linux/arch/x86/kernel/e820_32.c
Alexander van Heukelum dedd04be71 x86: reserve end-of-conventional-memory to 1MB on 32-bit
This patch adds explicit detection of the EBDA and reservation
of the rom and adapter address space 0xa0000-0x100000 to the
i386 kernels. Before this patch, the EBDA size was hardcoded
as 4Kb. Also, the reservation of the adapter range was done by
modifying the e820 map which is now not necessary any longer,
and that code is removed from copy_e820_map.

The amount of conventional memory and the start of the EBDA are
detected by reading the BIOS data area directly. Paravirtual
environments do not provide this area, so we bail out early
in that case. They will just have to set up a correct memory
map to start with.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17 17:40:51 +02:00

776 lines
20 KiB
C

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/string.h>
#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pfn.h>
#include <linux/uaccess.h>
#include <linux/suspend.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/setup.h>
struct e820map e820;
struct change_member {
struct e820entry *pbios; /* pointer to original bios entry */
unsigned long long addr; /* address for this change point */
};
static struct change_member change_point_list[2*E820MAX] __initdata;
static struct change_member *change_point[2*E820MAX] __initdata;
static struct e820entry *overlap_list[E820MAX] __initdata;
static struct e820entry new_bios[E820MAX] __initdata;
/* For PCI or other memory-mapped resources */
unsigned long pci_mem_start = 0x10000000;
#ifdef CONFIG_PCI
EXPORT_SYMBOL(pci_mem_start);
#endif
extern int user_defined_memmap;
static struct resource system_rom_resource = {
.name = "System ROM",
.start = 0xf0000,
.end = 0xfffff,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};
static struct resource extension_rom_resource = {
.name = "Extension ROM",
.start = 0xe0000,
.end = 0xeffff,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};
static struct resource adapter_rom_resources[] = { {
.name = "Adapter ROM",
.start = 0xc8000,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
.name = "Adapter ROM",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
.name = "Adapter ROM",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
.name = "Adapter ROM",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
.name = "Adapter ROM",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
.name = "Adapter ROM",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
} };
static struct resource video_rom_resource = {
.name = "Video ROM",
.start = 0xc0000,
.end = 0xc7fff,
.flags = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};
#define ROMSIGNATURE 0xaa55
static int __init romsignature(const unsigned char *rom)
{
const unsigned short * const ptr = (const unsigned short *)rom;
unsigned short sig;
return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
}
static int __init romchecksum(const unsigned char *rom, unsigned long length)
{
unsigned char sum, c;
for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
sum += c;
return !length && !sum;
}
static void __init probe_roms(void)
{
const unsigned char *rom;
unsigned long start, length, upper;
unsigned char c;
int i;
/* video rom */
upper = adapter_rom_resources[0].start;
for (start = video_rom_resource.start; start < upper; start += 2048) {
rom = isa_bus_to_virt(start);
if (!romsignature(rom))
continue;
video_rom_resource.start = start;
if (probe_kernel_address(rom + 2, c) != 0)
continue;
/* 0 < length <= 0x7f * 512, historically */
length = c * 512;
/* if checksum okay, trust length byte */
if (length && romchecksum(rom, length))
video_rom_resource.end = start + length - 1;
request_resource(&iomem_resource, &video_rom_resource);
break;
}
start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
if (start < upper)
start = upper;
/* system rom */
request_resource(&iomem_resource, &system_rom_resource);
upper = system_rom_resource.start;
/* check for extension rom (ignore length byte!) */
rom = isa_bus_to_virt(extension_rom_resource.start);
if (romsignature(rom)) {
length = extension_rom_resource.end - extension_rom_resource.start + 1;
if (romchecksum(rom, length)) {
request_resource(&iomem_resource, &extension_rom_resource);
upper = extension_rom_resource.start;
}
}
/* check for adapter roms on 2k boundaries */
for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
rom = isa_bus_to_virt(start);
if (!romsignature(rom))
continue;
if (probe_kernel_address(rom + 2, c) != 0)
continue;
/* 0 < length <= 0x7f * 512, historically */
length = c * 512;
/* but accept any length that fits if checksum okay */
if (!length || start + length > upper || !romchecksum(rom, length))
continue;
adapter_rom_resources[i].start = start;
adapter_rom_resources[i].end = start + length - 1;
request_resource(&iomem_resource, &adapter_rom_resources[i]);
start = adapter_rom_resources[i++].end & ~2047UL;
}
}
/*
* Request address space for all standard RAM and ROM resources
* and also for regions reported as reserved by the e820.
*/
void __init init_iomem_resources(struct resource *code_resource,
struct resource *data_resource,
struct resource *bss_resource)
{
int i;
probe_roms();
for (i = 0; i < e820.nr_map; i++) {
struct resource *res;
#ifndef CONFIG_RESOURCES_64BIT
if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
continue;
#endif
res = kzalloc(sizeof(struct resource), GFP_ATOMIC);
switch (e820.map[i].type) {
case E820_RAM: res->name = "System RAM"; break;
case E820_ACPI: res->name = "ACPI Tables"; break;
case E820_NVS: res->name = "ACPI Non-volatile Storage"; break;
default: res->name = "reserved";
}
res->start = e820.map[i].addr;
res->end = res->start + e820.map[i].size - 1;
res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
if (request_resource(&iomem_resource, res)) {
kfree(res);
continue;
}
if (e820.map[i].type == E820_RAM) {
/*
* We don't know which RAM region contains kernel data,
* so we try it repeatedly and let the resource manager
* test it.
*/
request_resource(res, code_resource);
request_resource(res, data_resource);
request_resource(res, bss_resource);
#ifdef CONFIG_KEXEC
if (crashk_res.start != crashk_res.end)
request_resource(res, &crashk_res);
#endif
}
}
}
#if defined(CONFIG_PM) && defined(CONFIG_HIBERNATION)
/**
* e820_mark_nosave_regions - Find the ranges of physical addresses that do not
* correspond to e820 RAM areas and mark the corresponding pages as nosave for
* hibernation.
*
* This function requires the e820 map to be sorted and without any
* overlapping entries and assumes the first e820 area to be RAM.
*/
void __init e820_mark_nosave_regions(void)
{
int i;
unsigned long pfn;
pfn = PFN_DOWN(e820.map[0].addr + e820.map[0].size);
for (i = 1; i < e820.nr_map; i++) {
struct e820entry *ei = &e820.map[i];
if (pfn < PFN_UP(ei->addr))
register_nosave_region(pfn, PFN_UP(ei->addr));
pfn = PFN_DOWN(ei->addr + ei->size);
if (ei->type != E820_RAM)
register_nosave_region(PFN_UP(ei->addr), pfn);
if (pfn >= max_low_pfn)
break;
}
}
#endif
void __init add_memory_region(unsigned long long start,
unsigned long long size, int type)
{
int x;
x = e820.nr_map;
if (x == E820MAX) {
printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
return;
}
e820.map[x].addr = start;
e820.map[x].size = size;
e820.map[x].type = type;
e820.nr_map++;
} /* add_memory_region */
/*
* Sanitize the BIOS e820 map.
*
* Some e820 responses include overlapping entries. The following
* replaces the original e820 map with a new one, removing overlaps.
*
*/
int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
{
struct change_member *change_tmp;
unsigned long current_type, last_type;
unsigned long long last_addr;
int chgidx, still_changing;
int overlap_entries;
int new_bios_entry;
int old_nr, new_nr, chg_nr;
int i;
/*
Visually we're performing the following (1,2,3,4 = memory types)...
Sample memory map (w/overlaps):
____22__________________
______________________4_
____1111________________
_44_____________________
11111111________________
____________________33__
___________44___________
__________33333_________
______________22________
___________________2222_
_________111111111______
_____________________11_
_________________4______
Sanitized equivalent (no overlap):
1_______________________
_44_____________________
___1____________________
____22__________________
______11________________
_________1______________
__________3_____________
___________44___________
_____________33_________
_______________2________
________________1_______
_________________4______
___________________2____
____________________33__
______________________4_
*/
/* if there's only one memory region, don't bother */
if (*pnr_map < 2) {
return -1;
}
old_nr = *pnr_map;
/* bail out if we find any unreasonable addresses in bios map */
for (i=0; i<old_nr; i++)
if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr) {
return -1;
}
/* create pointers for initial change-point information (for sorting) */
for (i=0; i < 2*old_nr; i++)
change_point[i] = &change_point_list[i];
/* record all known change-points (starting and ending addresses),
omitting those that are for empty memory regions */
chgidx = 0;
for (i=0; i < old_nr; i++) {
if (biosmap[i].size != 0) {
change_point[chgidx]->addr = biosmap[i].addr;
change_point[chgidx++]->pbios = &biosmap[i];
change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
change_point[chgidx++]->pbios = &biosmap[i];
}
}
chg_nr = chgidx; /* true number of change-points */
/* sort change-point list by memory addresses (low -> high) */
still_changing = 1;
while (still_changing) {
still_changing = 0;
for (i=1; i < chg_nr; i++) {
/* if <current_addr> > <last_addr>, swap */
/* or, if current=<start_addr> & last=<end_addr>, swap */
if ((change_point[i]->addr < change_point[i-1]->addr) ||
((change_point[i]->addr == change_point[i-1]->addr) &&
(change_point[i]->addr == change_point[i]->pbios->addr) &&
(change_point[i-1]->addr != change_point[i-1]->pbios->addr))
)
{
change_tmp = change_point[i];
change_point[i] = change_point[i-1];
change_point[i-1] = change_tmp;
still_changing=1;
}
}
}
/* create a new bios memory map, removing overlaps */
overlap_entries=0; /* number of entries in the overlap table */
new_bios_entry=0; /* index for creating new bios map entries */
last_type = 0; /* start with undefined memory type */
last_addr = 0; /* start with 0 as last starting address */
/* loop through change-points, determining affect on the new bios map */
for (chgidx=0; chgidx < chg_nr; chgidx++)
{
/* keep track of all overlapping bios entries */
if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
{
/* add map entry to overlap list (> 1 entry implies an overlap) */
overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
}
else
{
/* remove entry from list (order independent, so swap with last) */
for (i=0; i<overlap_entries; i++)
{
if (overlap_list[i] == change_point[chgidx]->pbios)
overlap_list[i] = overlap_list[overlap_entries-1];
}
overlap_entries--;
}
/* if there are overlapping entries, decide which "type" to use */
/* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
current_type = 0;
for (i=0; i<overlap_entries; i++)
if (overlap_list[i]->type > current_type)
current_type = overlap_list[i]->type;
/* continue building up new bios map based on this information */
if (current_type != last_type) {
if (last_type != 0) {
new_bios[new_bios_entry].size =
change_point[chgidx]->addr - last_addr;
/* move forward only if the new size was non-zero */
if (new_bios[new_bios_entry].size != 0)
if (++new_bios_entry >= E820MAX)
break; /* no more space left for new bios entries */
}
if (current_type != 0) {
new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
new_bios[new_bios_entry].type = current_type;
last_addr=change_point[chgidx]->addr;
}
last_type = current_type;
}
}
new_nr = new_bios_entry; /* retain count for new bios entries */
/* copy new bios mapping into original location */
memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
*pnr_map = new_nr;
return 0;
}
/*
* Copy the BIOS e820 map into a safe place.
*
* Sanity-check it while we're at it..
*
* If we're lucky and live on a modern system, the setup code
* will have given us a memory map that we can use to properly
* set up memory. If we aren't, we'll fake a memory map.
*
* We check to see that the memory map contains at least 2 elements
* before we'll use it, because the detection code in setup.S may
* not be perfect and most every PC known to man has two memory
* regions: one from 0 to 640k, and one from 1mb up. (The IBM
* thinkpad 560x, for example, does not cooperate with the memory
* detection code.)
*/
int __init copy_e820_map(struct e820entry *biosmap, int nr_map)
{
/* Only one memory region (or negative)? Ignore it */
if (nr_map < 2)
return -1;
do {
u64 start = biosmap->addr;
u64 size = biosmap->size;
u64 end = start + size;
u32 type = biosmap->type;
/* Overflow in 64 bits? Ignore the memory map. */
if (start > end)
return -1;
add_memory_region(start, size, type);
} while (biosmap++, --nr_map);
return 0;
}
/*
* Find the highest page frame number we have available
*/
void __init find_max_pfn(void)
{
int i;
max_pfn = 0;
for (i = 0; i < e820.nr_map; i++) {
unsigned long start, end;
/* RAM? */
if (e820.map[i].type != E820_RAM)
continue;
start = PFN_UP(e820.map[i].addr);
end = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
if (start >= end)
continue;
if (end > max_pfn)
max_pfn = end;
memory_present(0, start, end);
}
}
/*
* Register fully available low RAM pages with the bootmem allocator.
*/
void __init register_bootmem_low_pages(unsigned long max_low_pfn)
{
int i;
for (i = 0; i < e820.nr_map; i++) {
unsigned long curr_pfn, last_pfn, size;
/*
* Reserve usable low memory
*/
if (e820.map[i].type != E820_RAM)
continue;
/*
* We are rounding up the start address of usable memory:
*/
curr_pfn = PFN_UP(e820.map[i].addr);
if (curr_pfn >= max_low_pfn)
continue;
/*
* ... and at the end of the usable range downwards:
*/
last_pfn = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
if (last_pfn > max_low_pfn)
last_pfn = max_low_pfn;
/*
* .. finally, did all the rounding and playing
* around just make the area go away?
*/
if (last_pfn <= curr_pfn)
continue;
size = last_pfn - curr_pfn;
free_bootmem(PFN_PHYS(curr_pfn), PFN_PHYS(size));
}
}
void __init e820_register_memory(void)
{
unsigned long gapstart, gapsize, round;
unsigned long long last;
int i;
/*
* Search for the biggest gap in the low 32 bits of the e820
* memory space.
*/
last = 0x100000000ull;
gapstart = 0x10000000;
gapsize = 0x400000;
i = e820.nr_map;
while (--i >= 0) {
unsigned long long start = e820.map[i].addr;
unsigned long long end = start + e820.map[i].size;
/*
* Since "last" is at most 4GB, we know we'll
* fit in 32 bits if this condition is true
*/
if (last > end) {
unsigned long gap = last - end;
if (gap > gapsize) {
gapsize = gap;
gapstart = end;
}
}
if (start < last)
last = start;
}
/*
* See how much we want to round up: start off with
* rounding to the next 1MB area.
*/
round = 0x100000;
while ((gapsize >> 4) > round)
round += round;
/* Fun with two's complement */
pci_mem_start = (gapstart + round) & -round;
printk("Allocating PCI resources starting at %08lx (gap: %08lx:%08lx)\n",
pci_mem_start, gapstart, gapsize);
}
void __init print_memory_map(char *who)
{
int i;
for (i = 0; i < e820.nr_map; i++) {
printk(" %s: %016Lx - %016Lx ", who,
e820.map[i].addr,
e820.map[i].addr + e820.map[i].size);
switch (e820.map[i].type) {
case E820_RAM: printk("(usable)\n");
break;
case E820_RESERVED:
printk("(reserved)\n");
break;
case E820_ACPI:
printk("(ACPI data)\n");
break;
case E820_NVS:
printk("(ACPI NVS)\n");
break;
default: printk("type %u\n", e820.map[i].type);
break;
}
}
}
void __init limit_regions(unsigned long long size)
{
unsigned long long current_addr;
int i;
print_memory_map("limit_regions start");
for (i = 0; i < e820.nr_map; i++) {
current_addr = e820.map[i].addr + e820.map[i].size;
if (current_addr < size)
continue;
if (e820.map[i].type != E820_RAM)
continue;
if (e820.map[i].addr >= size) {
/*
* This region starts past the end of the
* requested size, skip it completely.
*/
e820.nr_map = i;
} else {
e820.nr_map = i + 1;
e820.map[i].size -= current_addr - size;
}
print_memory_map("limit_regions endfor");
return;
}
print_memory_map("limit_regions endfunc");
}
/*
* This function checks if any part of the range <start,end> is mapped
* with type.
*/
int
e820_any_mapped(u64 start, u64 end, unsigned type)
{
int i;
for (i = 0; i < e820.nr_map; i++) {
const struct e820entry *ei = &e820.map[i];
if (type && ei->type != type)
continue;
if (ei->addr >= end || ei->addr + ei->size <= start)
continue;
return 1;
}
return 0;
}
EXPORT_SYMBOL_GPL(e820_any_mapped);
/*
* This function checks if the entire range <start,end> is mapped with type.
*
* Note: this function only works correct if the e820 table is sorted and
* not-overlapping, which is the case
*/
int __init
e820_all_mapped(unsigned long s, unsigned long e, unsigned type)
{
u64 start = s;
u64 end = e;
int i;
for (i = 0; i < e820.nr_map; i++) {
struct e820entry *ei = &e820.map[i];
if (type && ei->type != type)
continue;
/* is the region (part) in overlap with the current region ?*/
if (ei->addr >= end || ei->addr + ei->size <= start)
continue;
/* if the region is at the beginning of <start,end> we move
* start to the end of the region since it's ok until there
*/
if (ei->addr <= start)
start = ei->addr + ei->size;
/* if start is now at or beyond end, we're done, full
* coverage */
if (start >= end)
return 1; /* we're done */
}
return 0;
}
static int __init parse_memmap(char *arg)
{
if (!arg)
return -EINVAL;
if (strcmp(arg, "exactmap") == 0) {
#ifdef CONFIG_CRASH_DUMP
/* If we are doing a crash dump, we
* still need to know the real mem
* size before original memory map is
* reset.
*/
find_max_pfn();
saved_max_pfn = max_pfn;
#endif
e820.nr_map = 0;
user_defined_memmap = 1;
} else {
/* If the user specifies memory size, we
* limit the BIOS-provided memory map to
* that size. exactmap can be used to specify
* the exact map. mem=number can be used to
* trim the existing memory map.
*/
unsigned long long start_at, mem_size;
mem_size = memparse(arg, &arg);
if (*arg == '@') {
start_at = memparse(arg+1, &arg);
add_memory_region(start_at, mem_size, E820_RAM);
} else if (*arg == '#') {
start_at = memparse(arg+1, &arg);
add_memory_region(start_at, mem_size, E820_ACPI);
} else if (*arg == '$') {
start_at = memparse(arg+1, &arg);
add_memory_region(start_at, mem_size, E820_RESERVED);
} else {
limit_regions(mem_size);
user_defined_memmap = 1;
}
}
return 0;
}
early_param("memmap", parse_memmap);
void __init update_memory_range(u64 start, u64 size, unsigned old_type,
unsigned new_type)
{
int i;
BUG_ON(old_type == new_type);
for (i = 0; i < e820.nr_map; i++) {
struct e820entry *ei = &e820.map[i];
u64 final_start, final_end;
if (ei->type != old_type)
continue;
/* totally covered? */
if (ei->addr >= start && ei->size <= size) {
ei->type = new_type;
continue;
}
/* partially covered */
final_start = max(start, ei->addr);
final_end = min(start + size, ei->addr + ei->size);
if (final_start >= final_end)
continue;
add_memory_region(final_start, final_end - final_start,
new_type);
}
}
void __init update_e820(void)
{
u8 nr_map;
nr_map = e820.nr_map;
if (sanitize_e820_map(e820.map, &nr_map))
return;
e820.nr_map = nr_map;
printk(KERN_INFO "modified physical RAM map:\n");
print_memory_map("modified");
}