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 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() *regs64 { return &(*ucontext)(c.ctxt).uc_mcontext.ss } 17 18func (c *sigctxt) r0() uint64 { return c.regs().x[0] } 19func (c *sigctxt) r1() uint64 { return c.regs().x[1] } 20func (c *sigctxt) r2() uint64 { return c.regs().x[2] } 21func (c *sigctxt) r3() uint64 { return c.regs().x[3] } 22func (c *sigctxt) r4() uint64 { return c.regs().x[4] } 23func (c *sigctxt) r5() uint64 { return c.regs().x[5] } 24func (c *sigctxt) r6() uint64 { return c.regs().x[6] } 25func (c *sigctxt) r7() uint64 { return c.regs().x[7] } 26func (c *sigctxt) r8() uint64 { return c.regs().x[8] } 27func (c *sigctxt) r9() uint64 { return c.regs().x[9] } 28func (c *sigctxt) r10() uint64 { return c.regs().x[10] } 29func (c *sigctxt) r11() uint64 { return c.regs().x[11] } 30func (c *sigctxt) r12() uint64 { return c.regs().x[12] } 31func (c *sigctxt) r13() uint64 { return c.regs().x[13] } 32func (c *sigctxt) r14() uint64 { return c.regs().x[14] } 33func (c *sigctxt) r15() uint64 { return c.regs().x[15] } 34func (c *sigctxt) r16() uint64 { return c.regs().x[16] } 35func (c *sigctxt) r17() uint64 { return c.regs().x[17] } 36func (c *sigctxt) r18() uint64 { return c.regs().x[18] } 37func (c *sigctxt) r19() uint64 { return c.regs().x[19] } 38func (c *sigctxt) r20() uint64 { return c.regs().x[20] } 39func (c *sigctxt) r21() uint64 { return c.regs().x[21] } 40func (c *sigctxt) r22() uint64 { return c.regs().x[22] } 41func (c *sigctxt) r23() uint64 { return c.regs().x[23] } 42func (c *sigctxt) r24() uint64 { return c.regs().x[24] } 43func (c *sigctxt) r25() uint64 { return c.regs().x[25] } 44func (c *sigctxt) r26() uint64 { return c.regs().x[26] } 45func (c *sigctxt) r27() uint64 { return c.regs().x[27] } 46func (c *sigctxt) r28() uint64 { return c.regs().x[28] } 47func (c *sigctxt) r29() uint64 { return c.regs().fp } 48func (c *sigctxt) lr() uint64 { return c.regs().lr } 49func (c *sigctxt) sp() uint64 { return c.regs().sp } 50 51//go:nosplit 52//go:nowritebarrierrec 53func (c *sigctxt) pc() uint64 { return c.regs().pc } 54 55func (c *sigctxt) fault() uintptr { return uintptr(unsafe.Pointer(c.info.si_addr)) } 56 57func (c *sigctxt) sigcode() uint64 { return uint64(c.info.si_code) } 58func (c *sigctxt) sigaddr() uint64 { return uint64(uintptr(unsafe.Pointer(c.info.si_addr))) } 59 60func (c *sigctxt) set_pc(x uint64) { c.regs().pc = x } 61func (c *sigctxt) set_sp(x uint64) { c.regs().sp = x } 62func (c *sigctxt) set_lr(x uint64) { c.regs().lr = x } 63func (c *sigctxt) set_r28(x uint64) { c.regs().x[28] = x } 64 65func (c *sigctxt) set_sigcode(x uint64) { c.info.si_code = int32(x) } 66func (c *sigctxt) set_sigaddr(x uint64) { 67 c.info.si_addr = (*byte)(unsafe.Pointer(uintptr(x))) 68} 69 70//go:nosplit 71func (c *sigctxt) fixsigcode(sig uint32) { 72 switch sig { 73 case _SIGTRAP: 74 // OS X sets c.sigcode() == TRAP_BRKPT unconditionally for all SIGTRAPs, 75 // leaving no way to distinguish a breakpoint-induced SIGTRAP 76 // from an asynchronous signal SIGTRAP. 77 // They all look breakpoint-induced by default. 78 // Try looking at the code to see if it's a breakpoint. 79 // The assumption is that we're very unlikely to get an 80 // asynchronous SIGTRAP at just the moment that the 81 // PC started to point at unmapped memory. 82 pc := uintptr(c.pc()) 83 // OS X will leave the pc just after the instruction. 84 code := (*uint32)(unsafe.Pointer(pc - 4)) 85 if *code != 0xd4200000 { 86 // SIGTRAP on something other than breakpoint. 87 c.set_sigcode(_SI_USER) 88 } 89 } 90} 91