cregit-Linux how code gets into the kernel

Release 4.11 arch/arm/include/asm/kgdb.h

/*
 * 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)); }

Contributors

PersonTokensPropCommitsCommitProp
Jason Wessel990.00%150.00%
Ben Dooks110.00%150.00%
Total10100.00%2100.00%

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__ */

Overall Contributors

PersonTokensPropCommitsCommitProp
Jason Wessel16794.35%250.00%
Rabin Vincent63.39%125.00%
Ben Dooks42.26%125.00%
Total177100.00%4100.00%
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