Linux-2.6.12-rc2

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / arch / um / kernel / physmem.c

/*
 * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
 * Licensed under the GPL
 */

#include "linux/mm.h"
#include "linux/rbtree.h"
#include "linux/slab.h"
#include "linux/vmalloc.h"
#include "linux/bootmem.h"
#include "linux/module.h"
#include "asm/types.h"
#include "asm/pgtable.h"
#include "kern_util.h"
#include "user_util.h"
#include "mode_kern.h"
#include "mem.h"
#include "mem_user.h"
#include "os.h"
#include "kern.h"
#include "init.h"

struct phys_desc {
        struct rb_node rb;
        int fd;
        __u64 offset;
        void *virt;
        unsigned long phys;
        struct list_head list;
};

static struct rb_root phys_mappings = RB_ROOT;

static struct rb_node **find_rb(void *virt)
{
        struct rb_node **n = &phys_mappings.rb_node;
        struct phys_desc *d;

        while(*n != NULL){
                d = rb_entry(*n, struct phys_desc, rb);
                if(d->virt == virt)
                        return(n);

                if(d->virt > virt)
                        n = &(*n)->rb_left;
                else
                        n = &(*n)->rb_right;
        }

        return(n);
}

static struct phys_desc *find_phys_mapping(void *virt)
{
        struct rb_node **n = find_rb(virt);

        if(*n == NULL)
                return(NULL);

        return(rb_entry(*n, struct phys_desc, rb));
}

static void insert_phys_mapping(struct phys_desc *desc)
{
        struct rb_node **n = find_rb(desc->virt);

        if(*n != NULL)
                panic("Physical remapping for %p already present",
                      desc->virt);

        rb_link_node(&desc->rb, (*n)->rb_parent, n);
        rb_insert_color(&desc->rb, &phys_mappings);
}

LIST_HEAD(descriptor_mappings);

struct desc_mapping {
        int fd;
        struct list_head list;
        struct list_head pages;
};

static struct desc_mapping *find_mapping(int fd)
{
        struct desc_mapping *desc;
        struct list_head *ele;

        list_for_each(ele, &descriptor_mappings){
                desc = list_entry(ele, struct desc_mapping, list);
                if(desc->fd == fd)
                        return(desc);
        }

        return(NULL);
}

static struct desc_mapping *descriptor_mapping(int fd)
{
        struct desc_mapping *desc;

        desc = find_mapping(fd);
        if(desc != NULL)
                return(desc);

        desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
        if(desc == NULL)
                return(NULL);

        *desc = ((struct desc_mapping)
                { .fd =         fd,
                  .list =       LIST_HEAD_INIT(desc->list),
                  .pages =      LIST_HEAD_INIT(desc->pages) });
        list_add(&desc->list, &descriptor_mappings);

        return(desc);
}

int physmem_subst_mapping(void *virt, int fd, __u64 offset, int w)
{
        struct desc_mapping *fd_maps;
        struct phys_desc *desc;
        unsigned long phys;
        int err;

        fd_maps = descriptor_mapping(fd);
        if(fd_maps == NULL)
                return(-ENOMEM);

        phys = __pa(virt);
        desc = find_phys_mapping(virt);
        if(desc != NULL)
                panic("Address 0x%p is already substituted\n", virt);

        err = -ENOMEM;
        desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
        if(desc == NULL)
                goto out;

        *desc = ((struct phys_desc)
                { .fd =                 fd,
                  .offset =             offset,
                  .virt =               virt,
                  .phys =               __pa(virt),
                  .list =               LIST_HEAD_INIT(desc->list) });
        insert_phys_mapping(desc);

        list_add(&desc->list, &fd_maps->pages);

        virt = (void *) ((unsigned long) virt & PAGE_MASK);
        err = os_map_memory(virt, fd, offset, PAGE_SIZE, 1, w, 0);
        if(!err)
                goto out;

        rb_erase(&desc->rb, &phys_mappings);
        kfree(desc);
 out:
        return(err);
}

static int physmem_fd = -1;

static void remove_mapping(struct phys_desc *desc)
{
        void *virt = desc->virt;
        int err;

        rb_erase(&desc->rb, &phys_mappings);
        list_del(&desc->list);
        kfree(desc);

        err = os_map_memory(virt, physmem_fd, __pa(virt), PAGE_SIZE, 1, 1, 0);
        if(err)
                panic("Failed to unmap block device page from physical memory, "
                      "errno = %d", -err);
}

int physmem_remove_mapping(void *virt)
{
        struct phys_desc *desc;

        virt = (void *) ((unsigned long) virt & PAGE_MASK);
        desc = find_phys_mapping(virt);
        if(desc == NULL)
                return(0);

        remove_mapping(desc);
        return(1);
}

void physmem_forget_descriptor(int fd)
{
        struct desc_mapping *desc;
        struct phys_desc *page;
        struct list_head *ele, *next;
        __u64 offset;
        void *addr;
        int err;

        desc = find_mapping(fd);
        if(desc == NULL)
                return;

        list_for_each_safe(ele, next, &desc->pages){
                page = list_entry(ele, struct phys_desc, list);
                offset = page->offset;
                addr = page->virt;
                remove_mapping(page);
                err = os_seek_file(fd, offset);
                if(err)
                        panic("physmem_forget_descriptor - failed to seek "
                              "to %lld in fd %d, error = %d\n",
                              offset, fd, -err);
                err = os_read_file(fd, addr, PAGE_SIZE);
                if(err < 0)
                        panic("physmem_forget_descriptor - failed to read "
                              "from fd %d to 0x%p, error = %d\n",
                              fd, addr, -err);
        }

        list_del(&desc->list);
        kfree(desc);
}

EXPORT_SYMBOL(physmem_forget_descriptor);
EXPORT_SYMBOL(physmem_remove_mapping);
EXPORT_SYMBOL(physmem_subst_mapping);

void arch_free_page(struct page *page, int order)
{
        void *virt;
        int i;

        for(i = 0; i < (1 << order); i++){
                virt = __va(page_to_phys(page + i));
                physmem_remove_mapping(virt);
        }
}

int is_remapped(void *virt)
{
        struct phys_desc *desc = find_phys_mapping(virt);

        return(desc != NULL);
}

/* Changed during early boot */
unsigned long high_physmem;

extern unsigned long physmem_size;

void *to_virt(unsigned long phys)
{
        return((void *) uml_physmem + phys);
}

unsigned long to_phys(void *virt)
{
        return(((unsigned long) virt) - uml_physmem);
}

int init_maps(unsigned long physmem, unsigned long iomem, unsigned long highmem)
{
        struct page *p, *map;
        unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
        unsigned long iomem_len, iomem_pages, total_len, total_pages;
        int i;

        phys_pages = physmem >> PAGE_SHIFT;
        phys_len = phys_pages * sizeof(struct page);

        iomem_pages = iomem >> PAGE_SHIFT;
        iomem_len = iomem_pages * sizeof(struct page);

        highmem_pages = highmem >> PAGE_SHIFT;
        highmem_len = highmem_pages * sizeof(struct page);

        total_pages = phys_pages + iomem_pages + highmem_pages;
        total_len = phys_len + iomem_pages + highmem_len;

        if(kmalloc_ok){
                map = kmalloc(total_len, GFP_KERNEL);
                if(map == NULL)
                        map = vmalloc(total_len);
        }
        else map = alloc_bootmem_low_pages(total_len);

        if(map == NULL)
                return(-ENOMEM);

        for(i = 0; i < total_pages; i++){
                p = &map[i];
                set_page_count(p, 0);
                SetPageReserved(p);
                INIT_LIST_HEAD(&p->lru);
        }

        max_mapnr = total_pages;
        return(0);
}

struct page *phys_to_page(const unsigned long phys)
{
        return(&mem_map[phys >> PAGE_SHIFT]);
}

struct page *__virt_to_page(const unsigned long virt)
{
        return(&mem_map[__pa(virt) >> PAGE_SHIFT]);
}

phys_t page_to_phys(struct page *page)
{
        return((page - mem_map) << PAGE_SHIFT);
}

pte_t mk_pte(struct page *page, pgprot_t pgprot)
{
        pte_t pte;

        pte_set_val(pte, page_to_phys(page), pgprot);
        if(pte_present(pte))
                pte_mknewprot(pte_mknewpage(pte));
        return(pte);
}

/* Changed during early boot */
static unsigned long kmem_top = 0;

unsigned long get_kmem_end(void)
{
        if(kmem_top == 0)
                kmem_top = CHOOSE_MODE(kmem_end_tt, kmem_end_skas);
        return(kmem_top);
}

void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
                int r, int w, int x)
{
        __u64 offset;
        int fd, err;

        fd = phys_mapping(phys, &offset);
        err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
        if(err) {
                if(err == -ENOMEM)
                        printk("try increasing the host's "
                               "/proc/sys/vm/max_map_count to <physical "
                               "memory size>/4096\n");
                panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
                      "err = %d\n", virt, fd, offset, len, r, w, x, err);
        }
}

#define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)

void setup_physmem(unsigned long start, unsigned long reserve_end,
                   unsigned long len, unsigned long highmem)
{
        unsigned long reserve = reserve_end - start;
        int pfn = PFN_UP(__pa(reserve_end));
        int delta = (len - reserve) >> PAGE_SHIFT;
        int err, offset, bootmap_size;

        physmem_fd = create_mem_file(len + highmem);

        offset = uml_reserved - uml_physmem;
        err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
                            len - offset, 1, 1, 0);
        if(err < 0){
                os_print_error(err, "Mapping memory");
                exit(1);
        }

        bootmap_size = init_bootmem(pfn, pfn + delta);
        free_bootmem(__pa(reserve_end) + bootmap_size,
                     len - bootmap_size - reserve);
}

int phys_mapping(unsigned long phys, __u64 *offset_out)
{
        struct phys_desc *desc = find_phys_mapping(__va(phys & PAGE_MASK));
        int fd = -1;

        if(desc != NULL){
                fd = desc->fd;
                *offset_out = desc->offset;
        }
        else if(phys < physmem_size){
                fd = physmem_fd;
                *offset_out = phys;
        }
        else if(phys < __pa(end_iomem)){
                struct iomem_region *region = iomem_regions;

                while(region != NULL){
                        if((phys >= region->phys) &&
                           (phys < region->phys + region->size)){
                                fd = region->fd;
                                *offset_out = phys - region->phys;
                                break;
                        }
                        region = region->next;
                }
        }
        else if(phys < __pa(end_iomem) + highmem){
                fd = physmem_fd;
                *offset_out = phys - iomem_size;
        }

        return(fd);
}

static int __init uml_mem_setup(char *line, int *add)
{
        char *retptr;
        physmem_size = memparse(line,&retptr);
        return 0;
}
__uml_setup("mem=", uml_mem_setup,
"mem=<Amount of desired ram>\n"
"    This controls how much \"physical\" memory the kernel allocates\n"
"    for the system. The size is specified as a number followed by\n"
"    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
"    This is not related to the amount of memory in the host.  It can\n"
"    be more, and the excess, if it's ever used, will just be swapped out.\n"
"       Example: mem=64M\n\n"
);

unsigned long find_iomem(char *driver, unsigned long *len_out)
{
        struct iomem_region *region = iomem_regions;

        while(region != NULL){
                if(!strcmp(region->driver, driver)){
                        *len_out = region->size;
                        return(region->virt);
                }
        }

        return(0);
}

int setup_iomem(void)
{
        struct iomem_region *region = iomem_regions;
        unsigned long iomem_start = high_physmem + PAGE_SIZE;
        int err;

        while(region != NULL){
                err = os_map_memory((void *) iomem_start, region->fd, 0,
                                    region->size, 1, 1, 0);
                if(err)
                        printk("Mapping iomem region for driver '%s' failed, "
                               "errno = %d\n", region->driver, -err);
                else {
                        region->virt = iomem_start;
                        region->phys = __pa(region->virt);
                }

                iomem_start += region->size + PAGE_SIZE;
                region = region->next;
        }

        return(0);
}

__initcall(setup_iomem);

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */