android_kernel_xiaomi_sm8350/arch/um/kernel/physmem.c
Jeff Dike 23bbd586ed [PATCH] uml: fix static binary segfault
When UML is built as a static binary, it segfaults when run.  The reason is
that a memory hole that is present in dynamic binaries isn't there in static
binaries, and it contains essential stuff.

This fix removes the code which maps some anonymous memory into that hole and
cleans up some related code.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:23 -07:00

453 lines
9.9 KiB
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 "linux/pfn.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, rb_parent(*n), 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 long physmem_size;
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_len + 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];
memset(p, 0, sizeof(struct page));
SetPageReserved(p);
INIT_LIST_HEAD(&p->lru);
}
max_mapnr = total_pages;
return(0);
}
/* 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);
}
}
extern int __syscall_stub_start;
void setup_physmem(unsigned long start, unsigned long reserve_end,
unsigned long len, unsigned long 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);
}
/* Special kludge - This page will be mapped in to userspace processes
* from physmem_fd, so it needs to be written out there.
*/
os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
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);
}
region = region->next;
}
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:
*/