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