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
The cper.c file needs to include an extra header, and efi_zboot_entry
needs an extern declaration to avoid these 'make W=1' warnings:
drivers/firmware/efi/libstub/zboot.c:65:1: error: no previous prototype for 'efi_zboot_entry' [-Werror=missing-prototypes]
drivers/firmware/efi/efi.c:176:16: error: no previous prototype for 'efi_attr_is_visible' [-Werror=missing-prototypes]
drivers/firmware/efi/cper.c:626:6: error: no previous prototype for 'cper_estatus_print' [-Werror=missing-prototypes]
drivers/firmware/efi/cper.c:649:5: error: no previous prototype for 'cper_estatus_check_header' [-Werror=missing-prototypes]
drivers/firmware/efi/cper.c:662:5: error: no previous prototype for 'cper_estatus_check' [-Werror=missing-prototypes]
To make this easier, move the cper specific declarations to
include/linux/cper.h.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Instead of relying on a dodgy dd hack to copy the image code size from
the uncompressed image's PE header to the end of the compressed image,
let's grab the code size from the symbol that is injected into the ELF
object by the Kbuild rules that generate the compressed payload.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
In some cases, we expose the kernel's struct screen_info to the EFI stub
directly, so it gets populated before even entering the kernel. This
means the early console is available as soon as the early param parsing
happens, which is nice. It also means we need two different ways to pass
this information, as this trick only works if the EFI stub is baked into
the core kernel image, which is not always the case.
Huacai reports that the preparatory refactoring that was needed to
implement this alternative method for zboot resulted in a non-functional
efifb earlycon for other cases as well, due to the reordering of the
kernel image relocation with the population of the screen_info struct,
and the latter now takes place after copying the image to its new
location, which means we copy the old, uninitialized state.
So let's ensure that the same-image version of alloc_screen_info()
produces the correct screen_info pointer, by taking the displacement of
the loaded image into account.
Reported-by: Huacai Chen <chenhuacai@loongson.cn>
Tested-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/
Fixes: 42c8ea3dca ("efi: libstub: Factor out EFI stub entrypoint into separate file")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
We no longer use the recsize argument for locating the string table in
an SMBIOS record, so we can drop it from the internal API.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Instead of using the SMBIOS type 1 record 'family' field, which is often
modified by OEMs, use the type 4 'processor ID' and 'processor version'
fields, which are set to a small set of probe-able values on all known
Ampere EFI systems in the field.
Fixes: 550b33cfd4 ("arm64: efi: Force the use of ...")
Tested-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Use the recently introduced EFI_MEMORY_ATTRIBUTES_PROTOCOL in the zboot
implementation to set the right attributes for the code and data
sections of the decompressed image, i.e., EFI_MEMORY_RO for code and
EFI_MEMORY_XP for data.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
EFI_MEMORY_ATTRIBUTE_PROTOCOL servers as a better alternative to
DXE services for setting memory attributes in EFI Boot Services
environment. This protocol is better since it is a part of UEFI
specification itself and not UEFI PI specification like DXE
services.
Add EFI_MEMORY_ATTRIBUTE_PROTOCOL definitions.
Support mixed mode properly for its calls.
Tested-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Evgeniy Baskov <baskov@ispras.ru>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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>
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>
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>
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>
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>
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>
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 23715a26c8 ("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>
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>
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>
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>
The EFI TCG spec, in §10.2.6 "Measuring UEFI Variables and UEFI GPT
Data", only reasons about the load options passed to a loaded image in
the context of boot options booted directly from the BDS, which are
measured into PCR #5 along with the rest of the Boot#### EFI variable.
However, the UEFI spec mentions the following in the documentation of
the LoadImage() boot service and the EFI_LOADED_IMAGE protocol:
The caller may fill in the image’s "load options" data, or add
additional protocol support to the handle before passing control to
the newly loaded image by calling EFI_BOOT_SERVICES.StartImage().
The typical boot sequence for Linux EFI systems is to load GRUB via a
boot option from the BDS, which [hopefully] calls LoadImage to load the
kernel image, passing the kernel command line via the mechanism
described above. This means that we cannot rely on the firmware
implementing TCG measured boot to ensure that the kernel command line
gets measured before the image is started, so the EFI stub will have to
take care of this itself.
Given that PCR #5 has an official use in the TCG measured boot spec,
let's avoid it in this case. Instead, add a measurement in PCR #9 (which
we already use for our initrd) and extend it with the LoadOptions
measurements
Co-developed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This is necessary because the EFI libstub refactoring patches are mostly
directed at enabling LoongArch to wire up generic EFI boot support
without being forced to consume DT properties that conflict with
information that EFI also provides, e.g., memory map and reservations,
etc.
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Merge tag 'efi-loongarch-for-v6.1-2' into HEAD
Second shared stable tag between EFI and LoongArch trees
This is necessary because the EFI libstub refactoring patches are mostly
directed at enabling LoongArch to wire up generic EFI boot support
without being forced to consume DT properties that conflict with
information that EFI also provides, e.g., memory map and reservations,
etc.
Expose the EFI boot time memory map to the kernel via a configuration
table. This is arch agnostic and enables future changes that remove the
dependency on DT on architectures that don't otherwise rely on it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Refactor the generic EFI stub entry code so that all the dependencies on
device tree are abstracted and hidden behind a generic efi_boot_kernel()
routine that can also be implemented in other ways. This allows users of
the generic stub to avoid using FDT for passing information to the core
kernel.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Use a EFI configuration table to pass the initrd to the core kernel,
instead of per-arch methods. This cleans up the code considerably, and
should make it easier for architectures to get rid of their reliance on
DT for doing EFI boot in the future.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Currently, struct efi_boot_memmap is a struct that is passed around
between callers of efi_get_memory_map() and the users of the resulting
data, and which carries pointers to various variables whose values are
provided by the EFI GetMemoryMap() boot service.
This is overly complex, and it is much easier to carry these values in
the struct itself. So turn the struct into one that carries these data
items directly, including a flex array for the variable number of EFI
memory descriptors that the boot service may return.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The virt map is a set of efi_memory_desc_t descriptors that are passed
to SetVirtualAddressMap() to inform the firmware about the desired
virtual mapping of the regions marked as EFI_MEMORY_RUNTIME. The only
reason we currently call the efi_get_memory_map() helper is that it
gives us an allocation that is guaranteed to be of sufficient size.
However, efi_get_memory_map() has grown some additional complexity over
the years, and today, we're actually better off calling the EFI boot
service directly with a zero size, which tells us how much memory should
be enough for the virt map.
While at it, avoid creating the VA map allocation if we will not be
using it anyway, i.e., if efi_novamap is true.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Even though it is unlikely to ever make a difference, let's use u32
consistently for the size of the load_options provided by the firmware
(aka the command line)
While at it, do some general cleanup too: use efi_char16_t, avoid using
options_chars in places where it really means options_size, etc.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The stub is used in different execution environments, but on arm64,
RISC-V and LoongArch, we still use the core kernel's implementation of
memcpy and memset, as they are just a branch instruction away, and can
generally be reused even from code such as the EFI stub that runs in a
completely different address space.
KAsan complicates this slightly, resulting in the need for some hacks to
expose the uninstrumented, __ prefixed versions as the normal ones, as
the latter are instrumented to include the KAsan checks, which only work
in the core kernel.
Unfortunately, #define'ing memcpy to __memcpy when building C code does
not guarantee that no explicit memcpy() calls will be emitted. And with
the upcoming zboot support, which consists of a separate binary which
therefore needs its own implementation of memcpy/memset anyway, it's
better to provide one explicitly instead of linking to the existing one.
Given that EFI exposes implementations of memmove() and memset() via the
boot services table, let's wire those up in the appropriate way, and
drop the references to the core kernel ones.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Define the correct prototypes for the load_image, start_image and
unload_image boot service pointers so we can call them from the EFI
zboot code.
Also add some prototypes related to installation and deinstallation of
protocols in to the EFI protocol database, including some definitions
related to device paths.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Add support for getting the boot hart ID from the Linux EFI stub using
RISCV_EFI_BOOT_PROTOCOL. This method is preferred over the existing DT
based approach since it works irrespective of DT or ACPI.
The specification of the protocol is hosted at:
https://github.com/riscv-non-isa/riscv-uefi
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Link: https://lore.kernel.org/r/20220519051512.136724-2-sunilvl@ventanamicro.com
[ardb: minor tweaks for coding style and whitespace]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
In a future patch, arm64's implementation of handle_kernel_image() will
omit randomizing the placement of the kernel if the load address was
chosen randomly by the loader. In order to do this, it needs to locate a
protocol on the image handle, so pass it to handle_kernel_image().
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
UEFI DXE services are not yet used in kernel code
but are required to manipulate page table memory
protection flags.
Add required declarations to use DXE services functions.
Signed-off-by: Baskov Evgeniy <baskov@ispras.ru>
Link: https://lore.kernel.org/r/20220303142120.1975-2-baskov@ispras.ru
[ardb: ignore absent DXE table but warn if the signature check fails]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Before adding TPM measurement of the initrd contents, refactor the
initrd handling slightly to be more self-contained and consistent.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Link: https://lore.kernel.org/r/20211119114745.1560453-4-ilias.apalodimas@linaro.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Define the right prototype for efi_tcg2_protocol::hash_log_extend_event()
and add the required structs so we can start using it to measure the initrd
into the TPM if it was loaded by the EFI stub itself.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Link: https://lore.kernel.org/r/20211119114745.1560453-2-ilias.apalodimas@linaro.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Move TPM related definitions that are only used in the EFI stub into
efistub.h, which is a local header.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Now that ARM started following the example of arm64 and RISC-V, and
no longer imposes any restrictions on the placement of the FDT in
memory at boot, we no longer need per-arch implementations of
efi_get_max_fdt_addr() to factor out the differences. So get rid of
it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Link: https://lore.kernel.org/r/20201029134901.9773-1-ardb@kernel.org
Generalize the efi_get_secureboot() function so not only efistub but also
other subsystems can use it.
Note that the MokSbState handling is not factored out: the variable is
boot time only, and so it cannot be parameterized as easily. Also, the
IMA code will switch to this version in a future patch, and it does not
incorporate the MokSbState exception in the first place.
Note that the new efi_get_secureboot_mode() helper treats any failures
to read SetupMode as setup mode being disabled.
Co-developed-by: Chester Lin <clin@suse.com>
Signed-off-by: Chester Lin <clin@suse.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
At least some versions of Dell EFI firmware pass the entire
EFI_LOAD_OPTION descriptor, rather than just the OptionalData part, to
the loaded image. This was verified with firmware revision 2.15.0 on a
Dell Precision T3620 by Jacobo Pantoja.
To handle this, add a quirk to check if the options look like a valid
EFI_LOAD_OPTION descriptor, and if so, use the OptionalData part as the
command line.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reported-by: Jacobo Pantoja <jacobopantoja@gmail.com>
Link: https://lore.kernel.org/linux-efi/20200907170021.GA2284449@rani.riverdale.lan/
Link: https://lore.kernel.org/r/20200914213535.933454-2-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Add an efi_warn logging helper for warnings, and implement an analog of
printk_once for once-only logging.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200914213535.933454-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Before commit
d0f9ca9be1 ("ARM: decompressor: run decompressor in place if loaded via UEFI")
we were rather limited in the choice of base address for the uncompressed
kernel, as we were relying on the logic in the decompressor that blindly
rounds down the decompressor execution address to the next multiple of 128
MiB, and decompresses the kernel there. For this reason, we have a lot of
complicated memory region handling code, to ensure that this memory window
is available, even though it could be occupied by reserved regions or
other allocations that may or may not collide with the uncompressed image.
Today, we simply pass the target address for the decompressed image to the
decompressor directly, and so we can choose a suitable window just by
finding a 16 MiB aligned region, while taking TEXT_OFFSET and the region
for the swapper page tables into account.
So let's get rid of the complicated logic, and instead, use the existing
bottom up allocation routine to allocate a suitable window as low as
possible, and carve out a memory region that has the right properties.
Note that this removes any dependencies on the 'dram_base' argument to
handle_kernel_image(), and so this is removed as well. Given that this
was the only remaining use of dram_base, the code that produces it is
removed entirely as well.
Reviewed-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Tested-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Permit arm32-stub.c to access efi_low_alloc_above() in a subsequent
patch by giving it external linkage and declaring it in efistub.h.
Reviewed-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Tested-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The prototype of the functions handle_kernel_image & efi_enter_kernel
are defined in efi-stub.c which may result in a compiler warnings if
-Wmissing-prototypes is set in gcc compiler.
Move the prototype to efistub.h to make the compiler happy.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Link: https://lore.kernel.org/r/20200706172609.25965-2-atish.patra@wdc.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
On 32-bit ARM, we may boot at HYP mode, or with the MMU and caches off
(or both), even though the EFI spec does not actually support this.
While booting at HYP mode is something we might tolerate, fiddling
with the caches is a more serious issue, as disabling the caches is
tricky to do safely from C code, and running without the Dcache makes
it impossible to support unaligned memory accesses, which is another
explicit requirement imposed by the EFI spec.
So take note of the CPU mode and MMU state in the EFI stub diagnostic
output so that we can easily diagnose any issues that may arise from
this. E.g.,
EFI stub: Entering in SVC mode with MMU enabled
Also, capture the CPSR and SCTLR system register values at EFI stub
entry, and after ExitBootServices() returns, and check whether the
MMU and Dcache were disabled at any point. If this is the case, a
diagnostic message like the following will be emitted:
efi: [Firmware Bug]: EFI stub was entered with MMU and Dcache disabled, please fix your firmware!
efi: CPSR at EFI stub entry : 0x600001d3
efi: SCTLR at EFI stub entry : 0x00c51838
efi: CPSR after ExitBootServices() : 0x600001d3
efi: SCTLR after ExitBootServices(): 0x00c50838
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
- Rename pr_efi/pr_efi_err to efi_info/efi_err, and use them consistently
- Simplify and unify initrd loading
- Parse the builtin command line on x86 (if provided)
- Implement printk() support, including support for wide character strings
- Some fixes for issues introduced by the first batch of v5.8 changes
- Fix a missing prototypes warning
- Simplify GDT handling in early mixed mode thunking code
- Some other minor fixes and cleanups
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Merge tag 'efi-changes-for-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core
More EFI changes for v5.8:
- Rename pr_efi/pr_efi_err to efi_info/efi_err, and use them consistently
- Simplify and unify initrd loading
- Parse the builtin command line on x86 (if provided)
- Implement printk() support, including support for wide character strings
- Some fixes for issues introduced by the first batch of v5.8 changes
- Fix a missing prototypes warning
- Simplify GDT handling in early mixed mode thunking code
- Some other minor fixes and cleanups
Conflicts:
drivers/firmware/efi/libstub/efistub.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix a missing prototype warning by adding a forward declaration
for the PE/COFF entrypoint, and while at it, align the function
name between the x86 and ARM versions of the stub.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Now that we removed the memory limit for the allocation of the
command line, there is no longer a need to use the page based
allocator so switch to a pool allocation instead.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
