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-rw-r--r--arch/x86/platform/efi/efi.c106
1 files changed, 100 insertions, 6 deletions
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 977d1ce7e17..4959e3f89d7 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -41,6 +41,7 @@
#include <linux/io.h>
#include <linux/reboot.h>
#include <linux/bcd.h>
+#include <linux/ucs2_string.h>
#include <asm/setup.h>
#include <asm/efi.h>
@@ -51,6 +52,13 @@
#define EFI_DEBUG 1
+/*
+ * There's some additional metadata associated with each
+ * variable. Intel's reference implementation is 60 bytes - bump that
+ * to account for potential alignment constraints
+ */
+#define VAR_METADATA_SIZE 64
+
struct efi __read_mostly efi = {
.mps = EFI_INVALID_TABLE_ADDR,
.acpi = EFI_INVALID_TABLE_ADDR,
@@ -72,6 +80,9 @@ static efi_system_table_t efi_systab __initdata;
static u64 efi_var_store_size;
static u64 efi_var_remaining_size;
static u64 efi_var_max_var_size;
+static u64 boot_used_size;
+static u64 boot_var_size;
+static u64 active_size;
unsigned long x86_efi_facility;
@@ -166,8 +177,53 @@ static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
efi_char16_t *name,
efi_guid_t *vendor)
{
- return efi_call_virt3(get_next_variable,
- name_size, name, vendor);
+ efi_status_t status;
+ static bool finished = false;
+ static u64 var_size;
+
+ status = efi_call_virt3(get_next_variable,
+ name_size, name, vendor);
+
+ if (status == EFI_NOT_FOUND) {
+ finished = true;
+ if (var_size < boot_used_size) {
+ boot_var_size = boot_used_size - var_size;
+ active_size += boot_var_size;
+ } else {
+ printk(KERN_WARNING FW_BUG "efi: Inconsistent initial sizes\n");
+ }
+ }
+
+ if (boot_used_size && !finished) {
+ unsigned long size;
+ u32 attr;
+ efi_status_t s;
+ void *tmp;
+
+ s = virt_efi_get_variable(name, vendor, &attr, &size, NULL);
+
+ if (s != EFI_BUFFER_TOO_SMALL || !size)
+ return status;
+
+ tmp = kmalloc(size, GFP_ATOMIC);
+
+ if (!tmp)
+ return status;
+
+ s = virt_efi_get_variable(name, vendor, &attr, &size, tmp);
+
+ if (s == EFI_SUCCESS && (attr & EFI_VARIABLE_NON_VOLATILE)) {
+ var_size += size;
+ var_size += ucs2_strsize(name, 1024);
+ active_size += size;
+ active_size += VAR_METADATA_SIZE;
+ active_size += ucs2_strsize(name, 1024);
+ }
+
+ kfree(tmp);
+ }
+
+ return status;
}
static efi_status_t virt_efi_set_variable(efi_char16_t *name,
@@ -176,9 +232,34 @@ static efi_status_t virt_efi_set_variable(efi_char16_t *name,
unsigned long data_size,
void *data)
{
- return efi_call_virt5(set_variable,
- name, vendor, attr,
- data_size, data);
+ efi_status_t status;
+ u32 orig_attr = 0;
+ unsigned long orig_size = 0;
+
+ status = virt_efi_get_variable(name, vendor, &orig_attr, &orig_size,
+ NULL);
+
+ if (status != EFI_BUFFER_TOO_SMALL)
+ orig_size = 0;
+
+ status = efi_call_virt5(set_variable,
+ name, vendor, attr,
+ data_size, data);
+
+ if (status == EFI_SUCCESS) {
+ if (orig_size) {
+ active_size -= orig_size;
+ active_size -= ucs2_strsize(name, 1024);
+ active_size -= VAR_METADATA_SIZE;
+ }
+ if (data_size) {
+ active_size += data_size;
+ active_size += ucs2_strsize(name, 1024);
+ active_size += VAR_METADATA_SIZE;
+ }
+ }
+
+ return status;
}
static efi_status_t virt_efi_query_variable_info(u32 attr,
@@ -720,6 +801,8 @@ void __init efi_init(void)
early_iounmap(data, sizeof(*efi_var_data));
}
+ boot_used_size = efi_var_store_size - efi_var_remaining_size;
+
set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);
/*
@@ -1042,10 +1125,21 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
if (!max_size && remaining_size > size)
printk_once(KERN_ERR FW_BUG "Broken EFI implementation"
" is returning MaxVariableSize=0\n");
+ /*
+ * Some firmware implementations refuse to boot if there's insufficient
+ * space in the variable store. We account for that by refusing the
+ * write if permitting it would reduce the available space to under
+ * 50%. However, some firmware won't reclaim variable space until
+ * after the used (not merely the actively used) space drops below
+ * a threshold. We can approximate that case with the value calculated
+ * above. If both the firmware and our calculations indicate that the
+ * available space would drop below 50%, refuse the write.
+ */
if (!storage_size || size > remaining_size ||
(max_size && size > max_size) ||
- (remaining_size - size) < (storage_size / 2))
+ ((active_size + size + VAR_METADATA_SIZE > storage_size / 2) &&
+ (remaining_size - size < storage_size / 2)))
return EFI_OUT_OF_RESOURCES;
return EFI_SUCCESS;