#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>
#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,
static struct efi efi_phys __initdata;
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;
/*
}
early_param("add_efi_memmap", setup_add_efi_memmap);
+static bool efi_no_storage_paranoia;
+
+static int __init setup_storage_paranoia(char *arg)
+{
+ efi_no_storage_paranoia = true;
+ return 0;
+}
+early_param("efi_no_storage_paranoia", setup_storage_paranoia);
+
static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
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,
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,
char vendor[100] = "unknown";
int i = 0;
void *tmp;
+ struct setup_data *data;
+ struct efi_var_bootdata *efi_var_data;
+ u64 pa_data;
#ifdef CONFIG_X86_32
if (boot_params.efi_info.efi_systab_hi ||
if (efi_systab_init(efi_phys.systab))
return;
+ pa_data = boot_params.hdr.setup_data;
+ while (pa_data) {
+ data = early_ioremap(pa_data, sizeof(*efi_var_data));
+ if (data->type == SETUP_EFI_VARS) {
+ efi_var_data = (struct efi_var_bootdata *)data;
+
+ efi_var_store_size = efi_var_data->store_size;
+ efi_var_remaining_size = efi_var_data->remaining_size;
+ efi_var_max_var_size = efi_var_data->max_var_size;
+ }
+ pa_data = data->next;
+ 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);
/*
}
return 0;
}
+
+/*
+ * Some firmware has serious problems when using more than 50% of the EFI
+ * variable store, i.e. it triggers bugs that can brick machines. Ensure that
+ * we never use more than this safe limit.
+ *
+ * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
+ * store.
+ */
+efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
+{
+ efi_status_t status;
+ u64 storage_size, remaining_size, max_size;
+
+ status = efi.query_variable_info(attributes, &storage_size,
+ &remaining_size, &max_size);
+ if (status != EFI_SUCCESS)
+ return status;
+
+ 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))
+ return EFI_OUT_OF_RESOURCES;
+
+ if (!efi_no_storage_paranoia &&
+ ((active_size + size + VAR_METADATA_SIZE > storage_size / 2) &&
+ (remaining_size - size < storage_size / 2)))
+ return EFI_OUT_OF_RESOURCES;
+
+ return EFI_SUCCESS;
+}
+EXPORT_SYMBOL_GPL(efi_query_variable_store);
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blobdiff