x86/efi: Round EFI memmap reservations to EFI_PAGE_SIZE

Mike Galbraith reported that his machine started rebooting during boot
after,

  commit 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")

The ESRT table on his machine is 56 bytes and at no point in the
efi_arch_mem_reserve() call path is that size rounded up to
EFI_PAGE_SIZE, nor is the start address on an EFI_PAGE_SIZE boundary.

Since the EFI memory map only deals with whole pages, inserting an EFI
memory region with 56 bytes results in a new entry covering zero
pages, and completely screws up the calculations for the old regions
that were trimmed.

Round all sizes upwards, and start addresses downwards, to the nearest
EFI_PAGE_SIZE boundary.

Additionally, efi_memmap_insert() expects the mem::range::end value to
be one less than the end address for the region.

Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Reported-by: Mike Krinkin <krinkin.m.u@gmail.com>
Tested-by: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index f14b7a9..10aca63 100644 (file)
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -201,8 +201,12 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
                return;
        }
 
+       size += addr % EFI_PAGE_SIZE;
+       size = round_up(size, EFI_PAGE_SIZE);
+       addr = round_down(addr, EFI_PAGE_SIZE);
+
        mr.range.start = addr;
-       mr.range.end = addr + size;
+       mr.range.end = addr + size - 1;
        mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
 
        num_entries = efi_memmap_split_count(&md, &mr.range);

diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c
index cd96086..f03ddec 100644 (file)
--- a/drivers/firmware/efi/memmap.c
+++ b/drivers/firmware/efi/memmap.c
@@ -225,6 +225,17 @@ void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
        m_end = mem->range.end;
        m_attr = mem->attribute;
 
+       /*
+        * The EFI memory map deals with regions in EFI_PAGE_SIZE
+        * units. Ensure that the region described by 'mem' is aligned
+        * correctly.
+        */
+       if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
+           !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
+               WARN_ON(1);
+               return;
+       }
+
        for (old = old_memmap->map, new = buf;
             old < old_memmap->map_end;
             old += old_memmap->desc_size, new += old_memmap->desc_size) {