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/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* 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.
*
* vineetg: March 2009
* -Implemented task_pt_regs( )
*
* Amit Bhor, Sameer Dhavale, Ashwin Chaugule: Codito Technologies 2004
*/
#ifndef __ASM_ARC_PROCESSOR_H
#define __ASM_ARC_PROCESSOR_H
#ifndef __ASSEMBLY__
#include <asm/ptrace.h>
#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
/* These DPFP regs need to be saved/restored across ctx-sw */
struct arc_fpu {
struct {
unsigned int l, h;
} aux_dpfp[2];
};
#endif
/* Arch specific stuff which needs to be saved per task.
* However these items are not so important so as to earn a place in
* struct thread_info
*/
struct thread_struct {
unsigned long ksp; /* kernel mode stack pointer */
unsigned long callee_reg; /* pointer to callee regs */
unsigned long fault_address; /* dbls as brkpt holder as well */
#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
struct arc_fpu fpu;
#endif
};
#define INIT_THREAD { \
.ksp = sizeof(init_stack) + (unsigned long) init_stack, \
}
/* Forward declaration, a strange C thing */
struct task_struct;
/* Return saved PC of a blocked thread */
unsigned long thread_saved_pc(struct task_struct *t);
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
/* Free all resources held by a thread */
#define release_thread(thread) do { } while (0)
/* Prepare to copy thread state - unlazy all lazy status */
#define prepare_to_copy(tsk) do { } while (0)
/*
* A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
* get optimised away by gcc
*/
#ifdef CONFIG_SMP
#define cpu_relax() __asm__ __volatile__ ("" : : : "memory")
#else
#define cpu_relax() do { } while (0)
#endif
#define cpu_relax_lowlatency() cpu_relax()
#define copy_segments(tsk, mm) do { } while (0)
#define release_segments(mm) do { } while (0)
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->ret)
/*
* Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
* Look in process.c for details of kernel stack layout
*/
#define KSTK_ESP(tsk) (tsk->thread.ksp)
#define KSTK_REG(tsk, off) (*((unsigned int *)(KSTK_ESP(tsk) + \
sizeof(struct callee_regs) + off)))
#define KSTK_BLINK(tsk) KSTK_REG(tsk, 4)
#define KSTK_FP(tsk) KSTK_REG(tsk, 0)
extern void start_thread(struct pt_regs * regs, unsigned long pc,
unsigned long usp);
extern unsigned int get_wchan(struct task_struct *p);
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
* Should the PC register be read instead ? This macro does not seem to
* be used in many places so this wont be all that bad.
*/
#define current_text_addr() ({ __label__ _l; _l: &&_l; })
#endif /* !__ASSEMBLY__ */
/* Kernels Virtual memory area.
* Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a
* "kernel translated" region (like KSEG2 in MIPS). So we use a upper part
* of the translated bottom 2GB for kernel virtual memory and protect
* these pages from user accesses by disabling Ru, Eu and Wu.
*/
#define VMALLOC_SIZE (0x10000000) /* 256M */
#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
#define VMALLOC_END (PAGE_OFFSET)
/* Most of the architectures seem to be keeping some kind of padding between
* userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET.
*/
#define USER_KERNEL_GUTTER 0x10000000
/* User address space:
* On ARC700, CPU allows the entire lower half of 32 bit address space to be
* translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space.
* However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another
* 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces
* Thus total User vaddr space is (0:0x5FFF_FFFF)
*/
#define TASK_SIZE (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX STACK_TOP
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE (TASK_SIZE / 3)
#endif /* __ASM_ARC_PROCESSOR_H */