xref: /freebsd/sys/powerpc/powerpc/gdb_machdep.c (revision e17f5b1d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2006 Marcel Moolenaar
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kdb.h>
35 #include <sys/kernel.h>
36 #include <sys/proc.h>
37 #include <sys/signal.h>
38 
39 #include <machine/gdb_machdep.h>
40 #include <machine/pcb.h>
41 #include <machine/reg.h>
42 
43 #include <machine/hid.h>
44 #include <machine/spr.h>
45 
46 #include <machine/trap.h>
47 
48 #include <gdb/gdb.h>
49 #include <gdb/gdb_int.h>
50 
51 extern vm_offset_t __startkernel;
52 
53 void *
54 gdb_cpu_getreg(int regnum, size_t *regsz)
55 {
56 
57 	*regsz = gdb_cpu_regsz(regnum);
58 
59 	if (kdb_thread == curthread) {
60 		if (regnum == 0 || (regnum >= 2 && regnum <= 31))
61 			return (kdb_frame->fixreg + regnum);
62 		if (regnum == 64)
63 			return (&kdb_frame->srr0);
64 		if (regnum == 67)
65 			return (&kdb_frame->lr);
66 	}
67 
68 	if (regnum == 1)
69 		return (&kdb_thrctx->pcb_sp);
70 	if (regnum == 2 && *regsz == 8)
71 		return (&kdb_thrctx->pcb_toc);
72 	if (regnum >= 12 && regnum <= 31)
73 		return (kdb_thrctx->pcb_context + (regnum - 12));
74 	if (regnum == 64)
75 		return (&kdb_thrctx->pcb_lr);
76 
77 	return (NULL);
78 }
79 
80 void
81 gdb_cpu_setreg(int regnum, void *val)
82 {
83 
84 	switch (regnum) {
85 	case GDB_REG_PC:
86 		break;
87 	}
88 }
89 
90 int
91 gdb_cpu_signal(int vector, int dummy __unused)
92 {
93 #if defined(BOOKE)
94 	if (vector == EXC_DEBUG || vector == EXC_PGM)
95 		return (SIGTRAP);
96 #else
97 	if (vector == EXC_TRC || vector == EXC_RUNMODETRC)
98 		return (SIGTRAP);
99 #endif
100 
101 	if (vector <= 255)
102 		return (vector);
103 	else
104 		return (SIGEMT);
105 }
106 
107 void
108 gdb_cpu_do_offsets(void)
109 {
110 	/*
111 	 * On PowerPC, .text starts at KERNBASE + SIZEOF_HEADERS and
112 	 * text segment at KERNBASE - SIZEOF_HEADERS.
113 	 * On PowerPC64, .text starts at KERNBASE and text segment at
114 	 * KERNBASE - 0x100.
115 	 * In both cases, the text segment offset is aligned to 64KB.
116 	 *
117 	 * The __startkernel variable holds the relocated KERNBASE offset.
118 	 * Thus, as long as SIZEOF_HEADERS doesn't get bigger than 0x100
119 	 * (which would lead to other issues), aligning __startkernel to
120 	 * 64KB gives the text segment offset.
121 	 *
122 	 * TODO: Add DataSeg to response. On PowerPC64 all sections reside
123 	 * in a single LOAD segment, but on PowerPC modifiable data reside
124 	 * in a separate segment, that GDB should also relocate.
125 	 */
126 	gdb_tx_begin(0);
127 	gdb_tx_str("TextSeg=");
128 	gdb_tx_varhex(__startkernel & ~0xffff);
129 	gdb_tx_end();
130 }
131