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Michal Simek4115ac82009-03-27 14:25:43 +01001/*
2 * Definitions used by low-level trap handlers
3 *
Michal Simekca545022009-05-26 16:30:21 +02004 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2007-2009 PetaLogix
Michal Simek4115ac82009-03-27 14:25:43 +01006 * Copyright (C) 2007 John Williams <john.williams@petalogix.com>
7 *
8 * This file is subject to the terms and conditions of the GNU General
9 * Public License. See the file COPYING in the main directory of this
10 * archive for more details.
11 */
12
13#ifndef _ASM_MICROBLAZE_ENTRY_H
14#define _ASM_MICROBLAZE_ENTRY_H
15
16#include <asm/percpu.h>
17#include <asm/ptrace.h>
18
19/*
20 * These are per-cpu variables required in entry.S, among other
21 * places
22 */
23
24#define PER_CPU(var) per_cpu__##var
25
26# ifndef __ASSEMBLY__
27DECLARE_PER_CPU(unsigned int, KSP); /* Saved kernel stack pointer */
28DECLARE_PER_CPU(unsigned int, KM); /* Kernel/user mode */
29DECLARE_PER_CPU(unsigned int, ENTRY_SP); /* Saved SP on kernel entry */
30DECLARE_PER_CPU(unsigned int, R11_SAVE); /* Temp variable for entry */
31DECLARE_PER_CPU(unsigned int, CURRENT_SAVE); /* Saved current pointer */
Michal Simek4115ac82009-03-27 14:25:43 +010032# endif /* __ASSEMBLY__ */
33
Michal Simekca545022009-05-26 16:30:21 +020034#ifndef CONFIG_MMU
35
Michal Simek2921e2b2009-04-21 14:08:47 +020036/* noMMU hasn't any space for args */
37# define STATE_SAVE_ARG_SPACE (0)
38
Michal Simekca545022009-05-26 16:30:21 +020039#else /* CONFIG_MMU */
40
41/* If true, system calls save and restore all registers (except result
42 * registers, of course). If false, then `call clobbered' registers
43 * will not be preserved, on the theory that system calls are basically
44 * function calls anyway, and the caller should be able to deal with it.
45 * This is a security risk, of course, as `internal' values may leak out
46 * after a system call, but that certainly doesn't matter very much for
47 * a processor with no MMU protection! For a protected-mode kernel, it
48 * would be faster to just zero those registers before returning.
49 *
50 * I can not rely on the glibc implementation. If you turn it off make
51 * sure that r11/r12 is saved in user-space. --KAA
52 *
53 * These are special variables using by the kernel trap/interrupt code
54 * to save registers in, at a time when there are no spare registers we
55 * can use to do so, and we can't depend on the value of the stack
56 * pointer. This means that they must be within a signed 16-bit
57 * displacement of 0x00000000.
58 */
59
60/* A `state save frame' is a struct pt_regs preceded by some extra space
61 * suitable for a function call stack frame. */
62
63/* Amount of room on the stack reserved for arguments and to satisfy the
64 * C calling conventions, in addition to the space used by the struct
65 * pt_regs that actually holds saved values. */
66#define STATE_SAVE_ARG_SPACE (6*4) /* Up to six arguments */
67
68#endif /* CONFIG_MMU */
69
Michal Simek4115ac82009-03-27 14:25:43 +010070#endif /* _ASM_MICROBLAZE_ENTRY_H */