linux/arch/x86/platform/efi/quirks.c
Matt Fleming 78ce248faa efi: Iterate over efi.memmap in for_each_efi_memory_desc()
Most of the users of for_each_efi_memory_desc() are equally happy
iterating over the EFI memory map in efi.memmap instead of 'memmap',
since the former is usually a pointer to the latter.

For those users that want to specify an EFI memory map other than
efi.memmap, that can be done using for_each_efi_memory_desc_in_map().
One such example is in the libstub code where the firmware is queried
directly for the memory map, it gets iterated over, and then freed.

This change goes part of the way toward deleting the global 'memmap'
variable, which is not universally available on all architectures
(notably IA64) and is rather poorly named.

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-7-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:33:50 +02:00

376 lines
10 KiB
C

#define pr_fmt(fmt) "efi: " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/time.h>
#include <linux/types.h>
#include <linux/efi.h>
#include <linux/slab.h>
#include <linux/memblock.h>
#include <linux/bootmem.h>
#include <linux/acpi.h>
#include <linux/dmi.h>
#include <asm/efi.h>
#include <asm/uv/uv.h>
#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 };
static bool efi_no_storage_paranoia;
/*
* Some firmware implementations refuse to boot if there's insufficient
* space in the variable store. The implementation of garbage collection
* in some FW versions causes stale (deleted) variables to take up space
* longer than intended and space is only freed once the store becomes
* almost completely full.
*
* Enabling this option disables the space checks in
* efi_query_variable_store() and forces garbage collection.
*
* Only enable this option if deleting EFI variables does not free up
* space in your variable store, e.g. if despite deleting variables
* you're unable to create new ones.
*/
static int __init setup_storage_paranoia(char *arg)
{
efi_no_storage_paranoia = true;
return 0;
}
early_param("efi_no_storage_paranoia", setup_storage_paranoia);
/*
* Deleting the dummy variable which kicks off garbage collection
*/
void efi_delete_dummy_variable(void)
{
efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS,
0, NULL);
}
/*
* In the nonblocking case we do not attempt to perform garbage
* collection if we do not have enough free space. Rather, we do the
* bare minimum check and give up immediately if the available space
* is below EFI_MIN_RESERVE.
*
* This function is intended to be small and simple because it is
* invoked from crash handler paths.
*/
static efi_status_t
query_variable_store_nonblocking(u32 attributes, unsigned long size)
{
efi_status_t status;
u64 storage_size, remaining_size, max_size;
status = efi.query_variable_info_nonblocking(attributes, &storage_size,
&remaining_size,
&max_size);
if (status != EFI_SUCCESS)
return status;
if (remaining_size - size < EFI_MIN_RESERVE)
return EFI_OUT_OF_RESOURCES;
return EFI_SUCCESS;
}
/*
* Some firmware implementations refuse to boot if there's insufficient space
* in the variable store. Ensure that we never use more than a 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,
bool nonblocking)
{
efi_status_t status;
u64 storage_size, remaining_size, max_size;
if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
return 0;
if (nonblocking)
return query_variable_store_nonblocking(attributes, size);
status = efi.query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);
if (status != EFI_SUCCESS)
return status;
/*
* We account for that by refusing the write if permitting it would
* reduce the available space to under 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 = kzalloc(dummy_size, GFP_ATOMIC);
if (!dummy)
return EFI_OUT_OF_RESOURCES;
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_delete_dummy_variable();
}
kfree(dummy);
/*
* 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 (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;
}
EXPORT_SYMBOL_GPL(efi_query_variable_store);
/*
* Helper function for efi_reserve_boot_services() to figure out if we
* can free regions in efi_free_boot_services().
*
* Use this function to ensure we do not free regions owned by somebody
* else. We must only reserve (and then free) regions:
*
* - Not within any part of the kernel
* - Not the BIOS reserved area (E820_RESERVED, E820_NVS, etc)
*/
static bool can_free_region(u64 start, u64 size)
{
if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
return false;
if (!e820_all_mapped(start, start+size, E820_RAM))
return false;
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;
for_each_efi_memory_desc(md) {
u64 start = md->phys_addr;
u64 size = md->num_pages << EFI_PAGE_SHIFT;
bool already_reserved;
if (md->type != EFI_BOOT_SERVICES_CODE &&
md->type != EFI_BOOT_SERVICES_DATA)
continue;
already_reserved = memblock_is_region_reserved(start, size);
/*
* Because the following memblock_reserve() is paired
* with free_bootmem_late() for this region in
* efi_free_boot_services(), we must be extremely
* careful not to reserve, and subsequently free,
* critical regions of memory (like the kernel image) or
* those regions that somebody else has already
* reserved.
*
* A good example of a critical region that must not be
* freed is page zero (first 4Kb of memory), which may
* contain boot services code/data but is marked
* E820_RESERVED by trim_bios_range().
*/
if (!already_reserved) {
memblock_reserve(start, size);
/*
* If we are the first to reserve the region, no
* one else cares about it. We own it and can
* free it later.
*/
if (can_free_region(start, size))
continue;
}
/*
* We don't own the region. We must not free it.
*
* Setting this bit for a boot services region really
* doesn't make sense as far as the firmware is
* concerned, but it does provide us with a way to tag
* those regions that must not be paired with
* free_bootmem_late().
*/
md->attribute |= EFI_MEMORY_RUNTIME;
}
}
void __init efi_free_boot_services(void)
{
efi_memory_desc_t *md;
for_each_efi_memory_desc(md) {
unsigned long long start = md->phys_addr;
unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
if (md->type != EFI_BOOT_SERVICES_CODE &&
md->type != EFI_BOOT_SERVICES_DATA)
continue;
/* Do not free, someone else owns it: */
if (md->attribute & EFI_MEMORY_RUNTIME)
continue;
free_bootmem_late(start, size);
}
efi_unmap_memmap();
}
/*
* A number of config table entries get remapped to virtual addresses
* after entering EFI virtual mode. However, the kexec kernel requires
* their physical addresses therefore we pass them via setup_data and
* correct those entries to their respective physical addresses here.
*
* Currently only handles smbios which is necessary for some firmware
* implementation.
*/
int __init efi_reuse_config(u64 tables, int nr_tables)
{
int i, sz, ret = 0;
void *p, *tablep;
struct efi_setup_data *data;
if (!efi_setup)
return 0;
if (!efi_enabled(EFI_64BIT))
return 0;
data = early_memremap(efi_setup, sizeof(*data));
if (!data) {
ret = -ENOMEM;
goto out;
}
if (!data->smbios)
goto out_memremap;
sz = sizeof(efi_config_table_64_t);
p = tablep = early_memremap(tables, nr_tables * sz);
if (!p) {
pr_err("Could not map Configuration table!\n");
ret = -ENOMEM;
goto out_memremap;
}
for (i = 0; i < efi.systab->nr_tables; i++) {
efi_guid_t guid;
guid = ((efi_config_table_64_t *)p)->guid;
if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
((efi_config_table_64_t *)p)->table = data->smbios;
p += sz;
}
early_memunmap(tablep, nr_tables * sz);
out_memremap:
early_memunmap(data, sizeof(*data));
out:
return ret;
}
static const struct dmi_system_id sgi_uv1_dmi[] = {
{ NULL, "SGI UV1",
{ DMI_MATCH(DMI_PRODUCT_NAME, "Stoutland Platform"),
DMI_MATCH(DMI_PRODUCT_VERSION, "1.0"),
DMI_MATCH(DMI_BIOS_VENDOR, "SGI.COM"),
}
},
{ } /* NULL entry stops DMI scanning */
};
void __init efi_apply_memmap_quirks(void)
{
/*
* Once setup is done earlier, unmap the EFI memory map on mismatched
* firmware/kernel architectures since there is no support for runtime
* services.
*/
if (!efi_runtime_supported()) {
pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
efi_unmap_memmap();
}
/* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */
if (dmi_check_system(sgi_uv1_dmi))
set_bit(EFI_OLD_MEMMAP, &efi.flags);
}
/*
* For most modern platforms the preferred method of powering off is via
* ACPI. However, there are some that are known to require the use of
* EFI runtime services and for which ACPI does not work at all.
*
* Using EFI is a last resort, to be used only if no other option
* exists.
*/
bool efi_reboot_required(void)
{
if (!acpi_gbl_reduced_hardware)
return false;
efi_reboot_quirk_mode = EFI_RESET_WARM;
return true;
}
bool efi_poweroff_required(void)
{
return !!acpi_gbl_reduced_hardware;
}