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