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Subject[PATCH] x86/efi: Round EFI memmap reservations to EFI_PAGE_SIZE
Date
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>
---
arch/x86/platform/efi/quirks.c | 6 +++++-
drivers/firmware/efi/memmap.c | 11 +++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index f14b7a9da24b..10aca63a50d7 100644
--- 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 cd96086fd851..f03ddecd232b 100644
--- 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) {
--
2.9.3
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