2015-11-30 13:28:18 +01:00
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/*
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* Extensible Firmware Interface
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*
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* Based on Extensible Firmware Interface Specification version 2.4
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*
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* Copyright (C) 2013, 2014 Linaro Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/efi.h>
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2015-11-30 13:28:19 +01:00
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#include <linux/io.h>
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2015-11-30 13:28:18 +01:00
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#include <linux/memblock.h>
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#include <linux/mm_types.h>
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#include <linux/preempt.h>
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#include <linux/rbtree.h>
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#include <linux/rwsem.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <asm/cacheflush.h>
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#include <asm/efi.h>
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#include <asm/mmu.h>
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2015-11-30 13:28:19 +01:00
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#include <asm/pgalloc.h>
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2015-11-30 13:28:18 +01:00
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#include <asm/pgtable.h>
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extern u64 efi_system_table;
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static struct mm_struct efi_mm = {
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.mm_rb = RB_ROOT,
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.mm_users = ATOMIC_INIT(2),
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.mm_count = ATOMIC_INIT(1),
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.mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
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.page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
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.mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
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};
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static bool __init efi_virtmap_init(void)
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{
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efi_memory_desc_t *md;
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efi/arm*: Drop writable mapping of the UEFI System table
Commit:
2eec5dedf770 ("efi/arm-init: Use read-only early mappings")
updated the early ARM UEFI init code to create the temporary, early
mapping of the UEFI System table using read-only attributes, as a
hardening measure against inadvertent modification.
However, this still leaves the permanent, writable mapping of the UEFI
System table, which is only ever referenced during invocations of UEFI
Runtime Services, at which time the UEFI virtual mapping is available,
which also covers the system table. (This is guaranteed by the fact that
SetVirtualAddressMap(), which is a runtime service itself, converts
various entries in the table to their virtual equivalents, which implies
that the table must be covered by a RuntimeServicesData region that has
the EFI_MEMORY_RUNTIME attribute.)
So instead of creating this permanent mapping, record the virtual address
of the system table inside the UEFI virtual mapping, and dereference that
when accessing the table. This protects the contents of the system table
from inadvertent (or deliberate) modification when no UEFI Runtime
Services calls are in progress.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.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/1461614832-17633-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-25 22:06:34 +02:00
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bool systab_found;
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2015-11-30 13:28:18 +01:00
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2015-11-30 13:28:19 +01:00
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efi_mm.pgd = pgd_alloc(&efi_mm);
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2015-11-30 13:28:18 +01:00
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init_new_context(NULL, &efi_mm);
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efi/arm*: Drop writable mapping of the UEFI System table
Commit:
2eec5dedf770 ("efi/arm-init: Use read-only early mappings")
updated the early ARM UEFI init code to create the temporary, early
mapping of the UEFI System table using read-only attributes, as a
hardening measure against inadvertent modification.
However, this still leaves the permanent, writable mapping of the UEFI
System table, which is only ever referenced during invocations of UEFI
Runtime Services, at which time the UEFI virtual mapping is available,
which also covers the system table. (This is guaranteed by the fact that
SetVirtualAddressMap(), which is a runtime service itself, converts
various entries in the table to their virtual equivalents, which implies
that the table must be covered by a RuntimeServicesData region that has
the EFI_MEMORY_RUNTIME attribute.)
So instead of creating this permanent mapping, record the virtual address
of the system table inside the UEFI virtual mapping, and dereference that
when accessing the table. This protects the contents of the system table
from inadvertent (or deliberate) modification when no UEFI Runtime
Services calls are in progress.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.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/1461614832-17633-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-25 22:06:34 +02:00
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systab_found = false;
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2016-04-25 22:06:38 +02:00
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for_each_efi_memory_desc(md) {
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2015-11-30 13:28:19 +01:00
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phys_addr_t phys = md->phys_addr;
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int ret;
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2015-11-30 13:28:18 +01:00
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if (!(md->attribute & EFI_MEMORY_RUNTIME))
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continue;
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if (md->virt_addr == 0)
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return false;
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2015-11-30 13:28:19 +01:00
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ret = efi_create_mapping(&efi_mm, md);
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if (!ret) {
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pr_info(" EFI remap %pa => %p\n",
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&phys, (void *)(unsigned long)md->virt_addr);
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} else {
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pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
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&phys, ret);
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return false;
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}
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efi/arm*: Drop writable mapping of the UEFI System table
Commit:
2eec5dedf770 ("efi/arm-init: Use read-only early mappings")
updated the early ARM UEFI init code to create the temporary, early
mapping of the UEFI System table using read-only attributes, as a
hardening measure against inadvertent modification.
However, this still leaves the permanent, writable mapping of the UEFI
System table, which is only ever referenced during invocations of UEFI
Runtime Services, at which time the UEFI virtual mapping is available,
which also covers the system table. (This is guaranteed by the fact that
SetVirtualAddressMap(), which is a runtime service itself, converts
various entries in the table to their virtual equivalents, which implies
that the table must be covered by a RuntimeServicesData region that has
the EFI_MEMORY_RUNTIME attribute.)
So instead of creating this permanent mapping, record the virtual address
of the system table inside the UEFI virtual mapping, and dereference that
when accessing the table. This protects the contents of the system table
from inadvertent (or deliberate) modification when no UEFI Runtime
Services calls are in progress.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.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/1461614832-17633-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-25 22:06:34 +02:00
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/*
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* If this entry covers the address of the UEFI system table,
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* calculate and record its virtual address.
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*/
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if (efi_system_table >= phys &&
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efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
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efi.systab = (void *)(unsigned long)(efi_system_table -
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phys + md->virt_addr);
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systab_found = true;
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}
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2015-11-30 13:28:18 +01:00
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}
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2016-04-25 22:06:46 +02:00
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if (!systab_found) {
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efi/arm*: Drop writable mapping of the UEFI System table
Commit:
2eec5dedf770 ("efi/arm-init: Use read-only early mappings")
updated the early ARM UEFI init code to create the temporary, early
mapping of the UEFI System table using read-only attributes, as a
hardening measure against inadvertent modification.
However, this still leaves the permanent, writable mapping of the UEFI
System table, which is only ever referenced during invocations of UEFI
Runtime Services, at which time the UEFI virtual mapping is available,
which also covers the system table. (This is guaranteed by the fact that
SetVirtualAddressMap(), which is a runtime service itself, converts
various entries in the table to their virtual equivalents, which implies
that the table must be covered by a RuntimeServicesData region that has
the EFI_MEMORY_RUNTIME attribute.)
So instead of creating this permanent mapping, record the virtual address
of the system table inside the UEFI virtual mapping, and dereference that
when accessing the table. This protects the contents of the system table
from inadvertent (or deliberate) modification when no UEFI Runtime
Services calls are in progress.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.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/1461614832-17633-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-25 22:06:34 +02:00
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pr_err("No virtual mapping found for the UEFI System Table\n");
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2016-04-25 22:06:46 +02:00
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return false;
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}
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if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
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return false;
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return true;
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2015-11-30 13:28:18 +01:00
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}
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/*
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* Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
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* non-early mapping of the UEFI system table and virtual mappings for all
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* EFI_MEMORY_RUNTIME regions.
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*/
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2015-11-30 13:28:19 +01:00
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static int __init arm_enable_runtime_services(void)
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2015-11-30 13:28:18 +01:00
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{
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u64 mapsize;
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if (!efi_enabled(EFI_BOOT)) {
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pr_info("EFI services will not be available.\n");
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return 0;
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}
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if (efi_runtime_disabled()) {
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pr_info("EFI runtime services will be disabled.\n");
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return 0;
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}
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2016-05-12 14:19:54 +02:00
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if (efi_enabled(EFI_RUNTIME_SERVICES)) {
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pr_info("EFI runtime services access via paravirt.\n");
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return 0;
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}
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2015-11-30 13:28:18 +01:00
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pr_info("Remapping and enabling EFI services.\n");
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2016-04-25 22:06:39 +02:00
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mapsize = efi.memmap.map_end - efi.memmap.map;
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2016-04-25 22:06:41 +02:00
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efi.memmap.map = memremap(efi.memmap.phys_map, mapsize, MEMREMAP_WB);
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2016-04-25 22:06:39 +02:00
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if (!efi.memmap.map) {
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2015-11-30 13:28:18 +01:00
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pr_err("Failed to remap EFI memory map\n");
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return -ENOMEM;
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}
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2016-04-25 22:06:39 +02:00
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efi.memmap.map_end = efi.memmap.map + mapsize;
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2015-11-30 13:28:18 +01:00
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if (!efi_virtmap_init()) {
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efi/arm*: Drop writable mapping of the UEFI System table
Commit:
2eec5dedf770 ("efi/arm-init: Use read-only early mappings")
updated the early ARM UEFI init code to create the temporary, early
mapping of the UEFI System table using read-only attributes, as a
hardening measure against inadvertent modification.
However, this still leaves the permanent, writable mapping of the UEFI
System table, which is only ever referenced during invocations of UEFI
Runtime Services, at which time the UEFI virtual mapping is available,
which also covers the system table. (This is guaranteed by the fact that
SetVirtualAddressMap(), which is a runtime service itself, converts
various entries in the table to their virtual equivalents, which implies
that the table must be covered by a RuntimeServicesData region that has
the EFI_MEMORY_RUNTIME attribute.)
So instead of creating this permanent mapping, record the virtual address
of the system table inside the UEFI virtual mapping, and dereference that
when accessing the table. This protects the contents of the system table
from inadvertent (or deliberate) modification when no UEFI Runtime
Services calls are in progress.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.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/1461614832-17633-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-25 22:06:34 +02:00
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pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
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2015-11-30 13:28:18 +01:00
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return -ENOMEM;
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}
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/* Set up runtime services function pointers */
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efi_native_runtime_setup();
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set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
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return 0;
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}
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2015-11-30 13:28:19 +01:00
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early_initcall(arm_enable_runtime_services);
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2015-11-30 13:28:18 +01:00
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void efi_virtmap_load(void)
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{
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preempt_disable();
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efi_set_pgd(&efi_mm);
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}
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void efi_virtmap_unload(void)
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{
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efi_set_pgd(current->active_mm);
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preempt_enable();
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}
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