/*
 * include/asm-alpha/processor.h
 *
 * Copyright (C) 1994 Linus Torvalds
 */

#ifndef __ASM_ALPHA_PROCESSOR_H
#define __ASM_ALPHA_PROCESSOR_H

/*
 * We have a 41-bit user address space: 2TB user VM...
 */
#define TASK_SIZE (0x40000000000UL)

/*
 * Bus types
 */
#define EISA_bus 1
#define EISA_bus__is_a_macro /* for versions in ksyms.c */
#define MCA_bus 0
#define MCA_bus__is_a_macro /* for versions in ksyms.c */

/*
 * The alpha has no problems with write protection
 */
#define wp_works_ok 1
#define wp_works_ok__is_a_macro /* for versions in ksyms.c */

/*
 * The VM exception save area. We need to save
 *	return address (r26)
 *	PC (r30)
 *	function-call-saved regs (r9-r15)
 * Count is used to do some basic sanity checking, and
 * to handle the case where a kernel service itself sets
 * up exceptions while another exception is active.
 *
 * NOTE: Exceptions are not "recursive": in the case above
 * the oldest exception is the one that is left active, but
 * the VM fault handler will notice a count != 1 and abort
 * because exceptions within exceptions are an error.
 */
struct exception_struct {
	unsigned long count;
	unsigned long r9, r10, r11, r12, r13, r14, r15;
	unsigned long r26, r30;
};

extern int __exception(struct exception_struct *);
extern void __handle_exception(struct exception_struct *) __attribute__((noreturn));

#define exception()	__exception(&current->tss.ex)
#define end_exception()	(current->tss.ex.count--)

struct thread_struct {
	/* the fields below are used by PALcode and must match struct pcb: */
	unsigned long ksp;
	unsigned long usp;
	unsigned long ptbr;
	unsigned int pcc;
	unsigned int asn;
	unsigned long unique;
	/*
	 * bit  0: floating point enable
	 * bit 62: performance monitor enable
	 */
	unsigned long pal_flags;
	unsigned long res1, res2;

	/* the fields below are Linux-specific: */
	/*
	 * bit 0:    perform syscall argument validation (get/set_fs)
	 * bit 1..5: IEEE_TRAP_ENABLE bits (see fpu.h)
	 */
	unsigned long flags;
	struct exception_struct ex;
};

#define INIT_MMAP { &init_mm, 0xfffffc0000000000,  0xfffffc0010000000, \
	PAGE_SHARED, VM_READ | VM_WRITE | VM_EXEC }

#define INIT_TSS  { \
	0, 0, 0, \
	0, 0, 0, \
	0, 0, 0, \
	0, \
	{ 0, } \
}

#define alloc_kernel_stack()    __get_free_page(GFP_KERNEL)
#define free_kernel_stack(page) free_page((page))

#include <asm/ptrace.h>

/*
 * Return saved PC of a blocked thread.  This assumes the frame
 * pointer is the 6th saved long on the kernel stack and that the
 * saved return address is the first long in the frame.  This all
 * holds provided the thread blocked through a call to schedule() ($15
 * is the frame pointer in schedule() and $15 is saved at offset 48 by
 * entry.S:do_switch_stack).
 */
extern inline unsigned long thread_saved_pc(struct thread_struct *t)
{
	unsigned long fp;

	fp = ((unsigned long*)t->ksp)[6];
	return *(unsigned long*)fp;
}

/*
 * Do necessary setup to start up a newly executed thread.
 */
extern void start_thread(struct pt_regs *, unsigned long, unsigned long);

#endif /* __ASM_ALPHA_PROCESSOR_H */
