diff options
Diffstat (limited to 'arch/x86_64/kernel/e820.c')
| -rw-r--r-- | arch/x86_64/kernel/e820.c | 513 |
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; +} + |