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mirror-linux/arch/x86/kernel/e820.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Low level x86 E820 memory map handling functions.
*
* The firmware and bootloader passes us the "E820 table", which is the primary
* physical memory layout description available about x86 systems.
*
* The kernel takes the E820 memory layout and optionally modifies it with
* quirks and other tweaks, and feeds that into the generic Linux memory
* allocation code routines via a platform independent interface (memblock, etc.).
*/
#include <linux/memblock.h>
#include <linux/suspend.h>
#include <linux/acpi.h>
#include <linux/firmware-map.h>
#include <linux/sort.h>
#include <linux/kvm_types.h>
#include <asm/e820/api.h>
#include <asm/setup.h>
/*
* We organize the E820 table into three main data structures:
*
* - 'e820_table_firmware': the original firmware version passed to us by the
* bootloader - not modified by the kernel. It is composed of two parts:
* the first 128 E820 memory entries in boot_params.e820_table and the remaining
* (if any) entries of the SETUP_E820_EXT nodes. We use this to:
*
* - the hibernation code uses it to generate a kernel-independent CRC32
* checksum of the physical memory layout of a system.
*
* - 'e820_table_kexec': a slightly modified (by the kernel) firmware version
* passed to us by the bootloader - the major difference between
* e820_table_firmware[] and this one is that e820_table_kexec[]
* might be modified by the kexec itself to fake an mptable.
* We use this to:
*
* - kexec, which is a bootloader in disguise, uses the original E820
* layout to pass to the kexec-ed kernel. This way the original kernel
* can have a restricted E820 map while the kexec()-ed kexec-kernel
* can have access to full memory - etc.
*
* Export the memory layout via /sys/firmware/memmap. kexec-tools uses
* the entries to create an E820 table for the kexec kernel.
*
* kexec_file_load in-kernel code uses the table for the kexec kernel.
*
* - 'e820_table': this is the main E820 table that is massaged by the
* low level x86 platform code, or modified by boot parameters, before
* passed on to higher level MM layers.
*
* Once the E820 map has been converted to the standard Linux memory layout
* information its role stops - modifying it has no effect and does not get
* re-propagated. So its main role is a temporary bootstrap storage of firmware
* specific memory layout data during early bootup.
*/
__initdata static struct e820_table e820_table_init;
__initdata static struct e820_table e820_table_kexec_init;
__initdata static struct e820_table e820_table_firmware_init;
__refdata struct e820_table *e820_table = &e820_table_init;
__refdata struct e820_table *e820_table_kexec = &e820_table_kexec_init;
__refdata struct e820_table *e820_table_firmware = &e820_table_firmware_init;
/* For PCI or other memory-mapped resources */
unsigned long pci_mem_start = 0xaeedbabe;
#ifdef CONFIG_PCI
EXPORT_SYMBOL(pci_mem_start);
#endif
/*
* This function checks if any part of the range <start,end> is mapped
* with type.
*/
static bool _e820__mapped_any(struct e820_table *table,
u64 start, u64 end, enum e820_type type)
{
u32 idx;
for (idx = 0; idx < table->nr_entries; idx++) {
struct e820_entry *entry = &table->entries[idx];
if (type && entry->type != type)
continue;
if (entry->addr >= end || entry->addr + entry->size <= start)
continue;
return true;
}
return false;
}
bool e820__mapped_raw_any(u64 start, u64 end, enum e820_type type)
{
return _e820__mapped_any(e820_table_firmware, start, end, type);
}
EXPORT_SYMBOL_FOR_KVM(e820__mapped_raw_any);
bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
{
return _e820__mapped_any(e820_table, start, end, type);
}
EXPORT_SYMBOL_GPL(e820__mapped_any);
/*
* This function checks if the entire <start,end> range is mapped with 'type'.
*
* Note: this function only works correctly once the E820 table is sorted and
* not-overlapping (at least for the range specified), which is the case normally.
*/
static struct e820_entry *__e820__mapped_all(u64 start, u64 end,
enum e820_type type)
{
u32 idx;
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = &e820_table->entries[idx];
if (type && entry->type != type)
continue;
/* Is the region (part) in overlap with the current region? */
if (entry->addr >= end || entry->addr + entry->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 (entry->addr <= start)
start = entry->addr + entry->size;
/*
* If 'start' is now at or beyond 'end', we're done, full
* coverage of the desired range exists:
*/
if (start >= end)
return entry;
}
return NULL;
}
/*
* This function checks if the entire range <start,end> is mapped with type.
*/
__init bool e820__mapped_all(u64 start, u64 end, enum e820_type type)
{
return __e820__mapped_all(start, end, type);
}
/*
* This function returns the type associated with the range <start,end>.
*/
int e820__get_entry_type(u64 start, u64 end)
{
struct e820_entry *entry = __e820__mapped_all(start, end, 0);
return entry ? entry->type : -EINVAL;
}
/*
* Add a memory region to the kernel E820 map.
*/
__init static void __e820__range_add(struct e820_table *table, u64 start, u64 size, enum e820_type type)
{
u32 idx = table->nr_entries;
struct e820_entry *entry_new;
if (idx >= ARRAY_SIZE(table->entries)) {
pr_err("E820 table full; ignoring [mem %#010llx-%#010llx]\n",
start, start + size-1);
return;
}
entry_new = table->entries + idx;
entry_new->addr = start;
entry_new->size = size;
entry_new->type = type;
table->nr_entries++;
}
__init void e820__range_add(u64 start, u64 size, enum e820_type type)
{
__e820__range_add(e820_table, start, size, type);
}
__init static void e820_print_type(enum e820_type type)
{
switch (type) {
case E820_TYPE_RAM: pr_cont(" System RAM"); break;
case E820_TYPE_RESERVED: pr_cont(" device reserved"); break;
case E820_TYPE_SOFT_RESERVED: pr_cont(" soft reserved"); break;
case E820_TYPE_ACPI: pr_cont(" ACPI data"); break;
case E820_TYPE_NVS: pr_cont(" ACPI NVS"); break;
case E820_TYPE_UNUSABLE: pr_cont(" unusable"); break;
case E820_TYPE_PMEM: /* Fall through: */
case E820_TYPE_PRAM: pr_cont(" persistent RAM (type %u)", type); break;
default: pr_cont(" type %u", type); break;
}
}
__init static void e820__print_table(const char *who)
{
u64 range_end_prev = 0;
u32 idx;
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = e820_table->entries + idx;
u64 range_start, range_end;
range_start = entry->addr;
range_end = entry->addr + entry->size;
/* Out of order E820 maps should not happen: */
if (range_start < range_end_prev)
pr_info(FW_BUG "out of order E820 entry!\n");
if (range_start > range_end_prev) {
pr_info("%s: [gap %#018Lx-%#018Lx]\n",
who,
range_end_prev,
range_start-1);
}
pr_info("%s: [mem %#018Lx-%#018Lx] ", who, range_start, range_end-1);
e820_print_type(entry->type);
pr_cont("\n");
range_end_prev = range_end;
}
}
/*
* Sanitize an E820 map.
*
* Some E820 layouts include overlapping entries. The following
* replaces the original E820 map with a new one, removing overlaps,
* and resolving conflicting memory types in favor of highest
* numbered type.
*
* The input parameter 'entries' points to an array of 'struct
* e820_entry' which on entry has elements in the range [0, *nr_entries)
* valid, and which has space for up to max_nr_entries entries.
* On return, the resulting sanitized E820 map entries will be in
* overwritten in the same location, starting at 'entries'.
*
* The integer pointed to by nr_entries must be valid on entry (the
* current number of valid entries located at 'entries'). If the
* sanitizing succeeds the *nr_entries will be updated with the new
* number of valid entries (something no more than max_nr_entries).
*
* The return value from e820__update_table() is zero if it
* successfully 'sanitized' the map entries passed in, and is -1
* if it did nothing, which can happen if either of (1) it was
* only passed one map entry, or (2) any of the input map entries
* were invalid (start + size < start, meaning that the size was
* so big the described memory range wrapped around through zero.)
*
* 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_
*/
struct change_member {
/* Pointer to the original entry: */
struct e820_entry *entry;
/* Address for this change point: */
u64 addr;
};
__initdata static struct change_member change_point_list[2*E820_MAX_ENTRIES];
__initdata static struct change_member *change_point[2*E820_MAX_ENTRIES];
__initdata static struct e820_entry *overlap_list[E820_MAX_ENTRIES];
__initdata static struct e820_entry new_entries[E820_MAX_ENTRIES];
__init static int cpcompare(const void *a, const void *b)
{
struct change_member * const *app = a, * const *bpp = b;
const struct change_member *ap = *app, *bp = *bpp;
/*
* Inputs are pointers to two elements of change_point[]. If their
* addresses are not equal, their difference dominates. If the addresses
* are equal, then consider one that represents the end of its region
* to be greater than one that does not.
*/
if (ap->addr != bp->addr)
return ap->addr > bp->addr ? 1 : -1;
return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
}
/*
* Can two consecutive E820 entries of this same E820 type be merged?
*/
static bool e820_type_mergeable(enum e820_type type)
{
/*
* These types may indicate distinct platform ranges aligned to
* NUMA node, protection domain, performance domain, or other
* boundaries. Do not merge them.
*/
if (type == E820_TYPE_PRAM)
return false;
if (type == E820_TYPE_SOFT_RESERVED)
return false;
return true;
}
__init int e820__update_table(struct e820_table *table)
{
struct e820_entry *entries = table->entries;
u32 max_nr_entries = ARRAY_SIZE(table->entries);
enum e820_type current_type, last_type;
u64 last_addr;
u32 new_nr_entries, overlap_entries;
u32 idx, chg_idx, chg_nr;
/* If there's only one memory region, don't bother: */
if (table->nr_entries < 2)
return -1;
BUG_ON(table->nr_entries > max_nr_entries);
/* Bail out if we find any unreasonable addresses in the map: */
for (idx = 0; idx < table->nr_entries; idx++) {
if (entries[idx].addr + entries[idx].size < entries[idx].addr)
return -1;
}
/* Create pointers for initial change-point information (for sorting): */
for (idx = 0; idx < 2 * table->nr_entries; idx++)
change_point[idx] = &change_point_list[idx];
/*
* Record all known change-points (starting and ending addresses),
* omitting empty memory regions:
*/
chg_idx = 0;
for (idx = 0; idx < table->nr_entries; idx++) {
if (entries[idx].size != 0) {
change_point[chg_idx]->addr = entries[idx].addr;
change_point[chg_idx++]->entry = &entries[idx];
change_point[chg_idx]->addr = entries[idx].addr + entries[idx].size;
change_point[chg_idx++]->entry = &entries[idx];
}
}
chg_nr = chg_idx;
/* Sort change-point list by memory addresses (low -> high): */
sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL);
/* Create a new memory map, removing overlaps: */
overlap_entries = 0; /* Number of entries in the overlap table */
new_nr_entries = 0; /* Index for creating new 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 effect on the new map: */
for (chg_idx = 0; chg_idx < chg_nr; chg_idx++) {
/* Keep track of all overlapping entries */
if (change_point[chg_idx]->addr == change_point[chg_idx]->entry->addr) {
/* Add map entry to overlap list (> 1 entry implies an overlap) */
overlap_list[overlap_entries++] = change_point[chg_idx]->entry;
} else {
/* Remove entry from list (order independent, so swap with last): */
for (idx = 0; idx < overlap_entries; idx++) {
if (overlap_list[idx] == change_point[chg_idx]->entry)
overlap_list[idx] = 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 (idx = 0; idx < overlap_entries; idx++) {
if (overlap_list[idx]->type > current_type)
current_type = overlap_list[idx]->type;
}
/* Continue building up new map based on this information: */
if (current_type != last_type || !e820_type_mergeable(current_type)) {
if (last_type) {
new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
/* Move forward only if the new size was non-zero: */
if (new_entries[new_nr_entries].size != 0)
/* No more space left for new entries? */
if (++new_nr_entries >= max_nr_entries)
break;
}
if (current_type) {
new_entries[new_nr_entries].addr = change_point[chg_idx]->addr;
new_entries[new_nr_entries].type = current_type;
last_addr = change_point[chg_idx]->addr;
}
last_type = current_type;
}
}
/* Copy the new entries into the original location: */
memcpy(entries, new_entries, new_nr_entries*sizeof(*entries));
table->nr_entries = new_nr_entries;
return 0;
}
/*
* Copy the BIOS E820 map into the kernel's e820_table.
*
* Sanity-check it while we're at it..
*/
__init static int append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
{
struct boot_e820_entry *entry = entries;
/* If there aren't any entries, we'll want to fall back to another source: */
if (!nr_entries)
return -ENOENT;
while (nr_entries) {
u64 start = entry->addr;
u64 size = entry->size;
u64 end = start + size-1;
u32 type = entry->type;
/* Ignore the remaining entries on 64-bit overflow: */
if (start > end && likely(size))
return -EINVAL;
e820__range_add(start, size, type);
entry++;
nr_entries--;
}
return 0;
}
__init static u64
__e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
{
u64 end;
u32 idx;
u64 real_updated_size = 0;
BUG_ON(old_type == new_type);
if (size > (ULLONG_MAX - start))
size = ULLONG_MAX - start;
end = start + size;
printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx]", start, end - 1);
e820_print_type(old_type);
pr_cont(" ==>");
e820_print_type(new_type);
pr_cont("\n");
for (idx = 0; idx < table->nr_entries; idx++) {
struct e820_entry *entry = &table->entries[idx];
u64 final_start, final_end;
u64 entry_end;
if (entry->type != old_type)
continue;
entry_end = entry->addr + entry->size;
/* Completely covered by new range? */
if (entry->addr >= start && entry_end <= end) {
entry->type = new_type;
real_updated_size += entry->size;
continue;
}
/* New range is completely covered? */
if (entry->addr < start && entry_end > end) {
__e820__range_add(table, start, size, new_type);
__e820__range_add(table, end, entry_end - end, entry->type);
entry->size = start - entry->addr;
real_updated_size += size;
continue;
}
/* Partially covered: */
final_start = max(start, entry->addr);
final_end = min(end, entry_end);
if (final_start >= final_end)
continue;
__e820__range_add(table, final_start, final_end - final_start, new_type);
real_updated_size += final_end - final_start;
/*
* Left range could be head or tail, so need to update
* its size first:
*/
entry->size -= final_end - final_start;
if (entry->addr < final_start)
continue;
entry->addr = final_end;
}
return real_updated_size;
}
__init u64 e820__range_update(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
{
return __e820__range_update(e820_table, start, size, old_type, new_type);
}
__init u64 e820__range_update_table(struct e820_table *t, u64 start, u64 size,
enum e820_type old_type, enum e820_type new_type)
{
return __e820__range_update(t, start, size, old_type, new_type);
}
/* Remove a range of memory from the E820 table: */
__init void e820__range_remove(u64 start, u64 size, enum e820_type filter_type)
{
u32 idx;
u64 end;
if (size > (ULLONG_MAX - start))
size = ULLONG_MAX - start;
end = start + size;
printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx]", start, end - 1);
if (filter_type)
e820_print_type(filter_type);
pr_cont("\n");
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = &e820_table->entries[idx];
u64 final_start, final_end;
u64 entry_end;
if (filter_type && entry->type != filter_type)
continue;
entry_end = entry->addr + entry->size;
/* Completely covered? */
if (entry->addr >= start && entry_end <= end) {
memset(entry, 0, sizeof(*entry));
continue;
}
/* Is the new range completely covered? */
if (entry->addr < start && entry_end > end) {
e820__range_add(end, entry_end - end, entry->type);
entry->size = start - entry->addr;
continue;
}
/* Partially covered: */
final_start = max(start, entry->addr);
final_end = min(end, entry_end);
if (final_start >= final_end)
continue;
/*
* Left range could be head or tail, so need to update
* the size first:
*/
entry->size -= final_end - final_start;
if (entry->addr < final_start)
continue;
entry->addr = final_end;
}
}
__init void e820__update_table_print(void)
{
if (e820__update_table(e820_table))
return;
pr_info("modified physical RAM map:\n");
e820__print_table("modified");
}
__init static void e820__update_table_kexec(void)
{
e820__update_table(e820_table_kexec);
}
#define MAX_GAP_END SZ_4G
/*
* Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
*/
__init static int e820_search_gap(unsigned long *max_gap_start, unsigned long *max_gap_size)
{
struct e820_entry *entry;
u64 range_end_prev = 0;
int found = 0;
u32 idx;
for (idx = 0; idx < e820_table->nr_entries; idx++) {
u64 range_start, range_end;
entry = e820_table->entries + idx;
range_start = entry->addr;
range_end = entry->addr + entry->size;
/* Process any gap before this entry: */
if (range_start > range_end_prev) {
u64 gap_start = range_end_prev;
u64 gap_end = range_start;
u64 gap_size;
if (gap_start < MAX_GAP_END) {
/* Make sure the entirety of the gap is below MAX_GAP_END: */
gap_end = min(gap_end, MAX_GAP_END);
gap_size = gap_end-gap_start;
if (gap_size >= *max_gap_size) {
*max_gap_start = gap_start;
*max_gap_size = gap_size;
found = 1;
}
}
}
range_end_prev = range_end;
}
/* Is there a usable gap beyond the last entry: */
if (entry->addr + entry->size < MAX_GAP_END) {
u64 gap_start = entry->addr + entry->size;
u64 gap_size = MAX_GAP_END-gap_start;
if (gap_size >= *max_gap_size) {
*max_gap_start = gap_start;
*max_gap_size = gap_size;
found = 1;
}
}
return found;
}
/*
* Search for the biggest gap in the low 32 bits of the E820
* memory space. We pass this space to the PCI subsystem, so
* that it can assign MMIO resources for hotplug or
* unconfigured devices in.
*
* Hopefully the BIOS let enough space left.
*/
__init void e820__setup_pci_gap(void)
{
unsigned long max_gap_start, max_gap_size;
int found;
/* The minimum eligible gap size is 4MB: */
max_gap_size = SZ_4M;
found = e820_search_gap(&max_gap_start, &max_gap_size);
if (!found) {
#ifdef CONFIG_X86_64
max_gap_start = (max_pfn << PAGE_SHIFT) + SZ_1M;
pr_err("Cannot find an available gap in the 32-bit address range\n");
pr_err("PCI devices with unassigned 32-bit BARs may not work!\n");
#else
max_gap_start = SZ_256M;
#endif
}
/*
* e820__reserve_resources_late() protects stolen RAM already:
*/
pci_mem_start = max_gap_start;
pr_info("[gap %#010lx-%#010lx] available for PCI devices\n",
max_gap_start, max_gap_start + max_gap_size-1);
}
/*
* Called late during init, in free_initmem().
*
* Initial e820_table and e820_table_kexec are largish __initdata arrays.
*
* Copy them to a (usually much smaller) dynamically allocated area that is
* sized precisely after the number of e820 entries.
*
* This is done after we've performed all the fixes and tweaks to the tables.
* All functions which modify them are __init functions, which won't exist
* after free_initmem().
*/
__init void e820__reallocate_tables(void)
{
struct e820_table *n;
int size;
size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table->nr_entries;
n = kmemdup(e820_table, size, GFP_KERNEL);
BUG_ON(!n);
e820_table = n;
size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_kexec->nr_entries;
n = kmemdup(e820_table_kexec, size, GFP_KERNEL);
BUG_ON(!n);
e820_table_kexec = n;
size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_firmware->nr_entries;
n = kmemdup(e820_table_firmware, size, GFP_KERNEL);
BUG_ON(!n);
e820_table_firmware = n;
}
/*
* Because of the small fixed size of struct boot_params, only the first
* 128 E820 memory entries are passed to the kernel via boot_params.e820_table,
* the remaining (if any) entries are passed via the SETUP_E820_EXT node of
* struct setup_data, which is parsed here.
*/
__init void e820__memory_setup_extended(u64 phys_addr, u32 data_len)
{
int entries;
struct boot_e820_entry *extmap;
struct setup_data *sdata;
sdata = early_memremap(phys_addr, data_len);
entries = sdata->len / sizeof(*extmap);
extmap = (struct boot_e820_entry *)(sdata->data);
append_e820_table(extmap, entries);
e820__update_table(e820_table);
memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
early_memunmap(sdata, data_len);
pr_info("extended physical RAM map:\n");
e820__print_table("extended");
}
/*
* Find the ranges of physical addresses that do not correspond to
* E820 RAM areas and register the corresponding pages as 'nosave' for
* hibernation (32-bit) or software suspend and suspend to RAM (64-bit).
*
* This function requires the E820 map to be sorted and without any
* overlapping entries.
*/
__init void e820__register_nosave_regions(unsigned long limit_pfn)
{
u32 idx;
u64 last_addr = 0;
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = &e820_table->entries[idx];
if (entry->type != E820_TYPE_RAM)
continue;
if (last_addr < entry->addr)
register_nosave_region(PFN_DOWN(last_addr), PFN_UP(entry->addr));
last_addr = entry->addr + entry->size;
}
register_nosave_region(PFN_DOWN(last_addr), limit_pfn);
}
#ifdef CONFIG_ACPI
/*
* Register ACPI NVS memory regions, so that we can save/restore them during
* hibernation and the subsequent resume:
*/
__init static int e820__register_nvs_regions(void)
{
u32 idx;
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = &e820_table->entries[idx];
if (entry->type == E820_TYPE_NVS)
acpi_nvs_register(entry->addr, entry->size);
}
return 0;
}
core_initcall(e820__register_nvs_regions);
#endif
/*
* Allocate the requested number of bytes with the requested alignment
* and return (the physical address) to the caller. Also register this
* range in the 'kexec' E820 table as a reserved range.
*
* This allows kexec to fake a new mptable, as if it came from the real
* system.
*/
__init u64 e820__memblock_alloc_reserved(u64 size, u64 align)
{
u64 addr;
addr = memblock_phys_alloc(size, align);
if (addr) {
e820__range_update_table(e820_table_kexec, addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
pr_info("update e820_table_kexec for e820__memblock_alloc_reserved()\n");
e820__update_table_kexec();
}
return addr;
}
#ifdef CONFIG_X86_32
# ifdef CONFIG_X86_PAE
# define MAX_ARCH_PFN (1ULL<<(36-PAGE_SHIFT))
# else
# define MAX_ARCH_PFN (1ULL<<(32-PAGE_SHIFT))
# endif
#else /* CONFIG_X86_32 */
# define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
#endif
/*
* Find the highest page frame number we have available
*/
__init static unsigned long e820__end_ram_pfn(unsigned long limit_pfn)
{
u32 idx;
unsigned long last_pfn = 0;
unsigned long max_arch_pfn = MAX_ARCH_PFN;
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = &e820_table->entries[idx];
unsigned long start_pfn;
unsigned long end_pfn;
if (entry->type != E820_TYPE_RAM &&
entry->type != E820_TYPE_ACPI)
continue;
start_pfn = entry->addr >> PAGE_SHIFT;
end_pfn = (entry->addr + entry->size) >> PAGE_SHIFT;
if (start_pfn >= limit_pfn)
continue;
if (end_pfn > limit_pfn) {
last_pfn = limit_pfn;
break;
}
if (end_pfn > last_pfn)
last_pfn = end_pfn;
}
if (last_pfn > max_arch_pfn)
last_pfn = max_arch_pfn;
pr_info("last_pfn = %#lx max_arch_pfn = %#lx\n",
last_pfn, max_arch_pfn);
return last_pfn;
}
__init unsigned long e820__end_of_ram_pfn(void)
{
return e820__end_ram_pfn(MAX_ARCH_PFN);
}
__init unsigned long e820__end_of_low_ram_pfn(void)
{
return e820__end_ram_pfn(1UL << (32 - PAGE_SHIFT));
}
__initdata static int userdef;
/* The "mem=nopentium" boot option disables 4MB page tables on 32-bit kernels: */
__init static int parse_memopt(char *p)
{
u64 mem_size;
if (!p)
return -EINVAL;
if (!strcmp(p, "nopentium")) {
#ifdef CONFIG_X86_32
setup_clear_cpu_cap(X86_FEATURE_PSE);
return 0;
#else
pr_warn("mem=nopentium ignored! (only supported on x86_32)\n");
return -EINVAL;
#endif
}
userdef = 1;
mem_size = memparse(p, &p);
/* Don't remove all memory when getting "mem={invalid}" parameter: */
if (mem_size == 0)
return -EINVAL;
e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM);
#ifdef CONFIG_MEMORY_HOTPLUG
max_mem_size = mem_size;
#endif
return 0;
}
early_param("mem", parse_memopt);
__init static int parse_memmap_one(char *p)
{
char *oldp;
u64 start_at, mem_size;
if (!p)
return -EINVAL;
if (!strncmp(p, "exactmap", 8)) {
e820_table->nr_entries = 0;
userdef = 1;
return 0;
}
oldp = p;
mem_size = memparse(p, &p);
if (p == oldp)
return -EINVAL;
userdef = 1;
if (*p == '@') {
start_at = memparse(p+1, &p);
e820__range_add(start_at, mem_size, E820_TYPE_RAM);
} else if (*p == '#') {
start_at = memparse(p+1, &p);
e820__range_add(start_at, mem_size, E820_TYPE_ACPI);
} else if (*p == '$') {
start_at = memparse(p+1, &p);
e820__range_add(start_at, mem_size, E820_TYPE_RESERVED);
} else if (*p == '!') {
start_at = memparse(p+1, &p);
e820__range_add(start_at, mem_size, E820_TYPE_PRAM);
} else if (*p == '%') {
enum e820_type from = 0, to = 0;
start_at = memparse(p + 1, &p);
if (*p == '-')
from = simple_strtoull(p + 1, &p, 0);
if (*p == '+')
to = simple_strtoull(p + 1, &p, 0);
if (*p != '\0')
return -EINVAL;
if (from && to)
e820__range_update(start_at, mem_size, from, to);
else if (to)
e820__range_add(start_at, mem_size, to);
else
e820__range_remove(start_at, mem_size, from);
} else {
e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM);
}
return *p == '\0' ? 0 : -EINVAL;
}
__init static int parse_memmap_opt(char *str)
{
while (str) {
char *k = strchr(str, ',');
if (k)
*k++ = 0;
parse_memmap_one(str);
str = k;
}
return 0;
}
early_param("memmap", parse_memmap_opt);
/*
* Called after parse_early_param(), after early parameters (such as mem=)
* have been processed, in which case we already have an E820 table filled in
* via the parameter callback function(s), but it's not sorted and printed yet:
*/
__init void e820__finish_early_params(void)
{
if (userdef) {
if (e820__update_table(e820_table) < 0)
panic("Invalid user supplied memory map");
pr_info("user-defined physical RAM map:\n");
e820__print_table("user");
}
}
__init static const char * e820_type_to_string(struct e820_entry *entry)
{
switch (entry->type) {
case E820_TYPE_RAM: return "System RAM";
case E820_TYPE_ACPI: return "ACPI Tables";
case E820_TYPE_NVS: return "ACPI Non-volatile Storage";
case E820_TYPE_UNUSABLE: return "Unusable memory";
case E820_TYPE_PRAM: return "Persistent Memory (legacy)";
case E820_TYPE_PMEM: return "Persistent Memory";
case E820_TYPE_RESERVED: return "Reserved";
case E820_TYPE_SOFT_RESERVED: return "Soft Reserved";
default: return "Unknown E820 type";
}
}
__init static unsigned long e820_type_to_iomem_type(struct e820_entry *entry)
{
switch (entry->type) {
case E820_TYPE_RAM: return IORESOURCE_SYSTEM_RAM;
case E820_TYPE_ACPI: /* Fall-through: */
case E820_TYPE_NVS: /* Fall-through: */
case E820_TYPE_UNUSABLE: /* Fall-through: */
case E820_TYPE_PRAM: /* Fall-through: */
case E820_TYPE_PMEM: /* Fall-through: */
case E820_TYPE_RESERVED: /* Fall-through: */
case E820_TYPE_SOFT_RESERVED: /* Fall-through: */
default: return IORESOURCE_MEM;
}
}
__init static unsigned long e820_type_to_iores_desc(struct e820_entry *entry)
{
switch (entry->type) {
case E820_TYPE_ACPI: return IORES_DESC_ACPI_TABLES;
case E820_TYPE_NVS: return IORES_DESC_ACPI_NV_STORAGE;
case E820_TYPE_PMEM: return IORES_DESC_PERSISTENT_MEMORY;
case E820_TYPE_PRAM: return IORES_DESC_PERSISTENT_MEMORY_LEGACY;
case E820_TYPE_RESERVED: return IORES_DESC_RESERVED;
case E820_TYPE_SOFT_RESERVED: return IORES_DESC_SOFT_RESERVED;
case E820_TYPE_RAM: /* Fall-through: */
case E820_TYPE_UNUSABLE: /* Fall-through: */
default: return IORES_DESC_NONE;
}
}
/*
* We assign one resource entry for each E820 map entry:
*/
__initdata static struct resource *e820_res;
/*
* Is this a device address region that should not be marked busy?
* (Versus system address regions that we register & lock early.)
*/
__init static bool e820_device_region(enum e820_type type, struct resource *res)
{
/* This is the legacy BIOS/DOS ROM-shadow + MMIO region: */
if (res->start < SZ_1M)
return false;
/*
* Treat persistent memory and other special memory ranges like
* device memory, i.e. keep it available for exclusive use of a
* driver:
*/
switch (type) {
case E820_TYPE_RESERVED:
case E820_TYPE_SOFT_RESERVED:
case E820_TYPE_PRAM:
case E820_TYPE_PMEM:
return true;
case E820_TYPE_RAM:
case E820_TYPE_ACPI:
case E820_TYPE_NVS:
case E820_TYPE_UNUSABLE:
default:
return false;
}
}
/*
* Mark E820 system regions as busy for the resource manager:
*/
__init void e820__reserve_resources(void)
{
u32 idx;
struct resource *res;
u64 end;
res = memblock_alloc_or_panic(sizeof(*res) * e820_table->nr_entries,
SMP_CACHE_BYTES);
e820_res = res;
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = e820_table->entries + idx;
end = entry->addr + entry->size - 1;
if (end != (resource_size_t)end) {
res++;
continue;
}
res->start = entry->addr;
res->end = end;
res->name = e820_type_to_string(entry);
res->flags = e820_type_to_iomem_type(entry);
res->desc = e820_type_to_iores_desc(entry);
/*
* Skip and don't register device regions that could be conflicted
* with PCI device BAR resources. They get inserted later in
* pcibios_resource_survey() -> e820__reserve_resources_late():
*/
if (!e820_device_region(entry->type, res)) {
res->flags |= IORESOURCE_BUSY;
insert_resource(&iomem_resource, res);
}
res++;
}
/* Expose the kexec e820 table to sysfs: */
for (idx = 0; idx < e820_table_kexec->nr_entries; idx++) {
struct e820_entry *entry = e820_table_kexec->entries + idx;
firmware_map_add_early(entry->addr, entry->addr + entry->size, e820_type_to_string(entry));
}
}
/*
* How much should we pad the end of RAM, depending on where it is?
*/
__init static unsigned long ram_alignment(resource_size_t pos)
{
unsigned long mb = pos >> 20;
/* To 64kB in the first megabyte */
if (!mb)
return 64*1024;
/* To 1MB in the first 16MB */
if (mb < 16)
return 1024*1024;
/* To 64MB for anything above that */
return 64*1024*1024;
}
#define MAX_RESOURCE_SIZE ((resource_size_t)-1)
__init void e820__reserve_resources_late(void)
{
/*
* Register device address regions listed in the E820 map,
* these can be claimed by device drivers later on:
*/
for (u32 idx = 0; idx < e820_table->nr_entries; idx++) {
struct resource *res = e820_res + idx;
/* skip added or uninitialized resources */
if (res->parent || !res->end)
continue;
/* set aside soft-reserved resources for driver consideration */
if (res->desc == IORES_DESC_SOFT_RESERVED) {
insert_resource_expand_to_fit(&soft_reserve_resource, res);
} else {
/* publish the rest immediately */
insert_resource_expand_to_fit(&iomem_resource, res);
}
}
/*
* Create additional 'gaps' at the end of RAM regions,
* rounding them up to 64k/1MB/64MB boundaries, should
* they be weirdly sized, and register extra, locked
* resource regions for them, to make sure drivers
* won't claim those addresses.
*
* These are basically blind guesses and heuristics to
* avoid resource conflicts with broken firmware that
* doesn't properly list 'stolen RAM' as a system region
* in the E820 map.
*/
for (u32 idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = &e820_table->entries[idx];
u64 start, end;
if (entry->type != E820_TYPE_RAM)
continue;
start = entry->addr + entry->size;
end = round_up(start, ram_alignment(start)) - 1;
if (end > MAX_RESOURCE_SIZE)
end = MAX_RESOURCE_SIZE;
if (start >= end)
continue;
pr_info("e820: register RAM buffer resource [mem %#010llx-%#010llx]\n", start, end);
reserve_region_with_split(&iomem_resource, start, end, "RAM buffer");
}
}
/*
* Pass the firmware (bootloader) E820 map to the kernel and process it:
*/
__init char * e820__memory_setup_default(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
*/
if (append_e820_table(boot_params.e820_table, boot_params.e820_entries) < 0) {
u64 mem_size;
/* Compare results from other methods and take the one that gives more RAM: */
if (boot_params.alt_mem_k < boot_params.screen_info.ext_mem_k) {
mem_size = boot_params.screen_info.ext_mem_k;
who = "BIOS-88";
} else {
mem_size = boot_params.alt_mem_k;
who = "BIOS-e801";
}
e820_table->nr_entries = 0;
e820__range_add(0, LOWMEMSIZE(), E820_TYPE_RAM);
e820__range_add(HIGH_MEMORY, mem_size << 10, E820_TYPE_RAM);
}
/* We just appended a lot of ranges, sanitize the table: */
e820__update_table(e820_table);
return who;
}
/*
* Calls e820__memory_setup_default() in essence to pick up the firmware/bootloader
* E820 map - with an optional platform quirk available for virtual platforms
* to override this method of boot environment processing:
*/
__init void e820__memory_setup(void)
{
char *who;
/* This is a firmware interface ABI - make sure we don't break it: */
BUILD_BUG_ON(sizeof(struct boot_e820_entry) != 20);
who = x86_init.resources.memory_setup();
memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
pr_info("BIOS-provided physical RAM map:\n");
e820__print_table(who);
}
__init void e820__memblock_setup(void)
{
u32 idx;
u64 end;
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Memory used by the kernel cannot be hot-removed because Linux
* cannot migrate the kernel pages. When memory hotplug is
* enabled, we should prevent memblock from allocating memory
* for the kernel.
*
* ACPI SRAT records all hotpluggable memory ranges. But before
* SRAT is parsed, we don't know about it.
*
* The kernel image is loaded into memory at very early time. We
* cannot prevent this anyway. So on NUMA system, we set any
* node the kernel resides in as un-hotpluggable.
*
* Since on modern servers, one node could have double-digit
* gigabytes memory, we can assume the memory around the kernel
* image is also un-hotpluggable. So before SRAT is parsed, just
* allocate memory near the kernel image to try the best to keep
* the kernel away from hotpluggable memory.
*/
if (movable_node_is_enabled())
memblock_set_bottom_up(true);
#endif
/*
* At this point only the first megabyte is mapped for sure, the
* rest of the memory cannot be used for memblock resizing
*/
memblock_set_current_limit(ISA_END_ADDRESS);
/*
* The bootstrap memblock region count maximum is 128 entries
* (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
* than that - so allow memblock resizing.
*
* This is safe, because this call happens pretty late during x86 setup,
* so we know about reserved memory regions already. (This is important
* so that memblock resizing does no stomp over reserved areas.)
*/
memblock_allow_resize();
for (idx = 0; idx < e820_table->nr_entries; idx++) {
struct e820_entry *entry = &e820_table->entries[idx];
end = entry->addr + entry->size;
if (end != (resource_size_t)end)
continue;
if (entry->type == E820_TYPE_SOFT_RESERVED)
memblock_reserve(entry->addr, entry->size);
if (entry->type != E820_TYPE_RAM)
continue;
memblock_add(entry->addr, entry->size);
}
/*
* At this point memblock is only allowed to allocate from memory
* below 1M (aka ISA_END_ADDRESS) up until direct map is completely set
* up in init_mem_mapping().
*
* KHO kernels are special and use only scratch memory for memblock
* allocations, but memory below 1M is ignored by kernel after early
* boot and cannot be naturally marked as scratch.
*
* To allow allocation of the real-mode trampoline and a few (if any)
* other very early allocations from below 1M forcibly mark the memory
* below 1M as scratch.
*
* After real mode trampoline is allocated, we clear that scratch
* marking.
*/
memblock_mark_kho_scratch(0, SZ_1M);
/*
* 32-bit systems are limited to 4BG of memory even with HIGHMEM and
* to even less without it.
* Discard memory after max_pfn - the actual limit detected at runtime.
*/
if (IS_ENABLED(CONFIG_X86_32))
memblock_remove(PFN_PHYS(max_pfn), -1);
/* Throw away partial pages: */
memblock_trim_memory(PAGE_SIZE);
memblock_dump_all();
}
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