Commit a758379b authored by Linus Torvalds's avatar Linus Torvalds

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

Pull EFI fixes from Ingo Molnar:
 "Two EFI fixes: one for x86, one for ARM, fixing a boot crash bug that
  can trigger under newer EFI firmware"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64/efi: Fix boot crash by not padding between EFI_MEMORY_RUNTIME regions
  x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down
parents 14f97d97 0ce3cc00
......@@ -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;
......
......@@ -704,6 +704,70 @@ out:
return ret;
}
/*
* 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
......
......@@ -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;
......
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