mirror of
https://github.com/torvalds/linux.git
synced 2024-12-15 07:33:56 +00:00
92dc33501b
Mike Galbraith reported that his machine started rebooting during boot
after,
commit 8e80632fb2
("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")
The ESRT table on his machine is 56 bytes and at no point in the
efi_arch_mem_reserve() call path is that size rounded up to
EFI_PAGE_SIZE, nor is the start address on an EFI_PAGE_SIZE boundary.
Since the EFI memory map only deals with whole pages, inserting an EFI
memory region with 56 bytes results in a new entry covering zero
pages, and completely screws up the calculations for the old regions
that were trimmed.
Round all sizes upwards, and start addresses downwards, to the nearest
EFI_PAGE_SIZE boundary.
Additionally, efi_memmap_insert() expects the mem::range::end value to
be one less than the end address for the region.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Reported-by: Mike Krinkin <krinkin.m.u@gmail.com>
Tested-by: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
498 lines
13 KiB
C
498 lines
13 KiB
C
#define pr_fmt(fmt) "efi: " fmt
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/time.h>
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#include <linux/types.h>
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#include <linux/efi.h>
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#include <linux/slab.h>
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#include <linux/memblock.h>
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#include <linux/bootmem.h>
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#include <linux/acpi.h>
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#include <linux/dmi.h>
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#include <asm/efi.h>
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#include <asm/uv/uv.h>
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#define EFI_MIN_RESERVE 5120
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#define EFI_DUMMY_GUID \
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EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
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static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };
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static bool efi_no_storage_paranoia;
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/*
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* Some firmware implementations refuse to boot if there's insufficient
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* space in the variable store. The implementation of garbage collection
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* in some FW versions causes stale (deleted) variables to take up space
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* longer than intended and space is only freed once the store becomes
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* almost completely full.
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*
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* Enabling this option disables the space checks in
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* efi_query_variable_store() and forces garbage collection.
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*
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* Only enable this option if deleting EFI variables does not free up
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* space in your variable store, e.g. if despite deleting variables
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* you're unable to create new ones.
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*/
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static int __init setup_storage_paranoia(char *arg)
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{
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efi_no_storage_paranoia = true;
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return 0;
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}
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early_param("efi_no_storage_paranoia", setup_storage_paranoia);
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/*
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* Deleting the dummy variable which kicks off garbage collection
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*/
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void efi_delete_dummy_variable(void)
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{
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efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
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EFI_VARIABLE_NON_VOLATILE |
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EFI_VARIABLE_BOOTSERVICE_ACCESS |
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EFI_VARIABLE_RUNTIME_ACCESS,
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0, NULL);
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}
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/*
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* In the nonblocking case we do not attempt to perform garbage
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* collection if we do not have enough free space. Rather, we do the
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* bare minimum check and give up immediately if the available space
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* is below EFI_MIN_RESERVE.
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*
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* This function is intended to be small and simple because it is
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* invoked from crash handler paths.
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*/
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static efi_status_t
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query_variable_store_nonblocking(u32 attributes, unsigned long size)
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{
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efi_status_t status;
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u64 storage_size, remaining_size, max_size;
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status = efi.query_variable_info_nonblocking(attributes, &storage_size,
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&remaining_size,
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&max_size);
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if (status != EFI_SUCCESS)
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return status;
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if (remaining_size - size < EFI_MIN_RESERVE)
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return EFI_OUT_OF_RESOURCES;
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return EFI_SUCCESS;
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}
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/*
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* Some firmware implementations refuse to boot if there's insufficient space
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* in the variable store. Ensure that we never use more than a safe limit.
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*
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* Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
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* store.
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*/
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efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
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bool nonblocking)
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{
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efi_status_t status;
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u64 storage_size, remaining_size, max_size;
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if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
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return 0;
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if (nonblocking)
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return query_variable_store_nonblocking(attributes, size);
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status = efi.query_variable_info(attributes, &storage_size,
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&remaining_size, &max_size);
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if (status != EFI_SUCCESS)
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return status;
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/*
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* We account for that by refusing the write if permitting it would
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* reduce the available space to under 5KB. This figure was provided by
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* Samsung, so should be safe.
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*/
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if ((remaining_size - size < EFI_MIN_RESERVE) &&
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!efi_no_storage_paranoia) {
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/*
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* Triggering garbage collection may require that the firmware
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* generate a real EFI_OUT_OF_RESOURCES error. We can force
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* that by attempting to use more space than is available.
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*/
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unsigned long dummy_size = remaining_size + 1024;
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void *dummy = kzalloc(dummy_size, GFP_ATOMIC);
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if (!dummy)
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return EFI_OUT_OF_RESOURCES;
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status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
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EFI_VARIABLE_NON_VOLATILE |
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EFI_VARIABLE_BOOTSERVICE_ACCESS |
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EFI_VARIABLE_RUNTIME_ACCESS,
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dummy_size, dummy);
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if (status == EFI_SUCCESS) {
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/*
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* This should have failed, so if it didn't make sure
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* that we delete it...
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*/
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efi_delete_dummy_variable();
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}
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kfree(dummy);
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/*
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* The runtime code may now have triggered a garbage collection
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* run, so check the variable info again
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*/
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status = efi.query_variable_info(attributes, &storage_size,
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&remaining_size, &max_size);
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if (status != EFI_SUCCESS)
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return status;
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/*
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* There still isn't enough room, so return an error
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*/
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if (remaining_size - size < EFI_MIN_RESERVE)
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return EFI_OUT_OF_RESOURCES;
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}
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return EFI_SUCCESS;
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}
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EXPORT_SYMBOL_GPL(efi_query_variable_store);
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/*
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* The UEFI specification makes it clear that the operating system is
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* free to do whatever it wants with boot services code after
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* ExitBootServices() has been called. Ignoring this recommendation a
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* significant bunch of EFI implementations continue calling into boot
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* services code (SetVirtualAddressMap). In order to work around such
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* buggy implementations we reserve boot services region during EFI
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* init and make sure it stays executable. Then, after
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* SetVirtualAddressMap(), it is discarded.
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*
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* However, some boot services regions contain data that is required
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* by drivers, so we need to track which memory ranges can never be
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* freed. This is done by tagging those regions with the
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* EFI_MEMORY_RUNTIME attribute.
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*
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* Any driver that wants to mark a region as reserved must use
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* efi_mem_reserve() which will insert a new EFI memory descriptor
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* into efi.memmap (splitting existing regions if necessary) and tag
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* it with EFI_MEMORY_RUNTIME.
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*/
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void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
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{
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phys_addr_t new_phys, new_size;
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struct efi_mem_range mr;
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efi_memory_desc_t md;
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int num_entries;
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void *new;
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if (efi_mem_desc_lookup(addr, &md)) {
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pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
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return;
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}
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if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
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pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
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return;
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}
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size += addr % EFI_PAGE_SIZE;
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size = round_up(size, EFI_PAGE_SIZE);
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addr = round_down(addr, EFI_PAGE_SIZE);
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mr.range.start = addr;
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mr.range.end = addr + size - 1;
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mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
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num_entries = efi_memmap_split_count(&md, &mr.range);
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num_entries += efi.memmap.nr_map;
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new_size = efi.memmap.desc_size * num_entries;
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new_phys = memblock_alloc(new_size, 0);
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if (!new_phys) {
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pr_err("Could not allocate boot services memmap\n");
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return;
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}
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new = early_memremap(new_phys, new_size);
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if (!new) {
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pr_err("Failed to map new boot services memmap\n");
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return;
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}
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efi_memmap_insert(&efi.memmap, new, &mr);
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early_memunmap(new, new_size);
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efi_memmap_install(new_phys, num_entries);
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}
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/*
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* Helper function for efi_reserve_boot_services() to figure out if we
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* can free regions in efi_free_boot_services().
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*
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* Use this function to ensure we do not free regions owned by somebody
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* else. We must only reserve (and then free) regions:
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*
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* - Not within any part of the kernel
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* - Not the BIOS reserved area (E820_RESERVED, E820_NVS, etc)
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*/
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static bool can_free_region(u64 start, u64 size)
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{
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if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
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return false;
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if (!e820_all_mapped(start, start+size, E820_RAM))
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return false;
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return true;
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}
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void __init efi_reserve_boot_services(void)
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{
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efi_memory_desc_t *md;
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for_each_efi_memory_desc(md) {
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u64 start = md->phys_addr;
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u64 size = md->num_pages << EFI_PAGE_SHIFT;
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bool already_reserved;
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if (md->type != EFI_BOOT_SERVICES_CODE &&
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md->type != EFI_BOOT_SERVICES_DATA)
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continue;
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already_reserved = memblock_is_region_reserved(start, size);
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/*
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* Because the following memblock_reserve() is paired
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* with free_bootmem_late() for this region in
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* efi_free_boot_services(), we must be extremely
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* careful not to reserve, and subsequently free,
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* critical regions of memory (like the kernel image) or
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* those regions that somebody else has already
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* reserved.
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*
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* A good example of a critical region that must not be
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* freed is page zero (first 4Kb of memory), which may
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* contain boot services code/data but is marked
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* E820_RESERVED by trim_bios_range().
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*/
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if (!already_reserved) {
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memblock_reserve(start, size);
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/*
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* If we are the first to reserve the region, no
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* one else cares about it. We own it and can
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* free it later.
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*/
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if (can_free_region(start, size))
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continue;
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}
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/*
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* We don't own the region. We must not free it.
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*
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* Setting this bit for a boot services region really
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* doesn't make sense as far as the firmware is
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* concerned, but it does provide us with a way to tag
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* those regions that must not be paired with
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* free_bootmem_late().
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*/
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md->attribute |= EFI_MEMORY_RUNTIME;
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}
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}
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void __init efi_free_boot_services(void)
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{
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phys_addr_t new_phys, new_size;
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efi_memory_desc_t *md;
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int num_entries = 0;
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void *new, *new_md;
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for_each_efi_memory_desc(md) {
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unsigned long long start = md->phys_addr;
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unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
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size_t rm_size;
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if (md->type != EFI_BOOT_SERVICES_CODE &&
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md->type != EFI_BOOT_SERVICES_DATA) {
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num_entries++;
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continue;
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}
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/* Do not free, someone else owns it: */
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if (md->attribute & EFI_MEMORY_RUNTIME) {
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num_entries++;
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continue;
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}
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/*
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* Nasty quirk: if all sub-1MB memory is used for boot
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* services, we can get here without having allocated the
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* real mode trampoline. It's too late to hand boot services
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* memory back to the memblock allocator, so instead
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* try to manually allocate the trampoline if needed.
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*
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* I've seen this on a Dell XPS 13 9350 with firmware
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* 1.4.4 with SGX enabled booting Linux via Fedora 24's
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* grub2-efi on a hard disk. (And no, I don't know why
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* this happened, but Linux should still try to boot rather
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* panicing early.)
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*/
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rm_size = real_mode_size_needed();
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if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
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set_real_mode_mem(start, rm_size);
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start += rm_size;
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size -= rm_size;
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}
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free_bootmem_late(start, size);
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}
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new_size = efi.memmap.desc_size * num_entries;
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new_phys = memblock_alloc(new_size, 0);
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if (!new_phys) {
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pr_err("Failed to allocate new EFI memmap\n");
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return;
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}
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new = memremap(new_phys, new_size, MEMREMAP_WB);
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if (!new) {
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pr_err("Failed to map new EFI memmap\n");
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return;
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}
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/*
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* Build a new EFI memmap that excludes any boot services
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* regions that are not tagged EFI_MEMORY_RUNTIME, since those
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* regions have now been freed.
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*/
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new_md = new;
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for_each_efi_memory_desc(md) {
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if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
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(md->type == EFI_BOOT_SERVICES_CODE ||
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md->type == EFI_BOOT_SERVICES_DATA))
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continue;
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memcpy(new_md, md, efi.memmap.desc_size);
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new_md += efi.memmap.desc_size;
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}
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memunmap(new);
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if (efi_memmap_install(new_phys, num_entries)) {
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pr_err("Could not install new EFI memmap\n");
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return;
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}
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}
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/*
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* A number of config table entries get remapped to virtual addresses
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* after entering EFI virtual mode. However, the kexec kernel requires
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* their physical addresses therefore we pass them via setup_data and
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* correct those entries to their respective physical addresses here.
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*
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* Currently only handles smbios which is necessary for some firmware
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* implementation.
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*/
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int __init efi_reuse_config(u64 tables, int nr_tables)
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{
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int i, sz, ret = 0;
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void *p, *tablep;
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struct efi_setup_data *data;
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if (!efi_setup)
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return 0;
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if (!efi_enabled(EFI_64BIT))
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return 0;
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data = early_memremap(efi_setup, sizeof(*data));
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if (!data) {
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ret = -ENOMEM;
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goto out;
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}
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if (!data->smbios)
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goto out_memremap;
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sz = sizeof(efi_config_table_64_t);
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p = tablep = early_memremap(tables, nr_tables * sz);
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if (!p) {
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pr_err("Could not map Configuration table!\n");
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ret = -ENOMEM;
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goto out_memremap;
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}
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for (i = 0; i < efi.systab->nr_tables; i++) {
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efi_guid_t guid;
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guid = ((efi_config_table_64_t *)p)->guid;
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if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
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((efi_config_table_64_t *)p)->table = data->smbios;
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p += sz;
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}
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early_memunmap(tablep, nr_tables * sz);
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out_memremap:
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early_memunmap(data, sizeof(*data));
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out:
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return ret;
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}
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static const struct dmi_system_id sgi_uv1_dmi[] = {
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{ NULL, "SGI UV1",
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{ DMI_MATCH(DMI_PRODUCT_NAME, "Stoutland Platform"),
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DMI_MATCH(DMI_PRODUCT_VERSION, "1.0"),
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DMI_MATCH(DMI_BIOS_VENDOR, "SGI.COM"),
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}
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},
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{ } /* NULL entry stops DMI scanning */
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};
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void __init efi_apply_memmap_quirks(void)
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{
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/*
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* Once setup is done earlier, unmap the EFI memory map on mismatched
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* firmware/kernel architectures since there is no support for runtime
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* services.
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*/
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if (!efi_runtime_supported()) {
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pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
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efi_memmap_unmap();
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}
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/* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */
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if (dmi_check_system(sgi_uv1_dmi))
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set_bit(EFI_OLD_MEMMAP, &efi.flags);
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}
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/*
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* For most modern platforms the preferred method of powering off is via
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* ACPI. However, there are some that are known to require the use of
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* EFI runtime services and for which ACPI does not work at all.
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*
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* Using EFI is a last resort, to be used only if no other option
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* exists.
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*/
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bool efi_reboot_required(void)
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{
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if (!acpi_gbl_reduced_hardware)
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return false;
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|
|
|
efi_reboot_quirk_mode = EFI_RESET_WARM;
|
|
return true;
|
|
}
|
|
|
|
bool efi_poweroff_required(void)
|
|
{
|
|
return acpi_gbl_reduced_hardware || acpi_no_s5;
|
|
}
|