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/* 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 (DBG_MAX_REG_NUM << 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__ */
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