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commit ee8b8f5d83eb2c9caaebcf633310905ee76856e9 upstream.
After calling uefi interface allocate_pool to apply for memory, we
should clear 0 to prevent the possibility of using random values.
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
Cc: <stable@vger.kernel.org> # v6.6+
Fixes: 732ea9db9d8a ("efi: libstub: Move screen_info handling to common code")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ae835a96d72cd025421910edb0e8faf706998727 upstream.
This is a partial revert of commit
8117961d98f ("x86/efi: Disregard setup header of loaded image")
which triggers boot issues on older Dell laptops. As it turns out,
switching back to a heap allocation for the struct boot_params
constructed by the EFI stub works around this, even though it is unclear
why.
Cc: Christian Heusel <christian@heusel.eu>
Reported-by: <mavrix#kernel@simplelogin.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit fb318ca0a522295edd6d796fb987e99ec41f0ee5 upstream.
The fail label is only used in a situation where the previous EFI API
call succeeded, and so status will be set to EFI_SUCCESS. Fix this, by
dropping the goto entirely, and call efi_exit() with the correct error
code.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5134acb15d9ef27aa2b90aad46d4e89fcef79fdc ]
When building ARCH=loongarch defconfig + CONFIG_UNWINDER_ORC=y using
LLVM, there is a warning from ld.lld when linking the EFI zboot image
due to the use of unreachable() in number() in vsprintf.c:
ld.lld: warning: drivers/firmware/efi/libstub/lib.a(vsprintf.stub.o):(.discard.unreachable+0x0): has non-ABS relocation R_LARCH_32_PCREL against symbol ''
If the compiler cannot eliminate the default case for any reason, the
.discard.unreachable section will remain in the final binary but the
entire point of any section prefixed with .discard is that it is only
used at compile time, so it can be discarded via /DISCARD/ in a linker
script. The asm-generic vmlinux.lds.h includes .discard and .discard.*
in the COMMON_DISCARDS macro but that is not used for zboot.lds, as it
is not a kernel image linker script.
Add .discard and .discard.* to /DISCARD/ in zboot.lds, so that any
sections meant to be discarded at link time are not included in the
final zboot image. This issue is not specific to LoongArch, it is just
the first architecture to select CONFIG_OBJTOOL, which defines
annotate_unreachable() as an asm statement to add the
.discard.unreachable section, and use the EFI stub.
Closes: https://github.com/ClangBuiltLinux/linux/issues/2023
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit beb2800074c15362cf9f6c7301120910046d6556 ]
Currently kernel entry in head.S is in DMW address range, firmware is
instructed to jump to this address after loading the kernel image.
However kernel should not make any assumption on firmware's DMW
setting, thus the entry point should be a physical address falls into
direct translation region.
Fix by converting entry address to physical and amend entry calculation
logic in libstub accordingly.
BTW, use ABSOLUTE() to calculate variables to make Clang/LLVM happy.
Cc: stable@vger.kernel.org
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 174a0c565cea74a7811ff79fbee1b70247570ade ]
The use of the 'kernel_offset' variable to position the image file that
has been loaded by UEFI or GRUB is unnecessary, because we can directly
position the loaded image file through using the image_base field of the
efi_loaded_image struct provided by UEFI.
Replace kernel_offset with image_base to position the image file that has
been loaded by UEFI or GRUB.
Signed-off-by: Wang Yao <wangyao@lemote.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Stable-dep-of: beb2800074c1 ("LoongArch: Fix entry point in kernel image header")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 4b2543f7e1e6b91cfc8dd1696e3cdf01c3ac8974 upstream.
priv.runtime_map is only allocated when efi_novamap is not set.
Otherwise, it is an uninitialized value. In the error path, it is freed
unconditionally. Avoid passing an uninitialized value to free_pool.
Free priv.runtime_map only when it was allocated.
This bug was discovered and resolved using Coverity Static Analysis
Security Testing (SAST) by Synopsys, Inc.
Fixes: f80d26043af9 ("efi: libstub: avoid efi_get_memory_map() for allocating the virt map")
Cc: <stable@vger.kernel.org>
Signed-off-by: Hagar Hemdan <hagarhem@amazon.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 15aa8fb852f995dd234a57f12dfb989044968bb6 upstream.
The legacy decompressor has elaborate logic to ensure that the
randomized physical placement of the decompressed kernel image does not
conflict with any memory reservations, including ones specified on the
command line using mem=, memmap=, efi_fake_mem= or hugepages=, which are
taken into account by the kernel proper at a later stage.
When booting in EFI mode, it is the firmware's job to ensure that the
chosen range does not conflict with any memory reservations that it
knows about, and this is trivially achieved by using the firmware's
memory allocation APIs.
That leaves reservations specified on the command line, though, which
the firmware knows nothing about, as these regions have no other special
significance to the platform. Since commit
a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
these reservations are not taken into account when randomizing the
physical placement, which may result in conflicts where the memory
cannot be reserved by the kernel proper because its own executable image
resides there.
To avoid having to duplicate or reuse the existing complicated logic,
disable physical KASLR entirely when such overrides are specified. These
are mostly diagnostic tools or niche features, and physical KASLR (as
opposed to virtual KASLR, which is much more important as it affects the
memory addresses observed by code executing in the kernel) is something
we can live without.
Closes: https://lkml.kernel.org/r/FA5F6719-8824-4B04-803E-82990E65E627%40akamai.com
Reported-by: Ben Chaney <bchaney@akamai.com>
Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
Cc: <stable@vger.kernel.org> # v6.1+
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cd0d9d92c8bb46e77de62efd7df13069ddd61e7d upstream.
The early SME/SEV code parses the command line very early, in order to
decide whether or not memory encryption should be enabled, which needs
to occur even before the initial page tables are created.
This is problematic for a number of reasons:
- this early code runs from the 1:1 mapping provided by the decompressor
or firmware, which uses a different translation than the one assumed by
the linker, and so the code needs to be built in a special way;
- parsing external input while the entire kernel image is still mapped
writable is a bad idea in general, and really does not belong in
security minded code;
- the current code ignores the built-in command line entirely (although
this appears to be the case for the entire decompressor)
Given that the decompressor/EFI stub is an intrinsic part of the x86
bootable kernel image, move the command line parsing there and out of
the core kernel. This removes the need to build lib/cmdline.o in a
special way, or to use RIP-relative LEA instructions in inline asm
blocks.
This involves a new xloadflag in the setup header to indicate
that mem_encrypt=on appeared on the kernel command line.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240227151907.387873-17-ardb+git@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9c55461040a9264b7e44444c53d26480b438eda6 upstream.
Currently, the EFI stub invokes the EFI memory attributes protocol to
strip any NX restrictions from the entire loaded kernel, resulting in
all code and data being mapped read-write-execute.
The point of the EFI memory attributes protocol is to remove the need
for all memory allocations to be mapped with both write and execute
permissions by default, and make it the OS loader's responsibility to
transition data mappings to code mappings where appropriate.
Even though the UEFI specification does not appear to leave room for
denying memory attribute changes based on security policy, let's be
cautious and avoid relying on the ability to create read-write-execute
mappings. This is trivially achievable, given that the amount of kernel
code executing via the firmware's 1:1 mapping is rather small and
limited to the .head.text region. So let's drop the NX restrictions only
on that subregion, but not before remapping it as read-only first.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7205f06e847422b66c1506eee01b9998ffc75d76 upstream.
Parse the mem_encrypt= command line parameter from the EFI stub if
CONFIG_ARCH_HAS_MEM_ENCRYPT=y, so that it can be passed to the early
boot code by the arch code in the stub.
This avoids the need for the core kernel to do any string parsing very
early in the boot.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240227151907.387873-16-ardb+git@google.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit decd347c2a75d32984beb8807d470b763a53b542 upstream.
Commit
8117961d98fb2 ("x86/efi: Disregard setup header of loaded image")
dropped the memcopy of the image's setup header into the boot_params
struct provided to the core kernel, on the basis that EFI boot does not
need it and should rely only on a single protocol to interface with the
boot chain. It is also a prerequisite for being able to increase the
section alignment to 4k, which is needed to enable memory protections
when running in the boot services.
So only the setup_header fields that matter to the core kernel are
populated explicitly, and everything else is ignored. One thing was
overlooked, though: the initrd_addr_max field in the setup_header is not
used by the core kernel, but it is used by the EFI stub itself when it
loads the initrd, where its default value of INT_MAX is used as the soft
limit for memory allocation.
This means that, in the old situation, the initrd was virtually always
loaded in the lower 2G of memory, but now, due to initrd_addr_max being
0x0, the initrd may end up anywhere in memory. This should not be an
issue principle, as most systems can deal with this fine. However, it
does appear to tickle some problems in older UEFI implementations, where
the memory ends up being corrupted, resulting in errors when unpacking
the initramfs.
So set the initrd_addr_max field to INT_MAX like it was before.
Fixes: 8117961d98fb2 ("x86/efi: Disregard setup header of loaded image")
Reported-by: Radek Podgorny <radek@podgorny.cz>
Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 61d130f261a3c15ae2c4b6f3ac3517d5d5b78855 upstream.
Avoid a type mismatch warning in max() by switching to max_t() and
providing the type explicitly.
Fixes: 3cb4a4827596abc82e ("efi/libstub: fix efi_random_alloc() ...")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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higher address
[ Upstream commit 3cb4a4827596abc82e55b80364f509d0fefc3051 ]
Following warning is sometimes observed while booting my servers:
[ 3.594838] DMA: preallocated 4096 KiB GFP_KERNEL pool for atomic allocations
[ 3.602918] swapper/0: page allocation failure: order:10, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0-1
...
[ 3.851862] DMA: preallocated 1024 KiB GFP_KERNEL|GFP_DMA pool for atomic allocation
If 'nokaslr' boot option is set, the warning always happens.
On x86, ZONE_DMA is small zone at the first 16MB of physical address
space. When this problem happens, most of that space seems to be used by
decompressed kernel. Thereby, there is not enough space at DMA_ZONE to
meet the request of DMA pool allocation.
The commit 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below
LOAD_PHYSICAL_ADDR") tried to fix this problem by introducing lower
bound of allocation.
But the fix is not complete.
efi_random_alloc() allocates pages by following steps.
1. Count total available slots ('total_slots')
2. Select a slot ('target_slot') to allocate randomly
3. Calculate a starting address ('target') to be included target_slot
4. Allocate pages, which starting address is 'target'
In step 1, 'alloc_min' is used to offset the starting address of memory
chunk. But in step 3 'alloc_min' is not considered at all. As the
result, 'target' can be miscalculated and become lower than 'alloc_min'.
When KASLR is disabled, 'target_slot' is always 0 and the problem
happens everytime if the EFI memory map of the system meets the
condition.
Fix this problem by calculating 'target' considering 'alloc_min'.
Cc: linux-efi@vger.kernel.org
Cc: Tom Englund <tomenglund26@gmail.com>
Cc: linux-kernel@vger.kernel.org
Fixes: 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDR")
Signed-off-by: Kazuma Kondo <kazuma-kondo@nec.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit df7ecce842b846a04d087ba85fdb79a90e26a1b0 ]
Clearing BSS should only be done once, at the very beginning.
efi_pe_entry() is the entrypoint from the firmware, which may not clear
BSS and so it is done explicitly. However, efi_pe_entry() is also used
as an entrypoint by the mixed mode startup code, in which case BSS will
already have been cleared, and doing it again at this point will corrupt
global variables holding the firmware's GDT/IDT and segment selectors.
So make the memset() conditional on whether the EFI stub is running in
native mode.
Fixes: b3810c5a2cc4a666 ("x86/efistub: Clear decompressor BSS in native EFI entrypoint")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit b3810c5a2cc4a6665f7a65bed5393c75ce3f3aa2 ]
The EFI stub on x86 no longer invokes the decompressor as a subsequent
boot stage, but calls into the decompression code directly while running
in the context of the EFI boot services.
This means that when using the native EFI entrypoint (as opposed to the
EFI handover protocol, which clears BSS explicitly), the firmware PE
image loader is being relied upon to ensure that BSS is zeroed before
the EFI stub is entered from the firmware.
As Radek's report proves, this is a bad idea. Not all loaders do this
correctly, which means some global variables that should be statically
initialized to 0x0 may have junk in them.
So clear BSS explicitly when entering via efi_pe_entry(). Note that
zeroing BSS from C code is not generally safe, but in this case, the
following assignment and dereference of a global pointer variable
ensures that the memset() cannot be deferred or reordered.
Cc: <stable@kernel.org> # v6.1+
Reported-by: Radek Podgorny <radek@podgorny.cz>
Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit afb2a4fb84555ef9e61061f6ea63ed7087b295d5 upstream.
The cflags for the RISC-V efistub were missing -mno-relax, thus were
under the risk that the compiler could use GP-relative addressing. That
happened for _edata with binutils-2.41 and kernel 6.1, causing the
relocation to fail due to an invalid kernel_size in handle_kernel_image.
It was not yet observed with newer versions, but that may just be luck.
Cc: <stable@vger.kernel.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7e50262229faad0c7b8c54477cd1c883f31cc4a7 upstream.
The native EFI entrypoint does not take a struct boot_params from the
loader, but instead, it constructs one from scratch, using the setup
header data placed at the start of the image.
This setup header is placed in a way that permits legacy loaders to
manipulate the contents (i.e., to pass the kernel command line or the
address and size of an initial ramdisk), but EFI boot does not use it in
that way - it only copies the contents that were placed there at build
time, but EFI loaders will not (and should not) manipulate the setup
header to configure the boot. (Commit 63bf28ceb3ebbe76 "efi: x86: Wipe
setup_data on pure EFI boot" deals with some of the fallout of using
setup_data in a way that breaks EFI boot.)
Given that none of the non-zero values that are copied from the setup
header into the EFI stub's struct boot_params are relevant to the boot
now that the EFI stub no longer enters via the legacy decompressor, the
copy can be omitted altogether.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230912090051.4014114-19-ardb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5f51c5d0e905608ba7be126737f7c84a793ae1aa upstream.
Now that the EFI stub always zero inits its BSS section upon entry,
there is no longer a need to place the BSS symbols carried by the stub
into the .data section.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230912090051.4014114-18-ardb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 2f77465b05b1270c832b5e2ee27037672ad2a10a ]
The EFI stub's kernel placement logic randomizes the physical placement
of the kernel by taking all available memory into account, and picking a
region at random, based on a random seed.
When KASLR is disabled, this seed is set to 0x0, and this results in the
lowest available region of memory to be selected for loading the kernel,
even if this is below LOAD_PHYSICAL_ADDR. Some of this memory is
typically reserved for the GFP_DMA region, to accommodate masters that
can only access the first 16 MiB of system memory.
Even if such devices are rare these days, we may still end up with a
warning in the kernel log, as reported by Tom:
swapper/0: page allocation failure: order:10, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
Fix this by tweaking the random allocation logic to accept a low bound
on the placement, and set it to LOAD_PHYSICAL_ADDR.
Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
Reported-by: Tom Englund <tomenglund26@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218404
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a7a6a01f88e87dec4bf2365571dd2dc7403d52d0 ]
The recently introduced EFI memory attributes protocol should be used
if it exists to ensure that the memory allocation created for the kernel
permits execution. This is needed for compatibility with tightened
requirements related to Windows logo certification for x86 PCs.
Currently, we simply strip the execute protect (XP) attribute from the
entire range, but this might be rejected under some firmware security
policies, and so in a subsequent patch, this will be changed to only
strip XP from the executable region that runs early, and make it
read-only (RO) as well.
In order to catch any issues early, ensure that the memory attribute
protocol works as intended, and give up if it produces spurious errors.
Note that the DXE services based fallback was always based on best
effort, so don't propagate any errors returned by that API.
Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 271f2a4a9576b87ed1f8584909d6d270039e52ea ]
The efi_relocate_kernel() may load the PIE kernel to anywhere, the
loaded address may not be equal to link address or
EFI_KIMG_PREFERRED_ADDRESS.
Acked-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Wang Yao <wangyao@lemote.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 50d7cdf7a9b1ab6f4f74a69c84e974d5dc0c1bf1 ]
River reports boot hangs with v6.6 and v6.7, and the bisect points to
commit
a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
which moves the memory allocation and kernel decompression from the
legacy decompressor (which executes *after* ExitBootServices()) to the
EFI stub, using boot services for allocating the memory. The memory
allocation succeeds but the subsequent call to decompress_kernel() never
returns, resulting in a failed boot and a hanging system.
As it turns out, this issue only occurs when physical address
randomization (KASLR) is enabled, and given that this is a feature we
can live without (virtual KASLR is much more important), let's disable
the physical part of KASLR when booting on AMI UEFI firmware claiming to
implement revision v2.0 of the specification (which was released in
2006), as this is the version these systems advertise.
Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218173
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Now that the x86 EFI stub calls into some APIs exposed by the
decompressor (e.g., kaslr_get_random_long()), it is necessary to ensure
that the global boot_params variable is set correctly before doing so.
Note that the decompressor and the kernel proper carry conflicting
declarations for the global variable 'boot_params' so refer to it via an
alias to work around this.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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setup_e820() is executed after UEFI's ExitBootService has been called.
This causes the firmware to throw an exception because the Console IO
protocol is supposed to work only during boot service environment. As
per UEFI 2.9, section 12.1:
"This protocol is used to handle input and output of text-based
information intended for the system user during the operation of code
in the boot services environment."
So drop the diagnostic warning from this function. We might add back a
warning that is issued later when initializing the kernel itself.
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Kyril reports that crashkernels fail to work on confidential VMs that
rely on the unaccepted memory table, and this appears to be caused by
the fact that it is not considered part of the set of firmware tables
that the crashkernel needs to map.
This is an oversight, and a result of the use of the EFI_LOADER_DATA
memory type for this table. The correct memory type to use for any
firmware table is EFI_ACPI_RECLAIM_MEMORY (including ones created by the
EFI stub), even though the name suggests that is it specific to ACPI.
ACPI reclaim means that the memory is used by the firmware to expose
information to the operating system, but that the memory region has no
special significance to the firmware itself, and the OS is free to
reclaim the memory and use it as ordinary memory if it is not interested
in the contents, or if it has already consumed them. In Linux, this
memory is never reclaimed, but it is always covered by the kernel direct
map and generally made accessible as ordinary memory.
On x86, ACPI reclaim memory is translated into E820_ACPI, which the
kexec logic already recognizes as memory that the crashkernel may need
to to access, and so it will be mapped and accessible to the booting
crash kernel.
Fixes: 745e3ed85f71 ("efi/libstub: Implement support for unaccepted memory")
Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Alexandre Ghiti <alexghiti@rivosinc.com> says:
The following KASLR implementation allows to randomize the kernel mapping:
- virtually: we expect the bootloader to provide a seed in the device-tree
- physically: only implemented in the EFI stub, it relies on the firmware to
provide a seed using EFI_RNG_PROTOCOL. arm64 has a similar implementation
hence the patch 3 factorizes KASLR related functions for riscv to take
advantage.
The new virtual kernel location is limited by the early page table that only
has one PUD and with the PMD alignment constraint, the kernel can only take
< 512 positions.
* b4-shazam-merge:
riscv: libstub: Implement KASLR by using generic functions
libstub: Fix compilation warning for rv32
arm64: libstub: Move KASLR handling functions to kaslr.c
riscv: Dump out kernel offset information on panic
riscv: Introduce virtual kernel mapping KASLR
Link: https://lore.kernel.org/r/20230722123850.634544-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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We can now use arm64 functions to handle the move of the kernel physical
mapping: if KASLR is enabled, we will try to get a random seed from the
firmware, if not possible, the kernel will be moved to a location that
suits its alignment constraints.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230722123850.634544-6-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
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Fix the following warning which appears when compiled for rv32 by using
unsigned long type instead of u64.
../drivers/firmware/efi/libstub/efi-stub-helper.c: In function 'efi_kaslr_relocate_kernel':
../drivers/firmware/efi/libstub/efi-stub-helper.c:846:28: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
846 | (u64)_end < EFI_ALLOC_LIMIT) {
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230722123850.634544-5-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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This prepares for riscv to use the same functions to handle the pĥysical
kernel move when KASLR is enabled.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230722123850.634544-4-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Pull drm updates from Dave Airlie:
"The drm core grew a new generic gpu virtual address manager, and new
execution locking helpers. These are used by nouveau now to provide
uAPI support for the userspace Vulkan driver. AMD had a bunch of new
IP core support, loads of refactoring around fbdev, but mostly just
the usual amount of stuff across the board.
core:
- fix gfp flags in drmm_kmalloc
gpuva:
- add new generic GPU VA manager (for nouveau initially)
syncobj:
- add new DRM_IOCTL_SYNCOBJ_EVENTFD ioctl
dma-buf:
- acquire resv lock for mmap() in exporters
- support dma-buf self import automatically
- docs fixes
backlight:
- fix fbdev interactions
atomic:
- improve logging
prime:
- remove struct gem_prim_mmap plus driver updates
gem:
- drm_exec: add locking over multiple GEM objects
- fix lockdep checking
fbdev:
- make fbdev userspace interfaces optional
- use linux device instead of fbdev device
- use deferred i/o helper macros in various drivers
- Make FB core selectable without drivers
- Remove obsolete flags FBINFO_DEFAULT and FBINFO_FLAG_DEFAULT
- Add helper macros and Kconfig tokens for DMA-allocated framebuffer
ttm:
- support init_on_free
- swapout fixes
panel:
- panel-edp: Support AUO B116XAB01.4
- Support Visionox R66451 plus DT bindings
- ld9040:
- Backlight support
- magic improved
- Kconfig fix
- Convert to of_device_get_match_data()
- Fix Kconfig dependencies
- simple:
- Set bpc value to fix warning
- Set connector type for AUO T215HVN01
- Support Innolux G156HCE-L01 plus DT bindings
- ili9881: Support TDO TL050HDV35 LCD panel plus DT bindings
- startek: Support KD070FHFID015 MIPI-DSI panel plus DT bindings
- sitronix-st7789v:
- Support Inanbo T28CP45TN89 plus DT bindings
- Support EDT ET028013DMA plus DT bindings
- Various cleanups
- edp: Add timings for N140HCA-EAC
- Allow panels and touchscreens to power sequence together
- Fix Innolux G156HCE-L01 LVDS clock
bridge:
- debugfs for chains support
- dw-hdmi:
- Improve support for YUV420 bus format
- CEC suspend/resume
- update EDID on HDMI detect
- dw-mipi-dsi: Fix enable/disable of DSI controller
- lt9611uxc: Use MODULE_FIRMWARE()
- ps8640: Remove broken EDID code
- samsung-dsim: Fix command transfer
- tc358764:
- Handle HS/VS polarity
- Use BIT() macro
- Various cleanups
- adv7511: Fix low refresh rate
- anx7625:
- Switch to macros instead of hardcoded values
- locking fixes
- tc358767: fix hardware delays
- sitronix-st7789v:
- Support panel orientation
- Support rotation property
- Add support for Jasonic JT240MHQS-HWT-EK-E3 plus DT bindings
amdgpu:
- SDMA 6.1.0 support
- HDP 6.1 support
- SMUIO 14.0 support
- PSP 14.0 support
- IH 6.1 support
- Lots of checkpatch cleanups
- GFX 9.4.3 updates
- Add USB PD and IFWI flashing documentation
- GPUVM updates
- RAS fixes
- DRR fixes
- FAMS fixes
- Virtual display fixes
- Soft IH fixes
- SMU13 fixes
- Rework PSP firmware loading for other IPs
- Kernel doc fixes
- DCN 3.0.1 fixes
- LTTPR fixes
- DP MST fixes
- DCN 3.1.6 fixes
- SMU 13.x fixes
- PSP 13.x fixes
- SubVP fixes
- GC 9.4.3 fixes
- Display bandwidth calculation fixes
- VCN4 secure submission fixes
- Allow building DC on RISC-V
- Add visible FB info to bo_print_info
- HBR3 fixes
- GFX9 MCBP fix
- GMC10 vmhub index fix
- GMC11 vmhub index fix
- Create a new doorbell manager
- SR-IOV fixes
- initial freesync panel replay support
- revert zpos properly until igt regression is fixeed
- use TTM to manage doorbell BAR
- Expose both current and average power via hwmon if supported
amdkfd:
- Cleanup CRIU dma-buf handling
- Use KIQ to unmap HIQ
- GFX 9.4.3 debugger updates
- GFX 9.4.2 debugger fixes
- Enable cooperative groups fof gfx11
- SVM fixes
- Convert older APUs to use dGPU path like newer APUs
- Drop IOMMUv2 path as it is no longer used
- TBA fix for aldebaran
i915:
- ICL+ DSI modeset sequence
- HDCP improvements
- MTL display fixes and cleanups
- HSW/BDW PSR1 restored
- Init DDI ports in VBT order
- General display refactors
- Start using plane scale factor for relative data rate
- Use shmem for dpt objects
- Expose RPS thresholds in sysfs
- Apply GuC SLPC min frequency softlimit correctly
- Extend Wa_14015795083 to TGL, RKL, DG1 and ADL
- Fix a VMA UAF for multi-gt platform
- Do not use stolen on MTL due to HW bug
- Check HuC and GuC version compatibility on MTL
- avoid infinite GPU waits due to premature release of request memory
- Fixes and updates for GSC memory allocation
- Display SDVO fixes
- Take stolen handling out of FBC code
- Make i915_coherent_map_type GT-centric
- Simplify shmem_create_from_object map_type
msm:
- SM6125 MDSS support
- DPU: SM6125 DPU support
- DSI: runtime PM support, burst mode support
- DSI PHY: SM6125 support in 14nm DSI PHY driver
- GPU: prepare for a7xx
- fix a690 firmware
- disable relocs on a6xx and newer
radeon:
- Lots of checkpatch cleanups
ast:
- improve device-model detection
- Represent BMV as virtual connector
- Report DP connection status
nouveau:
- add new exec/bind interface to support Vulkan
- document some getparam ioctls
- improve VRAM detection
- various fixes/cleanups
- workraound DPCD issues
ivpu:
- MMU updates
- debugfs support
- Support vpu4
virtio:
- add sync object support
atmel-hlcdc:
- Support inverted pixclock polarity
etnaviv:
- runtime PM cleanups
- hang handling fixes
exynos:
- use fbdev DMA helpers
- fix possible NULL ptr dereference
komeda:
- always attach encoder
omapdrm:
- use fbdev DMA helpers
ingenic:
- kconfig regmap fixes
loongson:
- support display controller
mediatek:
- Small mtk-dpi cleanups
- DisplayPort: support eDP and aux-bus
- Fix coverity issues
- Fix potential memory leak if vmap() fail
mgag200:
- minor fixes
mxsfb:
- support disabling overlay planes
panfrost:
- fix sync in IRQ handling
ssd130x:
- Support per-controller default resolution plus DT bindings
- Reduce memory-allocation overhead
- Improve intermediate buffer size computation
- Fix allocation of temporary buffers
- Fix pitch computation
- Fix shadow plane allocation
tegra:
- use fbdev DMA helpers
- Convert to devm_platform_ioremap_resource()
- support bridge/connector
- enable PM
tidss:
- Support TI AM625 plus DT bindings
- Implement new connector model plus driver updates
vkms:
- improve write back support
- docs fixes
- support gamma LUT
zynqmp-dpsub:
- misc fixes"
* tag 'drm-next-2023-08-30' of git://anongit.freedesktop.org/drm/drm: (1327 commits)
drm/gpuva_mgr: remove unused prev pointer in __drm_gpuva_sm_map()
drm/tests/drm_kunit_helpers: Place correct function name in the comment header
drm/nouveau: uapi: don't pass NO_PREFETCH flag implicitly
drm/nouveau: uvmm: fix unset region pointer on remap
drm/nouveau: sched: avoid job races between entities
drm/i915: Fix HPD polling, reenabling the output poll work as needed
drm: Add an HPD poll helper to reschedule the poll work
drm/i915: Fix TLB-Invalidation seqno store
drm/ttm/tests: Fix type conversion in ttm_pool_test
drm/msm/a6xx: Bail out early if setting GPU OOB fails
drm/msm/a6xx: Move LLC accessors to the common header
drm/msm/a6xx: Introduce a6xx_llc_read
drm/ttm/tests: Require MMU when testing
drm/panel: simple: Fix Innolux G156HCE-L01 LVDS clock
Revert "Revert "drm/amdgpu/display: change pipe policy for DCN 2.0""
drm/amdgpu: Add memory vendor information
drm/amd: flush any delayed gfxoff on suspend entry
drm/amdgpu: skip fence GFX interrupts disable/enable for S0ix
drm/amdgpu: Remove gfxoff check in GFX v9.4.3
drm/amd/pm: Update pci link speed for smu v13.0.6
...
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git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"This primarily covers some cleanup work on the EFI runtime wrappers,
which are shared between all EFI architectures except Itanium, and
which provide some level of isolation to prevent faults occurring in
the firmware code (which runs at the same privilege level as the
kernel) from bringing down the system.
Beyond that, there is a fix that did not make it into v6.5, and some
doc fixes and dead code cleanup.
- one bugfix for x86 mixed mode that did not make it into v6.5
- first pass of cleanup for the EFI runtime wrappers
- some cosmetic touchups"
* tag 'efi-next-for-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
x86/efistub: Fix PCI ROM preservation in mixed mode
efi/runtime-wrappers: Clean up white space and add __init annotation
acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers
efi/runtime-wrappers: Don't duplicate setup/teardown code
efi/runtime-wrappers: Remove duplicated macro for service returning void
efi/runtime-wrapper: Move workqueue manipulation out of line
efi/runtime-wrappers: Use type safe encapsulation of call arguments
efi/riscv: Move EFI runtime call setup/teardown helpers out of line
efi/arm64: Move EFI runtime call setup/teardown helpers out of line
efi/riscv: libstub: Fix comment about absolute relocation
efi: memmap: Remove kernel-doc warnings
efi: Remove unused extern declaration efi_lookup_mapped_addr()
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|
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preserve_pci_rom_image() was accessing the romsize field in
efi_pci_io_protocol_t directly instead of using the efi_table_attr()
helper. This prevents the ROM image from being saved correctly during a
mixed mode boot.
Fixes: 2c3625cb9fa2 ("efi/x86: Fold __setup_efi_pci32() and __setup_efi_pci64() into one function")
Signed-off-by: Mikel Rychliski <mikel@mikelr.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
|
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The bare metal decompressor code was never really intended to run in a
hosted environment such as the EFI boot services, and does a few things
that are becoming problematic in the context of EFI boot now that the
logo requirements are getting tighter: EFI executables will no longer be
allowed to consist of a single executable section that is mapped with
read, write and execute permissions if they are intended for use in a
context where Secure Boot is enabled (and where Microsoft's set of
certificates is used, i.e., every x86 PC built to run Windows).
To avoid stepping on reserved memory before having inspected the E820
tables, and to ensure the correct placement when running a kernel build
that is non-relocatable, the bare metal decompressor moves its own
executable image to the end of the allocation that was reserved for it,
in order to perform the decompression in place. This means the region in
question requires both write and execute permissions, which either need
to be given upfront (which EFI will no longer permit), or need to be
applied on demand using the existing page fault handling framework.
However, the physical placement of the kernel is usually randomized
anyway, and even if it isn't, a dedicated decompression output buffer
can be allocated anywhere in memory using EFI APIs when still running in
the boot services, given that EFI support already implies a relocatable
kernel. This means that decompression in place is never necessary, nor
is moving the compressed image from one end to the other.
Since EFI already maps all of memory 1:1, it is also unnecessary to
create new page tables or handle page faults when decompressing the
kernel. That means there is also no need to replace the special
exception handlers for SEV. Generally, there is little need to do
any of the things that the decompressor does beyond
- initialize SEV encryption, if needed,
- perform the 4/5 level paging switch, if needed,
- decompress the kernel
- relocate the kernel
So do all of this from the EFI stub code, and avoid the bare metal
decompressor altogether.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-24-ardb@kernel.org
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Before refactoring the EFI stub boot flow to avoid the legacy bare metal
decompressor, duplicate the SNP feature check in the EFI stub before
handing over to the kernel proper.
The SNP feature check can be performed while running under the EFI boot
services, which means it can force the boot to fail gracefully and
return an error to the bootloader if the loaded kernel does not
implement support for all the features that the hypervisor enabled.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-23-ardb@kernel.org
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x86 will need to limit the kernel memory allocation to the lowest 512
MiB of memory, to match the behavior of the existing bare metal KASLR
physical randomization logic. So in preparation for that, add a limit
parameter to efi_random_alloc() and wire it up.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-22-ardb@kernel.org
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Currently, the EFI stub relies on DXE services in some cases to clear
non-execute restrictions from page allocations that need to be
executable. This is dodgy, because DXE services are not specified by
UEFI but by PI, and they are not intended for consumption by OS loaders.
However, no alternative existed at the time.
Now, there is a new UEFI protocol that should be used instead, so if it
exists, prefer it over the DXE services calls.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-18-ardb@kernel.org
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In preparation for updating the EFI stub boot flow to avoid the bare
metal decompressor code altogether, implement the support code for
switching between 4 and 5 levels of paging before jumping to the kernel
proper.
Reuse the newly refactored trampoline that the bare metal decompressor
uses, but relies on EFI APIs to allocate 32-bit addressable memory and
remap it with the appropriate permissions. Given that the bare metal
decompressor will no longer call into the trampoline if the number of
paging levels is already set correctly, it is no longer needed to remove
NX restrictions from the memory range where this trampoline may end up.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-17-ardb@kernel.org
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The so-called EFI handover protocol is value-add from the distros that
permits a loader to simply copy a PE kernel image into memory and call
an alternative entrypoint that is described by an embedded boot_params
structure.
Most implementations of this protocol do not bother to check the PE
header for minimum alignment, section placement, etc, and therefore also
don't clear the image's BSS, or even allocate enough memory for it.
Allocating more memory on the fly is rather difficult, but at least
clear the BSS region explicitly when entering in this manner, so that
the EFI stub code does not get confused by global variables that were
not zero-initialized correctly.
When booting in mixed mode, this BSS clearing must occur before any
global state is created, so clear it in the 32-bit asm entry point.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-7-ardb@kernel.org
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Now that the EFI entry code in assembler is only used by the optional
and deprecated EFI handover protocol, and given that the EFI stub C code
no longer returns to it, most of it can simply be dropped.
While at it, clarify the symbol naming, by merging efi_main() and
efi_stub_entry(), making the latter the shared entry point for all
different boot modes that enter via the EFI stub.
The efi32_stub_entry() and efi64_stub_entry() names are referenced
explicitly by the tooling that populates the setup header, so these must
be retained, but can be emitted as aliases of efi_stub_entry() where
appropriate.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-5-ardb@kernel.org
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Instead of returning to the calling code in assembler that does nothing
more than perform an indirect call with the boot_params pointer in
register ESI/RSI, perform the jump directly from the EFI stub C code.
This will allow the asm entrypoint code to be dropped entirely in
subsequent patches.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-4-ardb@kernel.org
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We don't want absolute symbols references in the stub, so fix the double
negation in the comment.
Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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git://anongit.freedesktop.org/drm/drm-misc into drm-next
drm-misc-next for v6.6:
UAPI Changes:
* fbdev:
* Make fbdev userspace interfaces optional; only leaves the
framebuffer console active
* prime:
* Support dma-buf self-import for all drivers automatically: improves
support for many userspace compositors
Cross-subsystem Changes:
* backlight:
* Fix interaction with fbdev in several drivers
* base: Convert struct platform.remove to return void; part of a larger,
tree-wide effort
* dma-buf: Acquire reservation lock for mmap() in exporters; part
of an on-going effort to simplify locking around dma-bufs
* fbdev:
* Use Linux device instead of fbdev device in many places
* Use deferred-I/O helper macros in various drivers
* i2c: Convert struct i2c from .probe_new to .probe; part of a larger,
tree-wide effort
* video:
* Avoid including <linux/screen_info.h>
Core Changes:
* atomic:
* Improve logging
* prime:
* Remove struct drm_driver.gem_prime_mmap plus driver updates: all
drivers now implement this callback with drm_gem_prime_mmap()
* gem:
* Support execution contexts: provides locking over multiple GEM
objects
* ttm:
* Support init_on_free
* Swapout fixes
Driver Changes:
* accel:
* ivpu: MMU updates; Support debugfs
* ast:
* Improve device-model detection
* Cleanups
* bridge:
* dw-hdmi: Improve support for YUV420 bus format
* dw-mipi-dsi: Fix enable/disable of DSI controller
* lt9611uxc: Use MODULE_FIRMWARE()
* ps8640: Remove broken EDID code
* samsung-dsim: Fix command transfer
* tc358764: Handle HS/VS polarity; Use BIT() macro; Various cleanups
* Cleanups
* ingenic:
* Kconfig REGMAP fixes
* loongson:
* Support display controller
* mgag200:
* Minor fixes
* mxsfb:
* Support disabling overlay planes
* nouveau:
* Improve VRAM detection
* Various fixes and cleanups
* panel:
* panel-edp: Support AUO B116XAB01.4
* Support Visionox R66451 plus DT bindings
* Cleanups
* ssd130x:
* Support per-controller default resolution plus DT bindings
* Reduce memory-allocation overhead
* Cleanups
* tidss:
* Support TI AM625 plus DT bindings
* Implement new connector model plus driver updates
* vkms
* Improve write-back support
* Documentation fixes
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230713090830.GA23281@linux-uq9g
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The header file <linux/efi.h> does not need anything from
<linux/screen_info.h>. Declare struct screen_info and remove
the include statements. Update a number of source files that
require struct screen_info's definition.
v2:
* update loongarch (Jingfeng)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230706104852.27451-2-tzimmermann@suse.de
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git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"Although some more stuff is brewing, the EFI changes that are ready
for mainline are few this cycle:
- improve the PCI DMA paranoia logic in the EFI stub
- some constification changes
- add statfs support to efivarfs
- allow user space to enumerate updatable firmware resources without
CAP_SYS_ADMIN"
* tag 'efi-next-for-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi/libstub: Disable PCI DMA before grabbing the EFI memory map
efi/esrt: Allow ESRT access without CAP_SYS_ADMIN
efivarfs: expose used and total size
efi: make kobj_type structure constant
efi: x86: make kobj_type structure constant
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Currently, the EFI stub will disable PCI DMA as the very last thing it
does before calling ExitBootServices(), to avoid interfering with the
firmware's normal operation as much as possible.
However, the stub will invoke DisconnectController() on all endpoints
downstream of the PCI bridges it disables, and this may affect the
layout of the EFI memory map, making it substantially more likely that
ExitBootServices() will fail the first time around, and that the EFI
memory map needs to be reloaded.
This, in turn, increases the likelihood that the slack space we
allocated is insufficient (and we can no longer allocate memory via boot
services after having called ExitBootServices() once), causing the
second call to GetMemoryMap (and therefore the boot) to fail. This makes
the PCI DMA disable feature a bit more fragile than it already is, so
let's make it more robust, by allocating the space for the EFI memory
map after disabling PCI DMA.
Fixes: 4444f8541dad16fe ("efi: Allow disabling PCI busmastering on bridges during boot")
Reported-by: Glenn Washburn <development@efficientek.com>
Acked-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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The UEFI v2.9 specification includes a new memory type to be used in
environments where the OS must accept memory that is provided from its
host. Before the introduction of this memory type, all memory was
accepted eagerly in the firmware. In order for the firmware to safely
stop accepting memory on the OS's behalf, the OS must affirmatively
indicate support to the firmware. This is only a problem for AMD
SEV-SNP, since Linux has had support for it since 5.19. The other
technology that can make use of unaccepted memory, Intel TDX, does not
yet have Linux support, so it can strictly require unaccepted memory
support as a dependency of CONFIG_TDX and not require communication with
the firmware.
Enabling unaccepted memory requires calling a 0-argument enablement
protocol before ExitBootServices. This call is only made if the kernel
is compiled with UNACCEPTED_MEMORY=y
This protocol will be removed after the end of life of the first LTS
that includes it, in order to give firmware implementations an
expiration date for it. When the protocol is removed, firmware will
strictly infer that a SEV-SNP VM is running an OS that supports the
unaccepted memory type. At the earliest convenience, when unaccepted
memory support is added to Linux, SEV-SNP may take strict dependence in
it. After the firmware removes support for the protocol, this should be
reverted.
[tl: address some checkscript warnings]
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/0d5f3d9a20b5cf361945b7ab1263c36586a78a42.1686063086.git.thomas.lendacky@amd.com
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UEFI Specification version 2.9 introduces the concept of memory
acceptance: Some Virtual Machine platforms, such as Intel TDX or AMD
SEV-SNP, requiring memory to be accepted before it can be used by the
guest. Accepting happens via a protocol specific for the Virtual
Machine platform.
Accepting memory is costly and it makes VMM allocate memory for the
accepted guest physical address range. It's better to postpone memory
acceptance until memory is needed. It lowers boot time and reduces
memory overhead.
The kernel needs to know what memory has been accepted. Firmware
communicates this information via memory map: a new memory type --
EFI_UNACCEPTED_MEMORY -- indicates such memory.
Range-based tracking works fine for firmware, but it gets bulky for
the kernel: e820 (or whatever the arch uses) has to be modified on every
page acceptance. It leads to table fragmentation and there's a limited
number of entries in the e820 table.
Another option is to mark such memory as usable in e820 and track if the
range has been accepted in a bitmap. One bit in the bitmap represents a
naturally aligned power-2-sized region of address space -- unit.
For x86, unit size is 2MiB: 4k of the bitmap is enough to track 64GiB or
physical address space.
In the worst-case scenario -- a huge hole in the middle of the
address space -- It needs 256MiB to handle 4PiB of the address
space.
Any unaccepted memory that is not aligned to unit_size gets accepted
upfront.
The bitmap is allocated and constructed in the EFI stub and passed down
to the kernel via EFI configuration table. allocate_e820() allocates the
bitmap if unaccepted memory is present, according to the size of
unaccepted region.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230606142637.5171-4-kirill.shutemov@linux.intel.com
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