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Diffstat (limited to 'arch/arm/include/asm/kgdb.h')
-rw-r--r-- | arch/arm/include/asm/kgdb.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h new file mode 100644 index 0000000000..8de1100d10 --- /dev/null +++ b/arch/arm/include/asm/kgdb.h @@ -0,0 +1,107 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * ARM KGDB support + * + * Author: Deepak Saxena <dsaxena@mvista.com> + * + * Copyright (C) 2002 MontaVista Software Inc. + * + */ + +#ifndef __ARM_KGDB_H__ +#define __ARM_KGDB_H__ + +#include <linux/ptrace.h> +#include <asm/opcodes.h> + +/* + * GDB assumes that we're a user process being debugged, so + * it will send us an SWI command to write into memory as the + * debug trap. When an SWI occurs, the next instruction addr is + * placed into R14_svc before jumping to the vector trap. + * This doesn't work for kernel debugging as we are already in SVC + * we would loose the kernel's LR, which is a bad thing. This + * is bad thing. + * + * By doing this as an undefined instruction trap, we force a mode + * switch from SVC to UND mode, allowing us to save full kernel state. + * + * We also define a KGDB_COMPILED_BREAK which can be used to compile + * in breakpoints. This is important for things like sysrq-G and for + * the initial breakpoint from trap_init(). + * + * Note to ARM HW designers: Add real trap support like SH && PPC to + * make our lives much much simpler. :) + */ +#define BREAK_INSTR_SIZE 4 +#define GDB_BREAKINST 0xef9f0001 +#define KGDB_BREAKINST 0xe7ffdefe +#define KGDB_COMPILED_BREAK 0xe7ffdeff +#define CACHE_FLUSH_IS_SAFE 1 + +#ifndef __ASSEMBLY__ + +static inline void arch_kgdb_breakpoint(void) +{ + asm(__inst_arm(0xe7ffdeff)); +} + +extern void kgdb_handle_bus_error(void); +extern int kgdb_fault_expected; + +#endif /* !__ASSEMBLY__ */ + +/* + * From Kevin Hilman: + * + * gdb is expecting the following registers layout. + * + * r0-r15: 1 long word each + * f0-f7: unused, 3 long words each !! + * fps: unused, 1 long word + * cpsr: 1 long word + * + * Even though f0-f7 and fps are not used, they need to be + * present in the registers sent for correct processing in + * the host-side gdb. + * + * In particular, it is crucial that CPSR is in the right place, + * otherwise gdb will not be able to correctly interpret stepping over + * conditional branches. + */ +#define _GP_REGS 16 +#define _FP_REGS 8 +#define _EXTRA_REGS 2 +#define GDB_MAX_REGS (_GP_REGS + (_FP_REGS * 3) + _EXTRA_REGS) +#define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS) + +#define KGDB_MAX_NO_CPUS 1 +#define BUFMAX 400 +#define NUMREGBYTES (GDB_MAX_REGS << 2) +#define NUMCRITREGBYTES (32 << 2) + +#define _R0 0 +#define _R1 1 +#define _R2 2 +#define _R3 3 +#define _R4 4 +#define _R5 5 +#define _R6 6 +#define _R7 7 +#define _R8 8 +#define _R9 9 +#define _R10 10 +#define _FP 11 +#define _IP 12 +#define _SPT 13 +#define _LR 14 +#define _PC 15 +#define _CPSR (GDB_MAX_REGS - 1) + +/* + * So that we can denote the end of a frame for tracing, + * in the simple case: + */ +#define CFI_END_FRAME(func) __CFI_END_FRAME(_PC, _SPT, func) + +#endif /* __ASM_KGDB_H__ */ |