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page fault
After [1][2], if we catch exceptions due to EFI runtime service, we will
clear EFI_RUNTIME_SERVICES bit to disable EFI runtime service, then the
subsequent routine which invoke the EFI runtime service should fail.
But the userspace cat efivars through /sys/firmware/efi/efivars/ will stuck
and infinite loop calling read() due to efivarfs_file_read() return -EINTR.
The -EINTR is converted from EFI_ABORTED by efi_status_to_err(), and is
an improper return value in this situation, so let virt_efi_xxx() return
EFI_DEVICE_ERROR and converted to -EIO to invoker.
Cc: <stable@vger.kernel.org>
Fixes: 3425d934fc03 ("efi/x86: Handle page faults occurring while running EFI runtime services")
Fixes: 23715a26c8d8 ("arm64: efi: Recover from synchronous exceptions occurring in firmware")
Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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In cases where runtime services are not supported or have been disabled,
the runtime services workqueue will never have been allocated.
Do not try to destroy the workqueue unconditionally in the unlikely
event that EFI initialisation fails to avoid dereferencing a NULL
pointer.
Fixes: 98086df8b70c ("efi: add missed destroy_workqueue when efisubsys_init fails")
Cc: stable@vger.kernel.org
Cc: Li Heng <liheng40@huawei.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Do not try to refresh the RNG seed in case the firmware does not support
setting variables.
This is specifically needed to prevent a NULL-pointer dereference on the
Lenovo X13s with some firmware revisions, or more generally, whenever
the runtime services have been disabled (e.g. efi=noruntime or with
PREEMPT_RT).
Fixes: e7b813b32a42 ("efi: random: refresh non-volatile random seed when RNG is initialized")
Reported-by: Steev Klimaszewski <steev@kali.org>
Reported-by: Bjorn Andersson <andersson@kernel.org>
Tested-by: Steev Klimaszewski <steev@kali.org>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sc8280xp-lenovo-thinkpad-x13s
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Pull ARM updates from Russell King:
- update unwinder to cope with module PLTs
- enable UBSAN on ARM
- improve kernel fault message
- update UEFI runtime page tables dump
- avoid clang's __aeabi_uldivmod generated in NWFPE code
- disable FIQs on CPU shutdown paths
- update XOR register usage
- a number of build updates (using .arch, thread pointer, removal of
lazy evaluation in Makefile)
- conversion of stacktrace code to stackwalk
- findbit assembly updates
- hwcap feature updates for ARMv8 CPUs
- instruction dump updates for big-endian platforms
- support for function error injection
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (31 commits)
ARM: 9279/1: support function error injection
ARM: 9277/1: Make the dumped instructions are consistent with the disassembled ones
ARM: 9276/1: Refactor dump_instr()
ARM: 9275/1: Drop '-mthumb' from AFLAGS_ISA
ARM: 9274/1: Add hwcap for Speculative Store Bypassing Safe
ARM: 9273/1: Add hwcap for Speculation Barrier(SB)
ARM: 9272/1: vfp: Add hwcap for FEAT_AA32I8MM
ARM: 9271/1: vfp: Add hwcap for FEAT_AA32BF16
ARM: 9270/1: vfp: Add hwcap for FEAT_FHM
ARM: 9269/1: vfp: Add hwcap for FEAT_DotProd
ARM: 9268/1: vfp: Add hwcap FPHP and ASIMDHP for FEAT_FP16
ARM: 9267/1: Define Armv8 registers in AArch32 state
ARM: findbit: add unwinder information
ARM: findbit: operate by words
ARM: findbit: convert to macros
ARM: findbit: provide more efficient ARMv7 implementation
ARM: findbit: document ARMv5 bit offset calculation
ARM: 9259/1: stacktrace: Convert stacktrace to generic ARCH_STACKWALK
ARM: 9258/1: stacktrace: Make stack walk callback consistent with generic code
ARM: 9265/1: pass -march= only to compiler
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Borislav Petkov:
"A of early boot cleanups and fixes.
- Do some spring cleaning to the compressed boot code by moving the
EFI mixed-mode code to a separate compilation unit, the AMD memory
encryption early code where it belongs and fixing up build
dependencies. Make the deprecated EFI handover protocol optional
with the goal of removing it at some point (Ard Biesheuvel)
- Skip realmode init code on Xen PV guests as it is not needed there
- Remove an old 32-bit PIC code compiler workaround"
* tag 'x86_boot_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Remove x86_32 PIC using %ebx workaround
x86/boot: Skip realmode init code when running as Xen PV guest
x86/efi: Make the deprecated EFI handover protocol optional
x86/boot/compressed: Only build mem_encrypt.S if AMD_MEM_ENCRYPT=y
x86/boot/compressed: Adhere to calling convention in get_sev_encryption_bit()
x86/boot/compressed: Move startup32_check_sev_cbit() out of head_64.S
x86/boot/compressed: Move startup32_check_sev_cbit() into .text
x86/boot/compressed: Move startup32_load_idt() out of head_64.S
x86/boot/compressed: Move startup32_load_idt() into .text section
x86/boot/compressed: Pull global variable reference into startup32_load_idt()
x86/boot/compressed: Avoid touching ECX in startup32_set_idt_entry()
x86/boot/compressed: Simplify IDT/GDT preserve/restore in the EFI thunk
x86/boot/compressed, efi: Merge multiple definitions of image_offset into one
x86/boot/compressed: Move efi32_pe_entry() out of head_64.S
x86/boot/compressed: Move efi32_entry out of head_64.S
x86/boot/compressed: Move efi32_pe_entry into .text section
x86/boot/compressed: Move bootargs parsing out of 32-bit startup code
x86/boot/compressed: Move 32-bit entrypoint code into .text section
x86/boot/compressed: Rename efi_thunk_64.S to efi-mixed.S
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git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"Another fairly sizable pull request, by EFI subsystem standards.
Most of the work was done by me, some of it in collaboration with the
distro and bootloader folks (GRUB, systemd-boot), where the main focus
has been on removing pointless per-arch differences in the way EFI
boots a Linux kernel.
- Refactor the zboot code so that it incorporates all the EFI stub
logic, rather than calling the decompressed kernel as a EFI app.
- Add support for initrd= command line option to x86 mixed mode.
- Allow initrd= to be used with arbitrary EFI accessible file systems
instead of just the one the kernel itself was loaded from.
- Move some x86-only handling and manipulation of the EFI memory map
into arch/x86, as it is not used anywhere else.
- More flexible handling of any random seeds provided by the boot
environment (i.e., systemd-boot) so that it becomes available much
earlier during the boot.
- Allow improved arch-agnostic EFI support in loaders, by setting a
uniform baseline of supported features, and adding a generic magic
number to the DOS/PE header. This should allow loaders such as GRUB
or systemd-boot to reduce the amount of arch-specific handling
substantially.
- (arm64) Run EFI runtime services from a dedicated stack, and use it
to recover from synchronous exceptions that might occur in the
firmware code.
- (arm64) Ensure that we don't allocate memory outside of the 48-bit
addressable physical range.
- Make EFI pstore record size configurable
- Add support for decoding CXL specific CPER records"
* tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (43 commits)
arm64: efi: Recover from synchronous exceptions occurring in firmware
arm64: efi: Execute runtime services from a dedicated stack
arm64: efi: Limit allocations to 48-bit addressable physical region
efi: Put Linux specific magic number in the DOS header
efi: libstub: Always enable initrd command line loader and bump version
efi: stub: use random seed from EFI variable
efi: vars: prohibit reading random seed variables
efi: random: combine bootloader provided RNG seed with RNG protocol output
efi/cper, cxl: Decode CXL Error Log
efi/cper, cxl: Decode CXL Protocol Error Section
efi: libstub: fix efi_load_initrd_dev_path() kernel-doc comment
efi: x86: Move EFI runtime map sysfs code to arch/x86
efi: runtime-maps: Clarify purpose and enable by default for kexec
efi: pstore: Add module parameter for setting the record size
efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures
efi: memmap: Move manipulation routines into x86 arch tree
efi: memmap: Move EFI fake memmap support into x86 arch tree
efi: libstub: Undeprecate the command line initrd loader
efi: libstub: Add mixed mode support to command line initrd loader
efi: libstub: Permit mixed mode return types other than efi_status_t
...
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git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
- Replace prandom_u32_max() and various open-coded variants of it,
there is now a new family of functions that uses fast rejection
sampling to choose properly uniformly random numbers within an
interval:
get_random_u32_below(ceil) - [0, ceil)
get_random_u32_above(floor) - (floor, U32_MAX]
get_random_u32_inclusive(floor, ceil) - [floor, ceil]
Coccinelle was used to convert all current users of
prandom_u32_max(), as well as many open-coded patterns, resulting in
improvements throughout the tree.
I'll have a "late" 6.1-rc1 pull for you that removes the now unused
prandom_u32_max() function, just in case any other trees add a new
use case of it that needs to converted. According to linux-next,
there may be two trivial cases of prandom_u32_max() reintroductions
that are fixable with a 's/.../.../'. So I'll have for you a final
conversion patch doing that alongside the removal patch during the
second week.
This is a treewide change that touches many files throughout.
- More consistent use of get_random_canary().
- Updates to comments, documentation, tests, headers, and
simplification in configuration.
- The arch_get_random*_early() abstraction was only used by arm64 and
wasn't entirely useful, so this has been replaced by code that works
in all relevant contexts.
- The kernel will use and manage random seeds in non-volatile EFI
variables, refreshing a variable with a fresh seed when the RNG is
initialized. The RNG GUID namespace is then hidden from efivarfs to
prevent accidental leakage.
These changes are split into random.c infrastructure code used in the
EFI subsystem, in this pull request, and related support inside of
EFISTUB, in Ard's EFI tree. These are co-dependent for full
functionality, but the order of merging doesn't matter.
- Part of the infrastructure added for the EFI support is also used for
an improvement to the way vsprintf initializes its siphash key,
replacing an sleep loop wart.
- The hardware RNG framework now always calls its correct random.c
input function, add_hwgenerator_randomness(), rather than sometimes
going through helpers better suited for other cases.
- The add_latent_entropy() function has long been called from the fork
handler, but is a no-op when the latent entropy gcc plugin isn't
used, which is fine for the purposes of latent entropy.
But it was missing out on the cycle counter that was also being mixed
in beside the latent entropy variable. So now, if the latent entropy
gcc plugin isn't enabled, add_latent_entropy() will expand to a call
to add_device_randomness(NULL, 0), which adds a cycle counter,
without the absent latent entropy variable.
- The RNG is now reseeded from a delayed worker, rather than on demand
when used. Always running from a worker allows it to make use of the
CPU RNG on platforms like S390x, whose instructions are too slow to
do so from interrupts. It also has the effect of adding in new inputs
more frequently with more regularity, amounting to a long term
transcript of random values. Plus, it helps a bit with the upcoming
vDSO implementation (which isn't yet ready for 6.2).
- The jitter entropy algorithm now tries to execute on many different
CPUs, round-robining, in hopes of hitting even more memory latencies
and other unpredictable effects. It also will mix in a cycle counter
when the entropy timer fires, in addition to being mixed in from the
main loop, to account more explicitly for fluctuations in that timer
firing. And the state it touches is now kept within the same cache
line, so that it's assured that the different execution contexts will
cause latencies.
* tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits)
random: include <linux/once.h> in the right header
random: align entropy_timer_state to cache line
random: mix in cycle counter when jitter timer fires
random: spread out jitter callback to different CPUs
random: remove extraneous period and add a missing one in comments
efi: random: refresh non-volatile random seed when RNG is initialized
vsprintf: initialize siphash key using notifier
random: add back async readiness notifier
random: reseed in delayed work rather than on-demand
random: always mix cycle counter in add_latent_entropy()
hw_random: use add_hwgenerator_randomness() for early entropy
random: modernize documentation comment on get_random_bytes()
random: adjust comment to account for removed function
random: remove early archrandom abstraction
random: use random.trust_{bootloader,cpu} command line option only
stackprotector: actually use get_random_canary()
stackprotector: move get_random_canary() into stackprotector.h
treewide: use get_random_u32_inclusive() when possible
treewide: use get_random_u32_{above,below}() instead of manual loop
treewide: use get_random_u32_below() instead of deprecated function
...
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git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras
Pull EDAC updates from Borislav Petkov:
- Make ghes_edac a simple module like the rest of the EDAC drivers and
drop the forced built-in only configuration by disentangling it from
GHES (Jia He)
- The usual small cleanups and improvements all over EDAC land
* tag 'edac_updates_for_6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
EDAC/i10nm: fix refcount leak in pci_get_dev_wrapper()
EDAC/i5400: Fix typo in comment: vaious -> various
EDAC/mc_sysfs: Increase legacy channel support to 12
MAINTAINERS: Make Mauro EDAC reviewer
MAINTAINERS: Make Manivannan Sadhasivam the maintainer of qcom_edac
EDAC/igen6: Return the correct error type when not the MC owner
apei/ghes: Use xchg_release() for updating new cache slot instead of cmpxchg()
EDAC: Check for GHES preference in the chipset-specific EDAC drivers
EDAC/ghes: Make ghes_edac a proper module
EDAC/ghes: Prepare to make ghes_edac a proper module
EDAC/ghes: Add a notifier for reporting memory errors
efi/cper: Export several helpers for ghes_edac to use
EDAC/i5000: Mark as BROKEN
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"The highlights this time are support for dynamically enabling and
disabling Clang's Shadow Call Stack at boot and a long-awaited
optimisation to the way in which we handle the SVE register state on
system call entry to avoid taking unnecessary traps from userspace.
Summary:
ACPI:
- Enable FPDT support for boot-time profiling
- Fix CPU PMU probing to work better with PREEMPT_RT
- Update SMMUv3 MSI DeviceID parsing to latest IORT spec
- APMT support for probing Arm CoreSight PMU devices
CPU features:
- Advertise new SVE instructions (v2.1)
- Advertise range prefetch instruction
- Advertise CSSC ("Common Short Sequence Compression") scalar
instructions, adding things like min, max, abs, popcount
- Enable DIT (Data Independent Timing) when running in the kernel
- More conversion of system register fields over to the generated
header
CPU misfeatures:
- Workaround for Cortex-A715 erratum #2645198
Dynamic SCS:
- Support for dynamic shadow call stacks to allow switching at
runtime between Clang's SCS implementation and the CPU's pointer
authentication feature when it is supported (complete with scary
DWARF parser!)
Tracing and debug:
- Remove static ftrace in favour of, err, dynamic ftrace!
- Seperate 'struct ftrace_regs' from 'struct pt_regs' in core ftrace
and existing arch code
- Introduce and implement FTRACE_WITH_ARGS on arm64 to replace the
old FTRACE_WITH_REGS
- Extend 'crashkernel=' parameter with default value and fallback to
placement above 4G physical if initial (low) allocation fails
SVE:
- Optimisation to avoid disabling SVE unconditionally on syscall
entry and just zeroing the non-shared state on return instead
Exceptions:
- Rework of undefined instruction handling to avoid serialisation on
global lock (this includes emulation of user accesses to the ID
registers)
Perf and PMU:
- Support for TLP filters in Hisilicon's PCIe PMU device
- Support for the DDR PMU present in Amlogic Meson G12 SoCs
- Support for the terribly-named "CoreSight PMU" architecture from
Arm (and Nvidia's implementation of said architecture)
Misc:
- Tighten up our boot protocol for systems with memory above 52 bits
physical
- Const-ify static keys to satisty jump label asm constraints
- Trivial FFA driver cleanups in preparation for v1.1 support
- Export the kernel_neon_* APIs as GPL symbols
- Harden our instruction generation routines against instrumentation
- A bunch of robustness improvements to our arch-specific selftests
- Minor cleanups and fixes all over (kbuild, kprobes, kfence, PMU, ...)"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (151 commits)
arm64: kprobes: Return DBG_HOOK_ERROR if kprobes can not handle a BRK
arm64: kprobes: Let arch do_page_fault() fix up page fault in user handler
arm64: Prohibit instrumentation on arch_stack_walk()
arm64:uprobe fix the uprobe SWBP_INSN in big-endian
arm64: alternatives: add __init/__initconst to some functions/variables
arm_pmu: Drop redundant armpmu->map_event() in armpmu_event_init()
kselftest/arm64: Allow epoll_wait() to return more than one result
kselftest/arm64: Don't drain output while spawning children
kselftest/arm64: Hold fp-stress children until they're all spawned
arm64/sysreg: Remove duplicate definitions from asm/sysreg.h
arm64/sysreg: Convert ID_DFR1_EL1 to automatic generation
arm64/sysreg: Convert ID_DFR0_EL1 to automatic generation
arm64/sysreg: Convert ID_AFR0_EL1 to automatic generation
arm64/sysreg: Convert ID_MMFR5_EL1 to automatic generation
arm64/sysreg: Convert MVFR2_EL1 to automatic generation
arm64/sysreg: Convert MVFR1_EL1 to automatic generation
arm64/sysreg: Convert MVFR0_EL1 to automatic generation
arm64/sysreg: Convert ID_PFR2_EL1 to automatic generation
arm64/sysreg: Convert ID_PFR1_EL1 to automatic generation
arm64/sysreg: Convert ID_PFR0_EL1 to automatic generation
...
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git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Add NMI-safe SRCU reader API. It uses atomic_inc() instead of
this_cpu_inc() on strong load-store architectures.
- Introduce new console_list_lock to synchronize a manipulation of the
list of registered consoles and their flags.
This is a first step in removing the big-kernel-lock-like behavior of
console_lock(). This semaphore still serializes console->write()
calbacks against:
- each other. It primary prevents potential races between early
and proper console drivers using the same device.
- suspend()/resume() callbacks and init() operations in some
drivers.
- various other operations in the tty/vt and framebufer
susbsystems. It is likely that console_lock() serializes even
operations that are not directly conflicting with the
console->write() callbacks here. This is the most complicated
big-kernel-lock aspect of the console_lock() that will be hard
to untangle.
- Introduce new console_srcu lock that is used to safely iterate and
access the registered console drivers under SRCU read lock.
This is a prerequisite for introducing atomic console drivers and
console kthreads. It will reduce the complexity of serialization
against normal consoles and console_lock(). Also it should remove the
risk of deadlock during critical situations, like Oops or panic, when
only atomic consoles are registered.
- Check whether the console is registered instead of enabled on many
locations. It was a historical leftover.
- Cleanly force a preferred console in xenfb code instead of a dirty
hack.
- A lot of code and comment clean ups and improvements.
* tag 'printk-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (47 commits)
printk: htmldocs: add missing description
tty: serial: sh-sci: use setup() callback for early console
printk: relieve console_lock of list synchronization duties
tty: serial: kgdboc: use console_list_lock to trap exit
tty: serial: kgdboc: synchronize tty_find_polling_driver() and register_console()
tty: serial: kgdboc: use console_list_lock for list traversal
tty: serial: kgdboc: use srcu console list iterator
proc: consoles: use console_list_lock for list iteration
tty: tty_io: use console_list_lock for list synchronization
printk, xen: fbfront: create/use safe function for forcing preferred
netconsole: avoid CON_ENABLED misuse to track registration
usb: early: xhci-dbc: use console_is_registered()
tty: serial: xilinx_uartps: use console_is_registered()
tty: serial: samsung_tty: use console_is_registered()
tty: serial: pic32_uart: use console_is_registered()
tty: serial: earlycon: use console_is_registered()
tty: hvc: use console_is_registered()
efi: earlycon: use console_is_registered()
tty: nfcon: use console_is_registered()
serial_core: replace uart_console_enabled() with uart_console_registered()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull pstore updates from Kees Cook:
"A small collection of bug fixes, refactorings, and general
improvements:
- Reporting improvements and return path fixes (Guilherme G. Piccoli,
Wang Yufen, Kees Cook)
- Clean up kmsg_bytes module parameter usage (Guilherme G. Piccoli)
- Add Guilherme to pstore MAINTAINERS entry
- Choose friendlier allocation flags (Qiujun Huang, Stephen Boyd)"
* tag 'pstore-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore: Avoid kcore oops by vmap()ing with VM_IOREMAP
pstore/ram: Fix error return code in ramoops_probe()
pstore: Alert on backend write error
MAINTAINERS: Update pstore maintainers
pstore/ram: Set freed addresses to NULL
pstore/ram: Move internal definitions out of kernel-wide include
pstore/ram: Move pmsg init earlier
pstore/ram: Consolidate kfree() paths
efi: pstore: Follow convention for the efi-pstore backend name
pstore: Inform unregistered backend names as well
pstore: Expose kmsg_bytes as a module parameter
pstore: Improve error reporting in case of backend overlap
pstore/zone: Use GFP_ATOMIC to allocate zone buffer
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Unlike x86, which has machinery to deal with page faults that occur
during the execution of EFI runtime services, arm64 has nothing like
that, and a synchronous exception raised by firmware code brings down
the whole system.
With more EFI based systems appearing that were not built to run Linux
(such as the Windows-on-ARM laptops based on Qualcomm SOCs), as well as
the introduction of PRM (platform specific firmware routines that are
callable just like EFI runtime services), we are more likely to run into
issues of this sort, and it is much more likely that we can identify and
work around such issues if they don't bring down the system entirely.
Since we already use a EFI runtime services call wrapper in assembler,
we can quite easily add some code that captures the execution state at
the point where the call is made, allowing us to revert to this state
and proceed execution if the call triggered a synchronous exception.
Given that the kernel and the firmware don't share any data structures
that could end up in an indeterminate state, we can happily continue
running, as long as we mark the EFI runtime services as unavailable from
that point on.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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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>
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GRUB currently relies on the magic number in the image header of ARM and
arm64 EFI kernel images to decide whether or not the image in question
is a bootable kernel.
However, the purpose of the magic number is to identify the image as one
that implements the bare metal boot protocol, and so GRUB, which only
does EFI boot, is limited unnecessarily to booting images that could
potentially be booted in a non-EFI manner as well.
This is problematic for the new zboot decompressor image format, as it
can only boot in EFI mode, and must therefore not use the bare metal
boot magic number in its header.
For this reason, the strict magic number was dropped from GRUB, to
permit essentially any kind of EFI executable to be booted via the
'linux' command, blurring the line between the linux loader and the
chainloader.
So let's use the same field in the DOS header that RISC-V and arm64
already use for their 'bare metal' magic numbers to store a 'generic
Linux kernel' magic number, which can be used to identify bootable
kernel images in PE format which don't necessarily implement a bare
metal boot protocol in the same binary. Note that, in the context of
EFI, the MS-DOS header is only described in terms of the fields that it
shares with the hybrid PE/COFF image format, (i.e., the MS-DOS EXE magic
number at offset #0 and the PE header offset at byte offset #0x3c).
Since we aim for compatibility with EFI only, and not with MS-DOS or
MS-Windows, we can use the remaining space in the MS-DOS header however
we want.
Let's set the generic magic number for x86 images as well: existing
bootloaders already have their own methods to identify x86 Linux images
that can be booted in a non-EFI manner, and having the magic number in
place there will ease any future transitions in loader implementations
to merge the x86 and non-x86 EFI boot paths.
Note that 32-bit ARM already uses the same location in the header for a
different purpose, but the ARM support is already widely implemented and
the EFI zboot decompressor is not available on ARM anyway, so we just
disregard it here.
Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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The CON_ENABLED status of a console is a runtime setting that does not
involve the console driver. Drivers must not assume that if the console
is disabled then proper hardware management is not needed. For the EFI
earlycon case, it is about remapping/unmapping memory for the
framebuffer.
Use console_is_registered() instead of checking CON_ENABLED.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-25-john.ogness@linutronix.de
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In preparation for setting a cross-architecture baseline for EFI boot
support, remove the Kconfig option that permits the command line initrd
loader to be disabled. Also, bump the minor version so that any image
built with the new version can be identified as supporting this.
Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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EFI has a rather unique benefit that it has access to some limited
non-volatile storage, where the kernel can store a random seed. Read
that seed in EFISTUB and concatenate it with other seeds we wind up
passing onward to the kernel in the configuration table. This is
complementary to the current other two sources - previous bootloaders,
and the EFI RNG protocol.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
[ardb: check for non-NULL RNG protocol pointer, call GetVariable()
without buffer first to obtain the size]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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There is no need for head_32.S and head_64.S both declaring a copy of
the global 'image_offset' variable, so drop those and make the extern C
declaration the definition.
When image_offset is moved to the .c file, it needs to be placed
particularly in the .data section because it lands by default in the
.bss section which is cleared too late, in .Lrelocated, before the first
access to it and thus garbage gets read, leading to SEV guests exploding
in early boot.
This happens only when the SEV guest kernel is loaded through grub. If
supplied with qemu's -kernel command line option, that memory is always
cleared upfront by qemu and all is fine there.
[ bp: Expand commit message with SEV aspect. ]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-8-ardb@kernel.org
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EFI has a rather unique benefit that it has access to some limited
non-volatile storage, where the kernel can store a random seed. Register
a notification for when the RNG is initialized, and at that point, store
a new random seed.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Instead of blindly creating the EFI random seed configuration table if
the RNG protocol is implemented and works, check whether such a EFI
configuration table was provided by an earlier boot stage and if so,
concatenate the existing and the new seeds, leaving it up to the core
code to mix it in and credit it the way it sees fit.
This can be used for, e.g., systemd-boot, to pass an additional seed to
Linux in a way that can be consumed by the kernel very early. In that
case, the following definitions should be used to pass the seed to the
EFI stub:
struct linux_efi_random_seed {
u32 size; // of the 'seed' array in bytes
u8 seed[];
};
The memory for the struct must be allocated as EFI_ACPI_RECLAIM_MEMORY
pool memory, and the address of the struct in memory should be installed
as a EFI configuration table using the following GUID:
LINUX_EFI_RANDOM_SEED_TABLE_GUID 1ce1e5bc-7ceb-42f2-81e5-8aadf180f57b
Note that doing so is safe even on kernels that were built without this
patch applied, but the seed will simply be overwritten with a seed
derived from the EFI RNG protocol, if available. The recommended seed
size is 32 bytes, and seeds larger than 512 bytes are considered
corrupted and ignored entirely.
In order to preserve forward secrecy, seeds from previous bootloaders
are memzero'd out, and in order to preserve memory, those older seeds
are also freed from memory. Freeing from memory without first memzeroing
is not safe to do, as it's possible that nothing else will ever
overwrite those pages used by EFI.
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
[ardb: incorporate Jason's followup changes to extend the maximum seed
size on the consumer end, memzero() it and drop a needless printk]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Print the CXL Error Log field as found in CXL Protocol Error Section.
The CXL RAS Capability structure will be reused by OS First Handling
and the duplication/appropriate placement will be addressed eventually.
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Add support for decoding CXL Protocol Error Section as defined in UEFI 2.10
Section N.2.13.
Do the section decoding in a new cper_cxl.c file. This new file will be
used in the future for more CXL CPERs decode support. Add this to the
existing UEFI_CPER config.
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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commit f4dc7fffa987 ("efi: libstub: unify initrd loading between
architectures") merge the first and the second parameters into a
struct without updating the kernel-doc. Let's fix it.
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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The EFI runtime map code is only wired up on x86, which is the only
architecture that has a need for it in its implementation of kexec.
So let's move this code under arch/x86 and drop all references to it
from generic code. To ensure that the efi_runtime_map_init() is invoked
at the appropriate time use a 'sync' subsys_initcall() that will be
called right after the EFI initcall made from generic code where the
original invocation of efi_runtime_map_init() resided.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dave Young <dyoung@redhat.com>
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The current Kconfig logic for CONFIG_EFI_RUNTIME_MAPS does not convey
that without it, a kexec kernel is not able to boot in EFI mode at all.
So clarify this, and make the option only configurable via the menu
system if CONFIG_EXPERT is set.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dave Young <dyoung@redhat.com>
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By default, the efi-pstore backend hardcode the UEFI variable size
as 1024 bytes. The historical reasons for that were discussed by
Ard in threads [0][1]:
"there is some cargo cult from prehistoric EFI times going
on here, it seems. Or maybe just misinterpretation of the maximum
size for the variable *name* vs the variable itself.".
"OVMF has
OvmfPkg/OvmfPkgX64.dsc:
gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize|0x2000
OvmfPkg/OvmfPkgX64.dsc:
gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize|0x8400
where the first one is without secure boot and the second with secure
boot. Interestingly, the default is
gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize|0x400
so this is probably where this 1k number comes from."
With that, and since there is not such a limit in the UEFI spec, we
have the confidence to hereby add a module parameter to enable advanced
users to change the UEFI record size for efi-pstore data collection,
this way allowing a much easier reading of the collected log, which
wouldn't be scattered anymore among many small files.
Through empirical analysis we observed that extreme low values (like 8
bytes) could eventually cause writing issues, so given that and the OVMF
default discussed, we limited the minimum value to 1024 bytes, which also
is still the default.
[0] https://lore.kernel.org/lkml/CAMj1kXF4UyRMh2Y_KakeNBHvkHhTtavASTAxXinDO1rhPe_wYg@mail.gmail.com/
[1] https://lore.kernel.org/lkml/CAMj1kXFy-2KddGu+dgebAdU9v2sindxVoiHLWuVhqYw+R=kqng@mail.gmail.com/
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Currently, the EFI_PARAVIRT flag is only used by Xen dom0 boot on x86,
even though other architectures also support pseudo-EFI boot, where the
core kernel is invoked directly and provided with a set of data tables
that resemble the ones constructed by the EFI stub, which never actually
runs in that case.
Let's fix this inconsistency, and always set this flag when booting dom0
via the EFI boot path. Note that Xen on x86 does not provide the EFI
memory map in this case, whereas other architectures do, so move the
associated EFI_PARAVIRT check into the x86 platform code.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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The EFI memory map is a description of the memory layout as provided by
the firmware, and only x86 manipulates it in various different ways for
its own memory bookkeeping. So let's move the memmap routines that are
only used by x86 into the x86 arch tree.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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The EFI fake memmap support is specific to x86, which manipulates the
EFI memory map in various different ways after receiving it from the EFI
stub. On other architectures, we have managed to push back on this, and
the EFI memory map is kept pristine.
So let's move the fake memmap code into the x86 arch tree, where it
arguably belongs.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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The initrd= command line loader can be useful for development, but it
was limited to loading files from the same file system as the loaded
kernel (and it didn't work on x86 mixed mode).
As both issues have been fixed, and the initrd= can now be used with
files residing on any simple file system exposed by the EFI firmware,
let's permit it to be enabled on RISC-V and LoongArch, which did not
support it up to this point.
Note that LoadFile2 remains the preferred option, as it is much simpler
to use and implement, but generic loaders (including the UEFI shell) may
not implement this so there, initrd= can now be used as well (if enabled
in the build)
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Now that we have support for calling protocols that need additional
marshalling for mixed mode, wire up the initrd command line loader.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Rework the EFI stub macro wrappers around protocol method calls and
other indirect calls in order to allow return types other than
efi_status_t. This means the widening should be conditional on whether
or not the return type is efi_status_t, and should be omitted otherwise.
Also, switch to _Generic() to implement the type based compile time
conditionals, which is more concise, and distinguishes between
efi_status_t and u64 properly.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Currently, the initrd= command line option to the EFI stub only supports
loading files that reside on the same volume as the loaded image, which
is not workable for loaders like GRUB that don't even implement the
volume abstraction (EFI_SIMPLE_FILE_SYSTEM_PROTOCOL), and load the
kernel from an anonymous buffer in memory. For this reason, another
method was devised that relies on the LoadFile2 protocol.
However, the command line loader is rather useful when using the UEFI
shell or other generic loaders that have no awareness of Linux specific
protocols so let's make it a bit more flexible, by permitting textual
device paths to be provided to initrd= as well, provided that they refer
to a file hosted on a EFI_SIMPLE_FILE_SYSTEM_PROTOCOL volume. E.g.,
initrd=PciRoot(0x0)/Pci(0x3,0x0)/HD(1,MBR,0xBE1AFDFA,0x3F,0xFBFC1)/rootfs.cpio.gz
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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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>
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Ampere Altra machines are reported to misbehave when the SetTime() EFI
runtime service is called after ExitBootServices() but before calling
SetVirtualAddressMap(). Given that the latter is horrid, pointless and
explicitly documented as optional by the EFI spec, we no longer invoke
it at boot if the configured size of the VA space guarantees that the
EFI runtime memory regions can remain mapped 1:1 like they are at boot
time.
On Ampere Altra machines, this results in SetTime() calls issued by the
rtc-efi driver triggering synchronous exceptions during boot. We can
now recover from those without bringing down the system entirely, due to
commit 23715a26c8d81291 ("arm64: efi: Recover from synchronous
exceptions occurring in firmware"). However, it would be better to avoid
the issue entirely, given that the firmware appears to remain in a funny
state after this.
So attempt to identify these machines based on the 'family' field in the
type #1 SMBIOS record, and call SetVirtualAddressMap() unconditionally
in that case.
Tested-by: Alexandru Elisei <alexandru.elisei@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Enable asynchronous unwind table generation for both the core kernel as
well as modules, and emit the resulting .eh_frame sections as init code
so we can use the unwind directives for code patching at boot or module
load time.
This will be used by dynamic shadow call stack support, which will rely
on code patching rather than compiler codegen to emit the shadow call
stack push and pop instructions.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20221027155908.1940624-2-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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Even though our EFI zboot decompressor is pedantically spec compliant
and idiomatic for EFI image loaders, calling LoadImage() and
StartImage() for the nested image is a bit of a burden. Not only does it
create workflow issues for the distros (as both the inner and outer
PE/COFF images need to be signed for secure boot), it also copies the
image around in memory numerous times:
- first, the image is decompressed into a buffer;
- the buffer is consumed by LoadImage(), which copies the sections into
a newly allocated memory region to hold the executable image;
- once the EFI stub is invoked by StartImage(), it will also move the
image in memory in case of KASLR, mirrored memory or if the image must
execute from a certain a priori defined address.
There are only two EFI spec compliant ways to load code into memory and
execute it:
- use LoadImage() and StartImage(),
- call ExitBootServices() and take ownership of the entire system, after
which anything goes.
Given that the EFI zboot decompressor always invokes the EFI stub, and
given that both are built from the same set of objects, let's merge the
two, so that we can avoid LoadImage()/StartImage but still load our
image into memory without breaking the above rules.
This also means we can decompress the image directly into its final
location, which could be randomized or meet other platform specific
constraints that LoadImage() does not know how to adhere to. It also
means that, even if the encapsulated image still has the EFI stub
incorporated as well, it does not need to be signed for secure boot when
wrapping it in the EFI zboot decompressor.
In the future, we might decide to retire the EFI stub attached to the
decompressed image, but for the time being, they can happily coexist.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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The LoongArch 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.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Currently, the EFI entry code for LoongArch is set up to copy the
executable image to the preferred offset, but instead of branching
directly into that image, it branches to the local copy of kernel_entry,
and relies on the logic in that function to switch to the link time
address instead.
This is a bit sloppy, and not something we can support once we merge the
EFI decompressor with the EFI stub. So let's clean this up a bit, by
adding a helper that computes the offset of kernel_entry from the start
of the image, and simply adding the result to VMLINUX_LOAD_ADDRESS.
And considering that we cannot execute from anywhere else anyway, let's
avoid efi_relocate_kernel() and just allocate the pages instead.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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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>
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The RISC-V 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.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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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>
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In order to be able to switch from LoadImage() [which treats the
supplied PE/COFF image as file input only, and reconstructs the memory
image based on the section descriptors] to a mode where we allocate the
memory directly, and invoke the image in place, we need to now how much
memory to allocate beyond the end of the image. So copy this information
from the payload's PE/COFF header to the end of the compressed version
of the payload, so that the decompressor app can access it before
performing the decompression itself.
We'll also need to size of the code region once we switch arm64 to
jumping to the kernel proper with MMU and caches enabled, so let's
capture that information as well. Note that SizeOfCode does not account
for the header, so we need SizeOfHeaders as well.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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In preparation for allowing the EFI zboot decompressor to reuse most of
the EFI stub machinery, factor out the actual EFI PE/COFF entrypoint
into a separate file.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Clone the implementations of strrchr() and memchr() in lib/string.c so
we can use them in the standalone zboot decompressor app. These routines
are used by the FDT handling code.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Currently, arm64, RISC-V and LoongArch rely on the fact that struct
screen_info can be accessed directly, due to the fact that the EFI stub
and the core kernel are part of the same image. This will change after a
future patch, so let's ensure that the screen_info handling is able to
deal with this, by adopting the arm32 approach of passing it as a
configuration table. While at it, switch to ACPI reclaim memory to hold
the screen_info data, which is more appropriate for this kind of
allocation.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Split the efi_printk() routine into its own source file, and provide
local implementations of strlen() and strnlen() so that the standalone
zboot app can efi_err and efi_info etc.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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We will no longer be able to call into the kernel image once we merge
the decompressor with the EFI stub, so we need our own implementation of
memcmp(). Let's add the one from lib/string.c and simplify it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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In preparation for moving the EFI stub functionality into the zboot
decompressor, switch to the stub's implementation of strncmp()
unconditionally.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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