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[PATCH] i386: create e820.c for e820 map sanitize and copy function
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This patch moves bios e820 map sanitize and copy function from
setup.c to e820.c

Signed-off-by: bibo,mao <bibo.mao@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>

 arch/i386/kernel/e820.c  |  252 +++++++++++++++++++++++++++++++++++++++++++++++
 arch/i386/kernel/setup.c |  240 --------------------------------------------
 2 files changed, 252 insertions(+), 240 deletions(-)
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bibo,mao authored and Andi Kleen committed Dec 7, 2006
1 parent 269c2d8 commit 8e3342f
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Showing 2 changed files with 252 additions and 240 deletions.
252 changes: 252 additions & 0 deletions arch/i386/kernel/e820.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,14 @@ 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;
struct resource data_resource = {
.name = "Kernel data",
.start = 0,
Expand Down Expand Up @@ -287,3 +295,247 @@ static int __init request_standard_resources(void)
}

subsys_initcall(request_standard_resources);

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_
*/
printk("sanitize start\n");
/* if there's only one memory region, don't bother */
if (*pnr_map < 2) {
printk("sanitize bail 0\n");
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) {
printk("sanitize bail 1\n");
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;

printk("sanitize end\n");
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;
printk("copy_e820_map() start: %016Lx size: %016Lx end: %016Lx type: %ld\n", start, size, end, 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) {
printk("copy_e820_map() type is E820_RAM\n");
if (start < 0x100000ULL && end > 0xA0000ULL) {
printk("copy_e820_map() lies in range...\n");
if (start < 0xA0000ULL) {
printk("copy_e820_map() start < 0xA0000ULL\n");
add_memory_region(start, 0xA0000ULL-start, type);
}
if (end <= 0x100000ULL) {
printk("copy_e820_map() end <= 0x100000ULL\n");
continue;
}
start = 0x100000ULL;
size = end - start;
}
}
add_memory_region(start, size, type);
} while (biosmap++,--nr_map);
return 0;
}

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