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/*
****************************************************************************
* (C) 2003 - Rolf Neugebauer - Intel Research Cambridge
* (C) 2005 - Grzegorz Milos - Intel Research Cambridge
****************************************************************************
*
* File: mm.c
* Author: Rolf Neugebauer (neugebar@dcs.gla.ac.uk)
* Changes: Grzegorz Milos
*
* Date: Aug 2003, chages Aug 2005
*
* Environment: Xen Minimal OS
* Description: memory management related functions
* contains buddy page allocator from Xen.
*
****************************************************************************
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <mini-os/os.h>
#include <mini-os/hypervisor.h>
#include <xen/memory.h>
#include <mini-os/mm.h>
#include <mini-os/types.h>
#include <mini-os/lib.h>
#include <mini-os/xmalloc.h>
#ifdef MM_DEBUG
#define DEBUG(_f, _a...) \
printk("MINI_OS(file=mm.c, line=%d) " _f "\n", __LINE__, ## _a)
#else
#define DEBUG(_f, _a...) ((void)0)
#endif
/*********************
* ALLOCATION BITMAP
* One bit per page of memory. Bit set => page is allocated.
*/
static unsigned long *alloc_bitmap;
#define PAGES_PER_MAPWORD (sizeof(unsigned long) * 8)
#define allocated_in_map(_pn) \
(alloc_bitmap[(_pn)/PAGES_PER_MAPWORD] & (1UL<<((_pn)&(PAGES_PER_MAPWORD-1))))
/*
* Hint regarding bitwise arithmetic in map_{alloc,free}:
* -(1<<n) sets all bits >= n.
* (1<<n)-1 sets all bits < n.
* Variable names in map_{alloc,free}:
* *_idx == Index into `alloc_bitmap' array.
* *_off == Bit offset within an element of the `alloc_bitmap' array.
*/
static void map_alloc(unsigned long first_page, unsigned long nr_pages)
{
unsigned long start_off, end_off, curr_idx, end_idx;
curr_idx = first_page / PAGES_PER_MAPWORD;
start_off = first_page & (PAGES_PER_MAPWORD-1);
end_idx = (first_page + nr_pages) / PAGES_PER_MAPWORD;
end_off = (first_page + nr_pages) & (PAGES_PER_MAPWORD-1);
if ( curr_idx == end_idx )
{
alloc_bitmap[curr_idx] |= ((1UL<<end_off)-1) & -(1UL<<start_off);
}
else
{
alloc_bitmap[curr_idx] |= -(1UL<<start_off);
while ( ++curr_idx < end_idx ) alloc_bitmap[curr_idx] = ~0UL;
alloc_bitmap[curr_idx] |= (1UL<<end_off)-1;
}
}
static void map_free(unsigned long first_page, unsigned long nr_pages)
{
unsigned long start_off, end_off, curr_idx, end_idx;
curr_idx = first_page / PAGES_PER_MAPWORD;
start_off = first_page & (PAGES_PER_MAPWORD-1);
end_idx = (first_page + nr_pages) / PAGES_PER_MAPWORD;
end_off = (first_page + nr_pages) & (PAGES_PER_MAPWORD-1);
if ( curr_idx == end_idx )
{
alloc_bitmap[curr_idx] &= -(1UL<<end_off) | ((1UL<<start_off)-1);
}
else
{
alloc_bitmap[curr_idx] &= (1UL<<start_off)-1;
while ( ++curr_idx != end_idx ) alloc_bitmap[curr_idx] = 0;
alloc_bitmap[curr_idx] &= -(1UL<<end_off);
}
}
/*************************
* BINARY BUDDY ALLOCATOR
*/
typedef struct chunk_head_st chunk_head_t;
typedef struct chunk_tail_st chunk_tail_t;
struct chunk_head_st {
chunk_head_t *next;
chunk_head_t **pprev;
int level;
};
struct chunk_tail_st {
int level;
};
/* Linked lists of free chunks of different powers-of-two in size. */
#define FREELIST_SIZE ((sizeof(void*)<<3)-PAGE_SHIFT)
static chunk_head_t *free_head[FREELIST_SIZE];
static chunk_head_t free_tail[FREELIST_SIZE];
#define FREELIST_EMPTY(_l) ((_l)->next == NULL)
#define round_pgdown(_p) ((_p)&PAGE_MASK)
#define round_pgup(_p) (((_p)+(PAGE_SIZE-1))&PAGE_MASK)
#ifdef MM_DEBUG
/*
* Prints allocation[0/1] for @nr_pages, starting at @start
* address (virtual).
*/
USED static void print_allocation(void *start, int nr_pages)
{
unsigned long pfn_start = virt_to_pfn(start);
int count;
for(count = 0; count < nr_pages; count++)
if(allocated_in_map(pfn_start + count)) printk("1");
else printk("0");
printk("\n");
}
/*
* Prints chunks (making them with letters) for @nr_pages starting
* at @start (virtual).
*/
USED static void print_chunks(void *start, int nr_pages)
{
char chunks[1001], current='A';
int order, count;
chunk_head_t *head;
unsigned long pfn_start = virt_to_pfn(start);
memset(chunks, (int)'_', 1000);
if(nr_pages > 1000)
{
DEBUG("Can only pring 1000 pages. Increase buffer size.");
}
for(order=0; order < FREELIST_SIZE; order++)
{
head = free_head[order];
while(!FREELIST_EMPTY(head))
{
for(count = 0; count < 1UL<< head->level; count++)
{
if(count + virt_to_pfn(head) - pfn_start < 1000)
chunks[count + virt_to_pfn(head) - pfn_start] = current;
}
head = head->next;
current++;
}
}
chunks[nr_pages] = '\0';
printk("%s\n", chunks);
}
#endif
/*
* Initialise allocator, placing addresses [@min,@max] in free pool.
* @min and @max are PHYSICAL addresses.
*/
static void init_page_allocator(unsigned long min, unsigned long max)
{
int i;
unsigned long range, bitmap_size;
chunk_head_t *ch;
chunk_tail_t *ct;
for ( i = 0; i < FREELIST_SIZE; i++ )
{
free_head[i] = &free_tail[i];
free_tail[i].pprev = &free_head[i];
free_tail[i].next = NULL;
}
min = round_pgup (min);
max = round_pgdown(max);
/* Allocate space for the allocation bitmap. */
bitmap_size = (max+1) >> (PAGE_SHIFT+3);
bitmap_size = round_pgup(bitmap_size);
alloc_bitmap = (unsigned long *)to_virt(min);
min += bitmap_size;
range = max - min;
/* All allocated by default. */
memset(alloc_bitmap, ~0, bitmap_size);
/* Free up the memory we've been given to play with. */
map_free(PHYS_PFN(min), range>>PAGE_SHIFT);
/* The buddy lists are addressed in high memory. */
min = (unsigned long) to_virt(min);
max = (unsigned long) to_virt(max);
while ( range != 0 )
{
/*
* Next chunk is limited by alignment of min, but also
* must not be bigger than remaining range.
*/
for ( i = PAGE_SHIFT; (1UL<<(i+1)) <= range; i++ )
if ( min & (1UL<<i) ) break;
ch = (chunk_head_t *)min;
min += (1UL<<i);
range -= (1UL<<i);
ct = (chunk_tail_t *)min-1;
i -= PAGE_SHIFT;
ch->level = i;
ch->next = free_head[i];
ch->pprev = &free_head[i];
ch->next->pprev = &ch->next;
free_head[i] = ch;
ct->level = i;
}
}
/* Allocate 2^@order contiguous pages. Returns a VIRTUAL address. */
unsigned long alloc_pages(int order)
{
int i;
chunk_head_t *alloc_ch, *spare_ch;
chunk_tail_t *spare_ct;
/* Find smallest order which can satisfy the request. */
for ( i = order; i < FREELIST_SIZE; i++ ) {
if ( !FREELIST_EMPTY(free_head[i]) )
break;
}
if ( i == FREELIST_SIZE ) goto no_memory;
/* Unlink a chunk. */
alloc_ch = free_head[i];
free_head[i] = alloc_ch->next;
alloc_ch->next->pprev = alloc_ch->pprev;
/* We may have to break the chunk a number of times. */
while ( i != order )
{
/* Split into two equal parts. */
i--;
spare_ch = (chunk_head_t *)((char *)alloc_ch + (1UL<<(i+PAGE_SHIFT)));
spare_ct = (chunk_tail_t *)((char *)spare_ch + (1UL<<(i+PAGE_SHIFT)))-1;
/* Create new header for spare chunk. */
spare_ch->level = i;
spare_ch->next = free_head[i];
spare_ch->pprev = &free_head[i];
spare_ct->level = i;
/* Link in the spare chunk. */
spare_ch->next->pprev = &spare_ch->next;
free_head[i] = spare_ch;
}
map_alloc(PHYS_PFN(to_phys(alloc_ch)), 1UL<<order);
return((unsigned long)alloc_ch);
no_memory:
printk("Cannot handle page request order %d!\n", order);
return 0;
}
void free_pages(void *pointer, int order)
{
chunk_head_t *freed_ch, *to_merge_ch;
chunk_tail_t *freed_ct;
unsigned long mask;
/* First free the chunk */
map_free(virt_to_pfn(pointer), 1UL << order);
/* Create free chunk */
freed_ch = (chunk_head_t *)pointer;
freed_ct = (chunk_tail_t *)((char *)pointer + (1UL<<(order + PAGE_SHIFT)))-1;
/* Now, possibly we can conseal chunks together */
while(order < FREELIST_SIZE)
{
mask = 1UL << (order + PAGE_SHIFT);
if((unsigned long)freed_ch & mask)
{
to_merge_ch = (chunk_head_t *)((char *)freed_ch - mask);
if(allocated_in_map(virt_to_pfn(to_merge_ch)) ||
to_merge_ch->level != order)
break;
/* Merge with predecessor */
freed_ch = to_merge_ch;
}
else
{
to_merge_ch = (chunk_head_t *)((char *)freed_ch + mask);
if(allocated_in_map(virt_to_pfn(to_merge_ch)) ||
to_merge_ch->level != order)
break;
/* Merge with successor */
freed_ct = (chunk_tail_t *)((char *)to_merge_ch + mask) - 1;
}
/* We are commited to merging, unlink the chunk */
*(to_merge_ch->pprev) = to_merge_ch->next;
to_merge_ch->next->pprev = to_merge_ch->pprev;
order++;
}
/* Link the new chunk */
freed_ch->level = order;
freed_ch->next = free_head[order];
freed_ch->pprev = &free_head[order];
freed_ct->level = order;
freed_ch->next->pprev = &freed_ch->next;
free_head[order] = freed_ch;
}
#ifndef __ia64__
int free_physical_pages(xen_pfn_t *mfns, int n)
{
struct xen_memory_reservation reservation;
set_xen_guest_handle(reservation.extent_start, mfns);
reservation.nr_extents = n;
reservation.extent_order = 0;
reservation.domid = DOMID_SELF;
return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
}
#endif
#ifdef HAVE_LIBC
void *sbrk(ptrdiff_t increment)
{
unsigned long old_brk = brk;
unsigned long new_brk = old_brk + increment;
if (new_brk > heap_end) {
printk("Heap exhausted: %p + %lx = %p > %p\n", old_brk, increment, new_brk, heap_end);
return NULL;
}
if (new_brk > heap_mapped) {
unsigned long n = (new_brk - heap_mapped + PAGE_SIZE - 1) / PAGE_SIZE;
do_map_zero(heap_mapped, n);
heap_mapped += n * PAGE_SIZE;
}
brk = new_brk;
return (void *) old_brk;
}
#endif
void init_mm(void)
{
unsigned long start_pfn, max_pfn;
printk("MM: Init\n");
arch_init_mm(&start_pfn, &max_pfn);
/*
* now we can initialise the page allocator
*/
printk("MM: Initialise page allocator for %lx(%lx)-%lx(%lx)\n",
(u_long)to_virt(PFN_PHYS(start_pfn)), PFN_PHYS(start_pfn),
(u_long)to_virt(PFN_PHYS(max_pfn)), PFN_PHYS(max_pfn));
init_page_allocator(PFN_PHYS(start_pfn), PFN_PHYS(max_pfn));
printk("MM: done\n");
arch_init_p2m(max_pfn);
arch_init_demand_mapping_area(max_pfn);
}
void fini_mm(void)
{
}
void sanity_check(void)
{
int x;
chunk_head_t *head;
for (x = 0; x < FREELIST_SIZE; x++) {
for (head = free_head[x]; !FREELIST_EMPTY(head); head = head->next) {
ASSERT(!allocated_in_map(virt_to_pfn(head)));
if (head->next)
ASSERT(head->next->pprev == &head->next);
}
if (free_head[x]) {
ASSERT(free_head[x]->pprev == &free_head[x]);
}
}
}
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