diff options
Diffstat (limited to 'src/runtime/asm_amd64.s')
| -rw-r--r-- | src/runtime/asm_amd64.s | 38 |
1 files changed, 33 insertions, 5 deletions
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s index 7fb1ae2cff..7fe8528d19 100644 --- a/src/runtime/asm_amd64.s +++ b/src/runtime/asm_amd64.s @@ -918,7 +918,20 @@ GLOBL zeroTLS<>(SB),RODATA,$const_tlsSize TEXT ·cgocallback(SB),NOSPLIT,$24-24 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. + MOVQ fn+0(FP), AX + CMPQ AX, $0 + JNE loadg + // Restore the g from frame. + get_tls(CX) + MOVQ frame+8(FP), BX + MOVQ 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 m 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 @@ -956,9 +969,9 @@ needm: // a bad value in there, in case needm tries to use it. XORPS X15, X15 XORQ R14, R14 - MOVQ $runtime·needm<ABIInternal>(SB), AX + MOVQ $runtime·needAndBindM<ABIInternal>(SB), AX CALL AX - MOVQ $0, savedm-8(SP) // dropm on return + MOVQ $0, savedm-8(SP) get_tls(CX) MOVQ g(CX), BX MOVQ g_m(BX), BX @@ -1047,11 +1060,26 @@ havem: MOVQ 0(SP), AX MOVQ 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. MOVQ savedm-8(SP), BX CMPQ BX, $0 JNE done + + // Skip dropm to reuse it in the next call, when a pthread key has been created. + MOVQ _cgo_pthread_key_created(SB), AX + // It means cgo is disabled when _cgo_pthread_key_created is a nil pointer, need dropm. + CMPQ AX, $0 + JEQ dropm + CMPQ (AX), $0 + JNE done + +dropm: MOVQ $runtime·dropm(SB), AX CALL AX #ifdef GOOS_windows |