UEFI 2.11 introduced EFI_MEMORY_HOT_PLUGGABLE to annotate system memory
regions that are 'cold plugged' at boot, i.e., hot pluggable memory that
is available from early boot, and described as system RAM by the
firmware.
Existing loaders and EFI applications running in the boot context will
happily use this memory for allocating data structures that cannot be
freed or moved at runtime, and this prevents the memory from being
unplugged. Going forward, the new EFI_MEMORY_HOT_PLUGGABLE attribute
should be tested, and memory annotated as such should be avoided for
such allocations.
In the EFI stub, there are a couple of occurrences where, instead of the
high-level AllocatePages() UEFI boot service, a low-level code sequence
is used that traverses the EFI memory map and carves out the requested
number of pages from a free region. This is needed, e.g., for allocating
as low as possible, or for allocating pages at random.
While AllocatePages() should presumably avoid special purpose memory and
cold plugged regions, this manual approach needs to incorporate this
logic itself, in order to prevent the kernel itself from ending up in a
hot unpluggable region, preventing it from being unplugged.
So add the EFI_MEMORY_HOTPLUGGABLE macro definition, and check for it
where appropriate.
Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
GCC 15 changed the default C standard version to C23, which should not
have impacted the kernel because it requests the gnu11 standard via
'-std=' in the main Makefile. However, the EFI libstub Makefile uses its
own set of KBUILD_CFLAGS for x86 without a '-std=' value (i.e., using
the default), resulting in errors from the kernel's definitions of bool,
true, and false in stddef.h, which are reserved keywords under C23.
./include/linux/stddef.h:11:9: error: expected identifier before ‘false’
11 | false = 0,
./include/linux/types.h:35:33: error: two or more data types in declaration specifiers
35 | typedef _Bool bool;
Set '-std=gnu11' in the x86 cflags to resolve the error and consistently
use the same C standard version for the entire kernel. All other
architectures reuse KBUILD_CFLAGS from the rest of the kernel, so this
issue is not visible for them.
Cc: stable@vger.kernel.org
Reported-by: Kostadin Shishmanov <kostadinshishmanov@protonmail.com>
Closes: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvduultkgfAIRZI3vQpZylu7Gl929HaYFRGeMEalWCpeMzCIIhLxxRhq4U-Y=@protonmail.com/
Reported-by: Jakub Jelinek <jakub@redhat.com>
Closes: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Annotate some local buffer allocations as __free(efi_pool) and simplify
the associated error handling accordingly. This removes a couple of
gotos and simplifies the code.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The EFI stub may obtain the memory map from the firmware numerous times,
and this involves doing a EFI pool allocation first, which needs to be
freed after use.
Streamline this using a cleanup helper, which makes the code easier to
follow.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Use LocateHandleBuffer() and a __free() cleanup helper to simplify the
PCI I/O handle buffer traversal code.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The EFI stub implements various ways of setting the resolution of the
EFI framebuffer at boot, and this duplicates a lot of boilerplate for
iterating over the supported modes and extracting the resolution and
color depth.
Refactor this into a single helper that takes a callback, and use it for
the 'auto', 'list' and 'res' selection methods.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Use the LocateHandleBuffer() API and a __free() function to simplify the
logic that allocates a handle buffer to iterate over all GOP protocols
in the EFI database.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tweak the for_each_efi_handle() macro in order to avoid the need on the
part of the caller to provide a loop counter variable.
Also move efi_get_handle_num() to the callers, so that each occurrence
can be replaced with the actual number returned by the simplified
LocateHandleBuffer API.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
UGA is the EFI graphical output protocol that preceded GOP, and has been
long obsolete. Drop support for it from the x86 implementation of the
EFI stub - other architectures never bothered to implement it (save for
ia64)
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Recent platforms require more slack slots than the current value of
EFI_MMAP_NR_SLACK_SLOTS, otherwise they fail to boot. The current
workaround is to append `efi=disable_early_pci_dma` to the kernel's
cmdline. So, bump up EFI_MMAP_NR_SLACK_SLOTS to 32 to allow those
platforms to boot with the aforementioned workaround.
Signed-off-by: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Allen Pais <apais@linux.microsoft.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
For historical reasons, the legacy decompressor code on various
architectures supports 7 different compression types for the compressed
kernel image.
EFI zboot is not a compression library museum, and so the options can be
limited to what is likely to be useful in practice:
- GZIP is tried and tested, and is still one of the fastest at
decompression time, although the compression ratio is not very high;
moreover, Fedora is already shipping EFI zboot kernels for arm64 that
use GZIP, and QEMU implements direct support for it when booting a
kernel without firmware loaded;
- ZSTD has a very high compression ratio (although not the highest), and
is almost as fast as GZIP at decompression time.
Reducing the number of options makes it less of a hassle for other
consumers of the EFI zboot format (such as QEMU today, and kexec in the
future) to support it transparently without having to carry 7 different
decompression libraries.
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
When CONFIG_CMDLINE_OVERRIDE or CONFIG_CMDLINE_FORCE are configured, the
command line provided by the boot stack should be ignored, and only the
built-in command line should be taken into account.
Add the required handling of this when dealing with initrd= or dtb=
command line options in the EFI stub.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
CONFIG_CMDLINE, when set, is supposed to serve either as a fallback when
no command line is provided by the bootloader, or to be taken into account
unconditionally, depending on the configured options.
The initrd and dtb loader ignores CONFIG_CMDLINE in either case, and
only takes the EFI firmware provided load options into account. This
means that configuring the kernel with initrd= or dtb= on the built-in
command line does not produce the expected result.
Fix this by doing a separate pass over the built-in command line when
dealing with initrd= or dtb= options.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
When CONFIG_CMDLINE_EXTEND is set, the core kernel command line handling
logic appends CONFIG_CMDLINE to the bootloader provided command line.
The EFI stub does the opposite, and parses the builtin one first.
The usual behavior of command line options is that the last one takes
precedence if it appears multiple times, unless there is a meaningful
way to combine them. In either case, parsing the builtin command line
first while the core kernel does it in the opposite order is likely to
produce inconsistent results in such cases.
Therefore, switch the order in the stub to match the core kernel.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
cmdline_ptr is an out parameter, which is not allocated by the function
itself, and likely points into the caller's stack.
cmdline refers to the pool allocation that should be freed when cleaning
up after a failure, so pass this instead to free_pool().
Fixes: 42c8ea3dca ("efi: libstub: Factor out EFI stub entrypoint ...")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Current code fails to check for an error case when reading events
from final event log to calculate offsets. Check the error case,
and break early because all subsequent calls will also fail.
Signed-off-by: Gregory Price <gourry@gourry.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
__calc_tpm2_event_size returns 0 or a positive length, but return values
are often interpreted as ints. Convert everything over to u32 to avoid
signed/unsigned logic errors.
Signed-off-by: Gregory Price <gourry@gourry.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Currently the initrd is only measured if it can be loaded using the
INITRD_MEDIA_GUID, if we are loading it from a path provided via the
command line it is never measured. Lets move the check down a couple
lines so the measurement happens independent of the source.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
efi_convert_cmdline() always sets cmdline_size to at least 1 on success,
so the "cmdline_size > 0" does nothing and can be removed (the intent
was to avoid parsing an empty string, but there is nothing wrong with
parsing an empty string, it is only making boot negligibly slower).
Then the cmd_line_len argument to efi_convert_cmdline can be removed
because there is nothing left using it.
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
efi_convert_cmdline() always returns a size of at least 1 because it
counts the NUL terminator, so the "cmdline_size == 0" condition is never
satisfied.
Change it to check if the string starts with a NUL character to get the
intended behavior: to use CONFIG_CMDLINE when load_options_size == 0.
Fixes: 60f38de7a8 ("efi/libstub: Unify command line param parsing")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.
auto-generated by the following:
for i in `git grep -l -w asm/unaligned.h`; do
sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h
Pull EFI updates from Ard Biesheuvel:
"Not a lot happening in EFI land this cycle.
- Prevent kexec from crashing on a corrupted TPM log by using a
memory type that is reserved by default
- Log correctable errors reported via CPER
- A couple of cosmetic fixes"
* tag 'efi-next-for-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi: Remove redundant null pointer checks in efi_debugfs_init()
efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption
efi/cper: Print correctable AER information
efi: Remove unused declaration efi_initialize_iomem_resources()
The TPM event log table is a Linux specific construct, where the data
produced by the GetEventLog() boot service is cached in memory, and
passed on to the OS using an EFI configuration table.
The use of EFI_LOADER_DATA here results in the region being left
unreserved in the E820 memory map constructed by the EFI stub, and this
is the memory description that is passed on to the incoming kernel by
kexec, which is therefore unaware that the region should be reserved.
Even though the utility of the TPM2 event log after a kexec is
questionable, any corruption might send the parsing code off into the
weeds and crash the kernel. So let's use EFI_ACPI_RECLAIM_MEMORY
instead, which is always treated as reserved by the E820 conversion
logic.
Cc: <stable@vger.kernel.org>
Reported-by: Breno Leitao <leitao@debian.org>
Tested-by: Usama Arif <usamaarif642@gmail.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Pull ARM updates from Russell King:
- ftrace: don't assume stack frames are contiguous in memory
- remove unused mod_inwind_map structure
- spelling fixes
- allow use of LD dead code/data elimination
- fix callchain_trace() return value
- add support for stackleak gcc plugin
- correct some reset asm function prototypes for CFI
[ Missed the merge window because Russell forgot to push out ]
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux:
ARM: 9408/1: mm: CFI: Fix some erroneous reset prototypes
ARM: 9407/1: Add support for STACKLEAK gcc plugin
ARM: 9406/1: Fix callchain_trace() return value
ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
ARM: 9403/1: Alpine: Spelling s/initialiing/initializing/
ARM: 9402/1: Kconfig: Spelling s/Cortex A-/Cortex-A/
ARM: 9400/1: Remove unused struct 'mod_unwind_map'
Pull more RISC-V updates from Palmer Dabbelt:
- Support for NUMA (via SRAT and SLIT), console output (via SPCR), and
cache info (via PPTT) on ACPI-based systems.
- The trap entry/exit code no longer breaks the return address stack
predictor on many systems, which results in an improvement to trap
latency.
- Support for HAVE_ARCH_STACKLEAK.
- The sv39 linear map has been extended to support 128GiB mappings.
- The frequency of the mtime CSR is now visible via hwprobe.
* tag 'riscv-for-linus-6.11-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (21 commits)
RISC-V: Provide the frequency of time CSR via hwprobe
riscv: Extend sv39 linear mapping max size to 128G
riscv: enable HAVE_ARCH_STACKLEAK
riscv: signal: Remove unlikely() from WARN_ON() condition
riscv: Improve exception and system call latency
RISC-V: Select ACPI PPTT drivers
riscv: cacheinfo: initialize cacheinfo's level and type from ACPI PPTT
riscv: cacheinfo: remove the useless input parameter (node) of ci_leaf_init()
RISC-V: ACPI: Enable SPCR table for console output on RISC-V
riscv: boot: remove duplicated targets line
trace: riscv: Remove deprecated kprobe on ftrace support
riscv: cpufeature: Extract common elements from extension checking
riscv: Introduce vendor variants of extension helpers
riscv: Add vendor extensions to /proc/cpuinfo
riscv: Extend cpufeature.c to detect vendor extensions
RISC-V: run savedefconfig for defconfig
RISC-V: hwprobe: sort EXT_KEY()s in hwprobe_isa_ext0() alphabetically
ACPI: NUMA: replace pr_info with pr_debug in arch_acpi_numa_init
ACPI: NUMA: change the ACPI_NUMA to a hidden option
ACPI: NUMA: Add handler for SRAT RINTC affinity structure
...
Add support for the stackleak feature. Whenever the kernel returns to user
space the kernel stack is filled with a poison value.
At the same time, disables the plugin in EFI stub code because EFI stub
is out of scope for the protection.
Tested on qemu and milkv duo:
/ # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT
[ 38.675575] lkdtm: Performing direct entry STACKLEAK_ERASING
[ 38.678448] lkdtm: stackleak stack usage:
[ 38.678448] high offset: 288 bytes
[ 38.678448] current: 496 bytes
[ 38.678448] lowest: 1328 bytes
[ 38.678448] tracked: 1328 bytes
[ 38.678448] untracked: 448 bytes
[ 38.678448] poisoned: 14312 bytes
[ 38.678448] low offset: 8 bytes
[ 38.689887] lkdtm: OK: the rest of the thread stack is properly erased
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240623235316.2010-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Pull EFI fixes from Ard Biesheuvel:
- Wipe screen_info after allocating it from the heap - used by arm32
and EFI zboot, other EFI architectures allocate it statically
- Revert to allocating boot_params from the heap on x86 when entering
via the native PE entrypoint, to work around a regression on older
Dell hardware
* tag 'efi-fixes-for-v6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
x86/efistub: Revert to heap allocated boot_params for PE entrypoint
efi/libstub: Zero initialize heap allocated struct screen_info
Pull LoongArch updates from Huacai Chen:
- Define __ARCH_WANT_NEW_STAT in unistd.h
- Always enumerate MADT and setup logical-physical CPU mapping
- Add irq_work support via self IPIs
- Add RANDOMIZE_KSTACK_OFFSET support
- Add ARCH_HAS_PTE_DEVMAP support
- Add ARCH_HAS_DEBUG_VM_PGTABLE support
- Add writecombine support for DMW-based ioremap()
- Add architectural preparation for CPUFreq
- Add ACPI standard hardware register based S3 support
- Add support for relocating the kernel with RELR relocation
- Some bug fixes and other small changes
* tag 'loongarch-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
LoongArch: Make the users of larch_insn_gen_break() constant
LoongArch: Check TIF_LOAD_WATCH to enable user space watchpoint
LoongArch: Use rustc option -Zdirect-access-external-data
LoongArch: Add support for relocating the kernel with RELR relocation
LoongArch: Remove a redundant checking in relocator
LoongArch: Use correct API to map cmdline in relocate_kernel()
LoongArch: Automatically disable KASLR for hibernation
LoongArch: Add ACPI standard hardware register based S3 support
LoongArch: Add architectural preparation for CPUFreq
LoongArch: Add writecombine support for DMW-based ioremap()
LoongArch: Add ARCH_HAS_DEBUG_VM_PGTABLE support
LoongArch: Add ARCH_HAS_PTE_DEVMAP support
LoongArch: Add RANDOMIZE_KSTACK_OFFSET support
LoongArch: Add irq_work support via self IPIs
LoongArch: Always enumerate MADT and setup logical-physical CPU mapping
LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h
Currently, only TLB-based ioremap() support writecombine, so add the
counterpart for DMW-based ioremap() with help of DMW2. The base address
(WRITECOMBINE_BASE) is configured as 0xa000000000000000.
DMW3 is unused by kernel now, however firmware may leave garbage in them
and interfere kernel's address mapping. So clear it as necessary.
BTW, centralize the DMW configuration to macro SETUP_DMWINS.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This is a partial revert of commit
8117961d98 ("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>
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: 732ea9db9d ("efi: libstub: Move screen_info handling to common code")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
As it turns out, clearing the BSS was not the right fix for the issue
that was ultimately fixed by commit decd347c2a ("x86/efistub:
Reinstate soft limit for initrd loading"), and given that the Windows
EFI loader becomes very unhappy when entered with garbage in BSS, this
is one thing that x86 PC EFI implementations can be expected to get
right.
So drop it from the pure PE entrypoint. The handover protocol entrypoint
still needs this - it is used by the flaky distro bootloaders that
barely implement PE/COFF at all.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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>
0c18184de9 ("platform/x86: apple-gmux: support MMIO gmux on T2 Macs")
brought support for T2 Macs in apple-gmux. But in order to use dual GPU,
the integrated GPU has to be enabled. On such dual GPU EFI Macs, the EFI
stub needs to report that it is booting macOS in order to prevent the
firmware from disabling the iGPU.
This patch is also applicable for some non T2 Intel Macs.
Based on this patch for GRUB by Andreas Heider <andreas@heider.io>:
https://lists.gnu.org/archive/html/grub-devel/2013-12/msg00442.html
Credits also goto Kerem Karabay <kekrby@gmail.com> for helping porting
the patch to the Linux kernel.
Cc: Orlando Chamberlain <orlandoch.dev@gmail.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
[ardb: limit scope using list of DMI matches provided by Lukas and Orlando]
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Tested-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The smbios.c source file is not currently included in the x86 build, and
before we can do so, it needs some tweaks to build correctly in
combination with the EFI mixed mode support.
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Add the STACKLEAK gcc plugin to arm32 by adding the helper used by
stackleak common code: on_thread_stack(). It initialize the stack with the
poison value before returning from system calls which improves the kernel
security. Additionally, this disables the plugin in EFI stub code and
decompress code, which are out of scope for the protection.
Before the test on Qemu versatilepb board:
# echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT
lkdtm: Performing direct entry STACKLEAK_ERASING
lkdtm: XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n)
After:
# echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT
lkdtm: Performing direct entry STACKLEAK_ERASING
lkdtm: stackleak stack usage:
high offset: 80 bytes
current: 280 bytes
lowest: 696 bytes
tracked: 696 bytes
untracked: 192 bytes
poisoned: 7220 bytes
low offset: 4 bytes
lkdtm: OK: the rest of the thread stack is properly erased
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Update the efi_get_smbios_string() macro to take a pointer to the entire
record struct rather than the header. This removes the need to pass the
type explicitly, as it can be inferred from the typed pointer. Also,
drop 'type' from the prototype of __efi_get_smbios_string(), as it is
never referenced.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Between kexec and confidential VM support, handling the EFI memory maps
correctly on x86 is already proving to be rather difficult (as opposed
to other EFI architectures which manage to never modify the EFI memory
map to begin with)
EFI fake memory map support is essentially a development hack (for
testing new support for the 'special purpose' and 'more reliable' EFI
memory attributes) that leaked into production code. The regions marked
in this manner are not actually recognized as such by the firmware
itself or the EFI stub (and never have), and marking memory as 'more
reliable' seems rather futile if the underlying memory is just ordinary
RAM.
Marking memory as 'special purpose' in this way is also dubious, but may
be in use in production code nonetheless. However, the same should be
achievable by using the memmap= command line option with the ! operator.
EFI fake memmap support is not enabled by any of the major distros
(Debian, Fedora, SUSE, Ubuntu) and does not exist on other
architectures, so let's drop support for it.
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The current arm32 architecture does not yet support the
HAVE_LD_DEAD_CODE_DATA_ELIMINATION feature. arm32 is widely used in
embedded scenarios, and enabling this feature would be beneficial for
reducing the size of the kernel image.
In order to make this work, we keep the necessary tables by annotating
them with KEEP, also it requires further changes to linker script to KEEP
some tables and wildcard compiler generated sections into the right place.
When using ld.lld for linking, KEEP is not recognized within the OVERLAY
command, and Ard proposed a concise method to solve this problem.
It boots normally with defconfig, vexpress_defconfig and tinyconfig.
The size comparison of zImage is as follows:
defconfig vexpress_defconfig tinyconfig
5137712 5138024 424192 no dce
5032560 4997824 298384 dce
2.0% 2.7% 29.7% shrink
When using smaller config file, there is a significant reduction in the
size of the zImage.
We also tested this patch on a commercially available single-board
computer, and the comparison is as follows:
a15eb_config
2161384 no dce
2092240 dce
3.2% shrink
The zImage size has been reduced by approximately 3.2%, which is 70KB on
2.1M.
Signed-off-by: Yuntao Liu <liuyuntao12@huawei.com>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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>
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>
Pull EFI fix from Ard Biesheuvel:
- Followup fix for the EFI boot sequence refactor, which may result in
physical KASLR putting the kernel in a region which is being used for
a special purpose via a command line argument.
* tag 'efi-fixes-for-v6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
x86/efistub: Omit physical KASLR when memory reservations exist
Pull Kbuild updates from Masahiro Yamada:
- Avoid 'constexpr', which is a keyword in C23
- Allow 'dtbs_check' and 'dt_compatible_check' run independently of
'dt_binding_check'
- Fix weak references to avoid GOT entries in position-independent code
generation
- Convert the last use of 'optional' property in arch/sh/Kconfig
- Remove support for the 'optional' property in Kconfig
- Remove support for Clang's ThinLTO caching, which does not work with
the .incbin directive
- Change the semantics of $(src) so it always points to the source
directory, which fixes Makefile inconsistencies between upstream and
downstream
- Fix 'make tar-pkg' for RISC-V to produce a consistent package
- Provide reasonable default coverage for objtool, sanitizers, and
profilers
- Remove redundant OBJECT_FILES_NON_STANDARD, KASAN_SANITIZE, etc.
- Remove the last use of tristate choice in drivers/rapidio/Kconfig
- Various cleanups and fixes in Kconfig
* tag 'kbuild-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (46 commits)
kconfig: use sym_get_choice_menu() in sym_check_prop()
rapidio: remove choice for enumeration
kconfig: lxdialog: remove initialization with A_NORMAL
kconfig: m/nconf: merge two item_add_str() calls
kconfig: m/nconf: remove dead code to display value of bool choice
kconfig: m/nconf: remove dead code to display children of choice members
kconfig: gconf: show checkbox for choice correctly
kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal
Makefile: remove redundant tool coverage variables
kbuild: provide reasonable defaults for tool coverage
modules: Drop the .export_symbol section from the final modules
kconfig: use menu_list_for_each_sym() in sym_check_choice_deps()
kconfig: use sym_get_choice_menu() in conf_write_defconfig()
kconfig: add sym_get_choice_menu() helper
kconfig: turn defaults and additional prompt for choice members into error
kconfig: turn missing prompt for choice members into error
kconfig: turn conf_choice() into void function
kconfig: use linked list in sym_set_changed()
kconfig: gconf: use MENU_CHANGED instead of SYMBOL_CHANGED
kconfig: gconf: remove debug code
...
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
a1b87d54f4 ("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: a1b87d54f4 ("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>
Pull EFI updates from Ard Biesheuvel:
"Only a handful of changes this cycle, consisting of cleanup work and a
low-prio bugfix:
- Additional cleanup by Tim for the efivarfs variable name length
confusion
- Avoid freeing a bogus pointer when virtual remapping is omitted in
the EFI boot stub"
* tag 'efi-next-for-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi: libstub: only free priv.runtime_map when allocated
efi: Clear up misconceptions about a maximum variable name size
efivarfs: Remove unused internal struct members
Documentation: Mark the 'efivars' sysfs interface as removed
efi: pstore: Request at most 512 bytes for variable names
