diff options
Diffstat (limited to 'arch/i386/kernel/e820.c')
| -rw-r--r-- | arch/i386/kernel/e820.c | 894 |
1 files changed, 894 insertions, 0 deletions
diff --git a/arch/i386/kernel/e820.c b/arch/i386/kernel/e820.c new file mode 100644 index 0000000..2f7d0a9 --- /dev/null +++ b/arch/i386/kernel/e820.c @@ -0,0 +1,894 @@ +#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 <asm/pgtable.h> +#include <asm/page.h> +#include <asm/e820.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 +}; + +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 +} }; + +static int romsignature(const unsigned char *x) +{ + unsigned short sig; + int ret = 0; + if (probe_kernel_address((const unsigned short *)x, sig) == 0) + ret = (sig == 0xaa55); + return ret; +} + +static int __init romchecksum(unsigned char *rom, unsigned long length) +{ + unsigned char *p, sum = 0; + + for (p = rom; p < rom + length; p++) + sum += *p; + return sum == 0; +} + +static void __init probe_roms(void) +{ + unsigned long start, length, upper; + unsigned char *rom; + 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; + + /* 0 < length <= 0x7f * 512, historically */ + length = rom[2] * 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; + + /* 0 < length <= 0x7f * 512, historically */ + length = rom[2] * 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) +{ + 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); +#ifdef CONFIG_KEXEC + 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); + else + legacy_init_iomem_resources(&code_resource, &data_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); + +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; +} + +/* + * 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 register_memory(void) +{ + unsigned long gapstart, gapsize, round; + unsigned long long last; + int i; + + /* + * Search for the bigest 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 %lu\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 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); |
