Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:
 "The main changes are KASL related fixes and cleanups: in particular we
  now exclude certain physical memory ranges as KASLR randomization
  targets that have proven to be unreliable (early-)RAM on some firmware
  versions"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot/KASLR: Work around firmware bugs by excluding EFI_BOOT_SERVICES_* and EFI_LOADER_* from KASLR's choice
  x86/boot/KASLR: Prefer mirrored memory regions for the kernel physical address
  efi: Introduce efi_early_memdesc_ptr to get pointer to memmap descriptor
  x86/boot/KASLR: Rename process_e820_entry() into process_mem_region()
  x86/boot/KASLR: Switch to pass struct mem_vector to process_e820_entry()
  x86/boot/KASLR: Wrap e820 entries walking code into new function process_e820_entries()

1 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8269bcb8ccf7..a686ca9a7e5c 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1020,6 +1020,28 @@ extern int efi_memattr_init(void);
 extern int efi_memattr_apply_permissions(struct mm_struct *mm,
 					 efi_memattr_perm_setter fn);
 
+/*
+ * efi_early_memdesc_ptr - get the n-th EFI memmap descriptor
+ * @map: the start of efi memmap
+ * @desc_size: the size of space for each EFI memmap descriptor
+ * @n: the index of efi memmap descriptor
+ *
+ * EFI boot service provides the GetMemoryMap() function to get a copy of the
+ * current memory map which is an array of memory descriptors, each of
+ * which describes a contiguous block of memory. It also gets the size of the
+ * map, and the size of each descriptor, etc.
+ *
+ * Note that per section 6.2 of UEFI Spec 2.6 Errata A, the returned size of
+ * each descriptor might not be equal to sizeof(efi_memory_memdesc_t),
+ * since efi_memory_memdesc_t may be extended in the future. Thus the OS
+ * MUST use the returned size of the descriptor to find the start of each
+ * efi_memory_memdesc_t in the memory map array. This should only be used
+ * during bootup since for_each_efi_memory_desc_xxx() is available after the
+ * kernel initializes the EFI subsystem to set up struct efi_memory_map.
+ */
+#define efi_early_memdesc_ptr(map, desc_size, n)			\
+	(efi_memory_desc_t *)((void *)(map) + ((n) * (desc_size)))
+
 /* Iterate through an efi_memory_map */
 #define for_each_efi_memory_desc_in_map(m, md)				   \
 	for ((md) = (m)->map;						   \