}
EXPORT_SYMBOL_GPL(efi_query_variable_store);
+/*
+ * The UEFI specification makes it clear that the operating system is
+ * free to do whatever it wants with boot services code after
+ * ExitBootServices() has been called. Ignoring this recommendation a
+ * significant bunch of EFI implementations continue calling into boot
+ * services code (SetVirtualAddressMap). In order to work around such
+ * buggy implementations we reserve boot services region during EFI
+ * init and make sure it stays executable. Then, after
+ * SetVirtualAddressMap(), it is discarded.
+ *
+ * However, some boot services regions contain data that is required
+ * by drivers, so we need to track which memory ranges can never be
+ * freed. This is done by tagging those regions with the
+ * EFI_MEMORY_RUNTIME attribute.
+ *
+ * Any driver that wants to mark a region as reserved must use
+ * efi_mem_reserve() which will insert a new EFI memory descriptor
+ * into efi.memmap (splitting existing regions if necessary) and tag
+ * it with EFI_MEMORY_RUNTIME.
+ */
+void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
+{
+ phys_addr_t new_phys, new_size;
+ struct efi_mem_range mr;
+ efi_memory_desc_t md;
+ int num_entries;
+ void *new;
+
+ if (efi_mem_desc_lookup(addr, &md)) {
+ pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
+ return;
+ }
+
+ if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
+ pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
+ return;
+ }
+
+ mr.range.start = addr;
+ mr.range.end = addr + size;
+ mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
+
+ num_entries = efi_memmap_split_count(&md, &mr.range);
+ num_entries += efi.memmap.nr_map;
+
+ new_size = efi.memmap.desc_size * num_entries;
+
+ new_phys = memblock_alloc(new_size, 0);
+ if (!new_phys) {
+ pr_err("Could not allocate boot services memmap\n");
+ return;
+ }
+
+ new = early_memremap(new_phys, new_size);
+ if (!new) {
+ pr_err("Failed to map new boot services memmap\n");
+ return;
+ }
+
+ efi_memmap_insert(&efi.memmap, new, &mr);
+ early_memunmap(new, new_size);
+
+ efi_memmap_install(new_phys, num_entries);
+}
+
/*
* Helper function for efi_reserve_boot_services() to figure out if we
* can free regions in efi_free_boot_services().
return true;
}
-/*
- * The UEFI specification makes it clear that the operating system is free to do
- * whatever it wants with boot services code after ExitBootServices() has been
- * called. Ignoring this recommendation a significant bunch of EFI implementations
- * continue calling into boot services code (SetVirtualAddressMap). In order to
- * work around such buggy implementations we reserve boot services region during
- * EFI init and make sure it stays executable. Then, after SetVirtualAddressMap(), it
-* is discarded.
-*/
void __init efi_reserve_boot_services(void)
{
efi_memory_desc_t *md;
void __init efi_free_boot_services(void)
{
+ phys_addr_t new_phys, new_size;
efi_memory_desc_t *md;
+ int num_entries = 0;
+ void *new, *new_md;
for_each_efi_memory_desc(md) {
unsigned long long start = md->phys_addr;
size_t rm_size;
if (md->type != EFI_BOOT_SERVICES_CODE &&
- md->type != EFI_BOOT_SERVICES_DATA)
+ md->type != EFI_BOOT_SERVICES_DATA) {
+ num_entries++;
continue;
+ }
/* Do not free, someone else owns it: */
- if (md->attribute & EFI_MEMORY_RUNTIME)
+ if (md->attribute & EFI_MEMORY_RUNTIME) {
+ num_entries++;
continue;
+ }
/*
* Nasty quirk: if all sub-1MB memory is used for boot
free_bootmem_late(start, size);
}
+
+ new_size = efi.memmap.desc_size * num_entries;
+ new_phys = memblock_alloc(new_size, 0);
+ if (!new_phys) {
+ pr_err("Failed to allocate new EFI memmap\n");
+ return;
+ }
+
+ new = memremap(new_phys, new_size, MEMREMAP_WB);
+ if (!new) {
+ pr_err("Failed to map new EFI memmap\n");
+ return;
+ }
+
+ /*
+ * Build a new EFI memmap that excludes any boot services
+ * regions that are not tagged EFI_MEMORY_RUNTIME, since those
+ * regions have now been freed.
+ */
+ new_md = new;
+ for_each_efi_memory_desc(md) {
+ if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+ (md->type == EFI_BOOT_SERVICES_CODE ||
+ md->type == EFI_BOOT_SERVICES_DATA))
+ continue;
+
+ memcpy(new_md, md, efi.memmap.desc_size);
+ new_md += efi.memmap.desc_size;
+ }
+
+ memunmap(new);
+
+ if (efi_memmap_install(new_phys, num_entries)) {
+ pr_err("Could not install new EFI memmap\n");
+ return;
+ }
}
/*
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/ucs2_string.h>
+#include <linux/memblock.h>
#include <asm/early_ioremap.h>
return end;
}
+void __init __weak efi_arch_mem_reserve(phys_addr_t addr, u64 size) {}
+
+/**
+ * efi_mem_reserve - Reserve an EFI memory region
+ * @addr: Physical address to reserve
+ * @size: Size of reservation
+ *
+ * Mark a region as reserved from general kernel allocation and
+ * prevent it being released by efi_free_boot_services().
+ *
+ * This function should be called drivers once they've parsed EFI
+ * configuration tables to figure out where their data lives, e.g.
+ * efi_esrt_init().
+ */
+void __init efi_mem_reserve(phys_addr_t addr, u64 size)
+{
+ if (!memblock_is_region_reserved(addr, size))
+ memblock_reserve(addr, size);
+
+ /*
+ * Some architectures (x86) reserve all boot services ranges
+ * until efi_free_boot_services() because of buggy firmware
+ * implementations. This means the above memblock_reserve() is
+ * superfluous on x86 and instead what it needs to do is
+ * ensure the @start, @size is not freed.
+ */
+ efi_arch_mem_reserve(addr, size);
+}
+
static __initdata efi_config_table_type_t common_tables[] = {
{ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
{ACPI_TABLE_GUID, "ACPI", &efi.acpi},
projects / users / willy / pagecache.git / commitdiff