diff options
Diffstat (limited to 'src/runtime/asm_386.s')
| -rw-r--r-- | src/runtime/asm_386.s | 41 |
1 files changed, 35 insertions, 6 deletions
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s index febe27089f..5fd0ab9817 100644 --- a/src/runtime/asm_386.s +++ b/src/runtime/asm_386.s @@ -689,7 +689,20 @@ nosave: TEXT ·cgocallback(SB),NOSPLIT,$12-12 // Frame size must match commented places below NO_LOCAL_POINTERS - // If g is nil, Go did not create the current thread. + // Skip cgocallbackg, just dropm when fn is nil, and frame is the saved g. + // It is used to dropm while thread is exiting. + MOVL fn+0(FP), AX + CMPL AX, $0 + JNE loadg + // Restore the g from frame. + get_tls(CX) + MOVL frame+4(FP), BX + MOVL BX, g(CX) + JMP dropm + +loadg: + // If g is nil, Go did not create the current thread, + // or if this thread never called into Go on pthread platforms. // Call needm to obtain one for temporary use. // In this case, we're running on the thread stack, so there's // lots of space, but the linker doesn't know. Hide the call from @@ -707,9 +720,9 @@ TEXT ·cgocallback(SB),NOSPLIT,$12-12 // Frame size must match commented places MOVL BP, savedm-4(SP) // saved copy of oldm JMP havem needm: - MOVL $runtime·needm(SB), AX + MOVL $runtime·needAndBindM(SB), AX CALL AX - MOVL $0, savedm-4(SP) // dropm on return + MOVL $0, savedm-4(SP) get_tls(CX) MOVL g(CX), BP MOVL g_m(BP), BP @@ -784,13 +797,29 @@ havem: MOVL 0(SP), AX MOVL AX, (g_sched+gobuf_sp)(SI) - // If the m on entry was nil, we called needm above to borrow an m - // for the duration of the call. Since the call is over, return it with dropm. + // If the m on entry was nil, we called needm above to borrow an m, + // 1. for the duration of the call on non-pthread platforms, + // 2. or the duration of the C thread alive on pthread platforms. + // If the m on entry wasn't nil, + // 1. the thread might be a Go thread, + // 2. or it's wasn't the first call from a C thread on pthread platforms, + // since the we skip dropm to resue the m in the first call. MOVL savedm-4(SP), DX CMPL DX, $0 - JNE 3(PC) + JNE droppedm + + // Skip dropm to reuse it in the next call, when a pthread key has been created. + MOVL _cgo_pthread_key_created(SB), DX + // It means cgo is disabled when _cgo_pthread_key_created is a nil pointer, need dropm. + CMPL DX, $0 + JEQ dropm + CMPL (DX), $0 + JNE droppedm + +dropm: MOVL $runtime·dropm(SB), AX CALL AX +droppedm: // Done! RET |