1// Copyright 2014 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 5package runtime 6 7import "unsafe" 8 9type sigctxt struct { 10 info *siginfo 11 ctxt unsafe.Pointer 12} 13 14//go:nosplit 15//go:nowritebarrierrec 16func (c *sigctxt) regs() *regs32 { return &(*ucontext)(c.ctxt).uc_mcontext.ss } 17 18func (c *sigctxt) r0() uint32 { return c.regs().r[0] } 19func (c *sigctxt) r1() uint32 { return c.regs().r[1] } 20func (c *sigctxt) r2() uint32 { return c.regs().r[2] } 21func (c *sigctxt) r3() uint32 { return c.regs().r[3] } 22func (c *sigctxt) r4() uint32 { return c.regs().r[4] } 23func (c *sigctxt) r5() uint32 { return c.regs().r[5] } 24func (c *sigctxt) r6() uint32 { return c.regs().r[6] } 25func (c *sigctxt) r7() uint32 { return c.regs().r[7] } 26func (c *sigctxt) r8() uint32 { return c.regs().r[8] } 27func (c *sigctxt) r9() uint32 { return c.regs().r[9] } 28func (c *sigctxt) r10() uint32 { return c.regs().r[10] } 29func (c *sigctxt) fp() uint32 { return c.regs().r[11] } 30func (c *sigctxt) ip() uint32 { return c.regs().r[12] } 31func (c *sigctxt) sp() uint32 { return c.regs().sp } 32func (c *sigctxt) lr() uint32 { return c.regs().lr } 33 34//go:nosplit 35//go:nowritebarrierrec 36func (c *sigctxt) pc() uint32 { return c.regs().pc } 37 38func (c *sigctxt) cpsr() uint32 { return c.regs().cpsr } 39func (c *sigctxt) fault() uintptr { return uintptr(c.info.si_addr) } 40func (c *sigctxt) sigcode() uint32 { return uint32(c.info.si_code) } 41func (c *sigctxt) trap() uint32 { return 0 } 42func (c *sigctxt) error() uint32 { return 0 } 43func (c *sigctxt) oldmask() uint32 { return 0 } 44 45func (c *sigctxt) set_pc(x uint32) { c.regs().pc = x } 46func (c *sigctxt) set_sp(x uint32) { c.regs().sp = x } 47func (c *sigctxt) set_lr(x uint32) { c.regs().lr = x } 48func (c *sigctxt) set_r10(x uint32) { c.regs().r[10] = x } 49 50func (c *sigctxt) set_sigcode(x uint32) { c.info.si_code = int32(x) } 51func (c *sigctxt) set_sigaddr(x uint32) { c.info.si_addr = x } 52 53//go:nosplit 54func (c *sigctxt) fixsigcode(sig uint32) { 55 switch sig { 56 case _SIGTRAP: 57 // OS X sets c.sigcode() == TRAP_BRKPT unconditionally for all SIGTRAPs, 58 // leaving no way to distinguish a breakpoint-induced SIGTRAP 59 // from an asynchronous signal SIGTRAP. 60 // They all look breakpoint-induced by default. 61 // Try looking at the code to see if it's a breakpoint. 62 // The assumption is that we're very unlikely to get an 63 // asynchronous SIGTRAP at just the moment that the 64 // PC started to point at unmapped memory. 65 pc := uintptr(c.pc()) 66 // OS X will leave the pc just after the instruction. 67 code := (*uint32)(unsafe.Pointer(pc - 4)) 68 if *code != 0xe7f001f0 { 69 // SIGTRAP on something other than breakpoint. 70 c.set_sigcode(_SI_USER) 71 } 72 } 73} 74