p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
linux_old1/arch/x86/kernel/e820_32.c

958 lines
24 KiB
C
Raw Blame History

#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/efi.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>
#ifdef CONFIG_EFI
int efi_enabled = 0;
EXPORT_SYMBOL(efi_enabled);
#endif
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;
struct resource data_resource = {
.name = "Kernel data",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
struct resource code_resource = {
.name = "Kernel code",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
struct resource bss_resource = {
.name = "Kernel bss",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
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
};
static struct resource video_ram_resource = {
.name = "Video RAM area",
.start = 0xa0000,
.end = 0xbffff,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
static struct resource standard_io_resources[] = { {
.name = "dma1",
.start = 0x0000,
.end = 0x001f,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "pic1",
.start = 0x0020,
.end = 0x0021,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "timer0",
.start = 0x0040,
.end = 0x0043,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "timer1",
.start = 0x0050,
.end = 0x0053,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "keyboard",
.start = 0x0060,
.end = 0x006f,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "dma page reg",
.start = 0x0080,
.end = 0x008f,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "pic2",
.start = 0x00a0,
.end = 0x00a1,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "dma2",
.start = 0x00c0,
.end = 0x00df,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
}, {
.name = "fpu",
.start = 0x00f0,
.end = 0x00ff,
.flags = IORESOURCE_BUSY | IORESOURCE_IO
} };
#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.
*/
static void __init
legacy_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
}
}
}
/*
* Request address space for all standard resources
*
* This is called just before pcibios_init(), which is also a
* subsys_initcall, but is linked in later (in arch/i386/pci/common.c).
*/
static int __init request_standard_resources(void)
{
int i;
printk("Setting up standard PCI resources\n");
if (efi_enabled)
efi_initialize_iomem_resources(&code_resource,
&data_resource, &bss_resource);
else
legacy_init_iomem_resources(&code_resource,
&data_resource, &bss_resource);
/* EFI systems may still have VGA */
request_resource(&iomem_resource, &video_ram_resource);
/* request I/O space for devices used on all i[345]86 PCs */
for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
request_resource(&ioport_resource, &standard_io_resources[i]);
return 0;
}
subsys_initcall(request_standard_resources);
#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;
if (!efi_enabled) {
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 {
unsigned long long start = biosmap->addr;
unsigned long long size = biosmap->size;
unsigned long long end = start + size;
unsigned long type = biosmap->type;
/* Overflow in 64 bits? Ignore the memory map. */
if (start > end)
return -1;
/*
* Some BIOSes claim RAM in the 640k - 1M region.
* Not right. Fix it up.
*/
if (type == E820_RAM) {
if (start < 0x100000ULL && end > 0xA0000ULL) {
if (start < 0xA0000ULL)
add_memory_region(start, 0xA0000ULL-start, type);
if (end <= 0x100000ULL)
continue;
start = 0x100000ULL;
size = end - start;
}
}
add_memory_region(start, size, type);
} while (biosmap++,--nr_map);
return 0;
}
/*
* Callback for efi_memory_walk.
*/
static int __init
efi_find_max_pfn(unsigned long start, unsigned long end, void *arg)
{
unsigned long *max_pfn = arg, pfn;
if (start < end) {
pfn = PFN_UP(end -1);
if (pfn > *max_pfn)
*max_pfn = pfn;
}
return 0;
}
static int __init
efi_memory_present_wrapper(unsigned long start, unsigned long end, void *arg)
{
memory_present(0, PFN_UP(start), PFN_DOWN(end));
return 0;
}
/*
* Find the highest page frame number we have available
*/
void __init find_max_pfn(void)
{
int i;
max_pfn = 0;
if (efi_enabled) {
efi_memmap_walk(efi_find_max_pfn, &max_pfn);
efi_memmap_walk(efi_memory_present_wrapper, NULL);
return;
}
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);
}
}
/*
* Free all available memory for boot time allocation. Used
* as a callback function by efi_memory_walk()
*/
static int __init
free_available_memory(unsigned long start, unsigned long end, void *arg)
{
/* check max_low_pfn */
if (start >= (max_low_pfn << PAGE_SHIFT))
return 0;
if (end >= (max_low_pfn << PAGE_SHIFT))
end = max_low_pfn << PAGE_SHIFT;
if (start < end)
free_bootmem(start, end - start);
return 0;
}
/*
* Register fully available low RAM pages with the bootmem allocator.
*/
void __init register_bootmem_low_pages(unsigned long max_low_pfn)
{
int i;
if (efi_enabled) {
efi_memmap_walk(free_available_memory, NULL);
return;
}
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;
}
}
}
static __init __always_inline void efi_limit_regions(unsigned long long size)
{
unsigned long long current_addr = 0;
efi_memory_desc_t *md, *next_md;
void *p, *p1;
int i, j;
j = 0;
p1 = memmap.map;
for (p = p1, i = 0; p < memmap.map_end; p += memmap.desc_size, i++) {
md = p;
next_md = p1;
current_addr = md->phys_addr +
PFN_PHYS(md->num_pages);
if (is_available_memory(md)) {
if (md->phys_addr >= size) continue;
memcpy(next_md, md, memmap.desc_size);
if (current_addr >= size) {
next_md->num_pages -=
PFN_UP(current_addr-size);
}
p1 += memmap.desc_size;
next_md = p1;
j++;
} else if ((md->attribute & EFI_MEMORY_RUNTIME) ==
EFI_MEMORY_RUNTIME) {
/* In order to make runtime services
* available we have to include runtime
* memory regions in memory map */
memcpy(next_md, md, memmap.desc_size);
p1 += memmap.desc_size;
next_md = p1;
j++;
}
}
memmap.nr_map = j;
memmap.map_end = memmap.map +
(memmap.nr_map * memmap.desc_size);
}
void __init limit_regions(unsigned long long size)
{
unsigned long long current_addr;
int i;
print_memory_map("limit_regions start");
if (efi_enabled) {
efi_limit_regions(size);
return;
}
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);
Reference in New Issue View Git Blame Copy Permalink