71 lines
2.5 KiB
C
71 lines
2.5 KiB
C
/*
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* Definitions used by low-level trap handlers
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*
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* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2007-2009 PetaLogix
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* Copyright (C) 2007 John Williams <john.williams@petalogix.com>
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file COPYING in the main directory of this
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* archive for more details.
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*/
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#ifndef _ASM_MICROBLAZE_ENTRY_H
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#define _ASM_MICROBLAZE_ENTRY_H
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#include <asm/percpu.h>
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#include <asm/ptrace.h>
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/*
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* These are per-cpu variables required in entry.S, among other
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* places
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*/
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#define PER_CPU(var) per_cpu__##var
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# ifndef __ASSEMBLY__
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DECLARE_PER_CPU(unsigned int, KSP); /* Saved kernel stack pointer */
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DECLARE_PER_CPU(unsigned int, KM); /* Kernel/user mode */
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DECLARE_PER_CPU(unsigned int, ENTRY_SP); /* Saved SP on kernel entry */
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DECLARE_PER_CPU(unsigned int, R11_SAVE); /* Temp variable for entry */
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DECLARE_PER_CPU(unsigned int, CURRENT_SAVE); /* Saved current pointer */
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# endif /* __ASSEMBLY__ */
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#ifndef CONFIG_MMU
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/* noMMU hasn't any space for args */
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# define STATE_SAVE_ARG_SPACE (0)
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#else /* CONFIG_MMU */
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/* If true, system calls save and restore all registers (except result
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* registers, of course). If false, then `call clobbered' registers
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* will not be preserved, on the theory that system calls are basically
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* function calls anyway, and the caller should be able to deal with it.
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* This is a security risk, of course, as `internal' values may leak out
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* after a system call, but that certainly doesn't matter very much for
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* a processor with no MMU protection! For a protected-mode kernel, it
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* would be faster to just zero those registers before returning.
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*
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* I can not rely on the glibc implementation. If you turn it off make
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* sure that r11/r12 is saved in user-space. --KAA
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*
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* These are special variables using by the kernel trap/interrupt code
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* to save registers in, at a time when there are no spare registers we
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* can use to do so, and we can't depend on the value of the stack
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* pointer. This means that they must be within a signed 16-bit
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* displacement of 0x00000000.
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*/
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/* A `state save frame' is a struct pt_regs preceded by some extra space
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* suitable for a function call stack frame. */
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/* Amount of room on the stack reserved for arguments and to satisfy the
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* C calling conventions, in addition to the space used by the struct
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* pt_regs that actually holds saved values. */
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#define STATE_SAVE_ARG_SPACE (6*4) /* Up to six arguments */
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#endif /* CONFIG_MMU */
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#endif /* _ASM_MICROBLAZE_ENTRY_H */
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