diff options
Diffstat (limited to 'src/runtime/asm_arm.s')
| -rw-r--r-- | src/runtime/asm_arm.s | 58 |
1 files changed, 21 insertions, 37 deletions
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s index 51a50c604c..c54b4eb006 100644 --- a/src/runtime/asm_arm.s +++ b/src/runtime/asm_arm.s @@ -643,25 +643,9 @@ nosave: MOVW R0, ret+8(FP) RET -// cgocallback(void (*fn)(void*), void *frame, uintptr framesize, uintptr ctxt) -// Turn the fn into a Go func (by taking its address) and call -// cgocallback_gofunc. -TEXT runtime·cgocallback(SB),NOSPLIT,$16-16 - MOVW $fn+0(FP), R0 - MOVW R0, 4(R13) - MOVW frame+4(FP), R0 - MOVW R0, 8(R13) - MOVW framesize+8(FP), R0 - MOVW R0, 12(R13) - MOVW ctxt+12(FP), R0 - MOVW R0, 16(R13) - MOVW $runtime·cgocallback_gofunc(SB), R0 - BL (R0) - RET - -// cgocallback_gofunc(void (*fn)(void*), void *frame, uintptr framesize, uintptr ctxt) +// cgocallback(fn, frame unsafe.Pointer, ctxt uintptr) // See cgocall.go for more details. -TEXT ·cgocallback_gofunc(SB),NOSPLIT,$8-16 +TEXT ·cgocallback(SB),NOSPLIT,$12-12 NO_LOCAL_POINTERS // Load m and g from thread-local storage. @@ -686,7 +670,7 @@ needm: MOVW $runtime·needm(SB), R0 BL (R0) - // Set m->sched.sp = SP, so that if a panic happens + // Set m->g0->sched.sp = SP, so that if a panic happens // during the function we are about to execute, it will // have a valid SP to run on the g0 stack. // The next few lines (after the havem label) @@ -706,10 +690,10 @@ havem: // Save current m->g0->sched.sp on stack and then set it to SP. // Save current sp in m->g0->sched.sp in preparation for // switch back to m->curg stack. - // NOTE: unwindm knows that the saved g->sched.sp is at 4(R13) aka savedsp-8(SP). + // NOTE: unwindm knows that the saved g->sched.sp is at 4(R13) aka savedsp-12(SP). MOVW m_g0(R8), R3 MOVW (g_sched+gobuf_sp)(R3), R4 - MOVW R4, savedsp-8(SP) + MOVW R4, savedsp-12(SP) // must match frame size MOVW R13, (g_sched+gobuf_sp)(R3) // Switch to m->curg stack and call runtime.cgocallbackg. @@ -718,30 +702,30 @@ havem: // save that information (m->curg->sched) so we can restore it. // We can restore m->curg->sched.sp easily, because calling // runtime.cgocallbackg leaves SP unchanged upon return. - // To save m->curg->sched.pc, we push it onto the stack. - // This has the added benefit that it looks to the traceback - // routine like cgocallbackg is going to return to that - // PC (because the frame we allocate below has the same - // size as cgocallback_gofunc's frame declared above) - // so that the traceback will seamlessly trace back into - // the earlier calls. - // - // In the new goroutine, -4(SP) is unused (where SP refers to - // m->curg's SP while we're setting it up, before we've adjusted it). + // To save m->curg->sched.pc, we push it onto the curg stack and + // open a frame the same size as cgocallback's g0 frame. + // Once we switch to the curg stack, the pushed PC will appear + // to be the return PC of cgocallback, so that the traceback + // will seamlessly trace back into the earlier calls. MOVW m_curg(R8), R0 BL setg<>(SB) MOVW (g_sched+gobuf_sp)(g), R4 // prepare stack as R4 MOVW (g_sched+gobuf_pc)(g), R5 - MOVW R5, -12(R4) - MOVW ctxt+12(FP), R0 - MOVW R0, -8(R4) - MOVW $-12(R4), R13 + MOVW R5, -(12+4)(R4) // "saved LR"; must match frame size + // Gather our arguments into registers. + MOVW fn+0(FP), R1 + MOVW frame+4(FP), R2 + MOVW ctxt+8(FP), R3 + MOVW $-(12+4)(R4), R13 // switch stack; must match frame size + MOVW R1, 4(R13) + MOVW R2, 8(R13) + MOVW R3, 12(R13) BL runtime·cgocallbackg(SB) // Restore g->sched (== m->curg->sched) from saved values. MOVW 0(R13), R5 MOVW R5, (g_sched+gobuf_pc)(g) - MOVW $12(R13), R4 + MOVW $(12+4)(R13), R4 // must match frame size MOVW R4, (g_sched+gobuf_sp)(g) // Switch back to m->g0's stack and restore m->g0->sched.sp. @@ -751,7 +735,7 @@ havem: MOVW m_g0(R8), R0 BL setg<>(SB) MOVW (g_sched+gobuf_sp)(g), R13 - MOVW savedsp-8(SP), R4 + MOVW savedsp-12(SP), R4 // must match frame size MOVW R4, (g_sched+gobuf_sp)(g) // If the m on entry was nil, we called needm above to borrow an m |