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Jason Wessel5cbad0e2008-02-20 13:33:40 -06001/*
2 * ARM KGDB support
3 *
4 * Author: Deepak Saxena <dsaxena@mvista.com>
5 *
6 * Copyright (C) 2002 MontaVista Software Inc.
7 *
8 */
9
10#ifndef __ARM_KGDB_H__
11#define __ARM_KGDB_H__
12
13#include <linux/ptrace.h>
14
15/*
16 * GDB assumes that we're a user process being debugged, so
17 * it will send us an SWI command to write into memory as the
18 * debug trap. When an SWI occurs, the next instruction addr is
19 * placed into R14_svc before jumping to the vector trap.
20 * This doesn't work for kernel debugging as we are already in SVC
21 * we would loose the kernel's LR, which is a bad thing. This
22 * is bad thing.
23 *
24 * By doing this as an undefined instruction trap, we force a mode
25 * switch from SVC to UND mode, allowing us to save full kernel state.
26 *
27 * We also define a KGDB_COMPILED_BREAK which can be used to compile
28 * in breakpoints. This is important for things like sysrq-G and for
29 * the initial breakpoint from trap_init().
30 *
31 * Note to ARM HW designers: Add real trap support like SH && PPC to
32 * make our lives much much simpler. :)
33 */
34#define BREAK_INSTR_SIZE 4
35#define GDB_BREAKINST 0xef9f0001
36#define KGDB_BREAKINST 0xe7ffdefe
37#define KGDB_COMPILED_BREAK 0xe7ffdeff
38#define CACHE_FLUSH_IS_SAFE 1
39
40#ifndef __ASSEMBLY__
41
42static inline void arch_kgdb_breakpoint(void)
43{
44 asm(".word 0xe7ffdeff");
45}
46
47extern void kgdb_handle_bus_error(void);
48extern int kgdb_fault_expected;
49
50#endif /* !__ASSEMBLY__ */
51
52/*
53 * From Kevin Hilman:
54 *
55 * gdb is expecting the following registers layout.
56 *
57 * r0-r15: 1 long word each
58 * f0-f7: unused, 3 long words each !!
59 * fps: unused, 1 long word
60 * cpsr: 1 long word
61 *
62 * Even though f0-f7 and fps are not used, they need to be
63 * present in the registers sent for correct processing in
64 * the host-side gdb.
65 *
66 * In particular, it is crucial that CPSR is in the right place,
67 * otherwise gdb will not be able to correctly interpret stepping over
68 * conditional branches.
69 */
70#define _GP_REGS 16
71#define _FP_REGS 8
72#define _EXTRA_REGS 2
73#define GDB_MAX_REGS (_GP_REGS + (_FP_REGS * 3) + _EXTRA_REGS)
74
75#define KGDB_MAX_NO_CPUS 1
76#define BUFMAX 400
77#define NUMREGBYTES (GDB_MAX_REGS << 2)
78#define NUMCRITREGBYTES (32 << 2)
79
80#define _R0 0
81#define _R1 1
82#define _R2 2
83#define _R3 3
84#define _R4 4
85#define _R5 5
86#define _R6 6
87#define _R7 7
88#define _R8 8
89#define _R9 9
90#define _R10 10
91#define _FP 11
92#define _IP 12
93#define _SPT 13
94#define _LR 14
95#define _PC 15
96#define _CPSR (GDB_MAX_REGS - 1)
97
98/*
99 * So that we can denote the end of a frame for tracing,
100 * in the simple case:
101 */
102#define CFI_END_FRAME(func) __CFI_END_FRAME(_PC, _SPT, func)
103
104#endif /* __ASM_KGDB_H__ */