1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * ARM KGDB support
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Author: Deepak Saxena <dsaxena@mvista.com>
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Copyright (C) 2002 MontaVista Software Inc.
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun */
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #ifndef __ARM_KGDB_H__
12*4882a593Smuzhiyun #define __ARM_KGDB_H__
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #include <linux/ptrace.h>
15*4882a593Smuzhiyun #include <asm/opcodes.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun /*
18*4882a593Smuzhiyun * GDB assumes that we're a user process being debugged, so
19*4882a593Smuzhiyun * it will send us an SWI command to write into memory as the
20*4882a593Smuzhiyun * debug trap. When an SWI occurs, the next instruction addr is
21*4882a593Smuzhiyun * placed into R14_svc before jumping to the vector trap.
22*4882a593Smuzhiyun * This doesn't work for kernel debugging as we are already in SVC
23*4882a593Smuzhiyun * we would loose the kernel's LR, which is a bad thing. This
24*4882a593Smuzhiyun * is bad thing.
25*4882a593Smuzhiyun *
26*4882a593Smuzhiyun * By doing this as an undefined instruction trap, we force a mode
27*4882a593Smuzhiyun * switch from SVC to UND mode, allowing us to save full kernel state.
28*4882a593Smuzhiyun *
29*4882a593Smuzhiyun * We also define a KGDB_COMPILED_BREAK which can be used to compile
30*4882a593Smuzhiyun * in breakpoints. This is important for things like sysrq-G and for
31*4882a593Smuzhiyun * the initial breakpoint from trap_init().
32*4882a593Smuzhiyun *
33*4882a593Smuzhiyun * Note to ARM HW designers: Add real trap support like SH && PPC to
34*4882a593Smuzhiyun * make our lives much much simpler. :)
35*4882a593Smuzhiyun */
36*4882a593Smuzhiyun #define BREAK_INSTR_SIZE 4
37*4882a593Smuzhiyun #define GDB_BREAKINST 0xef9f0001
38*4882a593Smuzhiyun #define KGDB_BREAKINST 0xe7ffdefe
39*4882a593Smuzhiyun #define KGDB_COMPILED_BREAK 0xe7ffdeff
40*4882a593Smuzhiyun #define CACHE_FLUSH_IS_SAFE 1
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun #ifndef __ASSEMBLY__
43*4882a593Smuzhiyun
arch_kgdb_breakpoint(void)44*4882a593Smuzhiyun static inline void arch_kgdb_breakpoint(void)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun asm(__inst_arm(0xe7ffdeff));
47*4882a593Smuzhiyun }
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun extern void kgdb_handle_bus_error(void);
50*4882a593Smuzhiyun extern int kgdb_fault_expected;
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun #endif /* !__ASSEMBLY__ */
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun /*
55*4882a593Smuzhiyun * From Kevin Hilman:
56*4882a593Smuzhiyun *
57*4882a593Smuzhiyun * gdb is expecting the following registers layout.
58*4882a593Smuzhiyun *
59*4882a593Smuzhiyun * r0-r15: 1 long word each
60*4882a593Smuzhiyun * f0-f7: unused, 3 long words each !!
61*4882a593Smuzhiyun * fps: unused, 1 long word
62*4882a593Smuzhiyun * cpsr: 1 long word
63*4882a593Smuzhiyun *
64*4882a593Smuzhiyun * Even though f0-f7 and fps are not used, they need to be
65*4882a593Smuzhiyun * present in the registers sent for correct processing in
66*4882a593Smuzhiyun * the host-side gdb.
67*4882a593Smuzhiyun *
68*4882a593Smuzhiyun * In particular, it is crucial that CPSR is in the right place,
69*4882a593Smuzhiyun * otherwise gdb will not be able to correctly interpret stepping over
70*4882a593Smuzhiyun * conditional branches.
71*4882a593Smuzhiyun */
72*4882a593Smuzhiyun #define _GP_REGS 16
73*4882a593Smuzhiyun #define _FP_REGS 8
74*4882a593Smuzhiyun #define _EXTRA_REGS 2
75*4882a593Smuzhiyun #define GDB_MAX_REGS (_GP_REGS + (_FP_REGS * 3) + _EXTRA_REGS)
76*4882a593Smuzhiyun #define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS)
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun #define KGDB_MAX_NO_CPUS 1
79*4882a593Smuzhiyun #define BUFMAX 400
80*4882a593Smuzhiyun #define NUMREGBYTES (GDB_MAX_REGS << 2)
81*4882a593Smuzhiyun #define NUMCRITREGBYTES (32 << 2)
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun #define _R0 0
84*4882a593Smuzhiyun #define _R1 1
85*4882a593Smuzhiyun #define _R2 2
86*4882a593Smuzhiyun #define _R3 3
87*4882a593Smuzhiyun #define _R4 4
88*4882a593Smuzhiyun #define _R5 5
89*4882a593Smuzhiyun #define _R6 6
90*4882a593Smuzhiyun #define _R7 7
91*4882a593Smuzhiyun #define _R8 8
92*4882a593Smuzhiyun #define _R9 9
93*4882a593Smuzhiyun #define _R10 10
94*4882a593Smuzhiyun #define _FP 11
95*4882a593Smuzhiyun #define _IP 12
96*4882a593Smuzhiyun #define _SPT 13
97*4882a593Smuzhiyun #define _LR 14
98*4882a593Smuzhiyun #define _PC 15
99*4882a593Smuzhiyun #define _CPSR (GDB_MAX_REGS - 1)
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun /*
102*4882a593Smuzhiyun * So that we can denote the end of a frame for tracing,
103*4882a593Smuzhiyun * in the simple case:
104*4882a593Smuzhiyun */
105*4882a593Smuzhiyun #define CFI_END_FRAME(func) __CFI_END_FRAME(_PC, _SPT, func)
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun #endif /* __ASM_KGDB_H__ */
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