1 // Copyright 2016 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 ( 8 "runtime/internal/sys" 9 "unsafe" 10 ) 11 12 type sigctxt struct { 13 info *siginfo 14 ctxt unsafe.Pointer 15 } 16 17 //go:nosplit 18 //go:nowritebarrierrec 19 func (c *sigctxt) regs() *sigcontext { 20 return (*sigcontext)(unsafe.Pointer(&(*ucontext)(c.ctxt).uc_mcontext)) 21 } 22 23 func (c *sigctxt) r0() uint64 { return c.regs().gregs[0] } 24 func (c *sigctxt) r1() uint64 { return c.regs().gregs[1] } 25 func (c *sigctxt) r2() uint64 { return c.regs().gregs[2] } 26 func (c *sigctxt) r3() uint64 { return c.regs().gregs[3] } 27 func (c *sigctxt) r4() uint64 { return c.regs().gregs[4] } 28 func (c *sigctxt) r5() uint64 { return c.regs().gregs[5] } 29 func (c *sigctxt) r6() uint64 { return c.regs().gregs[6] } 30 func (c *sigctxt) r7() uint64 { return c.regs().gregs[7] } 31 func (c *sigctxt) r8() uint64 { return c.regs().gregs[8] } 32 func (c *sigctxt) r9() uint64 { return c.regs().gregs[9] } 33 func (c *sigctxt) r10() uint64 { return c.regs().gregs[10] } 34 func (c *sigctxt) r11() uint64 { return c.regs().gregs[11] } 35 func (c *sigctxt) r12() uint64 { return c.regs().gregs[12] } 36 func (c *sigctxt) r13() uint64 { return c.regs().gregs[13] } 37 func (c *sigctxt) r14() uint64 { return c.regs().gregs[14] } 38 func (c *sigctxt) r15() uint64 { return c.regs().gregs[15] } 39 func (c *sigctxt) link() uint64 { return c.regs().gregs[14] } 40 func (c *sigctxt) sp() uint64 { return c.regs().gregs[15] } 41 42 //go:nosplit 43 //go:nowritebarrierrec 44 func (c *sigctxt) pc() uint64 { return c.regs().psw_addr } 45 46 func (c *sigctxt) sigcode() uint32 { return uint32(c.info.si_code) } 47 func (c *sigctxt) sigaddr() uint64 { return c.info.si_addr } 48 49 func (c *sigctxt) set_r0(x uint64) { c.regs().gregs[0] = x } 50 func (c *sigctxt) set_r13(x uint64) { c.regs().gregs[13] = x } 51 func (c *sigctxt) set_link(x uint64) { c.regs().gregs[14] = x } 52 func (c *sigctxt) set_sp(x uint64) { c.regs().gregs[15] = x } 53 func (c *sigctxt) set_pc(x uint64) { c.regs().psw_addr = x } 54 func (c *sigctxt) set_sigcode(x uint32) { c.info.si_code = int32(x) } 55 func (c *sigctxt) set_sigaddr(x uint64) { 56 *(*uintptr)(add(unsafe.Pointer(c.info), 2*sys.PtrSize)) = uintptr(x) 57 } 58 59 func dumpregs(c *sigctxt) { 60 print("r0 ", hex(c.r0()), "\t") 61 print("r1 ", hex(c.r1()), "\n") 62 print("r2 ", hex(c.r2()), "\t") 63 print("r3 ", hex(c.r3()), "\n") 64 print("r4 ", hex(c.r4()), "\t") 65 print("r5 ", hex(c.r5()), "\n") 66 print("r6 ", hex(c.r6()), "\t") 67 print("r7 ", hex(c.r7()), "\n") 68 print("r8 ", hex(c.r8()), "\t") 69 print("r9 ", hex(c.r9()), "\n") 70 print("r10 ", hex(c.r10()), "\t") 71 print("r11 ", hex(c.r11()), "\n") 72 print("r12 ", hex(c.r12()), "\t") 73 print("r13 ", hex(c.r13()), "\n") 74 print("r14 ", hex(c.r14()), "\t") 75 print("r15 ", hex(c.r15()), "\n") 76 print("pc ", hex(c.pc()), "\t") 77 print("link ", hex(c.link()), "\n") 78 } 79 80 //go:nosplit 81 //go:nowritebarrierrec 82 func (c *sigctxt) sigpc() uintptr { return uintptr(c.pc()) } 83 84 func (c *sigctxt) sigsp() uintptr { return uintptr(c.sp()) } 85 func (c *sigctxt) siglr() uintptr { return uintptr(c.link()) } 86 func (c *sigctxt) fault() uintptr { return uintptr(c.sigaddr()) } 87 88 // preparePanic sets up the stack to look like a call to sigpanic. 89 func (c *sigctxt) preparePanic(sig uint32, gp *g) { 90 // We arrange link, and pc to pretend the panicking 91 // function calls sigpanic directly. 92 // Always save LINK to stack so that panics in leaf 93 // functions are correctly handled. This smashes 94 // the stack frame but we're not going back there 95 // anyway. 96 sp := c.sp() - sys.MinFrameSize 97 c.set_sp(sp) 98 *(*uint64)(unsafe.Pointer(uintptr(sp))) = c.link() 99 100 pc := uintptr(gp.sigpc) 101 102 // If we don't recognize the PC as code 103 // but we do recognize the link register as code, 104 // then assume this was a call to non-code and treat like 105 // pc == 0, to make unwinding show the context. 106 if pc != 0 && !findfunc(pc).valid() && findfunc(uintptr(c.link())).valid() { 107 pc = 0 108 } 109 110 // Don't bother saving PC if it's zero, which is 111 // probably a call to a nil func: the old link register 112 // is more useful in the stack trace. 113 if pc != 0 { 114 c.set_link(uint64(pc)) 115 } 116 117 // In case we are panicking from external C code 118 c.set_r0(0) 119 c.set_r13(uint64(uintptr(unsafe.Pointer(gp)))) 120 c.set_pc(uint64(funcPC(sigpanic))) 121 } 122
