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