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// +build darwin freebsd linux netbsd openbsd
6
7package runtime
8
9import (
10	"runtime/internal/sys"
11	"unsafe"
12)
13
14func dumpregs(c *sigctxt) {
15	print("r0      ", hex(c.r0()), "\n")
16	print("r1      ", hex(c.r1()), "\n")
17	print("r2      ", hex(c.r2()), "\n")
18	print("r3      ", hex(c.r3()), "\n")
19	print("r4      ", hex(c.r4()), "\n")
20	print("r5      ", hex(c.r5()), "\n")
21	print("r6      ", hex(c.r6()), "\n")
22	print("r7      ", hex(c.r7()), "\n")
23	print("r8      ", hex(c.r8()), "\n")
24	print("r9      ", hex(c.r9()), "\n")
25	print("r10     ", hex(c.r10()), "\n")
26	print("r11     ", hex(c.r11()), "\n")
27	print("r12     ", hex(c.r12()), "\n")
28	print("r13     ", hex(c.r13()), "\n")
29	print("r14     ", hex(c.r14()), "\n")
30	print("r15     ", hex(c.r15()), "\n")
31	print("r16     ", hex(c.r16()), "\n")
32	print("r17     ", hex(c.r17()), "\n")
33	print("r18     ", hex(c.r18()), "\n")
34	print("r19     ", hex(c.r19()), "\n")
35	print("r20     ", hex(c.r20()), "\n")
36	print("r21     ", hex(c.r21()), "\n")
37	print("r22     ", hex(c.r22()), "\n")
38	print("r23     ", hex(c.r23()), "\n")
39	print("r24     ", hex(c.r24()), "\n")
40	print("r25     ", hex(c.r25()), "\n")
41	print("r26     ", hex(c.r26()), "\n")
42	print("r27     ", hex(c.r27()), "\n")
43	print("r28     ", hex(c.r28()), "\n")
44	print("r29     ", hex(c.r29()), "\n")
45	print("lr      ", hex(c.lr()), "\n")
46	print("sp      ", hex(c.sp()), "\n")
47	print("pc      ", hex(c.pc()), "\n")
48	print("fault   ", hex(c.fault()), "\n")
49}
50
51//go:nosplit
52//go:nowritebarrierrec
53func (c *sigctxt) sigpc() uintptr { return uintptr(c.pc()) }
54
55func (c *sigctxt) sigsp() uintptr { return uintptr(c.sp()) }
56func (c *sigctxt) siglr() uintptr { return uintptr(c.lr()) }
57
58// preparePanic sets up the stack to look like a call to sigpanic.
59func (c *sigctxt) preparePanic(sig uint32, gp *g) {
60	// We arrange lr, and pc to pretend the panicking
61	// function calls sigpanic directly.
62	// Always save LR to stack so that panics in leaf
63	// functions are correctly handled. This smashes
64	// the stack frame but we're not going back there
65	// anyway.
66	sp := c.sp() - sys.SpAlign // needs only sizeof uint64, but must align the stack
67	c.set_sp(sp)
68	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
69
70	pc := gp.sigpc
71
72	if shouldPushSigpanic(gp, pc, uintptr(c.lr())) {
73		// Make it look the like faulting PC called sigpanic.
74		c.set_lr(uint64(pc))
75	}
76
77	// In case we are panicking from external C code
78	c.set_r28(uint64(uintptr(unsafe.Pointer(gp))))
79	c.set_pc(uint64(funcPC(sigpanic)))
80}
81
82const pushCallSupported = true
83
84func (c *sigctxt) pushCall(targetPC uintptr) {
85	// Push the LR to stack, as we'll clobber it in order to
86	// push the call. The function being pushed is responsible
87	// for restoring the LR and setting the SP back.
88	// This extra space is known to gentraceback.
89	sp := c.sp() - 16 // SP needs 16-byte alignment
90	c.set_sp(sp)
91	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
92	// Set up PC and LR to pretend the function being signaled
93	// calls targetPC at the faulting PC.
94	c.set_lr(c.pc())
95	c.set_pc(uint64(targetPC))
96}
97