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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Enrico Weigelt <info@metux.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
103 lines
3.3 KiB
C
103 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* AArch64 KGDB support
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*
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* Based on arch/arm/include/kgdb.h
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*
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* Copyright (C) 2013 Cavium Inc.
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* Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
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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/debug-monitors.h>
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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 ("brk %0" : : "I" (KGDB_COMPILED_DBG_BRK_IMM));
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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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* gdb remote procotol (well most versions of it) expects the following
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* register layout.
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*
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* General purpose regs:
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* r0-r30: 64 bit
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* sp,pc : 64 bit
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* pstate : 32 bit
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* Total: 33 + 1
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* FPU regs:
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* f0-f31: 128 bit
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* fpsr & fpcr: 32 bit
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* Total: 32 + 2
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*
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* To expand a little on the "most versions of it"... when the gdb remote
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* protocol for AArch64 was developed it depended on a statement in the
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* Architecture Reference Manual that claimed "SPSR_ELx is a 32-bit register".
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* and, as a result, allocated only 32-bits for the PSTATE in the remote
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* protocol. In fact this statement is still present in ARM DDI 0487A.i.
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*
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* Unfortunately "is a 32-bit register" has a very special meaning for
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* system registers. It means that "the upper bits, bits[63:32], are
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* RES0.". RES0 is heavily used in the ARM architecture documents as a
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* way to leave space for future architecture changes. So to translate a
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* little for people who don't spend their spare time reading ARM architecture
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* manuals, what "is a 32-bit register" actually means in this context is
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* "is a 64-bit register but one with no meaning allocated to any of the
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* upper 32-bits... *yet*".
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*
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* Perhaps then we should not be surprised that this has led to some
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* confusion. Specifically a patch, influenced by the above translation,
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* that extended PSTATE to 64-bit was accepted into gdb-7.7 but the patch
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* was reverted in gdb-7.8.1 and all later releases, when this was
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* discovered to be an undocumented protocol change.
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*
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* So... it is *not* wrong for us to only allocate 32-bits to PSTATE
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* here even though the kernel itself allocates 64-bits for the same
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* state. That is because this bit of code tells the kernel how the gdb
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* remote protocol (well most versions of it) describes the register state.
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*
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* Note that if you are using one of the versions of gdb that supports
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* the gdb-7.7 version of the protocol you cannot use kgdb directly
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* without providing a custom register description (gdb can load new
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* protocol descriptions at runtime).
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*/
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#define _GP_REGS 33
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#define _FP_REGS 32
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#define _EXTRA_REGS 3
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/*
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* general purpose registers size in bytes.
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* pstate is only 4 bytes. subtract 4 bytes
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*/
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#define GP_REG_BYTES (_GP_REGS * 8)
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#define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS)
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/*
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* Size of I/O buffer for gdb packet.
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* considering to hold all register contents, size is set
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*/
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#define BUFMAX 2048
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/*
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* Number of bytes required for gdb_regs buffer.
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* _GP_REGS: 8 bytes, _FP_REGS: 16 bytes and _EXTRA_REGS: 4 bytes each
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* GDB fails to connect for size beyond this with error
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* "'g' packet reply is too long"
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*/
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#define NUMREGBYTES ((_GP_REGS * 8) + (_FP_REGS * 16) + \
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(_EXTRA_REGS * 4))
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#endif /* __ASM_KGDB_H */
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