xref: /freebsd/sys/powerpc/powerpc/gdb_machdep.c (revision 4e8d558c)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 
42 #include <machine/hid.h>
43 #include <machine/spr.h>
44 
45 #include <machine/trap.h>
46 
47 #include <gdb/gdb.h>
48 #include <gdb/gdb_int.h>
49 
50 extern vm_offset_t __startkernel;
51 
52 void *
53 gdb_cpu_getreg(int regnum, size_t *regsz)
54 {
55 
56 	*regsz = gdb_cpu_regsz(regnum);
57 
58 	if (kdb_thread == curthread) {
59 		if (regnum == 0 || (regnum >= 2 && regnum <= 31))
60 			return (kdb_frame->fixreg + regnum);
61 		if (regnum == 64)
62 			return (&kdb_frame->srr0);
63 		if (regnum == 67)
64 			return (&kdb_frame->lr);
65 	}
66 
67 	if (regnum == 1)
68 		return (&kdb_thrctx->pcb_sp);
69 	if (regnum == 2 && *regsz == 8)
70 		return (&kdb_thrctx->pcb_toc);
71 	if (regnum >= 12 && regnum <= 31)
72 		return (kdb_thrctx->pcb_context + (regnum - 12));
73 	if (regnum == 64)
74 		return (&kdb_thrctx->pcb_lr);
75 
76 	return (NULL);
77 }
78 
79 void
80 gdb_cpu_setreg(int regnum, void *val)
81 {
82 
83 	switch (regnum) {
84 	case GDB_REG_PC:
85 		break;
86 	}
87 }
88 
89 int
90 gdb_cpu_signal(int vector, int dummy __unused)
91 {
92 #if defined(BOOKE)
93 	if (vector == EXC_DEBUG || vector == EXC_PGM)
94 		return (SIGTRAP);
95 #else
96 	if (vector == EXC_TRC || vector == EXC_RUNMODETRC)
97 		return (SIGTRAP);
98 #endif
99 
100 	return (SIGEMT);
101 }
102 
103 void
104 gdb_cpu_do_offsets(void)
105 {
106 	/*
107 	 * On PowerPC, .text starts at KERNBASE + SIZEOF_HEADERS and
108 	 * text segment at KERNBASE - SIZEOF_HEADERS.
109 	 * On PowerPC64, .text starts at KERNBASE and text segment at
110 	 * KERNBASE - 0x100.
111 	 * In both cases, the text segment offset is aligned to 64KB.
112 	 *
113 	 * The __startkernel variable holds the relocated KERNBASE offset.
114 	 * Thus, as long as SIZEOF_HEADERS doesn't get bigger than 0x100
115 	 * (which would lead to other issues), aligning __startkernel to
116 	 * 64KB gives the text segment offset.
117 	 *
118 	 * TODO: Add DataSeg to response. On PowerPC64 all sections reside
119 	 * in a single LOAD segment, but on PowerPC modifiable data reside
120 	 * in a separate segment, that GDB should also relocate.
121 	 */
122 	gdb_tx_begin(0);
123 	gdb_tx_str("TextSeg=");
124 	gdb_tx_varhex(__startkernel & ~0xffff);
125 	gdb_tx_end();
126 }
127