runtime/cgo: store M for C-created thread in pthread key

[gostls13.git] / src / runtime / asm_arm64.s

diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index ef70970f775715acbfb451b1fcfc129659be66ba..e35131051cb5223057c1bada71345934cca7b5af 100644 (file)
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -1014,10 +1014,20 @@ nosave:
 TEXT ·cgocallback(SB),NOSPLIT,$24-24
        NO_LOCAL_POINTERS
 
+       // Skip cgocallbackg, just dropm when fn is nil, and frame is the saved g.
+       // It is used to dropm while thread is exiting.
+       MOVD    fn+0(FP), R1
+       CBNZ    R1, loadg
+       // Restore the g from frame.
+       MOVD    frame+8(FP), g
+       B       dropm
+
+loadg:
        // Load g from thread-local storage.
        BL      runtime·load_g(SB)
 
-       // If g is nil, Go did not create the current thread.
+       // 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
@@ -1030,7 +1040,7 @@ TEXT ·cgocallback(SB),NOSPLIT,$24-24
 
 needm:
        MOVD    g, savedm-8(SP) // g is zero, so is m.
-       MOVD    $runtime·needm(SB), R0
+       MOVD    $runtime·needAndBindM(SB), R0
        BL      (R0)
 
        // Set m->g0->sched.sp = SP, so that if a panic happens
@@ -1111,10 +1121,24 @@ havem:
        MOVD    savedsp-16(SP), R4
        MOVD    R4, (g_sched+gobuf_sp)(g)
 
-       // 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.
        MOVD    savedm-8(SP), R6
        CBNZ    R6, droppedm
+
+       // Skip dropm to reuse it in the next call, when a pthread key has been created.
+       MOVD    _cgo_pthread_key_created(SB), R6
+       // It means cgo is disabled when _cgo_pthread_key_created is a nil pointer, need dropm.
+       CBZ     R6, dropm
+       MOVD    (R6), R6
+       CBNZ    R6, droppedm
+
+dropm:
        MOVD    $runtime·dropm(SB), R0
        BL      (R0)
 droppedm: