/*
 *  linux/arch/alpha/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 */

/* 2.3.x zone allocator, 1999 Andrea Arcangeli <andrea@suse.de> */

#include <linux/config.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/bootmem.h> /* max_low_pfn */
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/hwrpb.h>
#include <asm/dma.h>
#include <asm/mmu_context.h>

static unsigned long totalram_pages;

extern void die_if_kernel(char *,struct pt_regs *,long);

struct thread_struct original_pcb;

#ifndef CONFIG_SMP
struct pgtable_cache_struct quicklists;
#endif

void
__bad_pmd(pgd_t *pgd)
{
	printk("Bad pgd in pmd_alloc: %08lx\n", pgd_val(*pgd));
	pgd_set(pgd, BAD_PAGETABLE);
}

void
__bad_pte(pmd_t *pmd)
{
	printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
	pmd_set(pmd, (pte_t *) BAD_PAGETABLE);
}

pmd_t *
get_pmd_slow(pgd_t *pgd, unsigned long offset)
{
	pmd_t *pmd;

	pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
	if (pgd_none(*pgd)) {
		if (pmd) {
			clear_page((void *)pmd);
			pgd_set(pgd, pmd);
			return pmd + offset;
		}
		pgd_set(pgd, BAD_PAGETABLE);
		return NULL;
	}
	free_page((unsigned long)pmd);
	if (pgd_bad(*pgd)) {
		__bad_pmd(pgd);
		return NULL;
	}
	return (pmd_t *) pgd_page(*pgd) + offset;
}

pte_t *
get_pte_slow(pmd_t *pmd, unsigned long offset)
{
	pte_t *pte;

	pte = (pte_t *) __get_free_page(GFP_KERNEL);
	if (pmd_none(*pmd)) {
		if (pte) {
			clear_page((void *)pte);
			pmd_set(pmd, pte);
			return pte + offset;
		}
		pmd_set(pmd, (pte_t *) BAD_PAGETABLE);
		return NULL;
	}
	free_page((unsigned long)pte);
	if (pmd_bad(*pmd)) {
		__bad_pte(pmd);
		return NULL;
	}
	return (pte_t *) pmd_page(*pmd) + offset;
}

int do_check_pgt_cache(int low, int high)
{
	int freed = 0;
        if(pgtable_cache_size > high) {
                do {
                        if(pgd_quicklist)
                                free_pgd_slow(get_pgd_fast()), freed++;
                        if(pmd_quicklist)
                                free_pmd_slow(get_pmd_fast()), freed++;
                        if(pte_quicklist)
                                free_pte_slow(get_pte_fast()), freed++;
                } while(pgtable_cache_size > low);
        }
        return freed;
}

/*
 * BAD_PAGE is the page that is used for page faults when linux
 * is out-of-memory. Older versions of linux just did a
 * do_exit(), but using this instead means there is less risk
 * for a process dying in kernel mode, possibly leaving an inode
 * unused etc..
 *
 * BAD_PAGETABLE is the accompanying page-table: it is initialized
 * to point to BAD_PAGE entries.
 *
 * ZERO_PAGE is a special page that is used for zero-initialized
 * data and COW.
 */
pmd_t *
__bad_pagetable(void)
{
	memset((void *) EMPTY_PGT, 0, PAGE_SIZE);
	return (pmd_t *) EMPTY_PGT;
}

pte_t
__bad_page(void)
{
	memset((void *) EMPTY_PGE, 0, PAGE_SIZE);
	return pte_mkdirty(mk_pte(mem_map + MAP_NR(EMPTY_PGE), PAGE_SHARED));
}

void
show_mem(void)
{
	long i,free = 0,total = 0,reserved = 0;
	long shared = 0, cached = 0;

	printk("\nMem-info:\n");
	show_free_areas();
	printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
	i = max_mapnr;
	while (i-- > 0) {
		total++;
		if (PageReserved(mem_map+i))
			reserved++;
		else if (PageSwapCache(mem_map+i))
			cached++;
		else if (!atomic_read(&mem_map[i].count))
			free++;
		else
			shared += atomic_read(&mem_map[i].count) - 1;
	}
	printk("%ld pages of RAM\n",total);
	printk("%ld free pages\n",free);
	printk("%ld reserved pages\n",reserved);
	printk("%ld pages shared\n",shared);
	printk("%ld pages swap cached\n",cached);
	printk("%ld pages in page table cache\n",pgtable_cache_size);
	show_buffers();
}

static inline unsigned long
load_PCB(struct thread_struct * pcb)
{
	register unsigned long sp __asm__("$30");
	pcb->ksp = sp;
	return __reload_thread(pcb);
}

/*
 * paging_init() sets up the page tables: in the alpha version this actually
 * unmaps the bootup page table (as we're now in KSEG, so we don't need it).
 */
void
paging_init(void)
{
	unsigned long newptbr;
	unsigned long original_pcb_ptr;
	unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
	unsigned long dma_pfn, high_pfn;

	dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
	high_pfn = max_low_pfn;

#define ORDER_MASK (~((1 << (MAX_ORDER-1))-1))
#define ORDER_ALIGN(n)	(((n) +  ~ORDER_MASK) & ORDER_MASK)

	dma_pfn = ORDER_ALIGN(dma_pfn);
	high_pfn = ORDER_ALIGN(high_pfn);

#undef ORDER_MASK
#undef ORDER_ALIGN

	if (dma_pfn > high_pfn)
		zones_size[ZONE_DMA] = high_pfn;
	else {
		zones_size[ZONE_DMA] = dma_pfn;
		zones_size[ZONE_NORMAL] = high_pfn - dma_pfn;
	}

	/* Initialize mem_map[].  */
	free_area_init(zones_size);

	/* Initialize the kernel's page tables.  Linux puts the vptb in
	   the last slot of the L1 page table.  */
	memset((void *)ZERO_PGE, 0, PAGE_SIZE);
	memset(swapper_pg_dir, 0, PAGE_SIZE);
	newptbr = ((unsigned long) swapper_pg_dir - PAGE_OFFSET) >> PAGE_SHIFT;
	pgd_val(swapper_pg_dir[1023]) =
		(newptbr << 32) | pgprot_val(PAGE_KERNEL);

	/* Set the vptb.  This is often done by the bootloader, but 
	   shouldn't be required.  */
	if (hwrpb->vptb != 0xfffffffe00000000) {
		wrvptptr(0xfffffffe00000000);
		hwrpb->vptb = 0xfffffffe00000000;
		hwrpb_update_checksum(hwrpb);
	}

	/* Also set up the real kernel PCB while we're at it.  */
	init_task.thread.ptbr = newptbr;
	init_task.thread.pal_flags = 1;	/* set FEN, clear everything else */
	init_task.thread.flags = 0;
	original_pcb_ptr = load_PCB(&init_task.thread);
	tbia();

	/* Save off the contents of the original PCB so that we can
	   restore the original console's page tables for a clean reboot.

	   Note that the PCB is supposed to be a physical address, but
	   since KSEG values also happen to work, folks get confused.
	   Check this here.  */

	if (original_pcb_ptr < PAGE_OFFSET) {
		original_pcb_ptr = (unsigned long)
			phys_to_virt(original_pcb_ptr);
	}
	original_pcb = *(struct thread_struct *) original_pcb_ptr;
}

#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM)
void
srm_paging_stop (void)
{
	/* Move the vptb back to where the SRM console expects it.  */
	swapper_pg_dir[1] = swapper_pg_dir[1023];
	tbia();
	wrvptptr(0x200000000);
	hwrpb->vptb = 0x200000000;
	hwrpb_update_checksum(hwrpb);

	/* Reload the page tables that the console had in use.  */
	load_PCB(&original_pcb);
	tbia();
}
#endif

static void __init
printk_memory_info(void)
{
	unsigned long codesize, reservedpages, datasize, initsize, tmp;
	extern int page_is_ram(unsigned long) __init;
	extern char _text, _etext, _data, _edata;
	extern char __init_begin, __init_end;

	/* printk all informations */
	reservedpages = 0;
	for (tmp = 0; tmp < max_low_pfn; tmp++)
		/*
		 * Only count reserved RAM pages
		 */
		if (page_is_ram(tmp) && PageReserved(mem_map+tmp))
			reservedpages++;

	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
	datasize =  (unsigned long) &_edata - (unsigned long) &_data;
	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

	printk("Memory: %luk/%luk available (%luk kernel code, %luk reserved, %luk data, %luk init)\n",
	       (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
	       max_mapnr << (PAGE_SHIFT-10),
	       codesize >> 10,
	       reservedpages << (PAGE_SHIFT-10),
	       datasize >> 10,
	       initsize >> 10);
}

void __init
mem_init(void)
{
	max_mapnr = num_physpages = max_low_pfn;
	totalram_pages += free_all_bootmem();
	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);

	printk_memory_info();
}

void
free_initmem (void)
{
	extern char __init_begin, __init_end;
	unsigned long addr;

	addr = (unsigned long)(&__init_begin);
	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
		ClearPageReserved(mem_map + MAP_NR(addr));
		set_page_count(mem_map+MAP_NR(addr), 1);
		free_page(addr);
		totalram_pages++;
	}
	printk ("Freeing unused kernel memory: %ldk freed\n",
		(&__init_end - &__init_begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void
free_initrd_mem(unsigned long start, unsigned long end)
{
	for (; start < end; start += PAGE_SIZE) {
		ClearPageReserved(mem_map + MAP_NR(start));
		set_page_count(mem_map+MAP_NR(start), 1);
		free_page(start);
		totalram_pages++;
	}
	printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
}
#endif

void
si_meminfo(struct sysinfo *val)
{
	val->totalram = totalram_pages;
	val->sharedram = 0;
	val->freeram = nr_free_pages();
	val->bufferram = atomic_read(&buffermem_pages);
	val->totalhigh = 0;
	val->freehigh = 0;
	val->mem_unit = PAGE_SIZE;
}