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Merge tag 'efi-urgent' into x86/urgent
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 * More tweaking to the EFI variable anti-bricking algorithm. Quite a
   few users were reporting boot regressions in v3.9. This has now been
   fixed with a more accurate "minimum storage requirement to avoid
   bricking" value from Samsung (5K instead of 50%) and code to trigger
   garbage collection when we near our limit - Matthew Garrett.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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H. Peter Anvin committed Jun 13, 2013
2 parents c8a22d1 + f8b8404 commit 45df901
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Showing 4 changed files with 65 additions and 178 deletions.
47 changes: 0 additions & 47 deletions arch/x86/boot/compressed/eboot.c
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Original file line number Diff line number Diff line change
Expand Up @@ -251,51 +251,6 @@ static void find_bits(unsigned long mask, u8 *pos, u8 *size)
*size = len;
}

static efi_status_t setup_efi_vars(struct boot_params *params)
{
struct setup_data *data;
struct efi_var_bootdata *efidata;
u64 store_size, remaining_size, var_size;
efi_status_t status;

if (sys_table->runtime->hdr.revision < EFI_2_00_SYSTEM_TABLE_REVISION)
return EFI_UNSUPPORTED;

data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

while (data && data->next)
data = (struct setup_data *)(unsigned long)data->next;

status = efi_call_phys4((void *)sys_table->runtime->query_variable_info,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS, &store_size,
&remaining_size, &var_size);

if (status != EFI_SUCCESS)
return status;

status = efi_call_phys3(sys_table->boottime->allocate_pool,
EFI_LOADER_DATA, sizeof(*efidata), &efidata);

if (status != EFI_SUCCESS)
return status;

efidata->data.type = SETUP_EFI_VARS;
efidata->data.len = sizeof(struct efi_var_bootdata) -
sizeof(struct setup_data);
efidata->data.next = 0;
efidata->store_size = store_size;
efidata->remaining_size = remaining_size;
efidata->max_var_size = var_size;

if (data)
data->next = (unsigned long)efidata;
else
params->hdr.setup_data = (unsigned long)efidata;

}

static efi_status_t setup_efi_pci(struct boot_params *params)
{
efi_pci_io_protocol *pci;
Expand Down Expand Up @@ -1202,8 +1157,6 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,

setup_graphics(boot_params);

setup_efi_vars(boot_params);

setup_efi_pci(boot_params);

status = efi_call_phys3(sys_table->boottime->allocate_pool,
Expand Down
7 changes: 0 additions & 7 deletions arch/x86/include/asm/efi.h
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Original file line number Diff line number Diff line change
Expand Up @@ -102,13 +102,6 @@ extern void efi_call_phys_epilog(void);
extern void efi_unmap_memmap(void);
extern void efi_memory_uc(u64 addr, unsigned long size);

struct efi_var_bootdata {
struct setup_data data;
u64 store_size;
u64 remaining_size;
u64 max_var_size;
};

#ifdef CONFIG_EFI

static inline bool efi_is_native(void)
Expand Down
1 change: 0 additions & 1 deletion arch/x86/include/uapi/asm/bootparam.h
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,6 @@
#define SETUP_E820_EXT 1
#define SETUP_DTB 2
#define SETUP_PCI 3
#define SETUP_EFI_VARS 4

/* ram_size flags */
#define RAMDISK_IMAGE_START_MASK 0x07FF
Expand Down
188 changes: 65 additions & 123 deletions arch/x86/platform/efi/efi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,6 @@
#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>
Expand All @@ -54,12 +53,12 @@

#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
#define EFI_MIN_RESERVE 5120

#define EFI_DUMMY_GUID \
EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)

static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };

struct efi __read_mostly efi = {
.mps = EFI_INVALID_TABLE_ADDR,
Expand All @@ -79,13 +78,6 @@ struct efi_memory_map memmap;
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;

/*
Expand Down Expand Up @@ -188,53 +180,8 @@ static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
efi_char16_t *name,
efi_guid_t *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 = 0;
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;
return efi_call_virt3(get_next_variable,
name_size, name, vendor);
}

static efi_status_t virt_efi_set_variable(efi_char16_t *name,
Expand All @@ -243,34 +190,9 @@ static efi_status_t virt_efi_set_variable(efi_char16_t *name,
unsigned long data_size,
void *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;
return efi_call_virt5(set_variable,
name, vendor, attr,
data_size, data);
}

static efi_status_t virt_efi_query_variable_info(u32 attr,
Expand Down Expand Up @@ -786,9 +708,6 @@ void __init efi_init(void)
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 ||
Expand All @@ -806,22 +725,6 @@ void __init efi_init(void)
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);

/*
Expand Down Expand Up @@ -1085,6 +988,13 @@ void __init efi_enter_virtual_mode(void)
runtime_code_page_mkexec();

kfree(new_memmap);

/* clean DUMMY object */
efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS,
0, NULL);
}

/*
Expand Down Expand Up @@ -1136,33 +1046,65 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
efi_status_t status;
u64 storage_size, remaining_size, max_size;

if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
return 0;

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.
* 5KB. This figure was provided by Samsung, so should be safe.
*/
if ((remaining_size - size < EFI_MIN_RESERVE) &&
!efi_no_storage_paranoia) {

/*
* Triggering garbage collection may require that the firmware
* generate a real EFI_OUT_OF_RESOURCES error. We can force
* that by attempting to use more space than is available.
*/
unsigned long dummy_size = remaining_size + 1024;
void *dummy = kmalloc(dummy_size, GFP_ATOMIC);

status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS,
dummy_size, dummy);

if (status == EFI_SUCCESS) {
/*
* This should have failed, so if it didn't make sure
* that we delete it...
*/
efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS,
0, dummy);
}

if (!storage_size || size > remaining_size ||
(max_size && size > max_size))
return EFI_OUT_OF_RESOURCES;
/*
* The runtime code may now have triggered a garbage collection
* run, so check the variable info again
*/
status = efi.query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);

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;
if (status != EFI_SUCCESS)
return status;

/*
* There still isn't enough room, so return an error
*/
if (remaining_size - size < EFI_MIN_RESERVE)
return EFI_OUT_OF_RESOURCES;
}

return EFI_SUCCESS;
}
Expand Down

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