Since commit
5894cf571e ("acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers")
ACPI PRM calls are delegated to a workqueue which runs in a kernel
thread, making it easier to detect and mitigate faulting memory accesses
performed by the firmware.
Rafael reports that such PRM accesses may occur before efisubsys_init()
executes, which is where the workqueue is allocated, leading to NULL
pointer dereferences. Since acpi_init() [which triggers the early PRM
accesses] executes as a subsys_initcall() as well, and has its own
dependencies that may be sensitive to initcall ordering, deferring
acpi_init() is not an option.
So instead, split off the workqueue allocation into its own postcore
initcall, as this is the only missing piece to allow EFI runtime calls
to be made. This ensures that EFI runtime call (including PRM calls) are
accessible to all code running at subsys_initcall() level.
Cc: <stable@vger.kernel.org>
Fixes: 5894cf571e ("acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers")
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
- Enable boot graphics resource table (BGRT) on Xen/x86
- Correct a misguided assumption in the memory attributes table sanity
check
- Start tagging efi_mem_reserve()'d regions as MEMBLOCK_RSRV_KERN
- Some other minor fixes and cleanups
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Merge tag 'efi-next-for-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"Again not a busy cycle for EFI, just some minor tweaks and bug fixes:
- Enable boot graphics resource table (BGRT) on Xen/x86
- Correct a misguided assumption in the memory attributes table
sanity check
- Start tagging efi_mem_reserve()'d regions as MEMBLOCK_RSRV_KERN
- Some other minor fixes and cleanups"
* tag 'efi-next-for-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi/capsule-loader: fix incorrect sizeof in phys array reallocation
efi: Tag memblock reservations of boot services regions as RSRV_KERN
memblock: Permit existing reserved regions to be marked RSRV_KERN
efi/memattr: Fix thinko in table size sanity check
efi: libstub: fix type of fdt 32 and 64bit variables
efi: Drop unused efi_range_is_wc() function
efi: Enable BGRT loading under Xen
efi: make efi_mem_type() and efi_mem_attributes() work on Xen PV
By definition, EFI memory regions of type boot services code or data
have no special significance to the firmware at runtime, only to the OS.
In some cases, the firmware will allocate tables and other assets that
are passed in memory in regions of this type, and leave it up to the OS
to decide whether or not to treat the allocation as special, or simply
consume the contents at boot and recycle the RAM for ordinary use. The
reason for this approach is that it avoids needless memory reservations
for assets that the OS knows nothing about, and therefore doesn't know
how to free either.
This means that any memblock reservations covering such regions can be
marked as MEMBLOCK_RSRV_KERN - this is a better match semantically, and
is useful on x86 to distinguish true reservations from temporary
reservations that are only needed to work around firmware bugs.
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Xen doesn't give direct access to the EFI memory map, but provides a
hypercall interface for it. efi_mem_desc_lookup() was already adjusted
in aca1d27ac3 "efi: xen: Implement memory descriptor lookup based on
hypercall" to (optionally) use it. Now make efi_mem_type() and
efi_mem_attributes() use common efi_mem_desc_lookup() too.
This also reduces code duplication a bit.
efi_mem_type() retains separate check for -ENOTSUPP error case (even
though no caller seems to rely on this currently).
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
[ardb: Drop erroneous 'const' qualifier]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Exposing the efi_rts_wq workqueue via sysfs provides an easy mechanism
to restrict EFI firmware invocation to certain CPU(s).
This can be used to restrict EFI invocations to specific CPUs while
allowing other workqueue to use the remaning CPUs.
Expose the workqueue via sysfs. Change the name to efi_runtime which is
what will be visible under sysfs.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
The reserve_unaccepted() function incorrectly calculates the size of the
memblock reservation for the unaccepted memory table. It aligns the
size of the table, but fails to account for cases where the table's
starting physical address (efi.unaccepted) is not page-aligned.
If the table starts at an offset within a page and its end crosses into
a subsequent page that the aligned size does not cover, the end of the
table will not be reserved. This can lead to the table being overwritten
or inaccessible, causing a kernel panic in accept_memory().
This issue was observed when starting Intel TDX VMs with specific memory
sizes (e.g., > 64GB).
Fix this by calculating the end address first (including the unaligned
start) and then aligning it up, ensuring the entire range is covered
by the reservation.
Fixes: 8dbe33956d ("efi/unaccepted: Make sure unaccepted table is mapped")
Reported-by: Moritz Sanft <ms@edgeless.systems>
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
- Quirk the broken EFI framebuffer geometry on the Valve Steam Deck
- Capture the EDID information of the primary display also on non-x86
EFI systems when booting via the EFI stub.
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Merge tag 'efi-next-for-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
- Quirk the broken EFI framebuffer geometry on the Valve Steam Deck
- Capture the EDID information of the primary display also on non-x86
EFI systems when booting via the EFI stub.
* tag 'efi-next-for-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi: Support EDID information
sysfb: Move edid_info into sysfb_primary_display
sysfb: Pass sysfb_primary_display to devices
sysfb: Replace screen_info with sysfb_primary_display
sysfb: Add struct sysfb_display_info
efi: sysfb_efi: Reduce number of references to global screen_info
efi: earlycon: Reduce number of references to global screen_info
efi: sysfb_efi: Fix efidrmfb and simpledrmfb on Valve Steam Deck
efi: sysfb_efi: Convert swap width and height quirk to a callback
efi: sysfb_efi: Fix lfb_linelength calculation when applying quirks
efi: sysfb_efi: Replace open coded swap with the macro
The cpu_bitmap flexible array now contains more than just the cpu_bitmap.
In preparation for changing the static mm_struct definitions to cover for
the additional space required, change the cpu_bitmap type from "unsigned
long" to "char", require an unsigned long alignment of the flexible array,
and rename the field from "cpu_bitmap" to "flexible_array".
Introduce the MM_STRUCT_FLEXIBLE_ARRAY_INIT macro to statically initialize
the flexible array. This covers the init_mm and efi_mm static
definitions.
This is a preparation step for fixing the missing mm_cid size for static
mm_struct definitions.
Link: https://lkml.kernel.org/r/20251224173358.647691-3-mathieu.desnoyers@efficios.com
Fixes: af7f588d8f ("sched: Introduce per-memory-map concurrency ID")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Aboorva Devarajan <aboorvad@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Liam R . Howlett" <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Martin Liu <liumartin@google.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When the EFI stub itself loads the initrd and puts it in memory (rather
than simply passing on a struct boot_params or device tree that already
carries initrd information), it exposes this information to the core
kernel via a INITRD configuration table.
Given that config tables are preserved across kexec, this means that
subsequent kexec boots will observe the same information, even though it
most likely has become stale by that point. On x86, this information is
usually superseded by the initrd info passed via bootparams, in which
case this stale information is simply ignored. However, when performing
a kexec boot without passing an initrd, the loader falls back to this
stale information and explodes.
So wipe the base and size from the INITRD config table as soon as it has
been consumed. This fixes the issue for kexec on all EFI architectures.
Reported-by: James Le Cuirot <chewi@gentoo.org>
Tested-by: James Le Cuirot <chewi@gentoo.org>
Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Link: https://lore.kernel.org/all/20251126173209.374755-2-chewi@gentoo.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Linux 6.19-rc2 (9448598b22 ("Linux 6.19-rc2")) is crashing with a NULL
pointer dereference on arm64 hosts:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000c8
pc : cap_capable (security/commoncap.c:82 security/commoncap.c:128)
Call trace:
cap_capable (security/commoncap.c:82 security/commoncap.c:128) (P)
security_capable (security/security.c:?)
ns_capable_noaudit (kernel/capability.c:342 kernel/capability.c:381)
__ptrace_may_access (./include/linux/rcupdate.h:895 kernel/ptrace.c:326)
ptrace_may_access (kernel/ptrace.c:353)
do_task_stat (fs/proc/array.c:467)
proc_tgid_stat (fs/proc/array.c:673)
proc_single_show (fs/proc/base.c:803)
I've bissected the problem to commit a5baf582f4 ("arm64/efi: Call EFI
runtime services without disabling preemption").
>From my analyzes, the crash occurs because efi_mm lacks a user_ns field
initialization. This was previously harmless, but commit a5baf582f4
("arm64/efi: Call EFI runtime services without disabling preemption")
changed the EFI runtime call path to use kthread_use_mm(&efi_mm), which
temporarily adopts efi_mm as the current mm for the calling kthread.
When a thread has an active mm, LSM hooks like cap_capable() expect
mm->user_ns to be valid for credential checks. With efi_mm.user_ns being
NULL, capability checks during possible /proc access dereference the
NULL pointer and crash.
Fix by initializing efi_mm.user_ns to &init_user_ns.
Fixes: a5baf582f4 ("arm64/efi: Call EFI runtime services without disabling preemption")
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
In the EFI config table, rename LINUX_EFI_SCREEN_INFO_TABLE_GUID to
LINUX_EFI_PRIMARY_DISPLAY_TABLE_GUID. Read sysfb_primary_display from
the entry. In addition to the screen_info, the entry now also contains
EDID information.
In libstub, replace struct screen_info with struct sysfb_display_info
from the kernel's sysfb_primary_display and rename functions
accordingly. Transfer it to the runtime kernel using the kernel's
global state or the LINUX_EFI_PRIMARY_DISPLAY_TABLE_GUID config-table
entry.
With CONFIG_FIRMWARE_EDID=y, libstub now transfers the GOP device's EDID
information to the kernel. If CONFIG_FIRMWARE_EDID=n, EDID information
is disabled. Make the Kconfig symbol CONFIG_FIRMWARE_EDID available with
EFI. Setting the value to 'n' disables EDID support.
Also rename screen_info.c to primary_display.c and adapt the contained
comment according to the changes.
Link: https://lore.kernel.org/all/20251126160854.553077-8-tzimmermann@suse.de/
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
[ardb: depend on EFI_GENERIC_STUB not EFI, fix conflicts after dropping
the preceding patch from the series]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Core features:
- Basic Arm MPAM (Memory system resource Partitioning And Monitoring)
driver under drivers/resctrl/ which makes use of the fs/rectrl/ API
Perf and PMU:
- Avoid cycle counter on multi-threaded CPUs
- Extend CSPMU device probing and add additional filtering support for
NVIDIA implementations
- Add support for the PMUs on the NoC S3 interconnect
- Add additional compatible strings for new Cortex and C1 CPUs
- Add support for data source filtering to the SPE driver
- Add support for i.MX8QM and "DB" PMU in the imx PMU driver
Memory managemennt:
- Avoid broadcast TLBI if page reused in write fault
- Elide TLB invalidation if the old PTE was not valid
- Drop redundant cpu_set_*_tcr_t0sz() macros
- Propagate pgtable_alloc() errors outside of __create_pgd_mapping()
- Propagate return value from __change_memory_common()
ACPI and EFI:
- Call EFI runtime services without disabling preemption
- Remove unused ACPI function
Miscellaneous:
- ptrace support to disable streaming on SME-only systems
- Improve sysreg generation to include a 'Prefix' descriptor
- Replace __ASSEMBLY__ with __ASSEMBLER__
- Align register dumps in the kselftest zt-test
- Remove some no longer used macros/functions
- Various spelling corrections
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
"These are the arm64 updates for 6.19.
The biggest part is the Arm MPAM driver under drivers/resctrl/.
There's a patch touching mm/ to handle spurious faults for huge pmd
(similar to the pte version). The corresponding arm64 part allows us
to avoid the TLB maintenance if a (huge) page is reused after a write
fault. There's EFI refactoring to allow runtime services with
preemption enabled and the rest is the usual perf/PMU updates and
several cleanups/typos.
Summary:
Core features:
- Basic Arm MPAM (Memory system resource Partitioning And Monitoring)
driver under drivers/resctrl/ which makes use of the fs/rectrl/ API
Perf and PMU:
- Avoid cycle counter on multi-threaded CPUs
- Extend CSPMU device probing and add additional filtering support
for NVIDIA implementations
- Add support for the PMUs on the NoC S3 interconnect
- Add additional compatible strings for new Cortex and C1 CPUs
- Add support for data source filtering to the SPE driver
- Add support for i.MX8QM and "DB" PMU in the imx PMU driver
Memory managemennt:
- Avoid broadcast TLBI if page reused in write fault
- Elide TLB invalidation if the old PTE was not valid
- Drop redundant cpu_set_*_tcr_t0sz() macros
- Propagate pgtable_alloc() errors outside of __create_pgd_mapping()
- Propagate return value from __change_memory_common()
ACPI and EFI:
- Call EFI runtime services without disabling preemption
- Remove unused ACPI function
Miscellaneous:
- ptrace support to disable streaming on SME-only systems
- Improve sysreg generation to include a 'Prefix' descriptor
- Replace __ASSEMBLY__ with __ASSEMBLER__
- Align register dumps in the kselftest zt-test
- Remove some no longer used macros/functions
- Various spelling corrections"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (94 commits)
arm64/mm: Document why linear map split failure upon vm_reset_perms is not problematic
arm64/pageattr: Propagate return value from __change_memory_common
arm64/sysreg: Remove unused define ARM64_FEATURE_FIELD_BITS
KVM: arm64: selftests: Consider all 7 possible levels of cache
KVM: arm64: selftests: Remove ARM64_FEATURE_FIELD_BITS and its last user
arm64: atomics: lse: Remove unused parameters from ATOMIC_FETCH_OP_AND macros
Documentation/arm64: Fix the typo of register names
ACPI: GTDT: Get rid of acpi_arch_timer_mem_init()
perf: arm_spe: Add support for filtering on data source
perf: Add perf_event_attr::config4
perf/imx_ddr: Add support for PMU in DB (system interconnects)
perf/imx_ddr: Get and enable optional clks
perf/imx_ddr: Move ida_alloc() from ddr_perf_init() to ddr_perf_probe()
dt-bindings: perf: fsl-imx-ddr: Add compatible string for i.MX8QM, i.MX8QXP and i.MX8DXL
arm64: remove duplicate ARCH_HAS_MEM_ENCRYPT
arm64: mm: use untagged address to calculate page index
MAINTAINERS: new entry for MPAM Driver
arm_mpam: Add kunit tests for props_mismatch()
arm_mpam: Add kunit test for bitmap reset
arm_mpam: Add helper to reset saved mbwu state
...
Recent OVMF versions (edk2-stable202508 + newer) can write their debug
log to a memory buffer. This driver exposes the log content via sysfs
(/sys/firmware/efi/ovmf_debug_log).
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Building efidrm as module requires efi_mem_desc_lookup(). Export
the symbol.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250408091837.407401-2-tzimmermann@suse.de
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>
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>
When we load SSDT from efi variable (specified with efivar_ssdt=<var>
boot command line argument) a name for the variable is allocated
dynamically because we traverse all EFI variables. Unlike ACPI table
data, which is later used by ACPI engine, the name is no longer needed
once traverse is complete -- don't forget to free this memory.
Same time we silently ignore any errors happened here let's print a
message if something went wrong (but do not exit since this is not a
critical error and the system should continue to boot).
Also while here -- add a note why we keep SSDT table on success.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Since the debugfs_create_dir() never returns a null pointer, checking
the return value for a null pointer is redundant, and using IS_ERR is
safe enough.
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Check if get_next_variable() is actually valid pointer before
calling it. In kdump kernel this method is set to NULL that causes
panic during the kexec-ed kernel boot.
Tested with QEMU and OVMF firmware.
Fixes: bad267f9e1 ("efi: verify that variable services are supported")
Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
To allow event log info access after boot, EFI boot stub extracts
the event log information and installs it in an EFI configuration
table. Currently, EFI boot stub only supports installation of event
log only for TPM 1.2 and TPM 2.0 protocols. Extend the same support
for CC protocol. Since CC platform also uses TCG2 format, reuse TPM2
support code as much as possible.
Link: https://uefi.org/specs/UEFI/2.10/38_Confidential_Computing.html#efi-cc-measurement-protocol [1]
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://lkml.kernel.org/r/0229a87e-fb19-4dad-99fc-4afd7ed4099a%40collabora.com
[ardb: Split out final events table handling to avoid version confusion]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The LINUX_EFI_ GUID identifiers are only intended to be used to refer to
GUIDs that are part of the Linux implementation, and are not considered
external ABI. (Famous last words).
GUIDs that already have a symbolic name in the spec should use that
name, to avoid confusion between firmware components. So use the
official name EFI_TCG2_FINAL_EVENTS_TABLE_GUID for the TCG2 'final
events' configuration table.
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
efivar operation is updated when the tee_stmm_efi module is probed.
tee_stmm_efi module supports SetVariable runtime service, but user needs
to manually remount the efivarfs as RW to enable the write access if the
previous efivar operation does not support SetVariable and efivarfs is
mounted as read-only.
This commit notifies the update of efivar operation to efivarfs
subsystem, then drops SB_RDONLY flag if the efivar operation supports
SetVariable.
Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
[ardb: use per-superblock instance of the notifier block]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This is a preparation for supporting efivar operations provided by other
than efi subsystem. Both register and unregister functions are exposed
so that non-efi subsystem can revert the efi generic operation.
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Co-developed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The ia64 architecture gets its well-earned retirement as planned,
now that there is one last (mostly) working release that will
be maintained as an LTS kernel.
The architecture specific system call tables are updated for
the added map_shadow_stack() syscall and to remove references
to the long-gone sys_lookup_dcookie() syscall.
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Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull ia64 removal and asm-generic updates from Arnd Bergmann:
- The ia64 architecture gets its well-earned retirement as planned,
now that there is one last (mostly) working release that will be
maintained as an LTS kernel.
- The architecture specific system call tables are updated for the
added map_shadow_stack() syscall and to remove references to the
long-gone sys_lookup_dcookie() syscall.
* tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
hexagon: Remove unusable symbols from the ptrace.h uapi
asm-generic: Fix spelling of architecture
arch: Reserve map_shadow_stack() syscall number for all architectures
syscalls: Cleanup references to sys_lookup_dcookie()
Documentation: Drop or replace remaining mentions of IA64
lib/raid6: Drop IA64 support
Documentation: Drop IA64 from feature descriptions
kernel: Drop IA64 support from sig_fault handlers
arch: Remove Itanium (IA-64) architecture
In the previous code, there was a memory leak issue where the
previously allocated memory was not freed upon a failed krealloc
operation. This patch addresses the problem by releasing the old memory
before setting the pointer to NULL in case of a krealloc failure. This
ensures that memory is properly managed and avoids potential memory
leaks.
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Unaccepted table is now allocated from EFI_ACPI_RECLAIM_MEMORY. It
translates into E820_TYPE_ACPI, which is not added to memblock and
therefore not mapped in the direct mapping.
This causes a crash on the first touch of the table.
Use memblock_add() to make sure that the table is mapped in direct
mapping.
Align the range to the nearest page borders. Ranges smaller than page
size are not mapped.
Fixes: e7761d827e ("efi/unaccepted: Use ACPI reclaim memory for unaccepted memory table")
Reported-by: Hongyu Ning <hongyu.ning@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The Itanium architecture is obsolete, and an informal survey [0] reveals
that any residual use of Itanium hardware in production is mostly HP-UX
or OpenVMS based. The use of Linux on Itanium appears to be limited to
enthusiasts that occasionally boot a fresh Linux kernel to see whether
things are still working as intended, and perhaps to churn out some
distro packages that are rarely used in practice.
None of the original companies behind Itanium still produce or support
any hardware or software for the architecture, and it is listed as
'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers
that contributed on behalf of those companies (nor anyone else, for that
matter) have been willing to support or maintain the architecture
upstream or even be responsible for applying the odd fix. The Intel
firmware team removed all IA-64 support from the Tianocore/EDK2
reference implementation of EFI in 2018. (Itanium is the original
architecture for which EFI was developed, and the way Linux supports it
deviates significantly from other architectures.) Some distros, such as
Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have
dropped support years ago.
While the argument is being made [1] that there is a 'for the common
good' angle to being able to build and run existing projects such as the
Grid Community Toolkit [2] on Itanium for interoperability testing, the
fact remains that none of those projects are known to be deployed on
Linux/ia64, and very few people actually have access to such a system in
the first place. Even if there were ways imaginable in which Linux/ia64
could be put to good use today, what matters is whether anyone is
actually doing that, and this does not appear to be the case.
There are no emulators widely available, and so boot testing Itanium is
generally infeasible for ordinary contributors. GCC still supports IA-64
but its compile farm [3] no longer has any IA-64 machines. GLIBC would
like to get rid of IA-64 [4] too because it would permit some overdue
code cleanups. In summary, the benefits to the ecosystem of having IA-64
be part of it are mostly theoretical, whereas the maintenance overhead
of keeping it supported is real.
So let's rip off the band aid, and remove the IA-64 arch code entirely.
This follows the timeline proposed by the Debian/ia64 maintainer [5],
which removes support in a controlled manner, leaving IA-64 in a known
good state in the most recent LTS release. Other projects will follow
once the kernel support is removed.
[0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/
[1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/
[2] https://gridcf.org/gct-docs/latest/index.html
[3] https://cfarm.tetaneutral.net/machines/list/
[4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/
[5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Although some more stuff is brewing, the EFI changes that are ready for
mainline are few, so not a lot to pull this cycle:
- improve the PCI DMA paranoia logic in the EFI stub
- some constification changes
- add statfs support to efivarfs
- allow user space to enumerate updatable firmware resources without
CAP_SYS_ADMIN
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Merge tag 'efi-next-for-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"Although some more stuff is brewing, the EFI changes that are ready
for mainline are few this cycle:
- improve the PCI DMA paranoia logic in the EFI stub
- some constification changes
- add statfs support to efivarfs
- allow user space to enumerate updatable firmware resources without
CAP_SYS_ADMIN"
* tag 'efi-next-for-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi/libstub: Disable PCI DMA before grabbing the EFI memory map
efi/esrt: Allow ESRT access without CAP_SYS_ADMIN
efivarfs: expose used and total size
efi: make kobj_type structure constant
efi: x86: make kobj_type structure constant
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using it
and thus preventing a whole set of attacks against such guests like
memory replay and the like.
There are a couple of strategies of how memory should be accepted
- the current implementation does an on-demand way of accepting.
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Merge tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 confidential computing update from Borislav Petkov:
- Add support for unaccepted memory as specified in the UEFI spec v2.9.
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using
it and thus preventing a whole set of attacks against such guests
like memory replay and the like.
There are a couple of strategies of how memory should be accepted -
the current implementation does an on-demand way of accepting.
* tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
virt: sevguest: Add CONFIG_CRYPTO dependency
x86/efi: Safely enable unaccepted memory in UEFI
x86/sev: Add SNP-specific unaccepted memory support
x86/sev: Use large PSC requests if applicable
x86/sev: Allow for use of the early boot GHCB for PSC requests
x86/sev: Put PSC struct on the stack in prep for unaccepted memory support
x86/sev: Fix calculation of end address based on number of pages
x86/tdx: Add unaccepted memory support
x86/tdx: Refactor try_accept_one()
x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub
efi/unaccepted: Avoid load_unaligned_zeropad() stepping into unaccepted memory
efi: Add unaccepted memory support
x86/boot/compressed: Handle unaccepted memory
efi/libstub: Implement support for unaccepted memory
efi/x86: Get full memory map in allocate_e820()
mm: Add support for unaccepted memory
efi_config_parse_tables() reserves memory that holds unaccepted memory
configuration table so it won't be reused by page allocator.
Core-mm requires few helpers to support unaccepted memory:
- accept_memory() checks the range of addresses against the bitmap and
accept memory if needed.
- range_contains_unaccepted_memory() checks if anything within the
range requires acceptance.
Architectural code has to provide efi_get_unaccepted_table() that
returns pointer to the unaccepted memory configuration table.
arch_accept_memory() handles arch-specific part of memory acceptance.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230606142637.5171-6-kirill.shutemov@linux.intel.com
UEFI Specification version 2.9 introduces the concept of memory
acceptance: Some Virtual Machine platforms, such as Intel TDX or AMD
SEV-SNP, requiring memory to be accepted before it can be used by the
guest. Accepting happens via a protocol specific for the Virtual
Machine platform.
Accepting memory is costly and it makes VMM allocate memory for the
accepted guest physical address range. It's better to postpone memory
acceptance until memory is needed. It lowers boot time and reduces
memory overhead.
The kernel needs to know what memory has been accepted. Firmware
communicates this information via memory map: a new memory type --
EFI_UNACCEPTED_MEMORY -- indicates such memory.
Range-based tracking works fine for firmware, but it gets bulky for
the kernel: e820 (or whatever the arch uses) has to be modified on every
page acceptance. It leads to table fragmentation and there's a limited
number of entries in the e820 table.
Another option is to mark such memory as usable in e820 and track if the
range has been accepted in a bitmap. One bit in the bitmap represents a
naturally aligned power-2-sized region of address space -- unit.
For x86, unit size is 2MiB: 4k of the bitmap is enough to track 64GiB or
physical address space.
In the worst-case scenario -- a huge hole in the middle of the
address space -- It needs 256MiB to handle 4PiB of the address
space.
Any unaccepted memory that is not aligned to unit_size gets accepted
upfront.
The bitmap is allocated and constructed in the EFI stub and passed down
to the kernel via EFI configuration table. allocate_e820() allocates the
bitmap if unaccepted memory is present, according to the size of
unaccepted region.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230606142637.5171-4-kirill.shutemov@linux.intel.com
When writing EFI variables, one might get errors with no other message
on why it fails. Being able to see how much is used by EFI variables
helps analyzing such issues.
Since this is not a conventional filesystem, block size is intentionally
set to 1 instead of PAGE_SIZE.
x86 quirks of reserved size are taken into account; so that available
and free size can be different, further helping debugging space issues.
With this patch, one can see the remaining space in EFI variable storage
via efivarfs, like this:
$ df -h /sys/firmware/efi/efivars/
Filesystem Size Used Avail Use% Mounted on
efivarfs 176K 106K 66K 62% /sys/firmware/efi/efivars
Signed-off-by: Anisse Astier <an.astier@criteo.com>
[ardb: - rename efi_reserved_space() to efivar_reserved_space()
- whitespace/coding style tweaks]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
- Performance tweaks for efifb earlycon by Andy
- Preparatory refactoring and cleanup work in the efivar layer by Johan,
which is needed to accommodate the Snapdragon arm64 laptops that
expose their EFI variable store via a TEE secure world API.
- Enhancements to the EFI memory map handling so that Xen dom0 can
safely access EFI configuration tables (Demi Marie)
- Wire up the newly introduced IBT/BTI flag in the EFI memory attributes
table, so that firmware that is generated with ENDBR/BTI landing pads
will be mapped with enforcement enabled.
- Clean up how we check and print the EFI revision exposed by the
firmware.
- Incorporate EFI memory attributes protocol definition contributed by
Evgeniy and wire it up in the EFI zboot code. This ensures that these
images can execute under new and stricter rules regarding the default
memory permissions for EFI page allocations. (More work is in progress
here)
- CPER header cleanup by Dan Williams
- Use a raw spinlock to protect the EFI runtime services stack on arm64
to ensure the correct semantics under -rt. (Pierre)
- EFI framebuffer quirk for Lenovo Ideapad by Darrell.
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Merge tag 'efi-next-for-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"A healthy mix of EFI contributions this time:
- Performance tweaks for efifb earlycon (Andy)
- Preparatory refactoring and cleanup work in the efivar layer, which
is needed to accommodate the Snapdragon arm64 laptops that expose
their EFI variable store via a TEE secure world API (Johan)
- Enhancements to the EFI memory map handling so that Xen dom0 can
safely access EFI configuration tables (Demi Marie)
- Wire up the newly introduced IBT/BTI flag in the EFI memory
attributes table, so that firmware that is generated with ENDBR/BTI
landing pads will be mapped with enforcement enabled
- Clean up how we check and print the EFI revision exposed by the
firmware
- Incorporate EFI memory attributes protocol definition and wire it
up in the EFI zboot code (Evgeniy)
This ensures that these images can execute under new and stricter
rules regarding the default memory permissions for EFI page
allocations (More work is in progress here)
- CPER header cleanup (Dan Williams)
- Use a raw spinlock to protect the EFI runtime services stack on
arm64 to ensure the correct semantics under -rt (Pierre)
- EFI framebuffer quirk for Lenovo Ideapad (Darrell)"
* tag 'efi-next-for-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (24 commits)
firmware/efi sysfb_efi: Add quirk for Lenovo IdeaPad Duet 3
arm64: efi: Make efi_rt_lock a raw_spinlock
efi: Add mixed-mode thunk recipe for GetMemoryAttributes
efi: x86: Wire up IBT annotation in memory attributes table
efi: arm64: Wire up BTI annotation in memory attributes table
efi: Discover BTI support in runtime services regions
efi/cper, cxl: Remove cxl_err.h
efi: Use standard format for printing the EFI revision
efi: Drop minimum EFI version check at boot
efi: zboot: Use EFI protocol to remap code/data with the right attributes
efi/libstub: Add memory attribute protocol definitions
efi: efivars: prevent double registration
efi: verify that variable services are supported
efivarfs: always register filesystem
efi: efivars: add efivars printk prefix
efi: Warn if trying to reserve memory under Xen
efi: Actually enable the ESRT under Xen
efi: Apply allowlist to EFI configuration tables when running under Xen
efi: xen: Implement memory descriptor lookup based on hypercall
efi: memmap: Disregard bogus entries instead of returning them
...
The UEFI spec section 4.2.1 describes the way the human readable EFI
revision should be constructed from the 32-bit revision field in the
system table:
The upper 16 bits of this field contain the major revision value,
and the lower 16 bits contain the minor revision value. The minor
revision values are binary coded decimals and are limited to the
range of 00..99.
When printed or displayed UEFI spec revision is referred as (Major
revision).(Minor revision upper decimal).(Minor revision lower
decimal) or (Major revision).(Minor revision upper decimal) in case
Minor revision lower decimal is set to 0.
Let's adhere to this when logging the EFI revision to the kernel log.
Note that the bit about binary coded decimals is bogus, and the minor
revision lower decimal is simply the minor revision modulo 10, given the
symbolic definitions provided by the spec itself:
#define EFI_2_40_SYSTEM_TABLE_REVISION ((2<<16) | (40))
#define EFI_2_31_SYSTEM_TABLE_REVISION ((2<<16) | (31))
#define EFI_2_30_SYSTEM_TABLE_REVISION ((2<<16) | (30))
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
We currently pass a minimum major version to the generic EFI helper that
checks the system table magic and version, and refuse to boot if the
value is lower.
The motivation for this check is unknown, and even the code that uses
major version 2 as the minimum (ARM, arm64 and RISC-V) should make it
past this check without problems, and boot to a point where we have
access to a console or some other means to inform the user that the
firmware's major revision number made us unhappy. (Revision 2.0 of the
UEFI specification was released in January 2006, whereas ARM, arm64 and
RISC-V support where added in 2009, 2013 and 2017, respectively, so
checking for major version 2 or higher is completely arbitrary)
So just drop the check.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
When iterating on a linked list, a result of memremap is dereferenced
without checking it for NULL.
This patch adds a check that falls back on allocating a new page in
case memremap doesn't succeed.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 18df7577ad ("efi/memreserve: deal with memreserve entries in unmapped memory")
Signed-off-by: Anton Gusev <aagusev@ispras.ru>
[ardb: return -ENOMEM instead of breaking out of the loop]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Current Qualcomm UEFI firmware does not implement the variable services
but not all revisions clear the corresponding bits in the RT_PROP table
services mask and instead the corresponding calls return
EFI_UNSUPPORTED.
This leads to efi core registering the generic efivar ops even when the
variable services are not supported or when they are accessed through
some other interface (e.g. Google SMI or the upcoming Qualcomm SCM
implementation).
Instead of playing games with init call levels to make sure that the
custom implementations are registered after the generic one, make sure
that get_next_variable() is actually supported before registering the
generic ops.
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Doing so cannot work and should never happen.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
As it turns out, Xen does not guarantee that EFI boot services data
regions in memory are preserved, which means that EFI configuration
tables pointing into such memory regions may be corrupted before the
dom0 OS has had a chance to inspect them.
This is causing problems for Qubes OS when it attempts to perform system
firmware updates, which requires that the contents of the EFI System
Resource Table are valid when the fwupd userspace program runs.
However, other configuration tables such as the memory attributes table
or the runtime properties table are equally affected, and so we need a
comprehensive workaround that works for any table type.
So when running under Xen, check the EFI memory descriptor covering the
start of the table, and disregard the table if it does not reside in
memory that is preserved by Xen.
Co-developed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Xen on x86 boots dom0 in EFI mode but without providing a memory map.
This means that some consistency checks we would like to perform on
configuration tables or other data structures in memory are not
currently possible. Xen does, however, expose EFI memory descriptor
info via a Xen hypercall, so let's wire that up instead. It turns out
that the returned information is not identical to what Linux's
efi_mem_desc_lookup would return: the address returned is the address
passed to the hypercall, and the size returned is the number of bytes
remaining in the configuration table. However, none of the callers of
efi_mem_desc_lookup() currently care about this. In the future, Xen may
gain a hypercall that returns the actual start address, which can be
used instead.
Co-developed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The ESRT code currently contains two consistency checks on the memory
descriptor it obtains, but one of them is both incomplete and can only
trigger on invalid descriptors.
So let's drop these checks, and instead disregard descriptors entirely
if the start address is misaligned, or if the number of pages reaches
to or beyond the end of the address space. Note that the memory map as
a whole could still be inconsistent: multiple entries might cover the
same area, or the address could be outside of the addressable PA space,
but validating that goes beyond the scope of these helpers. Also note
that since the physical address space is never 64-bits wide, a
descriptor that includes the last page of memory is not valid. This is
fortunate, since it means that a valid physical address will never be an
error pointer and that the length of a memory descriptor in bytes will
fit in a 64-bit unsigned integer.
Co-developed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Since commit 0f5b2c69a4 ("efi: vars: Remove deprecated 'efivars' sysfs
interface") and the removal of the sysfs interface there are no users of
the efivars kobject.
Drop the kobject argument from efivars_register() and add a new
efivar_is_available() helper in favour of the old efivars_kobject().
Note that the new helper uses the prefix 'efivar' (i.e. without an 's')
for consistency with efivar_supports_writes() and the rest of the
interface (except the registration functions).
For the benefit of drivers with optional EFI support, also provide a
dummy implementation of efivar_is_available().
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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: 98086df8b7 ("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>
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: e7b813b32a ("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>
- 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
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Merge tag 'efi-next-for-v6.2' of 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
...
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>
