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Diffstat (limited to 'src/runtime/cgo/signal_ios_arm64.s')
| -rw-r--r-- | src/runtime/cgo/signal_ios_arm64.s | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/src/runtime/cgo/signal_ios_arm64.s b/src/runtime/cgo/signal_ios_arm64.s new file mode 100644 index 0000000..1ae00d1 --- /dev/null +++ b/src/runtime/cgo/signal_ios_arm64.s @@ -0,0 +1,56 @@ +// Copyright 2015 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "textflag.h" + +// xx_cgo_panicmem is the entrypoint for SIGSEGV as intercepted via a +// mach thread port as EXC_BAD_ACCESS. As the segfault may have happened +// in C code, we first need to load_g then call xx_cgo_panicmem. +// +// R1 - LR at moment of fault +// R2 - PC at moment of fault +TEXT xx_cgo_panicmem(SB),NOSPLIT|NOFRAME,$0 + // If in external C code, we need to load the g register. + BL runtime·load_g(SB) + CMP $0, g + BNE ongothread + + // On a foreign thread. + // TODO(crawshaw): call badsignal + MOVD.W $0, -16(RSP) + MOVW $139, R1 + MOVW R1, 8(RSP) + B runtime·exit(SB) + +ongothread: + // Trigger a SIGSEGV panic. + // + // The goal is to arrange the stack so it looks like the runtime + // function sigpanic was called from the PC that faulted. It has + // to be sigpanic, as the stack unwinding code in traceback.go + // looks explicitly for it. + // + // To do this we call into runtime·setsigsegv, which sets the + // appropriate state inside the g object. We give it the faulting + // PC on the stack, then put it in the LR before calling sigpanic. + + // Build a 32-byte stack frame for us for this call. + // Saved LR (none available) is at the bottom, + // then the PC argument for setsigsegv, + // then a copy of the LR for us to restore. + MOVD.W $0, -32(RSP) + MOVD R1, 8(RSP) + MOVD R2, 16(RSP) + BL runtime·setsigsegv(SB) + MOVD 8(RSP), R1 + MOVD 16(RSP), R2 + + // Build a 16-byte stack frame for the simulated + // call to sigpanic, by taking 16 bytes away from the + // 32-byte stack frame above. + // The saved LR in this frame is the LR at time of fault, + // and the LR on entry to sigpanic is the PC at time of fault. + MOVD.W R1, 16(RSP) + MOVD R2, R30 + B runtime·sigpanic(SB) |