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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/x86_64/kernel/e820.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/x86_64/kernel/e820.c')
-rw-r--r--arch/x86_64/kernel/e820.c513
1 files changed, 513 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
new file mode 100644
index 00000000000..657003e461e
--- /dev/null
+++ b/arch/x86_64/kernel/e820.c
@@ -0,0 +1,513 @@
+/*
+ * Handle the memory map.
+ * The functions here do the job until bootmem takes over.
+ * $Id: e820.c,v 1.4 2002/09/19 19:25:32 ak Exp $
+ */
+#include <linux/config.h>
+#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 <asm/page.h>
+#include <asm/e820.h>
+#include <asm/proto.h>
+#include <asm/bootsetup.h>
+
+extern char _end[];
+
+/*
+ * PFN of last memory page.
+ */
+unsigned long end_pfn;
+
+/*
+ * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
+ * The direct mapping extends to end_pfn_map, so that we can directly access
+ * apertures, ACPI and other tables without having to play with fixmaps.
+ */
+unsigned long end_pfn_map;
+
+/*
+ * Last pfn which the user wants to use.
+ */
+unsigned long end_user_pfn = MAXMEM>>PAGE_SHIFT;
+
+extern struct resource code_resource, data_resource;
+
+/* Check for some hardcoded bad areas that early boot is not allowed to touch */
+static inline int bad_addr(unsigned long *addrp, unsigned long size)
+{
+ unsigned long addr = *addrp, last = addr + size;
+
+ /* various gunk below that needed for SMP startup */
+ if (addr < 0x8000) {
+ *addrp = 0x8000;
+ return 1;
+ }
+
+ /* direct mapping tables of the kernel */
+ if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
+ *addrp = table_end << PAGE_SHIFT;
+ return 1;
+ }
+
+ /* initrd */
+#ifdef CONFIG_BLK_DEV_INITRD
+ if (LOADER_TYPE && INITRD_START && last >= INITRD_START &&
+ addr < INITRD_START+INITRD_SIZE) {
+ *addrp = INITRD_START + INITRD_SIZE;
+ return 1;
+ }
+#endif
+ /* kernel code + 640k memory hole (later should not be needed, but
+ be paranoid for now) */
+ if (last >= 640*1024 && addr < __pa_symbol(&_end)) {
+ *addrp = __pa_symbol(&_end);
+ return 1;
+ }
+ /* XXX ramdisk image here? */
+ return 0;
+}
+
+int __init e820_mapped(unsigned long start, unsigned long end, unsigned type)
+{
+ int i;
+ for (i = 0; i < e820.nr_map; i++) {
+ 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;
+}
+
+/*
+ * Find a free area in a specific range.
+ */
+unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size)
+{
+ int i;
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ unsigned long addr = ei->addr, last;
+ if (ei->type != E820_RAM)
+ continue;
+ if (addr < start)
+ addr = start;
+ if (addr > ei->addr + ei->size)
+ continue;
+ while (bad_addr(&addr, size) && addr+size < ei->addr + ei->size)
+ ;
+ last = addr + size;
+ if (last > ei->addr + ei->size)
+ continue;
+ if (last > end)
+ continue;
+ return addr;
+ }
+ return -1UL;
+}
+
+/*
+ * Free bootmem based on the e820 table for a node.
+ */
+void __init e820_bootmem_free(pg_data_t *pgdat, unsigned long start,unsigned long end)
+{
+ int i;
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ unsigned long last, addr;
+
+ if (ei->type != E820_RAM ||
+ ei->addr+ei->size <= start ||
+ ei->addr > end)
+ continue;
+
+ addr = round_up(ei->addr, PAGE_SIZE);
+ if (addr < start)
+ addr = start;
+
+ last = round_down(ei->addr + ei->size, PAGE_SIZE);
+ if (last >= end)
+ last = end;
+
+ if (last > addr && last-addr >= PAGE_SIZE)
+ free_bootmem_node(pgdat, addr, last-addr);
+ }
+}
+
+/*
+ * Find the highest page frame number we have available
+ */
+unsigned long __init e820_end_of_ram(void)
+{
+ int i;
+ unsigned long end_pfn = 0;
+
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ unsigned long start, end;
+
+ start = round_up(ei->addr, PAGE_SIZE);
+ end = round_down(ei->addr + ei->size, PAGE_SIZE);
+ if (start >= end)
+ continue;
+ if (ei->type == E820_RAM) {
+ if (end > end_pfn<<PAGE_SHIFT)
+ end_pfn = end>>PAGE_SHIFT;
+ } else {
+ if (end > end_pfn_map<<PAGE_SHIFT)
+ end_pfn_map = end>>PAGE_SHIFT;
+ }
+ }
+
+ if (end_pfn > end_pfn_map)
+ end_pfn_map = end_pfn;
+ if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
+ end_pfn_map = MAXMEM>>PAGE_SHIFT;
+ if (end_pfn > end_user_pfn)
+ end_pfn = end_user_pfn;
+ if (end_pfn > end_pfn_map)
+ end_pfn = end_pfn_map;
+
+ return end_pfn;
+}
+
+/*
+ * Mark e820 reserved areas as busy for the resource manager.
+ */
+void __init e820_reserve_resources(void)
+{
+ int i;
+ for (i = 0; i < e820.nr_map; i++) {
+ struct resource *res;
+ if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
+ continue;
+ res = alloc_bootmem_low(sizeof(struct resource));
+ 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;
+ request_resource(&iomem_resource, res);
+ 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);
+ }
+ }
+}
+
+/*
+ * Add a memory region to the kernel e820 map.
+ */
+void __init add_memory_region(unsigned long start, unsigned long size, int type)
+{
+ int 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++;
+}
+
+void __init e820_print_map(char *who)
+{
+ int i;
+
+ for (i = 0; i < e820.nr_map; i++) {
+ printk(" %s: %016Lx - %016Lx ", who,
+ (unsigned long long) e820.map[i].addr,
+ (unsigned long long) (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;
+ }
+ }
+}
+
+/*
+ * Sanitize the BIOS e820 map.
+ *
+ * Some e820 responses include overlapping entries. The following
+ * replaces the original e820 map with a new one, removing overlaps.
+ *
+ */
+static int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
+{
+ 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 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;
+ 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) */
+ chgidx = 0;
+ for (i=0; i < old_nr; i++) {
+ 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];
+ }
+
+ /* sort change-point list by memory addresses (low -> high) */
+ still_changing = 1;
+ while (still_changing) {
+ still_changing = 0;
+ for (i=1; i < 2*old_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 < 2*old_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.)
+ */
+static 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 start = biosmap->addr;
+ unsigned long size = biosmap->size;
+ unsigned 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.
+ *
+ * This should be removed on Hammer which is supposed to not
+ * have non e820 covered ISA mappings there, but I had some strange
+ * problems so it stays for now. -AK
+ */
+ 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;
+}
+
+void __init setup_memory_region(void)
+{
+ char *who = "BIOS-e820";
+
+ /*
+ * Try to copy the BIOS-supplied E820-map.
+ *
+ * Otherwise fake a memory map; one section from 0k->640k,
+ * the next section from 1mb->appropriate_mem_k
+ */
+ sanitize_e820_map(E820_MAP, &E820_MAP_NR);
+ if (copy_e820_map(E820_MAP, E820_MAP_NR) < 0) {
+ unsigned long mem_size;
+
+ /* compare results from other methods and take the greater */
+ if (ALT_MEM_K < EXT_MEM_K) {
+ mem_size = EXT_MEM_K;
+ who = "BIOS-88";
+ } else {
+ mem_size = ALT_MEM_K;
+ who = "BIOS-e801";
+ }
+
+ e820.nr_map = 0;
+ add_memory_region(0, LOWMEMSIZE(), E820_RAM);
+ add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
+ }
+ printk(KERN_INFO "BIOS-provided physical RAM map:\n");
+ e820_print_map(who);
+}
+
+void __init parse_memopt(char *p, char **from)
+{
+ end_user_pfn = memparse(p, from);
+ end_user_pfn >>= PAGE_SHIFT;
+}
+