93 lines
4.0 KiB
Diff
93 lines
4.0 KiB
Diff
From patchwork Wed Mar 30 07:46:23 2016
|
|
Content-Type: text/plain; charset="utf-8"
|
|
MIME-Version: 1.0
|
|
Content-Transfer-Encoding: 7bit
|
|
Subject: efi/arm64: don't apply MEMBLOCK_NOMAP to UEFI memory map mapping
|
|
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
|
|
X-Patchwork-Id: 8693271
|
|
Message-Id: <1459323983-9120-1-git-send-email-ard.biesheuvel@linaro.org>
|
|
To: linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
|
|
matt@codeblueprint.co.uk
|
|
Cc: mark.rutland@arm.com, mlangsdo@redhat.com,
|
|
Ard Biesheuvel <ard.biesheuvel@linaro.org>, leif.lindholm@linaro.org,
|
|
jeremy.linton@arm.com, msalter@redhat.com
|
|
Date: Wed, 30 Mar 2016 09:46:23 +0200
|
|
|
|
Hi Matt,
|
|
|
|
Could we queue this as a fix for v4.6 with a cc:stable for v4.5, please?
|
|
(assuming no objections from any of the cc'ees)
|
|
|
|
Thanks,
|
|
Ard.
|
|
|
|
----------8<--------------
|
|
Commit 4dffbfc48d65 ("arm64/efi: mark UEFI reserved regions as
|
|
MEMBLOCK_NOMAP") updated the mapping logic of both the RuntimeServices
|
|
regions as well as the kernel's copy of the UEFI memory map to set the
|
|
MEMBLOCK_NOMAP flag, which causes these regions to be omitted from the
|
|
kernel direct mapping, and from being covered by a struct page.
|
|
For the RuntimeServices regions, this is an obvious win, since the contents
|
|
of these regions have significance to the firmware executable code itself,
|
|
and are mapped in the EFI page tables using attributes that are described in
|
|
the UEFI memory map, and which may differ from the attributes we use for
|
|
mapping system RAM. It also prevents the contents from being modified
|
|
inadvertently, since the EFI page tables are only live during runtime
|
|
service invocations.
|
|
|
|
None of these concerns apply to the allocation that covers the UEFI memory
|
|
map, since it is entirely owned by the kernel. Setting the MEMBLOCK_NOMAP on
|
|
the region did allow us to use ioremap_cache() to map it both on arm64 and
|
|
on ARM, since the latter does not allow ioremap_cache() to be used on
|
|
regions that are covered by a struct page.
|
|
|
|
The ioremap_cache() on ARM restriction will be lifted in the v4.7 timeframe,
|
|
but in the mean time, it has been reported that commit 4dffbfc48d65 causes
|
|
a regression on 64k granule kernels. This is due to the fact that, given
|
|
the 64 KB page size, the region that we end up removing from the kernel
|
|
direct mapping is rounded up to 64 KB, and this 64 KB page frame may be
|
|
shared with the initrd when booting via GRUB (which does not align its
|
|
EFI_LOADER_DATA allocations to 64 KB like the stub does). This will crash
|
|
the kernel as soon as it tries to access the initrd.
|
|
|
|
Since the issue is specific to arm64, revert back to memblock_reserve()'ing
|
|
the UEFI memory map when running on arm64. This is a temporary fix for v4.5
|
|
and v4.6, and will be superseded in the v4.7 timeframe when we will be able
|
|
to move back to memblock_reserve() unconditionally.
|
|
|
|
Fixes: 4dffbfc48d65 ("arm64/efi: mark UEFI reserved regions as MEMBLOCK_NOMAP")
|
|
Reported-by: Mark Salter <msalter@redhat.com>
|
|
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
|
|
|
|
---
|
|
drivers/firmware/efi/arm-init.c | 18 +++++++++++++++---
|
|
1 file changed, 15 insertions(+), 3 deletions(-)
|
|
|
|
diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
|
|
index aa1f743152a2..8714f8c271ba 100644
|
|
--- a/drivers/firmware/efi/arm-init.c
|
|
+++ b/drivers/firmware/efi/arm-init.c
|
|
@@ -203,7 +203,19 @@ void __init efi_init(void)
|
|
|
|
reserve_regions();
|
|
early_memunmap(memmap.map, params.mmap_size);
|
|
- memblock_mark_nomap(params.mmap & PAGE_MASK,
|
|
- PAGE_ALIGN(params.mmap_size +
|
|
- (params.mmap & ~PAGE_MASK)));
|
|
+
|
|
+ if (IS_ENABLED(CONFIG_ARM)) {
|
|
+ /*
|
|
+ * ARM currently does not allow ioremap_cache() to be called on
|
|
+ * memory regions that are covered by struct page. So remove the
|
|
+ * UEFI memory map from the linear mapping.
|
|
+ */
|
|
+ memblock_mark_nomap(params.mmap & PAGE_MASK,
|
|
+ PAGE_ALIGN(params.mmap_size +
|
|
+ (params.mmap & ~PAGE_MASK)));
|
|
+ } else {
|
|
+ memblock_reserve(params.mmap & PAGE_MASK,
|
|
+ PAGE_ALIGN(params.mmap_size +
|
|
+ (params.mmap & ~PAGE_MASK)));
|
|
+ }
|
|
}
|