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>
In some cases, we expose the kernel's struct screen_info to the EFI stub
directly, so it gets populated before even entering the kernel. This
means the early console is available as soon as the early param parsing
happens, which is nice. It also means we need two different ways to pass
this information, as this trick only works if the EFI stub is baked into
the core kernel image, which is not always the case.
Huacai reports that the preparatory refactoring that was needed to
implement this alternative method for zboot resulted in a non-functional
efifb earlycon for other cases as well, due to the reordering of the
kernel image relocation with the population of the screen_info struct,
and the latter now takes place after copying the image to its new
location, which means we copy the old, uninitialized state.
So let's ensure that the same-image version of alloc_screen_info()
produces the correct screen_info pointer, by taking the displacement of
the loaded image into account.
Reported-by: Huacai Chen <chenhuacai@loongson.cn>
Tested-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/
Fixes: 42c8ea3dca ("efi: libstub: Factor out EFI stub entrypoint into separate file")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
After relocating the executable image, use the EFI memory attributes
protocol to remap the code and data regions with the appropriate
permissions.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Instead of cleaning the entire loaded kernel image to the PoC and
disabling the MMU and caches before branching to the kernel's bare metal
entry point, we can leave the MMU and caches enabled, and rely on EFI's
cacheable 1:1 mapping of all of system RAM (which is mandated by the
spec) to populate the initial page tables.
This removes the need for managing coherency in software, which is
tedious and error prone.
Note that we still need to clean the executable region of the image to
the PoU if this is required for I/D coherency, but only if we actually
decided to move the image in memory, as otherwise, this will have been
taken care of by the loader.
This change affects both the builtin EFI stub as well as the zboot
decompressor, which now carries the entire EFI stub along with the
decompression code and the compressed image.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230111102236.1430401-7-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The UEFI spec does not mention or reason about the configured size of
the virtual address space at all, but it does mention that all memory
should be identity mapped using a page size of 4 KiB.
This means that a LPA2 capable system that has any system memory outside
of the 48-bit addressable physical range and follows the spec to the
letter may serve page allocation requests from regions of memory that
the kernel cannot access unless it was built with LPA2 support and
enables it at runtime.
So let's ensure that all page allocations are limited to the 48-bit
range.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The EFI spec is not very clear about which permissions are being given
when allocating pages of a certain type. However, it is quite obvious
that EFI_LOADER_CODE is more likely to permit execution than
EFI_LOADER_DATA, which becomes relevant once we permit booting the
kernel proper with the firmware's 1:1 mapping still active.
Ostensibly, recent systems such as the Surface Pro X grant executable
permissions to EFI_LOADER_CODE regions but not EFI_LOADER_DATA regions.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The arm64 build of the EFI stub is part of the core kernel image, and
therefore accesses section markers directly when it needs to figure out
the size of the various section.
The zboot decompressor does not have access to those symbols, but
doesn't really need that either. So let's move handle_kernel_image()
into a separate file (or rather, move everything else into a separate
file) so that the zboot build does not pull in unused code that links to
symbols that it does not define.
While at it, introduce a helper routine that the generic zboot loader
will need to invoke after decompressing the image but before invoking
it, to ensure that the I-side view of memory is consistent.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Factor out the expressions that describe the preferred placement of the
loaded image as well as the minimum alignment so we can reuse them in
the decompressor.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The efi_enter_kernel() routine will be shared between the existing EFI
stub and the zboot decompressor, and the version of
dcache_clean_to_poc() that the core kernel exports to the stub will not
be available in the latter case.
So move the handling into the .c file which will remain part of the stub
build that integrates directly with the kernel proper.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
- implement EFI boot support for LoongArch
- implement generic EFI compressed boot support for arm64, RISC-V and
LoongArch, none of which implement a decompressor today
- measure the kernel command line into the TPM if measured boot is in
effect
- refactor the EFI stub code in order to isolate DT dependencies for
architectures other than x86
- avoid calling SetVirtualAddressMap() on arm64 if the configured size
of the VA space guarantees that doing so is unnecessary
- move some ARM specific code out of the generic EFI source files
- unmap kernel code from the x86 mixed mode 1:1 page tables
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Merge tag 'efi-next-for-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"A bit more going on than usual in the EFI subsystem. The main driver
for this has been the introduction of the LoonArch architecture last
cycle, which inspired some cleanup and refactoring of the EFI code.
Another driver for EFI changes this cycle and in the future is
confidential compute.
The LoongArch architecture does not use either struct bootparams or DT
natively [yet], and so passing information between the EFI stub and
the core kernel using either of those is undesirable. And in general,
overloading DT has been a source of issues on arm64, so using DT for
this on new architectures is a to avoid for the time being (even if we
might converge on something DT based for non-x86 architectures in the
future). For this reason, in addition to the patch that enables EFI
boot for LoongArch, there are a number of refactoring patches applied
on top of which separate the DT bits from the generic EFI stub bits.
These changes are on a separate topich branch that has been shared
with the LoongArch maintainers, who will include it in their pull
request as well. This is not ideal, but the best way to manage the
conflicts without stalling LoongArch for another cycle.
Another development inspired by LoongArch is the newly added support
for EFI based decompressors. Instead of adding yet another
arch-specific incarnation of this pattern for LoongArch, we are
introducing an EFI app based on the existing EFI libstub
infrastructure that encapulates the decompression code we use on other
architectures, but in a way that is fully generic. This has been
developed and tested in collaboration with distro and systemd folks,
who are eager to start using this for systemd-boot and also for arm64
secure boot on Fedora. Note that the EFI zimage files this introduces
can also be decompressed by non-EFI bootloaders if needed, as the
image header describes the location of the payload inside the image,
and the type of compression that was used. (Note that Fedora's arm64
GRUB is buggy [0] so you'll need a recent version or switch to
systemd-boot in order to use this.)
Finally, we are adding TPM measurement of the kernel command line
provided by EFI. There is an oversight in the TCG spec which results
in a blind spot for command line arguments passed to loaded images,
which means that either the loader or the stub needs to take the
measurement. Given the combinatorial explosion I am anticipating when
it comes to firmware/bootloader stacks and firmware based attestation
protocols (SEV-SNP, TDX, DICE, DRTM), it is good to set a baseline now
when it comes to EFI measured boot, which is that the kernel measures
the initrd and command line. Intermediate loaders can measure
additional assets if needed, but with the baseline in place, we can
deploy measured boot in a meaningful way even if you boot into Linux
straight from the EFI firmware.
Summary:
- implement EFI boot support for LoongArch
- implement generic EFI compressed boot support for arm64, RISC-V and
LoongArch, none of which implement a decompressor today
- measure the kernel command line into the TPM if measured boot is in
effect
- refactor the EFI stub code in order to isolate DT dependencies for
architectures other than x86
- avoid calling SetVirtualAddressMap() on arm64 if the configured
size of the VA space guarantees that doing so is unnecessary
- move some ARM specific code out of the generic EFI source files
- unmap kernel code from the x86 mixed mode 1:1 page tables"
* tag 'efi-next-for-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (24 commits)
efi/arm64: libstub: avoid SetVirtualAddressMap() when possible
efi: zboot: create MemoryMapped() device path for the parent if needed
efi: libstub: fix up the last remaining open coded boot service call
efi/arm: libstub: move ARM specific code out of generic routines
efi/libstub: measure EFI LoadOptions
efi/libstub: refactor the initrd measuring functions
efi/loongarch: libstub: remove dependency on flattened DT
efi: libstub: install boot-time memory map as config table
efi: libstub: remove DT dependency from generic stub
efi: libstub: unify initrd loading between architectures
efi: libstub: remove pointless goto kludge
efi: libstub: simplify efi_get_memory_map() and struct efi_boot_memmap
efi: libstub: avoid efi_get_memory_map() for allocating the virt map
efi: libstub: drop pointless get_memory_map() call
efi: libstub: fix type confusion for load_options_size
arm64: efi: enable generic EFI compressed boot
loongarch: efi: enable generic EFI compressed boot
riscv: efi: enable generic EFI compressed boot
efi/libstub: implement generic EFI zboot
efi/libstub: move efi_system_table global var into separate object
...
EFI's SetVirtualAddressMap() runtime service is a horrid hack that we'd
like to avoid using, if possible. For 64-bit architectures such as
arm64, the user and kernel mappings are entirely disjoint, and given
that we use the user region for mapping the UEFI runtime regions when
running under the OS, we don't rely on SetVirtualAddressMap() in the
conventional way, i.e., to permit kernel mappings of the OS to coexist
with kernel region mappings of the firmware regions. This means that, in
principle, we should be able to avoid SetVirtualAddressMap() altogether,
and simply use the 1:1 mapping that UEFI uses at boot time. (Note that
omitting SetVirtualAddressMap() is explicitly permitted by the UEFI
spec).
However, there is a corner case on arm64, which, if configured for
3-level paging (or 2-level paging when using 64k pages), may not be able
to cover the entire range of firmware mappings (which might contain both
memory and MMIO peripheral mappings).
So let's avoid SetVirtualAddressMap() on arm64, but only if the VA space
is guaranteed to be of sufficient size.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Expose the EFI boot time memory map to the kernel via a configuration
table. This is arch agnostic and enables future changes that remove the
dependency on DT on architectures that don't otherwise rely on it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Currently, struct efi_boot_memmap is a struct that is passed around
between callers of efi_get_memory_map() and the users of the resulting
data, and which carries pointers to various variables whose values are
provided by the EFI GetMemoryMap() boot service.
This is overly complex, and it is much easier to carry these values in
the struct itself. So turn the struct into one that carries these data
items directly, including a flex array for the variable number of EFI
memory descriptors that the boot service may return.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Normally we include the full register name in the defines for fields within
registers but this has not been followed for ID registers. In preparation
for automatic generation of defines add the _EL1s into the defines for
ID_AA64MMFR0_EL1 to follow the convention. No functional changes.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Kristina Martsenko <kristina.martsenko@arm.com>
Link: https://lore.kernel.org/r/20220905225425.1871461-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
If the loader has already placed the EFI kernel image randomly in
physical memory, and indicates having done so by installing the 'fixed
placement' protocol onto the image handle, don't bother randomizing the
placement again in the EFI stub.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
In a future patch, arm64's implementation of handle_kernel_image() will
omit randomizing the placement of the kernel if the load address was
chosen randomly by the loader. In order to do this, it needs to locate a
protocol on the image handle, so pass it to handle_kernel_image().
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The kernel is aligned at SEGMENT_SIZE and this is the size populated in the PE
headers:
arch/arm64/kernel/efi-header.S: .long SEGMENT_ALIGN // SectionAlignment
EFI_KIMG_ALIGN is defined as: (SEGMENT_ALIGN > THREAD_ALIGN ? SEGMENT_ALIGN :
THREAD_ALIGN)
So it depends on THREAD_ALIGN. On newer builds this message started to appear
even though the loader is taking into account the PE header (which is stating
SEGMENT_ALIGN).
Fixes: c32ac11da3 ("efi/libstub: arm64: Double check image alignment at entry")
Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
On arm64, the stub only moves the kernel image around in memory if
needed, which is typically only for KASLR, given that relocatable
kernels (which is the default) can run from any 64k aligned address,
which is also the minimum alignment communicated to EFI via the PE/COFF
header.
Unfortunately, some loaders appear to ignore this header, and load the
kernel at some arbitrary offset in memory. We can deal with this, but
let's check for this condition anyway, so non-compliant code can be
spotted and fixed.
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Randomization of the physical load address of the kernel image relies on
efi_random_alloc() returning successfully, and currently, we ignore any
failures and just carry on, using the ordinary, non-randomized page
allocator routine. This means we never find out if a failure occurs,
which could harm security, so let's at least warn about this condition.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Commit 82046702e2 ("efi/libstub/arm64: Replace 'preferred' offset with
alignment check") simplified the way the stub moves the kernel image
around in memory before booting it, given that a relocatable image does
not need to be copied to a 2M aligned offset if it was loaded on a 64k
boundary by EFI.
Commit d32de9130f ("efi/arm64: libstub: Deal gracefully with
EFI_RNG_PROTOCOL failure") inadvertently defeated this logic by
overriding the value of efi_nokaslr if EFI_RNG_PROTOCOL is not
available, which was mistaken by the loader logic as an explicit request
on the part of the user to disable KASLR and any associated relocation
of an Image not loaded on a 2M boundary.
So let's reinstate this functionality, by capturing the value of
efi_nokaslr at function entry to choose the minimum alignment.
Fixes: d32de9130f ("efi/arm64: libstub: Deal gracefully with EFI_RNG_PROTOCOL failure")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Distro versions of GRUB replace the usual LoadImage/StartImage calls
used to load the kernel image with some local code that fails to honor
the allocation requirements described in the PE/COFF header, as it
does not account for the image's BSS section at all: it fails to
allocate space for it, and fails to zero initialize it.
Since the EFI stub itself is allocated in the .init segment, which is
in the middle of the image, its BSS section is not impacted by this,
and the main consequence of this omission is that the BSS section may
overlap with memory regions that are already used by the firmware.
So let's warn about this condition, and force image reallocation to
occur in this case, which works around the problem.
Fixes: 82046702e2 ("efi/libstub/arm64: Replace 'preferred' offset with alignment check")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
As per ARM ARM DDI 0487G.a, when FEAT_LPA2 is implemented, ID_AA64MMFR0_EL1
might contain a range of values to describe supported translation granules
(4K and 16K pages sizes in particular) instead of just enabled or disabled
values. This changes __enable_mmu() function to handle complete acceptable
range of values (depending on whether the field is signed or unsigned) now
represented with ID_AA64MMFR0_TGRAN_SUPPORTED_[MIN..MAX] pair. While here,
also fix similar situations in EFI stub and KVM as well.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-efi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1615355590-21102-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Currently the EFI stub prints a diagnostic on boot saying that KASLR will
be disabled if it is unable to use the EFI RNG protocol to obtain a seed
for KASLR. With the addition of support for v8.5-RNG and the SMCCC RNG
protocol it is now possible for KASLR to obtain entropy even if the EFI
RNG protocol is unsupported in the system, and the main kernel now
explicitly says if KASLR is active itself. This can result in a boot
log where the stub says KASLR has been disabled and the main kernel says
that it is enabled which is confusing for users.
Remove the explicit reference to KASLR from the diagnostics, the warnings
are still useful as EFI is the only source of entropy the stub uses when
randomizing the physical address of the kernel and the other sources may
not be available.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210120163810.14973-1-broonie@kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
- Preliminary RISC-V enablement - the bulk of it will arrive via the RISCV tree.
- Relax decompressed image placement rules for 32-bit ARM
- Add support for passing MOK certificate table contents via a config table
rather than a EFI variable.
- Add support for 18 bit DIMM row IDs in the CPER records.
- Work around broken Dell firmware that passes the entire Boot#### variable
contents as the command line
- Add definition of the EFI_MEMORY_CPU_CRYPTO memory attribute so we can
identify it in the memory map listings.
- Don't abort the boot on arm64 if the EFI RNG protocol is available but
returns with an error
- Replace slashes with exclamation marks in efivarfs file names
- Split efi-pstore from the deprecated efivars sysfs code, so we can
disable the latter on !x86.
- Misc fixes, cleanups and updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'efi-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI changes from Ingo Molnar:
- Preliminary RISC-V enablement - the bulk of it will arrive via the
RISCV tree.
- Relax decompressed image placement rules for 32-bit ARM
- Add support for passing MOK certificate table contents via a config
table rather than a EFI variable.
- Add support for 18 bit DIMM row IDs in the CPER records.
- Work around broken Dell firmware that passes the entire Boot####
variable contents as the command line
- Add definition of the EFI_MEMORY_CPU_CRYPTO memory attribute so we
can identify it in the memory map listings.
- Don't abort the boot on arm64 if the EFI RNG protocol is available
but returns with an error
- Replace slashes with exclamation marks in efivarfs file names
- Split efi-pstore from the deprecated efivars sysfs code, so we can
disable the latter on !x86.
- Misc fixes, cleanups and updates.
* tag 'efi-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
efi: mokvar: add missing include of asm/early_ioremap.h
efi: efivars: limit availability to X86 builds
efi: remove some false dependencies on CONFIG_EFI_VARS
efi: gsmi: fix false dependency on CONFIG_EFI_VARS
efi: efivars: un-export efivars_sysfs_init()
efi: pstore: move workqueue handling out of efivars
efi: pstore: disentangle from deprecated efivars module
efi: mokvar-table: fix some issues in new code
efi/arm64: libstub: Deal gracefully with EFI_RNG_PROTOCOL failure
efivarfs: Replace invalid slashes with exclamation marks in dentries.
efi: Delete deprecated parameter comments
efi/libstub: Fix missing-prototypes in string.c
efi: Add definition of EFI_MEMORY_CPU_CRYPTO and ability to report it
cper,edac,efi: Memory Error Record: bank group/address and chip id
edac,ghes,cper: Add Row Extension to Memory Error Record
efi/x86: Add a quirk to support command line arguments on Dell EFI firmware
efi/libstub: Add efi_warn and *_once logging helpers
integrity: Load certs from the EFI MOK config table
integrity: Move import of MokListRT certs to a separate routine
efi: Support for MOK variable config table
...
Currently, on arm64, we abort on any failure from efi_get_random_bytes()
other than EFI_NOT_FOUND when it comes to setting the physical seed for
KASLR, but ignore such failures when obtaining the seed for virtual
KASLR or for early seeding of the kernel's entropy pool via the config
table. This is inconsistent, and may lead to unexpected boot failures.
So let's permit any failure for the physical seed, and simply report
the error code if it does not equal EFI_NOT_FOUND.
Cc: <stable@vger.kernel.org> # v5.8+
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Before commit
d0f9ca9be1 ("ARM: decompressor: run decompressor in place if loaded via UEFI")
we were rather limited in the choice of base address for the uncompressed
kernel, as we were relying on the logic in the decompressor that blindly
rounds down the decompressor execution address to the next multiple of 128
MiB, and decompresses the kernel there. For this reason, we have a lot of
complicated memory region handling code, to ensure that this memory window
is available, even though it could be occupied by reserved regions or
other allocations that may or may not collide with the uncompressed image.
Today, we simply pass the target address for the decompressed image to the
decompressor directly, and so we can choose a suitable window just by
finding a 16 MiB aligned region, while taking TEXT_OFFSET and the region
for the swapper page tables into account.
So let's get rid of the complicated logic, and instead, use the existing
bottom up allocation routine to allocate a suitable window as low as
possible, and carve out a memory region that has the right properties.
Note that this removes any dependencies on the 'dram_base' argument to
handle_kernel_image(), and so this is removed as well. Given that this
was the only remaining use of dram_base, the code that produces it is
removed entirely as well.
Reviewed-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Tested-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
TEXT_OFFSET serves no purpose, and for this reason, it was redefined
as 0x0 in the v5.8 timeframe. Since this does not appear to have caused
any issues that require us to revisit that decision, let's get rid of the
macro entirely, along with any references to it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Since commit 82046702e2 ("efi/libstub/arm64: Replace 'preferred' offset
with alignment check"), loading a relocatable arm64 kernel at a physical
address which is not 2MB aligned and subsequently booting with EFI will
leave the Image in-place, relying on the kernel to relocate itself early
during boot. In conjunction with commit dd4bc60765 ("arm64: warn on
incorrect placement of the kernel by the bootloader"), which enables
CONFIG_RELOCATABLE by default, this effectively means that entering an
arm64 kernel loaded at an alignment smaller than 2MB with EFI (e.g. using
QEMU) will result in silent relocation at runtime.
Unfortunately, this has a subtle but confusing affect for developers
trying to inspect the PC value during a crash and comparing it to the
symbol addresses in vmlinux using tools such as 'nm' or 'addr2line';
all text addresses will be displaced by a sub-2MB offset, resulting in
the wrong symbol being identified in many cases. Passing "nokaslr" on
the command line or disabling "CONFIG_RANDOMIZE_BASE" does not help,
since the EFI stub only copies the kernel Image to a 2MB boundary if it
is not relocatable.
Adjust the EFI stub for arm64 so that the minimum Image alignment is 2MB
unless KASLR is in use.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: David Brazdil <dbrazdil@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Rename pr_efi to efi_info and pr_efi_err to efi_err to make it more
obvious that they are part of the EFI stub and not generic printk infra.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200430182843.2510180-4-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The practice of using __pure getter functions to access global
variables in the EFI stub dates back to the time when we had to
carefully prevent GOT entries from being emitted, because we
could not rely on the toolchain to do this for us.
Today, we use the hidden visibility pragma for all EFI stub source
files, which now all live in the same subdirectory, and we apply a
sanity check on the objects, so we can get rid of these getter
functions and simply refer to global data objects directly.
So switch over the remaining boolean variables carrying options set
on the kernel command line.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
It is no longer necessary to locate the kernel as low as possible in
physical memory, and so we can switch from efi_low_alloc() [which is
a rather nasty concoction on top of GetMemoryMap()] to a new helper
called efi_allocate_pages_aligned(), which simply rounds up the size
to account for the alignment, and frees the misaligned pages again.
So considering that the kernel can live anywhere in the physical
address space, as long as its alignment requirements are met, let's
switch to efi_allocate_pages_aligned() to allocate the pages.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The KASLR code path in the arm64 version of the EFI stub incorporates
some overly complicated logic to randomly allocate a region of the right
alignment: there is no need to randomize the placement of the kernel
modulo 2 MiB separately from the placement of the 2 MiB aligned allocation
itself - we can simply follow the same logic used by the non-randomized
placement, which is to allocate at the correct alignment, and only take
TEXT_OFFSET into account if it is not a round multiple of the alignment.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The notion of a 'preferred' load offset for the kernel dates back to the
times when the kernel's primary mapping overlapped with the linear region,
and memory below it could not be used at all.
Today, the arm64 kernel does not really care where it is loaded in physical
memory, as long as the alignment requirements are met, and so there is no
point in unconditionally moving the kernel to a new location in memory at
boot. Instead, we can
- check for a KASLR seed, and randomly reallocate the kernel if one is
provided
- otherwise, check whether the alignment requirements are met for the
current placement of the kernel, and just run it in place if they are
- finally, do an ordinary page allocation and reallocate the kernel to a
suitably aligned buffer anywhere in memory.
By the same reasoning, there is no need to take TEXT_OFFSET into account
if it is a round multiple of the minimum alignment, which is the usual
case for relocatable kernels with TEXT_OFFSET randomization disabled.
Otherwise, it suffices to use the relative misaligment of TEXT_OFFSET
when reallocating the kernel.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
- Ensure that the compiler and linker versions are aligned so that ld
doesn't complain about not understanding a .note.gnu.property section
(emitted when pointer authentication is enabled).
- Force -mbranch-protection=none when the feature is not enabled, in
case a compiler may choose a different default value.
- Remove CONFIG_DEBUG_ALIGN_RODATA. It was never in defconfig and rarely
enabled.
- Fix checking 16-bit Thumb-2 instructions checking mask in the
emulation of the SETEND instruction (it could match the bottom half of
a 32-bit Thumb-2 instruction).
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Catalin Marinas:
- Ensure that the compiler and linker versions are aligned so that ld
doesn't complain about not understanding a .note.gnu.property section
(emitted when pointer authentication is enabled).
- Force -mbranch-protection=none when the feature is not enabled, in
case a compiler may choose a different default value.
- Remove CONFIG_DEBUG_ALIGN_RODATA. It was never in defconfig and
rarely enabled.
- Fix checking 16-bit Thumb-2 instructions checking mask in the
emulation of the SETEND instruction (it could match the bottom half
of a 32-bit Thumb-2 instruction).
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: armv8_deprecated: Fix undef_hook mask for thumb setend
arm64: remove CONFIG_DEBUG_ALIGN_RODATA feature
arm64: Always force a branch protection mode when the compiler has one
arm64: Kconfig: ptrauth: Add binutils version check to fix mismatch
init/kconfig: Add LD_VERSION Kconfig
When CONFIG_DEBUG_ALIGN_RODATA is enabled, kernel segments mapped with
different permissions (r-x for .text, r-- for .rodata, rw- for .data,
etc) are rounded up to 2 MiB so they can be mapped more efficiently.
In particular, it permits the segments to be mapped using level 2
block entries when using 4k pages, which is expected to result in less
TLB pressure.
However, the mappings for the bulk of the kernel will use level 2
entries anyway, and the misaligned fringes are organized such that they
can take advantage of the contiguous bit, and use far fewer level 3
entries than would be needed otherwise.
This makes the value of this feature dubious at best, and since it is not
enabled in defconfig or in the distro configs, it does not appear to be
in wide use either. So let's just remove it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Laura Abbott <labbott@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit:
9f9223778e ("efi/libstub/arm: Make efi_entry() an ordinary PE/COFF entrypoint")
did some code refactoring to get rid of the EFI entry point assembler
code, and in the process, it got rid of the assignment of image_addr
to the value of _text. Instead, it switched to using the image_base
field of the efi_loaded_image struct provided by UEFI, which should
contain the same value.
However, Michael reports that this is not the case: older GRUB builds
corrupt this value in some way, and since we can easily switch back to
referring to _text to discover this value, let's simply do that.
While at it, fix another issue in commit 9f9223778e, which may result
in the unassigned image_addr to be misidentified as the preferred load
offset of the kernel, which is unlikely but will cause a boot crash if
it does occur.
Finally, let's add a warning if the _text vs. image_base discrepancy is
detected, so we can tell more easily how widespread this issue actually
is.
Reported-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-efi@vger.kernel.org
Instead of setting the visibility pragma for a small set of symbol
declarations that could result in absolute references that we cannot
support in the stub, declare hidden visibility for all code in the
EFI stub, which is more robust and future proof.
To ensure that the #pragma is taken into account before any other
includes are processed, put it in a header file of its own and
include it via the compiler command line using the -include option.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Expose efi_entry() as the PE/COFF entrypoint directly, instead of
jumping into a wrapper that fiddles with stack buffers and other
stuff that the compiler is much better at. The only reason this
code exists is to obtain a pointer to the base of the image, but
we can get the same value from the loaded_image protocol, which
we already need for other reasons anyway.
Update the return type as well, to make it consistent with what
is required for a PE/COFF executable entrypoint.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The macros efi_call_early and efi_call_runtime are used to call EFI
boot services and runtime services, respectively. However, the naming
is confusing, given that the early vs runtime distinction may suggest
that these are used for calling the same set of services either early
or late (== at runtime), while in reality, the sets of services they
can be used with are completely disjoint, and efi_call_runtime is also
only usable in 'early' code.
So do a global sweep to replace all occurrences with efi_bs_call or
efi_rt_call, respectively, where BS and RT match the idiom used by
the UEFI spec to refer to boot time or runtime services.
While at it, use 'func' as the macro parameter name for the function
pointers, which is less likely to collide and cause weird build errors.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191224151025.32482-24-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We have a helper efi_system_table() that gives us the address of the
EFI system table in memory, so there is no longer point in passing
it around from each function to the next.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191224151025.32482-20-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As a first step towards getting rid of the need to pass around a function
parameter 'sys_table_arg' pointing to the EFI system table, remove the
references to it in the printing code, which is represents the majority
of the use cases.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191224151025.32482-19-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Replace all GPL license blurbs with an equivalent SPDX header (most
files are GPLv2, some are GPLv2+). While at it, drop some outdated
header changelogs as well.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Alexander Graf <agraf@suse.de>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190202094119.13230-7-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When CONFIG_RANDOMIZE_TEXT_OFFSET=y, TEXT_OFFSET is an arbitrary
multiple of PAGE_SIZE in the interval [0, 2MB).
The EFI stub does not account for the potential misalignment of
TEXT_OFFSET relative to EFI_KIMG_ALIGN, and produces a randomized
physical offset which is always a round multiple of EFI_KIMG_ALIGN.
This may result in statically allocated objects whose alignment exceeds
PAGE_SIZE to appear misaligned in memory. This has been observed to
result in spurious stack overflow reports and failure to make use of
the IRQ stacks, and theoretically could result in a number of other
issues.
We can OR in the low bits of TEXT_OFFSET to ensure that we have the
necessary offset (and hence preserve the misalignment of TEXT_OFFSET
relative to EFI_KIMG_ALIGN), so let's do that.
Reported-by: Kim Phillips <kim.phillips@arm.com>
Tested-by: Kim Phillips <kim.phillips@arm.com>
[ardb: clarify comment and commit log, drop unneeded parens]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Fixes: 6f26b36711 ("arm64: kaslr: increase randomization granularity")
Link: http://lkml.kernel.org/r/20180518140841.9731-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull EFI updates from Ingo Molnar:
"The main changes in this cycle were:
- Transparently fall back to other poweroff method(s) if EFI poweroff
fails (and returns)
- Use separate PE/COFF section headers for the RX and RW parts of the
ARM stub loader so that the firmware can use strict mapping
permissions
- Add support for requesting the firmware to wipe RAM at warm reboot
- Increase the size of the random seed obtained from UEFI so CRNG
fast init can complete earlier
- Update the EFI framebuffer address if it points to a BAR that gets
moved by the PCI resource allocation code
- Enable "reset attack mitigation" of TPM environments: this is
enabled if the kernel is configured with
CONFIG_RESET_ATTACK_MITIGATION=y.
- Clang related fixes
- Misc cleanups, constification, refactoring, etc"
* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi/bgrt: Use efi_mem_type()
efi: Move efi_mem_type() to common code
efi/reboot: Make function pointer orig_pm_power_off static
efi/random: Increase size of firmware supplied randomness
efi/libstub: Enable reset attack mitigation
firmware/efi/esrt: Constify attribute_group structures
firmware/efi: Constify attribute_group structures
firmware/dcdbas: Constify attribute_group structures
arm/efi: Split zImage code and data into separate PE/COFF sections
arm/efi: Replace open coded constants with symbolic ones
arm/efi: Remove pointless dummy .reloc section
arm/efi: Remove forbidden values from the PE/COFF header
drivers/fbdev/efifb: Allow BAR to be moved instead of claiming it
efi/reboot: Fall back to original power-off method if EFI_RESET_SHUTDOWN returns
efi/arm/arm64: Add missing assignment of efi.config_table
efi/libstub/arm64: Set -fpie when building the EFI stub
efi/libstub/arm64: Force 'hidden' visibility for section markers
efi/libstub/arm64: Use hidden attribute for struct screen_info reference
efi/arm: Don't mark ACPI reclaim memory as MEMBLOCK_NOMAP
To prevent the compiler from emitting absolute references to the section
markers when running in PIC mode, override the visibility to 'hidden' for
all contents of asm/sections.h
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170818194947.19347-4-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The EFI stub is intimately coupled with the kernel, and takes advantage
of this by relocating the kernel at a weaker alignment than the
documented boot protocol mandates.
However, it does so by assuming it can align the kernel to the segment
alignment, and assumes that this is 64K. In subsequent patches, we'll
have to consider other details to determine this de-facto alignment
constraint.
This patch adds a new EFI_KIMG_ALIGN definition that will track the
kernel's de-facto alignment requirements. Subsequent patches will modify
this as required.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Currently, our KASLR implementation randomizes the placement of the core
kernel at 2 MB granularity. This is based on the arm64 kernel boot
protocol, which mandates that the kernel is loaded TEXT_OFFSET bytes above
a 2 MB aligned base address. This requirement is a result of the fact that
the block size used by the early mapping code may be 2 MB at the most (for
a 4 KB granule kernel)
But we can do better than that: since a KASLR kernel needs to be relocated
in any case, we can tolerate a physical misalignment as long as the virtual
misalignment relative to this 2 MB block size is equal in size, and code to
deal with this is already in place.
Since we align the kernel segments to 64 KB, let's randomize the physical
offset at 64 KB granularity as well (unless CONFIG_DEBUG_ALIGN_RODATA is
enabled). This way, the page table and TLB footprint is not affected.
The higher granularity allows for 5 bits of additional entropy to be used.
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
