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/*
* include/asm-m68k/processor.h
*
* Copyright (C) 1995 Hamish Macdonald
*/
#ifndef __ASM_M68K_PROCESSOR_H
#define __ASM_M68K_PROCESSOR_H
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
*/
#define current_text_addr() ({ __label__ _l; _l: &&_l;})
#include <asm/segment.h>
#include <asm/fpu.h>
/*
* User space process size: 3.75GB. This is hardcoded into a few places,
* so don't change it unless you know what you are doing.
*/
#define TASK_SIZE (0xF0000000UL)
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE 0xC0000000UL
#define TASK_UNMAPPED_ALIGN(addr, off) PAGE_ALIGN(addr)
/*
* Bus types
*/
#define EISA_bus 0
#define MCA_bus 0
/*
* if you change this structure, you must change the code and offsets
* in m68k/machasm.S
*/
struct thread_struct {
unsigned long ksp; /* kernel stack pointer */
unsigned long usp; /* user stack pointer */
unsigned short sr; /* saved status register */
unsigned short fs; /* saved fs (sfc, dfc) */
unsigned long crp[2]; /* cpu root pointer */
unsigned long esp0; /* points to SR of stack frame */
unsigned long fp[8*3];
unsigned long fpcntl[3]; /* fp control regs */
unsigned char fpstate[FPSTATESIZE]; /* floating point state */
};
#define INIT_MMAP { &init_mm, 0, 0x40000000, NULL, __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED), VM_READ | VM_WRITE | VM_EXEC, 1, NULL, NULL }
#define INIT_TSS { \
sizeof(init_stack) + (unsigned long) init_stack, 0, \
PS_S, __KERNEL_DS, \
{0, 0}, 0, {0,}, {0, 0, 0}, {0,}, \
}
/*
* Do necessary setup to start up a newly executed thread.
*/
static inline void start_thread(struct pt_regs * regs, unsigned long pc,
unsigned long usp)
{
/* reads from user space */
set_fs(USER_DS);
regs->pc = pc;
regs->sr &= ~0x2000;
wrusp(usp);
}
/* Free all resources held by a thread. */
static inline void release_thread(struct task_struct *dead_task)
{
}
extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
#define copy_segments(nr, tsk, mm) do { } while (0)
#define release_segments(mm) do { } while (0)
#define forget_segments() do { } while (0)
/*
* Free current thread data structures etc..
*/
static inline void exit_thread(void)
{
}
/*
* Return saved PC of a blocked thread.
*/
extern inline unsigned long thread_saved_pc(struct thread_struct *t)
{
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
struct switch_stack *sw = (struct switch_stack *)t->ksp;
/* Check whether the thread is blocked in resume() */
if (sw->retpc > (unsigned long)scheduling_functions_start_here &&
sw->retpc < (unsigned long)scheduling_functions_end_here)
return ((unsigned long *)sw->a6)[1];
else
return sw->retpc;
}
/* Allocation and freeing of basic task resources. */
#define alloc_task_struct() \
((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
#define free_task_struct(p) free_pages((unsigned long)(p),1)
#define init_task (init_task_union.task)
#define init_stack (init_task_union.stack)
/*
* Return_address is a replacement for __builtin_return_address(count)
* which on certain architectures cannot reasonably be implemented in GCC
* (MIPS, Alpha) or is unuseable with -fomit-frame-pointer (i386).
* Note that __builtin_return_address(x>=1) is forbidden because the GCC
* aborts compilation on some CPUs. It's simply not possible to unwind
* some CPU's stackframes.
*/
#define return_address() __builtin_return_address(0)
#endif
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