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Diffstat (limited to 'arch/x86/kernel/e820.c')
-rw-r--r--arch/x86/kernel/e820.c319
1 files changed, 206 insertions, 113 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 532da61d605c..b15b97d3cb52 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Low level x86 E820 memory map handling functions.
*
@@ -9,12 +10,13 @@
* allocation code routines via a platform independent interface (memblock, etc.).
*/
#include <linux/crash_dump.h>
-#include <linux/bootmem.h>
+#include <linux/memblock.h>
#include <linux/suspend.h>
#include <linux/acpi.h>
#include <linux/firmware-map.h>
-#include <linux/memblock.h>
#include <linux/sort.h>
+#include <linux/memory_hotplug.h>
+#include <linux/kvm_types.h>
#include <asm/e820/api.h>
#include <asm/setup.h>
@@ -27,18 +29,13 @@
* 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:
*
- * - inform the user about the firmware's notion of memory layout
- * via /sys/firmware/memmap
- *
- * - the hibernation code uses it to generate a kernel-independent MD5
- * fingerprint of the physical memory layout of a system.
+ * - 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, the latter marks the setup_data
- * list created by the EFI boot stub as reserved, so that kexec can reuse the
- * setup_data information in the second kernel. Besides, e820_table_kexec[]
- * might also be modified by the kexec itself to fake a mptable.
+ * 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
@@ -46,13 +43,18 @@
* 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 itsmain role is a temporary bootstrap storage of firmware
+ * re-propagated. So its main role is a temporary bootstrap storage of firmware
* specific memory layout data during early bootup.
*/
static struct e820_table e820_table_init __initdata;
@@ -73,20 +75,32 @@ EXPORT_SYMBOL(pci_mem_start);
* This function checks if any part of the range <start,end> is mapped
* with type.
*/
-bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
+static bool _e820__mapped_any(struct e820_table *table,
+ u64 start, u64 end, enum e820_type type)
{
int i;
- for (i = 0; i < e820_table->nr_entries; i++) {
- struct e820_entry *entry = &e820_table->entries[i];
+ for (i = 0; i < table->nr_entries; i++) {
+ struct e820_entry *entry = &table->entries[i];
if (type && entry->type != type)
continue;
if (entry->addr >= end || entry->addr + entry->size <= start)
continue;
- return 1;
+ return true;
}
- return 0;
+ 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);
@@ -96,7 +110,8 @@ EXPORT_SYMBOL_GPL(e820__mapped_any);
* 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.
*/
-bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
+static struct e820_entry *__e820__mapped_all(u64 start, u64 end,
+ enum e820_type type)
{
int i;
@@ -122,9 +137,28 @@ bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
* coverage of the desired range exists:
*/
if (start >= end)
- return 1;
+ return entry;
}
- return 0;
+
+ return NULL;
+}
+
+/*
+ * This function checks if the entire range <start,end> is mapped with type.
+ */
+bool __init 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;
}
/*
@@ -135,7 +169,8 @@ static void __init __e820__range_add(struct e820_table *table, u64 start, u64 si
int x = table->nr_entries;
if (x >= ARRAY_SIZE(table->entries)) {
- pr_err("e820: too many entries; ignoring [mem %#010llx-%#010llx]\n", start, start + size - 1);
+ pr_err("too many entries; ignoring [mem %#010llx-%#010llx]\n",
+ start, start + size - 1);
return;
}
@@ -153,9 +188,9 @@ void __init e820__range_add(u64 start, u64 size, enum e820_type type)
static void __init e820_print_type(enum e820_type type)
{
switch (type) {
- case E820_TYPE_RAM: /* Fall through: */
- case E820_TYPE_RESERVED_KERN: pr_cont("usable"); break;
+ case E820_TYPE_RAM: pr_cont("usable"); break;
case E820_TYPE_RESERVED: pr_cont("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;
@@ -170,9 +205,10 @@ void __init e820__print_table(char *who)
int i;
for (i = 0; i < e820_table->nr_entries; i++) {
- pr_info("%s: [mem %#018Lx-%#018Lx] ", who,
- e820_table->entries[i].addr,
- e820_table->entries[i].addr + e820_table->entries[i].size - 1);
+ pr_info("%s: [mem %#018Lx-%#018Lx] ",
+ who,
+ e820_table->entries[i].addr,
+ e820_table->entries[i].addr + e820_table->entries[i].size - 1);
e820_print_type(e820_table->entries[i].type);
pr_cont("\n");
@@ -269,6 +305,20 @@ static int __init cpcompare(const void *a, const void *b)
return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
}
+static bool e820_nomerge(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 true;
+ if (type == E820_TYPE_SOFT_RESERVED)
+ return true;
+ return false;
+}
+
int __init e820__update_table(struct e820_table *table)
{
struct e820_entry *entries = table->entries;
@@ -344,8 +394,8 @@ int __init e820__update_table(struct e820_table *table)
}
/* Continue building up new map based on this information: */
- if (current_type != last_type || current_type == E820_TYPE_PRAM) {
- if (last_type != 0) {
+ if (current_type != last_type || e820_nomerge(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)
@@ -353,7 +403,7 @@ int __init e820__update_table(struct e820_table *table)
if (++new_nr_entries >= max_nr_entries)
break;
}
- if (current_type != 0) {
+ 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;
@@ -482,9 +532,10 @@ u64 __init e820__range_update(u64 start, u64 size, enum e820_type old_type, enum
return __e820__range_update(e820_table, start, size, old_type, new_type);
}
-static u64 __init e820__range_update_kexec(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
+u64 __init 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(e820_table_kexec, start, size, old_type, new_type);
+ return __e820__range_update(t, start, size, old_type, new_type);
}
/* Remove a range of memory from the E820 table: */
@@ -554,7 +605,7 @@ void __init e820__update_table_print(void)
if (e820__update_table(e820_table))
return;
- pr_info("e820: modified physical RAM map:\n");
+ pr_info("modified physical RAM map:\n");
e820__print_table("modified");
}
@@ -616,9 +667,8 @@ __init void e820__setup_pci_gap(void)
if (!found) {
#ifdef CONFIG_X86_64
gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
- pr_err(
- "e820: Cannot find an available gap in the 32-bit address range\n"
- "e820: PCI devices with unassigned 32-bit BARs may not work!\n");
+ 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
gapstart = 0x10000000;
#endif
@@ -629,7 +679,8 @@ __init void e820__setup_pci_gap(void)
*/
pci_mem_start = gapstart;
- pr_info("e820: [mem %#010lx-%#010lx] available for PCI devices\n", gapstart, gapstart + gapsize - 1);
+ pr_info("[mem %#010lx-%#010lx] available for PCI devices\n",
+ gapstart, gapstart + gapsize - 1);
}
/*
@@ -650,21 +701,18 @@ __init void e820__reallocate_tables(void)
int size;
size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table->nr_entries;
- n = kmalloc(size, GFP_KERNEL);
+ n = kmemdup(e820_table, size, GFP_KERNEL);
BUG_ON(!n);
- memcpy(n, e820_table, size);
e820_table = n;
size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_kexec->nr_entries;
- n = kmalloc(size, GFP_KERNEL);
+ n = kmemdup(e820_table_kexec, size, GFP_KERNEL);
BUG_ON(!n);
- memcpy(n, e820_table_kexec, size);
e820_table_kexec = n;
size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_firmware->nr_entries;
- n = kmalloc(size, GFP_KERNEL);
+ n = kmemdup(e820_table_firmware, size, GFP_KERNEL);
BUG_ON(!n);
- memcpy(n, e820_table_firmware, size);
e820_table_firmware = n;
}
@@ -691,7 +739,7 @@ void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
early_memunmap(sdata, data_len);
- pr_info("e820: extended physical RAM map:\n");
+ pr_info("extended physical RAM map:\n");
e820__print_table("extended");
}
@@ -706,22 +754,21 @@ void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
void __init e820__register_nosave_regions(unsigned long limit_pfn)
{
int i;
- unsigned long pfn = 0;
+ u64 last_addr = 0;
for (i = 0; i < e820_table->nr_entries; i++) {
struct e820_entry *entry = &e820_table->entries[i];
- if (pfn < PFN_UP(entry->addr))
- register_nosave_region(pfn, PFN_UP(entry->addr));
-
- pfn = PFN_DOWN(entry->addr + entry->size);
+ if (entry->type != E820_TYPE_RAM)
+ continue;
- if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
- register_nosave_region(PFN_UP(entry->addr), pfn);
+ if (last_addr < entry->addr)
+ register_nosave_region(PFN_DOWN(last_addr), PFN_UP(entry->addr));
- if (pfn >= limit_pfn)
- break;
+ last_addr = entry->addr + entry->size;
}
+
+ register_nosave_region(PFN_DOWN(last_addr), limit_pfn);
}
#ifdef CONFIG_ACPI
@@ -746,7 +793,7 @@ core_initcall(e820__register_nvs_regions);
#endif
/*
- * Allocate the requested number of bytes with the requsted alignment
+ * 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.
*
@@ -757,10 +804,10 @@ u64 __init e820__memblock_alloc_reserved(u64 size, u64 align)
{
u64 addr;
- addr = __memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
+ addr = memblock_phys_alloc(size, align);
if (addr) {
- e820__range_update_kexec(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
- pr_info("e820: update e820_table_kexec for e820__memblock_alloc_reserved()\n");
+ 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();
}
@@ -780,7 +827,7 @@ u64 __init e820__memblock_alloc_reserved(u64 size, u64 align)
/*
* Find the highest page frame number we have available
*/
-static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type type)
+static unsigned long __init e820__end_ram_pfn(unsigned long limit_pfn)
{
int i;
unsigned long last_pfn = 0;
@@ -791,7 +838,8 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type
unsigned long start_pfn;
unsigned long end_pfn;
- if (entry->type != type)
+ if (entry->type != E820_TYPE_RAM &&
+ entry->type != E820_TYPE_ACPI)
continue;
start_pfn = entry->addr >> PAGE_SHIFT;
@@ -810,19 +858,19 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type
if (last_pfn > max_arch_pfn)
last_pfn = max_arch_pfn;
- pr_info("e820: last_pfn = %#lx max_arch_pfn = %#lx\n",
- last_pfn, max_arch_pfn);
+ pr_info("last_pfn = %#lx max_arch_pfn = %#lx\n",
+ last_pfn, max_arch_pfn);
return last_pfn;
}
unsigned long __init e820__end_of_ram_pfn(void)
{
- return e820_end_pfn(MAX_ARCH_PFN, E820_TYPE_RAM);
+ return e820__end_ram_pfn(MAX_ARCH_PFN);
}
unsigned long __init e820__end_of_low_ram_pfn(void)
{
- return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_TYPE_RAM);
+ return e820__end_ram_pfn(1UL << (32 - PAGE_SHIFT));
}
static void __init early_panic(char *msg)
@@ -860,6 +908,10 @@ static int __init parse_memopt(char *p)
e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
+#ifdef CONFIG_MEMORY_HOTPLUG
+ max_mem_size = mem_size;
+#endif
+
return 0;
}
early_param("mem", parse_memopt);
@@ -873,14 +925,6 @@ static int __init parse_memmap_one(char *p)
return -EINVAL;
if (!strncmp(p, "exactmap", 8)) {
-#ifdef CONFIG_CRASH_DUMP
- /*
- * If we are doing a crash dump, we still need to know
- * the real memory size before the original memory map is
- * reset.
- */
- saved_max_pfn = e820__end_of_ram_pfn();
-#endif
e820_table->nr_entries = 0;
userdef = 1;
return 0;
@@ -904,6 +948,24 @@ static int __init parse_memmap_one(char *p)
} 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 if (from)
+ e820__range_remove(start_at, mem_size, from, 1);
+ else
+ e820__range_remove(start_at, mem_size, 0, 0);
} else {
e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
}
@@ -928,35 +990,6 @@ static int __init parse_memmap_opt(char *str)
early_param("memmap", parse_memmap_opt);
/*
- * Reserve all entries from the bootloader's extensible data nodes list,
- * because if present we are going to use it later on to fetch e820
- * entries from it:
- */
-void __init e820__reserve_setup_data(void)
-{
- struct setup_data *data;
- u64 pa_data;
-
- pa_data = boot_params.hdr.setup_data;
- if (!pa_data)
- return;
-
- while (pa_data) {
- data = early_memremap(pa_data, sizeof(*data));
- e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
- e820__range_update_kexec(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
- pa_data = data->next;
- early_memunmap(data, sizeof(*data));
- }
-
- e820__update_table(e820_table);
- e820__update_table(e820_table_kexec);
-
- pr_info("extended physical RAM map:\n");
- e820__print_table("reserve setup_data");
-}
-
-/*
* 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:
@@ -967,7 +1000,7 @@ void __init e820__finish_early_params(void)
if (e820__update_table(e820_table) < 0)
early_panic("Invalid user supplied memory map");
- pr_info("e820: user-defined physical RAM map:\n");
+ pr_info("user-defined physical RAM map:\n");
e820__print_table("user");
}
}
@@ -975,7 +1008,6 @@ void __init e820__finish_early_params(void)
static const char *__init e820_type_to_string(struct e820_entry *entry)
{
switch (entry->type) {
- case E820_TYPE_RESERVED_KERN: /* Fall-through: */
case E820_TYPE_RAM: return "System RAM";
case E820_TYPE_ACPI: return "ACPI Tables";
case E820_TYPE_NVS: return "ACPI Non-volatile Storage";
@@ -983,6 +1015,7 @@ static const char *__init e820_type_to_string(struct e820_entry *entry)
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";
}
}
@@ -990,7 +1023,6 @@ static const char *__init e820_type_to_string(struct e820_entry *entry)
static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)
{
switch (entry->type) {
- case E820_TYPE_RESERVED_KERN: /* Fall-through: */
case E820_TYPE_RAM: return IORESOURCE_SYSTEM_RAM;
case E820_TYPE_ACPI: /* Fall-through: */
case E820_TYPE_NVS: /* Fall-through: */
@@ -998,6 +1030,7 @@ static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)
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;
}
}
@@ -1009,10 +1042,10 @@ static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry)
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_KERN: /* Fall-through: */
+ 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: */
- case E820_TYPE_RESERVED: /* Fall-through: */
default: return IORES_DESC_NONE;
}
}
@@ -1024,15 +1057,15 @@ static bool __init do_mark_busy(enum e820_type type, struct resource *res)
return true;
/*
- * Treat persistent memory like device memory, i.e. reserve it
- * for exclusive use of a driver
+ * Treat persistent memory and other special memory ranges like
+ * device memory, i.e. reserve it 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 false;
- case E820_TYPE_RESERVED_KERN:
case E820_TYPE_RAM:
case E820_TYPE_ACPI:
case E820_TYPE_NVS:
@@ -1054,7 +1087,8 @@ void __init e820__reserve_resources(void)
struct resource *res;
u64 end;
- res = alloc_bootmem(sizeof(*res) * e820_table->nr_entries);
+ res = memblock_alloc_or_panic(sizeof(*res) * e820_table->nr_entries,
+ SMP_CACHE_BYTES);
e820_res = res;
for (i = 0; i < e820_table->nr_entries; i++) {
@@ -1083,9 +1117,9 @@ void __init e820__reserve_resources(void)
res++;
}
- /* Expose the bootloader-provided memory layout to the sysfs. */
- for (i = 0; i < e820_table_firmware->nr_entries; i++) {
- struct e820_entry *entry = e820_table_firmware->entries + i;
+ /* Expose the kexec e820 table to the sysfs. */
+ for (i = 0; i < e820_table_kexec->nr_entries; i++) {
+ struct e820_entry *entry = e820_table_kexec->entries + i;
firmware_map_add_early(entry->addr, entry->addr + entry->size, e820_type_to_string(entry));
}
@@ -1200,7 +1234,7 @@ void __init e820__memory_setup(void)
memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
- pr_info("e820: BIOS-provided physical RAM map:\n");
+ pr_info("BIOS-provided physical RAM map:\n");
e820__print_table(who);
}
@@ -1209,6 +1243,36 @@ void __init e820__memblock_setup(void)
int i;
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
@@ -1227,12 +1291,41 @@ void __init e820__memblock_setup(void)
if (end != (resource_size_t)end)
continue;
- if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
+ 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);
generated by cgit (git 2.34.1) at 2025-12-25 10:34:29 +0000