grub/kern/mm.c
okuji 4b13b216f4 2004-04-04 Yoshinori K. Okuji <okuji@enbug.org>
All symbols prefixed with PUPA_ and pupa_ are renamed to GRUB_
	and grub_, respectively. Because the conversion is trivial and
	mechanical, I omit the details here. Please refer to the CVS
	if you need more information.
2004-04-04 13:46:03 +00:00

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/* mm.c - functions for memory manager */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002 Free Software Foundation, Inc.
*
* GRUB is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <config.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/err.h>
#include <grub/types.h>
#include <grub/disk.h>
#include <grub/dl.h>
/* Magic words. */
#define GRUB_MM_FREE_MAGIC 0x2d3c2808
#define GRUB_MM_ALLOC_MAGIC 0x6db08fa4
typedef struct grub_mm_header
{
struct grub_mm_header *next;
grub_size_t size;
grub_size_t magic;
#if GRUB_CPU_SIZEOF_VOID_P == 4
char padding[4];
#elif GRUB_CPU_SIZEOF_VOID_P == 8
char padding[8];
#else
# error "unknown word size"
#endif
}
*grub_mm_header_t;
#if GRUB_CPU_SIZEOF_VOID_P == 4
# define GRUB_MM_ALIGN_LOG2 4
#elif GRUB_CPU_SIZEOF_VOID_P == 8
# define GRUB_MM_ALIGN_LOG2 8
#endif
#define GRUB_MM_ALIGN (1 << GRUB_MM_ALIGN_LOG2)
typedef struct grub_mm_region
{
struct grub_mm_header *first;
struct grub_mm_region *next;
grub_addr_t addr;
grub_size_t size;
}
*grub_mm_region_t;
static grub_mm_region_t base;
/* Get a header from the pointer PTR, and set *P and *R to a pointer
to the header and a pointer to its region, respectively. PTR must
be allocated. */
static void
get_header_from_pointer (void *ptr, grub_mm_header_t *p, grub_mm_region_t *r)
{
if ((unsigned) ptr & (GRUB_MM_ALIGN - 1))
grub_fatal ("unaligned pointer %p", ptr);
for (*r = base; *r; *r = (*r)->next)
if ((unsigned) ptr > (*r)->addr
&& (unsigned) ptr <= (*r)->addr + (*r)->size)
break;
if (! *r)
grub_fatal ("out of range pointer %p", ptr);
*p = (grub_mm_header_t) ptr - 1;
if ((*p)->magic != GRUB_MM_ALLOC_MAGIC)
grub_fatal ("alloc magic is broken at %p", *p);
}
/* Initialize a region starting from ADDR and whose size is SIZE,
to use it as free space. */
void
grub_mm_init_region (void *addr, grub_size_t size)
{
grub_mm_header_t h;
grub_mm_region_t r, *p, q;
#if 0
grub_printf ("%s:%d: addr=%p, size=%u\n", __FILE__, __LINE__, addr, size);
#endif
/* If this region is too small, ignore it. */
if (size < GRUB_MM_ALIGN * 2)
return;
/* Allocate a region from the head. */
r = (grub_mm_region_t) (((grub_addr_t) addr + GRUB_MM_ALIGN - 1)
& (~(GRUB_MM_ALIGN - 1)));
size -= (char *) r - (char *) addr + sizeof (*r);
h = (grub_mm_header_t) ((char *) r + GRUB_MM_ALIGN);
h->next = h;
h->magic = GRUB_MM_FREE_MAGIC;
h->size = (size >> GRUB_MM_ALIGN_LOG2);
r->first = h;
r->addr = (grub_addr_t) h;
r->size = (h->size << GRUB_MM_ALIGN_LOG2);
/* Find where to insert this region. Put a smaller one before bigger ones,
to prevent fragmentations. */
for (p = &base, q = *p; q; p = &(q->next), q = *p)
if (q->size > r->size)
break;
*p = r;
r->next = q;
}
/* Allocate the number of units N with the alignment ALIGN from the ring
buffer starting from *FIRST. ALIGN must be a power of two. Return a
non-NULL if successful, otherwise return NULL. */
static void *
grub_real_malloc (grub_mm_header_t *first, grub_size_t n, grub_size_t align)
{
grub_mm_header_t p, q;
if ((*first)->magic == GRUB_MM_ALLOC_MAGIC)
return 0;
for (q = *first, p = q->next; ; q = p, p = p->next)
{
grub_off_t extra;
extra = ((grub_addr_t) (p + 1) >> GRUB_MM_ALIGN_LOG2) % align;
if (extra)
extra = align - extra;
if (! p)
grub_fatal ("null in the ring");
if (p->magic != GRUB_MM_FREE_MAGIC)
grub_fatal ("free magic is broken at %p: 0x%x", p, p->magic);
if (p->size >= n + extra)
{
if (extra == 0 && p->size == n)
{
q->next = p->next;
p->magic = GRUB_MM_ALLOC_MAGIC;
}
else if (extra == 0 || p->size == n + extra)
{
p->size -= n;
p += p->size;
p->size = n;
p->magic = GRUB_MM_ALLOC_MAGIC;
}
else
{
grub_mm_header_t r;
r = p + extra + n;
r->magic = GRUB_MM_FREE_MAGIC;
r->size = p->size - extra - n;
r->next = p->next;
p->size = extra;
p->next = r;
p += extra;
p->size = n;
p->magic = GRUB_MM_ALLOC_MAGIC;
}
*first = q;
return p + 1;
}
if (p == *first)
break;
}
return 0;
}
/* Allocate SIZE bytes with the alignment ALIGN and return the pointer. */
void *
grub_memalign (grub_size_t align, grub_size_t size)
{
grub_mm_region_t r;
grub_size_t n = ((size + GRUB_MM_ALIGN - 1) >> GRUB_MM_ALIGN_LOG2) + 1;
int count = 0;
align = (align >> GRUB_MM_ALIGN_LOG2);
if (align == 0)
align = 1;
again:
for (r = base; r; r = r->next)
{
void *p;
p = grub_real_malloc (&(r->first), n, align);
if (p)
return p;
}
/* If failed, increase free memory somehow. */
switch (count)
{
case 0:
/* Invalidate disk caches. */
grub_disk_cache_invalidate_all ();
count++;
goto again;
case 1:
/* Unload unneeded modules. */
grub_dl_unload_unneeded ();
count++;
goto again;
default:
break;
}
grub_error (GRUB_ERR_OUT_OF_MEMORY, "out of memory");
return 0;
}
/* Allocate SIZE bytes and return the pointer. */
void *
grub_malloc (grub_size_t size)
{
return grub_memalign (0, size);
}
/* Deallocate the pointer PTR. */
void
grub_free (void *ptr)
{
grub_mm_header_t p;
grub_mm_region_t r;
if (! ptr)
return;
get_header_from_pointer (ptr, &p, &r);
if (r->first->magic == GRUB_MM_ALLOC_MAGIC)
{
p->magic = GRUB_MM_FREE_MAGIC;
r->first = p->next = p;
}
else
{
grub_mm_header_t q;
#if 0
q = r->first;
do
{
grub_printf ("%s:%d: q=%p, q->size=0x%x, q->magic=0x%x\n",
__FILE__, __LINE__, q, q->size, q->magic);
q = q->next;
}
while (q != r->first);
#endif
for (q = r->first; q >= p || q->next <= p; q = q->next)
{
if (q->magic != GRUB_MM_FREE_MAGIC)
grub_fatal ("free magic is broken at %p: 0x%x", q, q->magic);
if (q >= q->next && (q < p || q->next > p))
break;
}
p->magic = GRUB_MM_FREE_MAGIC;
p->next = q->next;
q->next = p;
if (p + p->size == p->next)
{
p->next->magic = 0;
p->size += p->next->size;
p->next = p->next->next;
}
if (q + q->size == p)
{
p->magic = 0;
q->size += p->size;
q->next = p->next;
}
r->first = q;
}
}
/* Reallocate SIZE bytes and return the pointer. The contents will be
the same as that of PTR. */
void *
grub_realloc (void *ptr, grub_size_t size)
{
grub_mm_header_t p;
grub_mm_region_t r;
void *q;
grub_size_t n;
if (! ptr)
return grub_malloc (size);
if (! size)
{
grub_free (ptr);
return 0;
}
/* FIXME: Not optimal. */
n = ((size + GRUB_MM_ALIGN - 1) >> GRUB_MM_ALIGN_LOG2) + 1;
get_header_from_pointer (ptr, &p, &r);
if (p->size >= n)
return p;
q = grub_malloc (size);
if (! q)
return q;
grub_memcpy (q, ptr, size);
grub_free (ptr);
return q;
}
#if MM_DEBUG
void
grub_mm_dump (unsigned lineno)
{
grub_mm_region_t r;
grub_printf ("called at line %u\n", lineno);
for (r = base; r; r = r->next)
{
grub_mm_header_t p;
for (p = (grub_mm_header_t) ((r->addr + GRUB_MM_ALIGN - 1)
& (~(GRUB_MM_ALIGN - 1)));
(grub_addr_t) p < r->addr + r->size;
p++)
{
switch (p->magic)
{
case GRUB_MM_FREE_MAGIC:
grub_printf ("F:%p:%u:%p\n",
p, p->size << GRUB_MM_ALIGN_LOG2, p->next);
break;
case GRUB_MM_ALLOC_MAGIC:
grub_printf ("A:%p:%u\n", p, p->size << GRUB_MM_ALIGN_LOG2);
break;
}
}
}
grub_printf ("\n");
}
#endif /* MM_DEBUG */