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path: root/drivers/firmware/efi/libstub/arm-stub.c
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Diffstat (limited to 'drivers/firmware/efi/libstub/arm-stub.c')
-rw-r--r--drivers/firmware/efi/libstub/arm-stub.c88
1 files changed, 73 insertions, 15 deletions
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 @@ fail:
*/
#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;