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//go:build (linux || openbsd) && (mips64 || mips64le)
6
7package runtime
8
9import (
10	"internal/abi"
11	"internal/goarch"
12	"unsafe"
13)
14
15func dumpregs(c *sigctxt) {
16	print("r0   ", hex(c.r0()), "\t")
17	print("r1   ", hex(c.r1()), "\n")
18	print("r2   ", hex(c.r2()), "\t")
19	print("r3   ", hex(c.r3()), "\n")
20	print("r4   ", hex(c.r4()), "\t")
21	print("r5   ", hex(c.r5()), "\n")
22	print("r6   ", hex(c.r6()), "\t")
23	print("r7   ", hex(c.r7()), "\n")
24	print("r8   ", hex(c.r8()), "\t")
25	print("r9   ", hex(c.r9()), "\n")
26	print("r10  ", hex(c.r10()), "\t")
27	print("r11  ", hex(c.r11()), "\n")
28	print("r12  ", hex(c.r12()), "\t")
29	print("r13  ", hex(c.r13()), "\n")
30	print("r14  ", hex(c.r14()), "\t")
31	print("r15  ", hex(c.r15()), "\n")
32	print("r16  ", hex(c.r16()), "\t")
33	print("r17  ", hex(c.r17()), "\n")
34	print("r18  ", hex(c.r18()), "\t")
35	print("r19  ", hex(c.r19()), "\n")
36	print("r20  ", hex(c.r20()), "\t")
37	print("r21  ", hex(c.r21()), "\n")
38	print("r22  ", hex(c.r22()), "\t")
39	print("r23  ", hex(c.r23()), "\n")
40	print("r24  ", hex(c.r24()), "\t")
41	print("r25  ", hex(c.r25()), "\n")
42	print("r26  ", hex(c.r26()), "\t")
43	print("r27  ", hex(c.r27()), "\n")
44	print("r28  ", hex(c.r28()), "\t")
45	print("r29  ", hex(c.r29()), "\n")
46	print("r30  ", hex(c.r30()), "\t")
47	print("r31  ", hex(c.r31()), "\n")
48	print("pc   ", hex(c.pc()), "\t")
49	print("link ", hex(c.link()), "\n")
50	print("lo   ", hex(c.lo()), "\t")
51	print("hi   ", hex(c.hi()), "\n")
52}
53
54//go:nosplit
55//go:nowritebarrierrec
56func (c *sigctxt) sigpc() uintptr { return uintptr(c.pc()) }
57
58func (c *sigctxt) sigsp() uintptr { return uintptr(c.sp()) }
59func (c *sigctxt) siglr() uintptr { return uintptr(c.link()) }
60func (c *sigctxt) fault() uintptr { return uintptr(c.sigaddr()) }
61
62// preparePanic sets up the stack to look like a call to sigpanic.
63func (c *sigctxt) preparePanic(sig uint32, gp *g) {
64	// We arrange link, and pc to pretend the panicking
65	// function calls sigpanic directly.
66	// Always save LINK to stack so that panics in leaf
67	// functions are correctly handled. This smashes
68	// the stack frame but we're not going back there
69	// anyway.
70	sp := c.sp() - goarch.PtrSize
71	c.set_sp(sp)
72	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.link()
73
74	pc := gp.sigpc
75
76	if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
77		// Make it look the like faulting PC called sigpanic.
78		c.set_link(uint64(pc))
79	}
80
81	// In case we are panicking from external C code
82	sigpanicPC := uint64(abi.FuncPCABIInternal(sigpanic))
83	c.set_r28(sigpanicPC >> 32 << 32) // RSB register
84	c.set_r30(uint64(uintptr(unsafe.Pointer(gp))))
85	c.set_pc(sigpanicPC)
86}
87
88func (c *sigctxt) pushCall(targetPC, resumePC uintptr) {
89	// Push the LR to stack, as we'll clobber it in order to
90	// push the call. The function being pushed is responsible
91	// for restoring the LR and setting the SP back.
92	// This extra slot is known to gentraceback.
93	sp := c.sp() - 8
94	c.set_sp(sp)
95	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.link()
96	// Set up PC and LR to pretend the function being signaled
97	// calls targetPC at resumePC.
98	c.set_link(uint64(resumePC))
99	c.set_pc(uint64(targetPC))
100}
101