1/* 2 * Definitions used by low-level trap handlers 3 * 4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> 5 * Copyright (C) 2007-2009 PetaLogix 6 * 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) 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 */ 32# endif /* __ASSEMBLY__ */ 33 34#ifndef CONFIG_MMU 35 36/* noMMU hasn't any space for args */ 37# define STATE_SAVE_ARG_SPACE (0) 38 39#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 70#endif /* _ASM_MICROBLAZE_ENTRY_H */ 71