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