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Date: Sat, 3 Oct 2015 12:11:55 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org,
Matt Fleming <matt.fleming@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] EFI fixes
Linus,
Please pull the latest core-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core-urgent-for-linus
# HEAD: 0ce3cc008ec04258b6a6314b09f1a6012810881a arm64/efi: Fix boot crash by not padding between EFI_MEMORY_RUNTIME regions
Two EFI fixes: one for x86, one for ARM, fixing a boot crash bug that can trigger
under newer EFI firmware.
Thanks,
Ingo
------------------>
Ard Biesheuvel (1):
arm64/efi: Fix boot crash by not padding between EFI_MEMORY_RUNTIME regions
Matt Fleming (1):
x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down
arch/arm64/kernel/efi.c | 3 +-
arch/x86/platform/efi/efi.c | 67 ++++++++++++++++++++++++-
drivers/firmware/efi/libstub/arm-stub.c | 88 +++++++++++++++++++++++++++------
3 files changed, 141 insertions(+), 17 deletions(-)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index e8ca6eaedd02..13671a9cf016 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -258,7 +258,8 @@ static bool __init efi_virtmap_init(void)
*/
if (!is_normal_ram(md))
prot = __pgprot(PROT_DEVICE_nGnRE);
- else if (md->type == EFI_RUNTIME_SERVICES_CODE)
+ else if (md->type == EFI_RUNTIME_SERVICES_CODE ||
+ !PAGE_ALIGNED(md->phys_addr))
prot = PAGE_KERNEL_EXEC;
else
prot = PAGE_KERNEL;
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 1db84c0758b7..6a28ded74211 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -705,6 +705,70 @@ static void *realloc_pages(void *old_memmap, int old_shift)
}
/*
+ * Iterate the EFI memory map in reverse order because the regions
+ * will be mapped top-down. The end result is the same as if we had
+ * mapped things forward, but doesn't require us to change the
+ * existing implementation of efi_map_region().
+ */
+static inline void *efi_map_next_entry_reverse(void *entry)
+{
+ /* Initial call */
+ if (!entry)
+ return memmap.map_end - memmap.desc_size;
+
+ entry -= memmap.desc_size;
+ if (entry < memmap.map)
+ return NULL;
+
+ return entry;
+}
+
+/*
+ * efi_map_next_entry - Return the next EFI memory map descriptor
+ * @entry: Previous EFI memory map descriptor
+ *
+ * This is a helper function to iterate over the EFI memory map, which
+ * we do in different orders depending on the current configuration.
+ *
+ * To begin traversing the memory map @entry must be %NULL.
+ *
+ * Returns %NULL when we reach the end of the memory map.
+ */
+static void *efi_map_next_entry(void *entry)
+{
+ if (!efi_enabled(EFI_OLD_MEMMAP) && efi_enabled(EFI_64BIT)) {
+ /*
+ * Starting in UEFI v2.5 the EFI_PROPERTIES_TABLE
+ * config table feature requires us to map all entries
+ * in the same order as they appear in the EFI memory
+ * map. That is to say, entry N must have a lower
+ * virtual address than entry N+1. This is because the
+ * firmware toolchain leaves relative references in
+ * the code/data sections, which are split and become
+ * separate EFI memory regions. Mapping things
+ * out-of-order leads to the firmware accessing
+ * unmapped addresses.
+ *
+ * Since we need to map things this way whether or not
+ * the kernel actually makes use of
+ * EFI_PROPERTIES_TABLE, let's just switch to this
+ * scheme by default for 64-bit.
+ */
+ return efi_map_next_entry_reverse(entry);
+ }
+
+ /* Initial call */
+ if (!entry)
+ return memmap.map;
+
+ entry += memmap.desc_size;
+ if (entry >= memmap.map_end)
+ return NULL;
+
+ return entry;
+}
+
+/*
* Map the efi memory ranges of the runtime services and update new_mmap with
* virtual addresses.
*/
@@ -714,7 +778,8 @@ static void * __init efi_map_regions(int *count, int *pg_shift)
unsigned long left = 0;
efi_memory_desc_t *md;
- for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+ p = NULL;
+ while ((p = efi_map_next_entry(p))) {
md = p;
if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
#ifdef CONFIG_X86_64
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index e29560e6b40b..950c87f5d279 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -13,6 +13,7 @@
*/
#include <linux/efi.h>
+#include <linux/sort.h>
#include <asm/efi.h>
#include "efistub.h"
@@ -305,6 +306,44 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
*/
#define EFI_RT_VIRTUAL_BASE 0x40000000
+static int cmp_mem_desc(const void *l, const void *r)
+{
+ const efi_memory_desc_t *left = l, *right = r;
+
+ return (left->phys_addr > right->phys_addr) ? 1 : -1;
+}
+
+/*
+ * Returns whether region @left ends exactly where region @right starts,
+ * or false if either argument is NULL.
+ */
+static bool regions_are_adjacent(efi_memory_desc_t *left,
+ efi_memory_desc_t *right)
+{
+ u64 left_end;
+
+ if (left == NULL || right == NULL)
+ return false;
+
+ left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
+
+ return left_end == right->phys_addr;
+}
+
+/*
+ * Returns whether region @left and region @right have compatible memory type
+ * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
+ */
+static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
+ efi_memory_desc_t *right)
+{
+ static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
+ EFI_MEMORY_WC | EFI_MEMORY_UC |
+ EFI_MEMORY_RUNTIME;
+
+ return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
+}
+
/*
* efi_get_virtmap() - create a virtual mapping for the EFI memory map
*
@@ -317,33 +356,52 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
int *count)
{
u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
- efi_memory_desc_t *out = runtime_map;
+ efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
int l;
- for (l = 0; l < map_size; l += desc_size) {
- efi_memory_desc_t *in = (void *)memory_map + l;
+ /*
+ * To work around potential issues with the Properties Table feature
+ * introduced in UEFI 2.5, which may split PE/COFF executable images
+ * in memory into several RuntimeServicesCode and RuntimeServicesData
+ * regions, we need to preserve the relative offsets between adjacent
+ * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
+ * The easiest way to find adjacent regions is to sort the memory map
+ * before traversing it.
+ */
+ sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
+
+ for (l = 0; l < map_size; l += desc_size, prev = in) {
u64 paddr, size;
+ in = (void *)memory_map + l;
if (!(in->attribute & EFI_MEMORY_RUNTIME))
continue;
+ paddr = in->phys_addr;
+ size = in->num_pages * EFI_PAGE_SIZE;
+
/*
* Make the mapping compatible with 64k pages: this allows
* a 4k page size kernel to kexec a 64k page size kernel and
* vice versa.
*/
- paddr = round_down(in->phys_addr, SZ_64K);
- size = round_up(in->num_pages * EFI_PAGE_SIZE +
- in->phys_addr - paddr, SZ_64K);
-
- /*
- * Avoid wasting memory on PTEs by choosing a virtual base that
- * is compatible with section mappings if this region has the
- * appropriate size and physical alignment. (Sections are 2 MB
- * on 4k granule kernels)
- */
- if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
- efi_virt_base = round_up(efi_virt_base, SZ_2M);
+ if (!regions_are_adjacent(prev, in) ||
+ !regions_have_compatible_memory_type_attrs(prev, in)) {
+
+ paddr = round_down(in->phys_addr, SZ_64K);
+ size += in->phys_addr - paddr;
+
+ /*
+ * Avoid wasting memory on PTEs by choosing a virtual
+ * base that is compatible with section mappings if this
+ * region has the appropriate size and physical
+ * alignment. (Sections are 2 MB on 4k granule kernels)
+ */
+ if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
+ efi_virt_base = round_up(efi_virt_base, SZ_2M);
+ else
+ efi_virt_base = round_up(efi_virt_base, SZ_64K);
+ }
in->virt_addr = efi_virt_base + in->phys_addr - paddr;
efi_virt_base += size;
--
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