/*
 *  include/asm-s390/processor.h
 *
 *  S390 version
 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Hartmut Penner (hp@de.ibm.com),
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 *  Derived from "include/asm-i386/processor.h"
 *    Copyright (C) 1994, Linus Torvalds
 */

#ifndef __ASM_S390_PROCESSOR_H
#define __ASM_S390_PROCESSOR_H

#include <asm/page.h>
#include <asm/ptrace.h>

#ifdef __KERNEL__
/*
 * Default implementation of macro that returns current
 * instruction pointer ("program counter").
 */
#define current_text_addr() ({ void *pc; __asm__("basr %0,0":"=a"(pc)); pc; })

/*
 *  CPU type and hardware bug flags. Kept separately for each CPU.
 *  Members of this structure are referenced in head.S, so think twice
 *  before touching them. [mj]
 */

typedef struct
{
        unsigned int version :  8;
        unsigned int ident   : 24;
        unsigned int machine : 16;
        unsigned int unused  : 16;
} __attribute__ ((packed)) cpuid_t;

struct cpuinfo_S390
{
        cpuid_t  cpu_id;
        __u16    cpu_addr;
        __u16    cpu_nr;
        unsigned long loops_per_jiffy;
        unsigned long *pgd_quick;
        unsigned long *pte_quick;
        unsigned long pgtable_cache_sz;
};

extern void print_cpu_info(struct cpuinfo_S390 *);

/* Lazy FPU handling on uni-processor */
extern struct task_struct *last_task_used_math;

/*
 * User space process size: 2GB (default).
 */
#define TASK_SIZE       (0x80000000)
/* This decides where the kernel will search for a free chunk of vm
 * space during mmap's.
 */
#define TASK_UNMAPPED_BASE      (TASK_SIZE / 2)

#define THREAD_SIZE (2*PAGE_SIZE)

typedef struct {
        unsigned long ar4;
} mm_segment_t;

/* if you change the thread_struct structure, you must
 * update the _TSS_* defines in entry.S
 */

struct thread_struct
 {
	s390_fp_regs fp_regs;
        __u32   ar2;                   /* kernel access register 2         */
        __u32   ar4;                   /* kernel access register 4         */
        __u32   ksp;                   /* kernel stack pointer             */
        __u32   user_seg;              /* HSTD                             */
        __u32   error_code;            /* error-code of last prog-excep.   */
        __u32   prot_addr;             /* address of protection-excep.     */
        __u32   trap_no;
        per_struct per_info;/* Must be aligned on an 4 byte boundary*/
	/* Used to give failing instruction back to user for ieee exceptions */
	addr_t  ieee_instruction_pointer; 
        /* pfault_wait is used to block the process on a pfault event */
	addr_t  pfault_wait;
};

typedef struct thread_struct thread_struct;

#define INIT_THREAD {{0,{{0},{0},{0},{0},{0},{0},{0},{0},{0},{0}, \
			    {0},{0},{0},{0},{0},{0}}},            \
                     0, 0,                                        \
                    sizeof(init_stack) + (__u32) &init_stack,     \
              (__pa((__u32) &swapper_pg_dir[0]) + _SEGMENT_TABLE),\
                     0,0,0,                                       \
                     (per_struct) {{{{0,}}},0,0,0,0,{{0,}}},      \
                     0, 0                                         \
}

/* need to define ... */
#define start_thread(regs, new_psw, new_stackp) do {            \
        regs->psw.mask  = _USER_PSW_MASK;                       \
        regs->psw.addr  = new_psw | 0x80000000;                 \
        regs->gprs[15]  = new_stackp ;                          \
} while (0)

/* Forward declaration, a strange C thing */
struct mm_struct;

/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);

/* Copy and release all segment info associated with a VM */
#define copy_segments(nr, mm)           do { } while (0)
#define release_segments(mm)            do { } while (0)

/*
 * Return saved PC of a blocked thread. used in kernel/sched.
 * resume in entry.S does not create a new stack frame, it
 * just stores the registers %r6-%r15 to the frame given by
 * schedule. We want to return the address of the caller of
 * schedule, so we have to walk the backchain one time to
 * find the frame schedule() store its return address.
 */
extern inline unsigned long thread_saved_pc(struct thread_struct *t)
{
	unsigned long bc;
	bc = *((unsigned long *) t->ksp);
	return *((unsigned long *) (bc+56));
}

unsigned long get_wchan(struct task_struct *p);
#define __KSTK_PTREGS(tsk) ((struct pt_regs *) \
	(((unsigned long) tsk + THREAD_SIZE - sizeof(struct pt_regs)) & -8L))
#define KSTK_EIP(tsk)	(__KSTK_PTREGS(tsk)->psw.addr)
#define KSTK_ESP(tsk)	(__KSTK_PTREGS(tsk)->gprs[15])

/* Allocation and freeing of basic task resources. */
/*
 * NOTE! The task struct and the stack go together
 */
#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 get_task_struct(tsk)      atomic_inc(&virt_to_page(tsk)->count)

#define init_task       (init_task_union.task)
#define init_stack      (init_task_union.stack)

#define cpu_relax()	do { } while (0)

/*
 * Set of msr bits that gdb can change on behalf of a process.
 */
/* Only let our hackers near the condition codes */
#define PSW_MASK_DEBUGCHANGE    0x00003000UL
/* Don't let em near the addressing mode either */    
#define PSW_ADDR_DEBUGCHANGE    0x7FFFFFFFUL
#define PSW_ADDR_MASK           0x7FFFFFFFUL
/* Program event recording mask */    
#define PSW_PER_MASK            0x40000000UL
#define USER_STD_MASK           0x00000080UL
#define PSW_PROBLEM_STATE       0x00010000UL

/*
 * Set PSW mask to specified value, while leaving the
 * PSW addr pointing to the next instruction.
 */

static inline void __load_psw_mask (unsigned long mask)
{
	unsigned long addr;

	psw_t psw;
	psw.mask = mask;

	asm volatile (
		"    basr %0,0\n"
		"0:  ahi  %0,1f-0b\n"
		"    st   %0,4(%1)\n"
		"    lpsw 0(%1)\n"
		"1:"
		: "=&d" (addr) : "a" (&psw) : "memory", "cc" );
}
 
/*
 * Function to stop a processor until an interruption occured
 */
static inline void enabled_wait(void)
{
	unsigned long reg;
	psw_t wait_psw;

	wait_psw.mask = 0x070e0000;
	asm volatile (
		"    basr %0,0\n"
		"0:  la   %0,1f-0b(%0)\n"
		"    st   %0,4(%1)\n"
		"    oi   4(%1),0x80\n"
		"    lpsw 0(%1)\n"
		"1:"
		: "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
}

/*
 * Function to drop a processor into disabled wait state
 */

static inline void disabled_wait(unsigned long code)
{
        char psw_buffer[2*sizeof(psw_t)];
        char ctl_buf[4];
        psw_t *dw_psw = (psw_t *)(((unsigned long) &psw_buffer+sizeof(psw_t)-1)
                                  & -sizeof(psw_t));

        dw_psw->mask = 0x000a0000;
        dw_psw->addr = code;
        /* 
         * Store status and then load disabled wait psw,
         * the processor is dead afterwards
         */

        asm volatile ("    stctl 0,0,0(%1)\n"
                      "    ni    0(%1),0xef\n" /* switch off protection */
                      "    lctl  0,0,0(%1)\n"
                      "    stpt  0xd8\n"       /* store timer */
                      "    stckc 0xe0\n"       /* store clock comparator */
                      "    stpx  0x108\n"      /* store prefix register */
                      "    stam  0,15,0x120\n" /* store access registers */
                      "    std   0,0x160\n"    /* store f0 */
                      "    std   2,0x168\n"    /* store f2 */
                      "    std   4,0x170\n"    /* store f4 */
                      "    std   6,0x178\n"    /* store f6 */
                      "    stm   0,15,0x180\n" /* store general registers */
                      "    stctl 0,15,0x1c0\n" /* store control registers */
                      "    oi    0(%1),0x10\n" /* fake protection bit */
                      "    lpsw 0(%0)"
                      : : "a" (dw_psw), "a" (&ctl_buf) : "cc" );
}

#endif

#endif                                 /* __ASM_S390_PROCESSOR_H           */
