diff options
Diffstat (limited to 'freed-ora/current/f24/efi-arm64-don-t-apply-MEMBLOCK_NOMAP-to-UEFI-memory-map-mapping.patch')
| -rw-r--r-- | freed-ora/current/f24/efi-arm64-don-t-apply-MEMBLOCK_NOMAP-to-UEFI-memory-map-mapping.patch | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/freed-ora/current/f24/efi-arm64-don-t-apply-MEMBLOCK_NOMAP-to-UEFI-memory-map-mapping.patch b/freed-ora/current/f24/efi-arm64-don-t-apply-MEMBLOCK_NOMAP-to-UEFI-memory-map-mapping.patch new file mode 100644 index 000000000..2e3ae0c9b --- /dev/null +++ b/freed-ora/current/f24/efi-arm64-don-t-apply-MEMBLOCK_NOMAP-to-UEFI-memory-map-mapping.patch @@ -0,0 +1,92 @@ +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))); ++ } + } |
