/*
* pmm.c - POST(Power On Self Test) Memory Manager
* according to the specification described in
* http://www.phoenix.com/NR/rdonlyres/873A00CF-33AC-4775-B77E-08E7B9754993/0/specspmm101.pdf
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; If not, see .
*
* Copyright (C) 2009 FUJITSU LIMITED
*
* Author: Kouya Shimura
*/
/*
* Algorithm:
*
* This is not a fast storage allocator but simple one. There is no
* segregated management by block size and it does nothing special for
* avoiding the fragmentation.
*
* The allocation algorithm is a first-fit. All memory blocks are
* managed by linear single linked list in order of the address.
* (i.e. There is no backward pointer) It searches the first available
* equal or larger block from the head (lowest address) of memory
* heap. The larger block is splitted into two blocks unless one side
* becomes too small.
*
* For de-allocation, the specified block is just marked as available
* and it does nothing else. Thus, the fragmentation will occur. The
* collection of continuous available blocks are done on the search
* phase of another block allocation.
*
* The following is an abstract of this algorithm. The actual code
* looks complicated on account of alignment and checking the handle.
*
* static memblk_t *
* alloc(heap_t *heap, uint32_t size)
* {
* static memblk_t *mb;
* for_each_memblk(heap, mb) // search memory blocks
* if (memblk_is_avail(mb))
* {
* collect_avail_memblks(heap, mb);
* if (size <= memblk_bufsize(mb))
* {
* split_memblk(mb, size);
* set_inuse(mb);
* return mb;
* }
* }
* return NULL;
* }
*/
#include
#include
#include "config.h"
#include "e820.h"
#include "util.h"
#define DEBUG_PMM 0
#define __stringify(a) #a
#define stringify(a) __stringify(a)
#define ASSERT(_expr, _action) \
if (!(_expr)) { \
printf("ASSERTION FAIL: %s %s:%d %s()\n", \
stringify(_expr), __FILE__, __LINE__, __func__); \
_action; \
} else
#if DEBUG_PMM
# define PMM_DEBUG(format, p...) printf("PMM " format, ##p)
#else
# define PMM_DEBUG(format, p...)
#endif
struct pmmAllocArgs {
uint16_t function;
uint32_t length;
uint32_t handle;
uint16_t flags;
} __attribute__ ((packed));
struct pmmFindArgs {
uint16_t function;
uint32_t handle;
} __attribute__ ((packed));
struct pmmDeallocateArgs {
uint16_t function;
uint32_t buffer;
} __attribute__ ((packed));
#define PMM_FUNCTION_ALLOCATE 0
#define PMM_FUNCTION_FIND 1
#define PMM_FUNCTION_DEALLOC 2
#define PARAGRAPH_LENGTH 16 // unit of length
#define PMM_HANDLE_ANONYMOUS 0xffffffff
#define PMM_FLAGS_MEMORY_TYPE_MASK 0x0003
#define PMM_FLAGS_MEMORY_INVALID 0
#define PMM_FLAGS_MEMORY_CONVENTIONAL 1 // 0 to 1MB
#define PMM_FLAGS_MEMORY_EXTENDED 2 // 1MB to 4GB
#define PMM_FLAGS_MEMORY_ANY 3 // whichever is available
#define PMM_FLAGS_ALIGINMENT 0x0004
/* Error code */
#define PMM_ENOMEM (0) // Out of memory, duplicate handle
#define PMM_EINVAL (-1) // Invalid argument
#define ALIGN_UP(addr, size) (((addr)+((size)-1))&(~((size)-1)))
#define ALIGN_DOWN(addr, size) ((addr)&(~((size)-1)))
typedef struct memblk {
uint32_t magic; // inuse or available
struct memblk *next; // points the very next of this memblk
uint32_t handle; // identifier of this block
uint32_t __fill; // for 16byte alignment, not used
uint8_t buffer[0];
} memblk_t;
typedef struct heap {
memblk_t *head; // start address of heap
memblk_t *end; // end address of heap
} heap_t;
#define HEAP_NOT_INITIALIZED (memblk_t *)-1
#define HEAP_ALIGNMENT 16
/*
* PMM handles two memory heaps, the caller chooses either.
*
* - conventional memroy (below 1MB)
* In HVM, the area is fixed. 0x00010000-0x0007FFFF
* (LOWHEAP_SIZE bytes from LOWHEAP_PHYSICAL_ADDRESS)
*
* - extended memory (start at 1MB, below 4GB)
* In HVM, the area starts at memory address 0x00100000.
* The end address is variable. We read low RAM address from e820 table.
*
* The following struct must be located in the data segment since bss
* in 32bitbios doesn't be relocated.
*/
static struct {
heap_t heap; // conventional memory
heap_t ext_heap; // extended memory
} pmm_data = { {HEAP_NOT_INITIALIZED, NULL}, {NULL, NULL} };
/* These values are private use, not a spec in PMM */
#define MEMBLK_MAGIC_INUSE 0x2A4D4D50 // 'PMM*'
#define MEMBLK_MAGIC_AVAIL 0x5F4D4D50 // 'PMM_'
#define memblk_is_inuse(_mb) ((_mb)->magic == MEMBLK_MAGIC_INUSE)
#define memblk_is_avail(_mb) ((_mb)->magic == MEMBLK_MAGIC_AVAIL)
static void set_inuse(memblk_t *mb, uint32_t handle)
{
mb->magic = MEMBLK_MAGIC_INUSE;
mb->handle = handle;
}
static void set_avail(memblk_t *mb)
{
mb->magic = MEMBLK_MAGIC_AVAIL;
mb->handle = PMM_HANDLE_ANONYMOUS;
}
#define MEMBLK_HEADER_SIZE ((int)(&((memblk_t *)0)->buffer))
#define MIN_MEMBLK_SIZE (MEMBLK_HEADER_SIZE + PARAGRAPH_LENGTH)
#define memblk_size(_mb) ((void *)((_mb)->next) - (void *)(_mb))
#define memblk_buffer(_mb) ((uint32_t)(&(_mb)->buffer))
#define memblk_bufsize(_mb) (memblk_size(_mb) - MEMBLK_HEADER_SIZE)
#define buffer_memblk(_buf) (memblk_t *)((_buf) - MEMBLK_HEADER_SIZE)
#define memblk_loop_mbondition(_h, _mb) \
(((_mb) < (_h)->end) && (/* avoid infinite loop */ (_mb) < (_mb)->next))
#define for_each_memblk(_h, _mb) \
for ((_mb) = (_h)->head; \
memblk_loop_mbondition(_h, _mb); \
(_mb) = (_mb)->next)
#define for_remain_memblk(_h, _mb) \
for (; \
memblk_loop_mbondition(_h, _mb); \
(_mb) = (_mb)->next)
/*
* <-size->
* +==================+======+ +========+========+======+
* | avail | | | avail | avail | |
* | memblk |memblk|... | memblk | memblk |memblk|...
* +==================+======+ => +========+========+======+
* ^ | ^ | ^ | ^ | ^ | ^
* | |next | |next| |next | |next | |next|
* | \________________/ \____/ \______/ \______/ \____/
* | ^
* | |
* mb +- sb(return value)
*/
static memblk_t *
split_memblk(memblk_t *mb, uint32_t size)
{
memblk_t *sb = (void *)memblk_buffer(mb) + size;
/* Only split if the remaining fragment is big enough. */
if ( (memblk_bufsize(mb) - size) < MIN_MEMBLK_SIZE)
return mb;
sb->next = mb->next;
set_avail(sb);
mb->next = sb;
return sb;
}
/*
* +======+======+======+======+ +=================+======+
* |avail |avail |avail |inuse | | avail |inuse |
* |memblk|memblk|memblk|memblk|... | memblk |memblk|...
* +======+======+======+======+ => +=================+======+
* ^ | ^ | ^ | ^ | ^ | ^ | ^
* | |next| |next| |next| |next| |next | |next|
* | \____/ \____/ \____/ \____/ \_______________/ \____/
* |
* mb
*/
static void
collect_avail_memblks(heap_t *heap, memblk_t *mb)
{
memblk_t *nb = mb->next;
for_remain_memblk ( heap, nb )
if ( memblk_is_inuse(nb) )
break;
mb->next = nb;
}
static void
pmm_init_heap(heap_t *heap, uint32_t from_addr, uint32_t to_addr)
{
memblk_t *mb = (memblk_t *)ALIGN_UP(from_addr, HEAP_ALIGNMENT);
mb->next = (memblk_t *)ALIGN_DOWN(to_addr, HEAP_ALIGNMENT);
set_avail(mb);
heap->head = mb;
heap->end = mb->next;
}
static void
pmm_initalize(void)
{
int i, e820_nr = *E820_NR;
struct e820entry *e820 = E820;
/* Extended memory: RAM below 4GB, 0x100000-0xXXXXXXXX */
for ( i = 0; i < e820_nr; i++ )
{
if ( (e820[i].type == E820_RAM) && (e820[i].addr >= 0x00100000) )
{
pmm_init_heap(&pmm_data.ext_heap, e820[i].addr,
e820[i].addr + e820[i].size);
break;
}
}
/* convectional memory: RAM below 1MB, 0x10000-0x7FFFF */
pmm_init_heap(&pmm_data.heap,
LOWHEAP_PHYSICAL_ADDRESS,
LOWHEAP_PHYSICAL_ADDRESS+LOWHEAP_SIZE);
}
static uint32_t
pmm_max_avail_length(heap_t *heap)
{
memblk_t *mb;
uint32_t size, max = 0;
for_each_memblk ( heap, mb )
{
if ( !memblk_is_avail(mb) )
continue;
collect_avail_memblks(heap, mb);
size = memblk_bufsize(mb);
if ( size > max )
max = size;
}
return (max / PARAGRAPH_LENGTH);
}
static memblk_t *
first_fit(heap_t *heap, uint32_t size, uint32_t handle, uint32_t flags)
{
memblk_t *mb;
int32_t align = 0;
if ( flags & PMM_FLAGS_ALIGINMENT )
align = ((size ^ (size - 1)) >> 1) + 1;
for_each_memblk ( heap, mb )
{
if ( memblk_is_avail(mb) )
{
collect_avail_memblks(heap, mb);
if ( align )
{
uint32_t addr = memblk_buffer(mb);
uint32_t offset = ALIGN_UP(addr, align) - addr;
if ( offset > 0 )
{
ASSERT(offset >= MEMBLK_HEADER_SIZE, continue);
if ( (offset + size) > memblk_bufsize(mb) )
continue;
mb = split_memblk(mb, offset - MEMBLK_HEADER_SIZE);
return mb;
}
}
if ( size <= memblk_bufsize(mb) )
return mb;
}
else
{
ASSERT(memblk_is_inuse(mb), return NULL);
/* Duplication check for handle. */
if ( (handle != PMM_HANDLE_ANONYMOUS) && (mb->handle == handle) )
return NULL;
}
}
return NULL;
}
static memblk_t *
pmm_find_handle(heap_t *heap, uint32_t handle)
{
memblk_t *mb;
if ( handle == PMM_HANDLE_ANONYMOUS )
return NULL;
for_each_memblk ( heap, mb )
if ( mb->handle == handle )
return mb;
return NULL;
}
/*
* allocate a memory block of the specified type and size, and returns
* the address of the memory block.
*
* A client-specified identifier to be associated with the allocated
* memory block. A handle of 0xFFFFFFFF indicates that no identifier
* should be associated with the block. Such a memory block is known
* as an "anonymous" memory block and cannot be found using the
* pmmFind function. If a specified handle for a requested memory
* block is already used in a currently allocated memory block, the
* error value of 0x00000000 is returned
*
* If length is 0x00000000, no memory is allocated and the value
* returned is the size of the largest memory block available for the
* memory type specified in the flags parameter. The alignment bit in
* the flags register is ignored when calculating the largest memory
* block available.
*
* If a specified handle for a requested memory block is already used
* in a currently allocated memory block, the error value of
* 0x00000000 is returned.
*
* A return value of 0x00000000 indicates that an error occurred and
* no memory has been allocated.
*/
static uint32_t
pmmAllocate(uint32_t length, uint32_t handle, uint16_t flags)
{
heap_t *heap;
memblk_t *mb;
uint32_t size;
switch ( flags & PMM_FLAGS_MEMORY_TYPE_MASK )
{
case PMM_FLAGS_MEMORY_CONVENTIONAL:
heap = &pmm_data.heap;
break;
case PMM_FLAGS_MEMORY_EXTENDED:
case PMM_FLAGS_MEMORY_ANY: /* XXX: ignore conventional memory for now */
heap = &pmm_data.ext_heap;
break;
default:
return PMM_EINVAL;
}
/* return the largest memory block available */
if ( length == 0 )
return pmm_max_avail_length(heap);
size = length * PARAGRAPH_LENGTH;
mb = first_fit(heap, size, handle, flags);
if ( mb == NULL )
return PMM_ENOMEM;
/* duplication check for handle */
if ( handle != PMM_HANDLE_ANONYMOUS )
{
memblk_t *nb = mb->next;
for_remain_memblk(heap, nb)
if (nb->handle == handle)
return PMM_ENOMEM;
}
split_memblk(mb, size);
set_inuse(mb, handle);
return memblk_buffer(mb);
}
/*
* returns the address of the memory block associated with the
* specified handle.
*
* A return value of 0x00000000 indicates that the handle does not
* correspond to a currently allocated memory block.
*/
static uint32_t
pmmFind(uint32_t handle)
{
memblk_t *mb;
if ( handle == PMM_HANDLE_ANONYMOUS )
return 0;
mb = pmm_find_handle(&pmm_data.heap, handle);
if ( mb == NULL )
mb = pmm_find_handle(&pmm_data.ext_heap, handle);
return mb ? memblk_buffer(mb) : 0;
}
/*
* frees the specified memory block that was previously allocated by
* pmmAllocate.
*
* If the memory block was deallocated correctly, the return value is
* 0x00000000. If there was an error, the return value is non-zero.
*/
static uint32_t
pmmDeallocate(uint32_t buffer)
{
memblk_t *mb = buffer_memblk(buffer);
if ( !memblk_is_inuse(mb) )
return PMM_EINVAL;
set_avail(mb);
return 0;
}
union pmm_args {
uint16_t function;
struct pmmAllocArgs alloc;
struct pmmFindArgs find;
struct pmmDeallocateArgs dealloc;
} __attribute__ ((packed));
/*
* entry function of all PMM services.
*
* Values returned to the caller are placed in the DX:AX register
* pair. The flags and all registers, other than DX and AX, are
* preserved across calls to PMM services.
*/
uint32_t
pmm(void *argp)
{
union pmm_args *ap = argp;
uint32_t ret = PMM_EINVAL;
if ( pmm_data.heap.head == HEAP_NOT_INITIALIZED )
pmm_initalize();
switch ( ap->function )
{
case PMM_FUNCTION_ALLOCATE:
ret = pmmAllocate(ap->alloc.length, ap->alloc.handle, ap->alloc.flags);
PMM_DEBUG("Alloc length=%x handle=%x flags=%x ret=%x\n",
ap->alloc.length, ap->alloc.handle, ap->alloc.flags, ret);
break;
case PMM_FUNCTION_FIND:
ret = pmmFind(ap->find.handle);
PMM_DEBUG("Find handle=%x ret=%x\n", ap->find.handle, ret);
break;
case PMM_FUNCTION_DEALLOC:
ret = pmmDeallocate(ap->dealloc.buffer);
PMM_DEBUG("Dealloc buffer=%x ret=%x\n", ap->dealloc.buffer, ret);
break;
default:
PMM_DEBUG("Invalid function:%d\n", ap->function);
break;
}
return ret;
}