again for real. + // update lockword, cmpxchg necessary for read barrier bits. + lock cmpxchg %edx, MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) // eax: old val, edx: new val. + jnz .Lretry_lock // cmpxchg failed retry ret .Lslow_lock: SETUP_REFS_ONLY_CALLEE_SAVE_FRAME @@ -985,19 +994,37 @@ END_FUNCTION art_quick_lock_object DEFINE_FUNCTION art_quick_unlock_object testl %edi, %edi // null check object/edi jz .Lslow_unlock +.Lretry_unlock: movl MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi), %ecx // ecx := lock word movl %gs:THREAD_ID_OFFSET, %edx // edx := thread id - test LITERAL(0xC0000000), %ecx + test LITERAL(LOCK_WORD_STATE_MASK), %ecx jnz .Lslow_unlock // lock word contains a monitor cmpw %cx, %dx // does the thread id match? jne .Lslow_unlock - cmpl LITERAL(65536), %ecx + movl %ecx, %edx // copy the lock word to detect new count of 0. + andl LITERAL(LOCK_WORD_READ_BARRIER_STATE_MASK_TOGGLED), %edx // zero the read barrier bits. + cmpl LITERAL(LOCK_WORD_THIN_LOCK_COUNT_ONE), %edx jae .Lrecursive_thin_unlock - movl LITERAL(0), MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) + // update lockword, cmpxchg necessary for read barrier bits. + movl %ecx, %eax // eax: old lock word. + andl LITERAL(LOCK_WORD_READ_BARRIER_STATE_MASK), %ecx // ecx: new lock word zero except original rb bits. +#ifndef USE_READ_BARRIER + movl %ecx, MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) +#else + lock cmpxchg %ecx, MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) // eax: old val, ecx: new val. + jnz .Lretry_unlock // cmpxchg failed retry +#endif ret -.Lrecursive_thin_unlock: - subl LITERAL(65536), %ecx +.Lrecursive_thin_unlock: // ecx: original lock word, edi: obj + // update lockword, cmpxchg necessary for read barrier bits. + movl %ecx, %eax // eax: old lock word. + subl LITERAL(LOCK_WORD_THIN_LOCK_COUNT_ONE), %ecx +#ifndef USE_READ_BARRIER mov %ecx, MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) +#else + lock cmpxchg %ecx, MIRROR_OBJECT_LOCK_WORD_OFFSET(%edi) // eax: old val, ecx: new val. + jnz .Lretry_unlock // cmpxchg failed retry +#endif ret .Lslow_unlock: SETUP_REFS_ONLY_CALLEE_SAVE_FRAME |