1 // Copyright 2015 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 #include "textflag.h" 6 7 // xx_cgo_panicmem is the entrypoint for SIGSEGV as intercepted via a 8 // mach thread port as EXC_BAD_ACCESS. As the segfault may have happened 9 // in C code, we first need to load_g then call xx_cgo_panicmem. 10 // 11 // R1 - LR at moment of fault 12 // R2 - PC at moment of fault 13 TEXT xx_cgo_panicmem(SB),NOSPLIT,$-4 14 // If in external C code, we need to load the g register. 15 BL runtimeload_g(SB) 16 CMP $0, g 17 BNE ongothread 18 19 // On a foreign thread. We call badsignal, which will, if all 20 // goes according to plan, not return. 21 SUB $4, R13 22 MOVW $11, R1 23 MOVW $11, R2 24 MOVM.DB.W [R1,R2], (R13) 25 // TODO: badsignal should not return, but it does. Issue #10139. 26 //BL runtimebadsignal(SB) 27 MOVW $139, R1 28 MOVW R1, 4(R13) 29 B runtimeexit(SB) 30 31 ongothread: 32 // Trigger a SIGSEGV panic. 33 // 34 // The goal is to arrange the stack so it looks like the runtime 35 // function sigpanic was called from the PC that faulted. It has 36 // to be sigpanic, as the stack unwinding code in traceback.go 37 // looks explicitly for it. 38 // 39 // To do this we call into runtimesetsigsegv, which sets the 40 // appropriate state inside the g object. We give it the faulting 41 // PC on the stack, then put it in the LR before calling sigpanic. 42 MOVM.DB.W [R1,R2], (R13) 43 BL runtimesetsigsegv(SB) 44 MOVM.IA.W (R13), [R1,R2] 45 46 SUB $4, R13 47 MOVW R1, 0(R13) 48 MOVW R2, R14 49 B runtimesigpanic(SB) 50
