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2024-04-10x86/boot: Move mem_encrypt= parsing to the decompressorArd Biesheuvel1-0/+3
commit cd0d9d92c8bb46e77de62efd7df13069ddd61e7d upstream. The early SME/SEV code parses the command line very early, in order to decide whether or not memory encryption should be enabled, which needs to occur even before the initial page tables are created. This is problematic for a number of reasons: - this early code runs from the 1:1 mapping provided by the decompressor or firmware, which uses a different translation than the one assumed by the linker, and so the code needs to be built in a special way; - parsing external input while the entire kernel image is still mapped writable is a bad idea in general, and really does not belong in security minded code; - the current code ignores the built-in command line entirely (although this appears to be the case for the entire decompressor) Given that the decompressor/EFI stub is an intrinsic part of the x86 bootable kernel image, move the command line parsing there and out of the core kernel. This removes the need to build lib/cmdline.o in a special way, or to use RIP-relative LEA instructions in inline asm blocks. This involves a new xloadflag in the setup header to indicate that mem_encrypt=on appeared on the kernel command line. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240227151907.387873-17-ardb+git@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-10x86/efistub: Remap kernel text read-only before dropping NX attributeArd Biesheuvel1-1/+10
commit 9c55461040a9264b7e44444c53d26480b438eda6 upstream. Currently, the EFI stub invokes the EFI memory attributes protocol to strip any NX restrictions from the entire loaded kernel, resulting in all code and data being mapped read-write-execute. The point of the EFI memory attributes protocol is to remove the need for all memory allocations to be mapped with both write and execute permissions by default, and make it the OS loader's responsibility to transition data mappings to code mappings where appropriate. Even though the UEFI specification does not appear to leave room for denying memory attribute changes based on security policy, let's be cautious and avoid relying on the ability to create read-write-execute mappings. This is trivially achievable, given that the amount of kernel code executing via the firmware's 1:1 mapping is rather small and limited to the .head.text region. So let's drop the NX restrictions only on that subregion, but not before remapping it as read-only first. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-10efi/libstub: Add generic support for parsing mem_encrypt=Ard Biesheuvel2-1/+9
commit 7205f06e847422b66c1506eee01b9998ffc75d76 upstream. Parse the mem_encrypt= command line parameter from the EFI stub if CONFIG_ARCH_HAS_MEM_ENCRYPT=y, so that it can be passed to the early boot code by the arch code in the stub. This avoids the need for the core kernel to do any string parsing very early in the boot. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240227151907.387873-16-ardb+git@google.com Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-03x86/efistub: Reinstate soft limit for initrd loadingArd Biesheuvel1-0/+1
commit decd347c2a75d32984beb8807d470b763a53b542 upstream. Commit 8117961d98fb2 ("x86/efi: Disregard setup header of loaded image") dropped the memcopy of the image's setup header into the boot_params struct provided to the core kernel, on the basis that EFI boot does not need it and should rely only on a single protocol to interface with the boot chain. It is also a prerequisite for being able to increase the section alignment to 4k, which is needed to enable memory protections when running in the boot services. So only the setup_header fields that matter to the core kernel are populated explicitly, and everything else is ignored. One thing was overlooked, though: the initrd_addr_max field in the setup_header is not used by the core kernel, but it is used by the EFI stub itself when it loads the initrd, where its default value of INT_MAX is used as the soft limit for memory allocation. This means that, in the old situation, the initrd was virtually always loaded in the lower 2G of memory, but now, due to initrd_addr_max being 0x0, the initrd may end up anywhere in memory. This should not be an issue principle, as most systems can deal with this fine. However, it does appear to tickle some problems in older UEFI implementations, where the memory ends up being corrupted, resulting in errors when unpacking the initramfs. So set the initrd_addr_max field to INT_MAX like it was before. Fixes: 8117961d98fb2 ("x86/efi: Disregard setup header of loaded image") Reported-by: Radek Podgorny <radek@podgorny.cz> Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-03efi/libstub: Cast away type warning in use of max()Ard Biesheuvel1-1/+1
commit 61d130f261a3c15ae2c4b6f3ac3517d5d5b78855 upstream. Avoid a type mismatch warning in max() by switching to max_t() and providing the type explicitly. Fixes: 3cb4a4827596abc82e ("efi/libstub: fix efi_random_alloc() ...") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-03efi: fix panic in kdump kernelOleksandr Tymoshenko1-0/+2
[ Upstream commit 62b71cd73d41ddac6b1760402bbe8c4932e23531 ] 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: bad267f9e18f ("efi: verify that variable services are supported") Signed-off-by: Oleksandr Tymoshenko <ovt@google.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-03efi/libstub: fix efi_random_alloc() to allocate memory at alloc_min or ↵KONDO KAZUMA(近藤 和真)1-1/+1
higher address [ Upstream commit 3cb4a4827596abc82e55b80364f509d0fefc3051 ] Following warning is sometimes observed while booting my servers: [ 3.594838] DMA: preallocated 4096 KiB GFP_KERNEL pool for atomic allocations [ 3.602918] swapper/0: page allocation failure: order:10, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0-1 ... [ 3.851862] DMA: preallocated 1024 KiB GFP_KERNEL|GFP_DMA pool for atomic allocation If 'nokaslr' boot option is set, the warning always happens. On x86, ZONE_DMA is small zone at the first 16MB of physical address space. When this problem happens, most of that space seems to be used by decompressed kernel. Thereby, there is not enough space at DMA_ZONE to meet the request of DMA pool allocation. The commit 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDR") tried to fix this problem by introducing lower bound of allocation. But the fix is not complete. efi_random_alloc() allocates pages by following steps. 1. Count total available slots ('total_slots') 2. Select a slot ('target_slot') to allocate randomly 3. Calculate a starting address ('target') to be included target_slot 4. Allocate pages, which starting address is 'target' In step 1, 'alloc_min' is used to offset the starting address of memory chunk. But in step 3 'alloc_min' is not considered at all. As the result, 'target' can be miscalculated and become lower than 'alloc_min'. When KASLR is disabled, 'target_slot' is always 0 and the problem happens everytime if the EFI memory map of the system meets the condition. Fix this problem by calculating 'target' considering 'alloc_min'. Cc: linux-efi@vger.kernel.org Cc: Tom Englund <tomenglund26@gmail.com> Cc: linux-kernel@vger.kernel.org Fixes: 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDR") Signed-off-by: Kazuma Kondo <kazuma-kondo@nec.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-27x86/efistub: Don't clear BSS twice in mixed modeArd Biesheuvel1-1/+2
[ Upstream commit df7ecce842b846a04d087ba85fdb79a90e26a1b0 ] Clearing BSS should only be done once, at the very beginning. efi_pe_entry() is the entrypoint from the firmware, which may not clear BSS and so it is done explicitly. However, efi_pe_entry() is also used as an entrypoint by the mixed mode startup code, in which case BSS will already have been cleared, and doing it again at this point will corrupt global variables holding the firmware's GDT/IDT and segment selectors. So make the memset() conditional on whether the EFI stub is running in native mode. Fixes: b3810c5a2cc4a666 ("x86/efistub: Clear decompressor BSS in native EFI entrypoint") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-27x86/efistub: Clear decompressor BSS in native EFI entrypointArd Biesheuvel1-2/+4
[ Upstream commit b3810c5a2cc4a6665f7a65bed5393c75ce3f3aa2 ] The EFI stub on x86 no longer invokes the decompressor as a subsequent boot stage, but calls into the decompression code directly while running in the context of the EFI boot services. This means that when using the native EFI entrypoint (as opposed to the EFI handover protocol, which clears BSS explicitly), the firmware PE image loader is being relied upon to ensure that BSS is zeroed before the EFI stub is entered from the firmware. As Radek's report proves, this is a bad idea. Not all loaders do this correctly, which means some global variables that should be statically initialized to 0x0 may have junk in them. So clear BSS explicitly when entering via efi_pe_entry(). Note that zeroing BSS from C code is not generally safe, but in this case, the following assignment and dereference of a global pointer variable ensures that the memset() cannot be deferred or reordered. Cc: <stable@kernel.org> # v6.1+ Reported-by: Radek Podgorny <radek@podgorny.cz> Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-06efi/capsule-loader: fix incorrect allocation sizeArnd Bergmann1-1/+1
[ Upstream commit fccfa646ef3628097d59f7d9c1a3e84d4b6bb45e ] gcc-14 notices that the allocation with sizeof(void) on 32-bit architectures is not enough for a 64-bit phys_addr_t: drivers/firmware/efi/capsule-loader.c: In function 'efi_capsule_open': drivers/firmware/efi/capsule-loader.c:295:24: error: allocation of insufficient size '4' for type 'phys_addr_t' {aka 'long long unsigned int'} with size '8' [-Werror=alloc-size] 295 | cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL); | ^ Use the correct type instead here. Fixes: f24c4d478013 ("efi/capsule-loader: Reinstate virtual capsule mapping") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01efi: Don't add memblocks for soft-reserved memoryAndrew Bresticker1-9/+10
[ Upstream commit 0bcff59ef7a652fcdc6d535554b63278c2406c8f ] Adding memblocks for soft-reserved regions prevents them from later being hotplugged in by dax_kmem. Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01efi: runtime: Fix potential overflow of soft-reserved region sizeAndrew Bresticker2-2/+2
[ Upstream commit de1034b38a346ef6be25fe8792f5d1e0684d5ff4 ] md_size will have been narrowed if we have >= 4GB worth of pages in a soft-reserved region. Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01riscv/efistub: Ensure GP-relative addressing is not usedJan Kiszka1-1/+1
commit afb2a4fb84555ef9e61061f6ea63ed7087b295d5 upstream. The cflags for the RISC-V efistub were missing -mno-relax, thus were under the risk that the compiler could use GP-relative addressing. That happened for _edata with binutils-2.41 and kernel 6.1, causing the relocation to fail due to an invalid kernel_size in handle_kernel_image. It was not yet observed with newer versions, but that may just be luck. Cc: <stable@vger.kernel.org> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23x86/efi: Disregard setup header of loaded imageArd Biesheuvel1-40/+6
commit 7e50262229faad0c7b8c54477cd1c883f31cc4a7 upstream. The native EFI entrypoint does not take a struct boot_params from the loader, but instead, it constructs one from scratch, using the setup header data placed at the start of the image. This setup header is placed in a way that permits legacy loaders to manipulate the contents (i.e., to pass the kernel command line or the address and size of an initial ramdisk), but EFI boot does not use it in that way - it only copies the contents that were placed there at build time, but EFI loaders will not (and should not) manipulate the setup header to configure the boot. (Commit 63bf28ceb3ebbe76 "efi: x86: Wipe setup_data on pure EFI boot" deals with some of the fallout of using setup_data in a way that breaks EFI boot.) Given that none of the non-zero values that are copied from the setup header into the EFI stub's struct boot_params are relevant to the boot now that the EFI stub no longer enters via the legacy decompressor, the copy can be omitted altogether. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230912090051.4014114-19-ardb@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23x86/efi: Drop EFI stub .bss from .data sectionArd Biesheuvel1-7/+0
commit 5f51c5d0e905608ba7be126737f7c84a793ae1aa upstream. Now that the EFI stub always zero inits its BSS section upon entry, there is no longer a need to place the BSS symbols carried by the stub into the .data section. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230912090051.4014114-18-ardb@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-16x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDRArd Biesheuvel5-8/+12
[ Upstream commit 2f77465b05b1270c832b5e2ee27037672ad2a10a ] The EFI stub's kernel placement logic randomizes the physical placement of the kernel by taking all available memory into account, and picking a region at random, based on a random seed. When KASLR is disabled, this seed is set to 0x0, and this results in the lowest available region of memory to be selected for loading the kernel, even if this is below LOAD_PHYSICAL_ADDR. Some of this memory is typically reserved for the GFP_DMA region, to accommodate masters that can only access the first 16 MiB of system memory. Even if such devices are rare these days, we may still end up with a warning in the kernel log, as reported by Tom: swapper/0: page allocation failure: order:10, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0 Fix this by tweaking the random allocation logic to accept a low bound on the placement, and set it to LOAD_PHYSICAL_ADDR. Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot") Reported-by: Tom Englund <tomenglund26@gmail.com> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218404 Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-02-16x86/efistub: Give up if memory attribute protocol returns an errorArd Biesheuvel2-12/+16
[ Upstream commit a7a6a01f88e87dec4bf2365571dd2dc7403d52d0 ] The recently introduced EFI memory attributes protocol should be used if it exists to ensure that the memory allocation created for the kernel permits execution. This is needed for compatibility with tightened requirements related to Windows logo certification for x86 PCs. Currently, we simply strip the execute protect (XP) attribute from the entire range, but this might be rejected under some firmware security policies, and so in a subsequent patch, this will be changed to only strip XP from the executable region that runs early, and make it read-only (RO) as well. In order to catch any issues early, ensure that the memory attribute protocol works as intended, and give up if it produces spurious errors. Note that the DXE services based fallback was always based on best effort, so don't propagate any errors returned by that API. Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-20efi/loongarch: Use load address to calculate kernel entry addressWang Yao2-5/+5
[ Upstream commit 271f2a4a9576b87ed1f8584909d6d270039e52ea ] The efi_relocate_kernel() may load the PIE kernel to anywhere, the loaded address may not be equal to link address or EFI_KIMG_PREFERRED_ADDRESS. Acked-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Wang Yao <wangyao@lemote.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-20efi/x86: Avoid physical KASLR on older Dell systemsArd Biesheuvel1-7/+24
[ Upstream commit 50d7cdf7a9b1ab6f4f74a69c84e974d5dc0c1bf1 ] River reports boot hangs with v6.6 and v6.7, and the bisect points to commit a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot") which moves the memory allocation and kernel decompression from the legacy decompressor (which executes *after* ExitBootServices()) to the EFI stub, using boot services for allocating the memory. The memory allocation succeeds but the subsequent call to decompress_kernel() never returns, resulting in a failed boot and a hanging system. As it turns out, this issue only occurs when physical address randomization (KASLR) is enabled, and given that this is a feature we can live without (virtual KASLR is much more important), let's disable the physical part of KASLR when booting on AMI UEFI firmware claiming to implement revision v2.0 of the specification (which was released in 2006), as this is the version these systems advertise. Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218173 Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-08efi/unaccepted: Fix off-by-one when checking for overlapping rangesMichael Roth1-1/+1
[ Upstream commit 01b1e3ca0e5ce47bbae8217d47376ad01b331b07 ] When a task needs to accept memory it will scan the accepting_list to see if any ranges already being processed by other tasks overlap with its range. Due to an off-by-one in the range comparisons, a task might falsely determine that an overlapping range is being accepted, leading to an unnecessary delay before it begins processing the range. Fix the off-by-one in the range comparison to prevent this and slightly improve performance. Fixes: 50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by parallel memory acceptance") Link: https://lore.kernel.org/linux-mm/20231101004523.vseyi5bezgfaht5i@amd.com/T/#me2eceb9906fcae5fe958b3fe88e41f920f8335b6 Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-20Merge 3rd batch of EFI fixes into efi/urgentArd Biesheuvel4-10/+71
2023-10-20efi/unaccepted: Fix soft lockups caused by parallel memory acceptanceKirill A. Shutemov1-4/+60
Michael reported soft lockups on a system that has unaccepted memory. This occurs when a user attempts to allocate and accept memory on multiple CPUs simultaneously. The root cause of the issue is that memory acceptance is serialized with a spinlock, allowing only one CPU to accept memory at a time. The other CPUs spin and wait for their turn, leading to starvation and soft lockup reports. To address this, the code has been modified to release the spinlock while accepting memory. This allows for parallel memory acceptance on multiple CPUs. A newly introduced "accepting_list" keeps track of which memory is currently being accepted. This is necessary to prevent parallel acceptance of the same memory block. If a collision occurs, the lock is released and the process is retried. Such collisions should rarely occur. The main path for memory acceptance is the page allocator, which accepts memory in MAX_ORDER chunks. As long as MAX_ORDER is equal to or larger than the unit_size, collisions will never occur because the caller fully owns the memory block being accepted. Aside from the page allocator, only memblock and deferered_free_range() accept memory, but this only happens during boot. The code has been tested with unit_size == 128MiB to trigger collisions and validate the retry codepath. Fixes: 2053bc57f367 ("efi: Add unaccepted memory support") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Michael Roth <michael.roth@amd.com Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Michael Roth <michael.roth@amd.com> [ardb: drop unnecessary cpu_relax() call] Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-10-17x86/boot: efistub: Assign global boot_params variableArd Biesheuvel2-0/+4
Now that the x86 EFI stub calls into some APIs exposed by the decompressor (e.g., kaslr_get_random_long()), it is necessary to ensure that the global boot_params variable is set correctly before doing so. Note that the decompressor and the kernel proper carry conflicting declarations for the global variable 'boot_params' so refer to it via an alias to work around this. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-10-13efi: fix memory leak in krealloc failure handlingKuan-Wei Chiu1-2/+6
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>
2023-10-13x86/efistub: Don't try to print after ExitBootService()Nikolay Borisov1-4/+1
setup_e820() is executed after UEFI's ExitBootService has been called. This causes the firmware to throw an exception because the Console IO protocol is supposed to work only during boot service environment. As per UEFI 2.9, section 12.1: "This protocol is used to handle input and output of text-based information intended for the system user during the operation of code in the boot services environment." So drop the diagnostic warning from this function. We might add back a warning that is issued later when initializing the kernel itself. Signed-off-by: Nikolay Borisov <nik.borisov@suse.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-09-19efi/unaccepted: Make sure unaccepted table is mappedKirill A. Shutemov1-3/+29
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: e7761d827e99 ("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>
2023-09-11efi/unaccepted: Use ACPI reclaim memory for unaccepted memory tableArd Biesheuvel1-1/+1
Kyril reports that crashkernels fail to work on confidential VMs that rely on the unaccepted memory table, and this appears to be caused by the fact that it is not considered part of the set of firmware tables that the crashkernel needs to map. This is an oversight, and a result of the use of the EFI_LOADER_DATA memory type for this table. The correct memory type to use for any firmware table is EFI_ACPI_RECLAIM_MEMORY (including ones created by the EFI stub), even though the name suggests that is it specific to ACPI. ACPI reclaim means that the memory is used by the firmware to expose information to the operating system, but that the memory region has no special significance to the firmware itself, and the OS is free to reclaim the memory and use it as ordinary memory if it is not interested in the contents, or if it has already consumed them. In Linux, this memory is never reclaimed, but it is always covered by the kernel direct map and generally made accessible as ordinary memory. On x86, ACPI reclaim memory is translated into E820_ACPI, which the kexec logic already recognizes as memory that the crashkernel may need to to access, and so it will be mapped and accessible to the booting crash kernel. Fixes: 745e3ed85f71 ("efi/libstub: Implement support for unaccepted memory") Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-09-08Merge patch series "riscv: Introduce KASLR"Palmer Dabbelt5-124/+197
Alexandre Ghiti <alexghiti@rivosinc.com> says: The following KASLR implementation allows to randomize the kernel mapping: - virtually: we expect the bootloader to provide a seed in the device-tree - physically: only implemented in the EFI stub, it relies on the firmware to provide a seed using EFI_RNG_PROTOCOL. arm64 has a similar implementation hence the patch 3 factorizes KASLR related functions for riscv to take advantage. The new virtual kernel location is limited by the early page table that only has one PUD and with the PMD alignment constraint, the kernel can only take < 512 positions. * b4-shazam-merge: riscv: libstub: Implement KASLR by using generic functions libstub: Fix compilation warning for rv32 arm64: libstub: Move KASLR handling functions to kaslr.c riscv: Dump out kernel offset information on panic riscv: Introduce virtual kernel mapping KASLR Link: https://lore.kernel.org/r/20230722123850.634544-1-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-09-06riscv: libstub: Implement KASLR by using generic functionsAlexandre Ghiti2-19/+16
We can now use arm64 functions to handle the move of the kernel physical mapping: if KASLR is enabled, we will try to get a random seed from the firmware, if not possible, the kernel will be moved to a location that suits its alignment constraints. Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Song Shuai <songshuaishuai@tinylab.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20230722123850.634544-6-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-09-06libstub: Fix compilation warning for rv32Alexandre Ghiti1-1/+1
Fix the following warning which appears when compiled for rv32 by using unsigned long type instead of u64. ../drivers/firmware/efi/libstub/efi-stub-helper.c: In function 'efi_kaslr_relocate_kernel': ../drivers/firmware/efi/libstub/efi-stub-helper.c:846:28: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] 846 | (u64)_end < EFI_ALLOC_LIMIT) { Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Song Shuai <songshuaishuai@tinylab.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20230722123850.634544-5-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-09-06arm64: libstub: Move KASLR handling functions to kaslr.cAlexandre Ghiti4-105/+181
This prepares for riscv to use the same functions to handle the pĥysical kernel move when KASLR is enabled. Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Song Shuai <songshuaishuai@tinylab.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20230722123850.634544-4-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-08-30Merge tag 'drm-next-2023-08-30' of git://anongit.freedesktop.org/drm/drmLinus Torvalds2-0/+4
Pull drm updates from Dave Airlie: "The drm core grew a new generic gpu virtual address manager, and new execution locking helpers. These are used by nouveau now to provide uAPI support for the userspace Vulkan driver. AMD had a bunch of new IP core support, loads of refactoring around fbdev, but mostly just the usual amount of stuff across the board. core: - fix gfp flags in drmm_kmalloc gpuva: - add new generic GPU VA manager (for nouveau initially) syncobj: - add new DRM_IOCTL_SYNCOBJ_EVENTFD ioctl dma-buf: - acquire resv lock for mmap() in exporters - support dma-buf self import automatically - docs fixes backlight: - fix fbdev interactions atomic: - improve logging prime: - remove struct gem_prim_mmap plus driver updates gem: - drm_exec: add locking over multiple GEM objects - fix lockdep checking fbdev: - make fbdev userspace interfaces optional - use linux device instead of fbdev device - use deferred i/o helper macros in various drivers - Make FB core selectable without drivers - Remove obsolete flags FBINFO_DEFAULT and FBINFO_FLAG_DEFAULT - Add helper macros and Kconfig tokens for DMA-allocated framebuffer ttm: - support init_on_free - swapout fixes panel: - panel-edp: Support AUO B116XAB01.4 - Support Visionox R66451 plus DT bindings - ld9040: - Backlight support - magic improved - Kconfig fix - Convert to of_device_get_match_data() - Fix Kconfig dependencies - simple: - Set bpc value to fix warning - Set connector type for AUO T215HVN01 - Support Innolux G156HCE-L01 plus DT bindings - ili9881: Support TDO TL050HDV35 LCD panel plus DT bindings - startek: Support KD070FHFID015 MIPI-DSI panel plus DT bindings - sitronix-st7789v: - Support Inanbo T28CP45TN89 plus DT bindings - Support EDT ET028013DMA plus DT bindings - Various cleanups - edp: Add timings for N140HCA-EAC - Allow panels and touchscreens to power sequence together - Fix Innolux G156HCE-L01 LVDS clock bridge: - debugfs for chains support - dw-hdmi: - Improve support for YUV420 bus format - CEC suspend/resume - update EDID on HDMI detect - dw-mipi-dsi: Fix enable/disable of DSI controller - lt9611uxc: Use MODULE_FIRMWARE() - ps8640: Remove broken EDID code - samsung-dsim: Fix command transfer - tc358764: - Handle HS/VS polarity - Use BIT() macro - Various cleanups - adv7511: Fix low refresh rate - anx7625: - Switch to macros instead of hardcoded values - locking fixes - tc358767: fix hardware delays - sitronix-st7789v: - Support panel orientation - Support rotation property - Add support for Jasonic JT240MHQS-HWT-EK-E3 plus DT bindings amdgpu: - SDMA 6.1.0 support - HDP 6.1 support - SMUIO 14.0 support - PSP 14.0 support - IH 6.1 support - Lots of checkpatch cleanups - GFX 9.4.3 updates - Add USB PD and IFWI flashing documentation - GPUVM updates - RAS fixes - DRR fixes - FAMS fixes - Virtual display fixes - Soft IH fixes - SMU13 fixes - Rework PSP firmware loading for other IPs - Kernel doc fixes - DCN 3.0.1 fixes - LTTPR fixes - DP MST fixes - DCN 3.1.6 fixes - SMU 13.x fixes - PSP 13.x fixes - SubVP fixes - GC 9.4.3 fixes - Display bandwidth calculation fixes - VCN4 secure submission fixes - Allow building DC on RISC-V - Add visible FB info to bo_print_info - HBR3 fixes - GFX9 MCBP fix - GMC10 vmhub index fix - GMC11 vmhub index fix - Create a new doorbell manager - SR-IOV fixes - initial freesync panel replay support - revert zpos properly until igt regression is fixeed - use TTM to manage doorbell BAR - Expose both current and average power via hwmon if supported amdkfd: - Cleanup CRIU dma-buf handling - Use KIQ to unmap HIQ - GFX 9.4.3 debugger updates - GFX 9.4.2 debugger fixes - Enable cooperative groups fof gfx11 - SVM fixes - Convert older APUs to use dGPU path like newer APUs - Drop IOMMUv2 path as it is no longer used - TBA fix for aldebaran i915: - ICL+ DSI modeset sequence - HDCP improvements - MTL display fixes and cleanups - HSW/BDW PSR1 restored - Init DDI ports in VBT order - General display refactors - Start using plane scale factor for relative data rate - Use shmem for dpt objects - Expose RPS thresholds in sysfs - Apply GuC SLPC min frequency softlimit correctly - Extend Wa_14015795083 to TGL, RKL, DG1 and ADL - Fix a VMA UAF for multi-gt platform - Do not use stolen on MTL due to HW bug - Check HuC and GuC version compatibility on MTL - avoid infinite GPU waits due to premature release of request memory - Fixes and updates for GSC memory allocation - Display SDVO fixes - Take stolen handling out of FBC code - Make i915_coherent_map_type GT-centric - Simplify shmem_create_from_object map_type msm: - SM6125 MDSS support - DPU: SM6125 DPU support - DSI: runtime PM support, burst mode support - DSI PHY: SM6125 support in 14nm DSI PHY driver - GPU: prepare for a7xx - fix a690 firmware - disable relocs on a6xx and newer radeon: - Lots of checkpatch cleanups ast: - improve device-model detection - Represent BMV as virtual connector - Report DP connection status nouveau: - add new exec/bind interface to support Vulkan - document some getparam ioctls - improve VRAM detection - various fixes/cleanups - workraound DPCD issues ivpu: - MMU updates - debugfs support - Support vpu4 virtio: - add sync object support atmel-hlcdc: - Support inverted pixclock polarity etnaviv: - runtime PM cleanups - hang handling fixes exynos: - use fbdev DMA helpers - fix possible NULL ptr dereference komeda: - always attach encoder omapdrm: - use fbdev DMA helpers ingenic: - kconfig regmap fixes loongson: - support display controller mediatek: - Small mtk-dpi cleanups - DisplayPort: support eDP and aux-bus - Fix coverity issues - Fix potential memory leak if vmap() fail mgag200: - minor fixes mxsfb: - support disabling overlay planes panfrost: - fix sync in IRQ handling ssd130x: - Support per-controller default resolution plus DT bindings - Reduce memory-allocation overhead - Improve intermediate buffer size computation - Fix allocation of temporary buffers - Fix pitch computation - Fix shadow plane allocation tegra: - use fbdev DMA helpers - Convert to devm_platform_ioremap_resource() - support bridge/connector - enable PM tidss: - Support TI AM625 plus DT bindings - Implement new connector model plus driver updates vkms: - improve write back support - docs fixes - support gamma LUT zynqmp-dpsub: - misc fixes" * tag 'drm-next-2023-08-30' of git://anongit.freedesktop.org/drm/drm: (1327 commits) drm/gpuva_mgr: remove unused prev pointer in __drm_gpuva_sm_map() drm/tests/drm_kunit_helpers: Place correct function name in the comment header drm/nouveau: uapi: don't pass NO_PREFETCH flag implicitly drm/nouveau: uvmm: fix unset region pointer on remap drm/nouveau: sched: avoid job races between entities drm/i915: Fix HPD polling, reenabling the output poll work as needed drm: Add an HPD poll helper to reschedule the poll work drm/i915: Fix TLB-Invalidation seqno store drm/ttm/tests: Fix type conversion in ttm_pool_test drm/msm/a6xx: Bail out early if setting GPU OOB fails drm/msm/a6xx: Move LLC accessors to the common header drm/msm/a6xx: Introduce a6xx_llc_read drm/ttm/tests: Require MMU when testing drm/panel: simple: Fix Innolux G156HCE-L01 LVDS clock Revert "Revert "drm/amdgpu/display: change pipe policy for DCN 2.0"" drm/amdgpu: Add memory vendor information drm/amd: flush any delayed gfxoff on suspend entry drm/amdgpu: skip fence GFX interrupts disable/enable for S0ix drm/amdgpu: Remove gfxoff check in GFX v9.4.3 drm/amd/pm: Update pci link speed for smu v13.0.6 ...
2023-08-29Merge tag 'efi-next-for-v6.6' of ↵Linus Torvalds4-128/+249
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi Pull EFI updates from Ard Biesheuvel: "This primarily covers some cleanup work on the EFI runtime wrappers, which are shared between all EFI architectures except Itanium, and which provide some level of isolation to prevent faults occurring in the firmware code (which runs at the same privilege level as the kernel) from bringing down the system. Beyond that, there is a fix that did not make it into v6.5, and some doc fixes and dead code cleanup. - one bugfix for x86 mixed mode that did not make it into v6.5 - first pass of cleanup for the EFI runtime wrappers - some cosmetic touchups" * tag 'efi-next-for-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: x86/efistub: Fix PCI ROM preservation in mixed mode efi/runtime-wrappers: Clean up white space and add __init annotation acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers efi/runtime-wrappers: Don't duplicate setup/teardown code efi/runtime-wrappers: Remove duplicated macro for service returning void efi/runtime-wrapper: Move workqueue manipulation out of line efi/runtime-wrappers: Use type safe encapsulation of call arguments efi/riscv: Move EFI runtime call setup/teardown helpers out of line efi/arm64: Move EFI runtime call setup/teardown helpers out of line efi/riscv: libstub: Fix comment about absolute relocation efi: memmap: Remove kernel-doc warnings efi: Remove unused extern declaration efi_lookup_mapped_addr()
2023-08-28Merge remote-tracking branch 'linux-efi/urgent' into efi/nextArd Biesheuvel1-1/+1
2023-08-24x86/efistub: Fix PCI ROM preservation in mixed modeMikel Rychliski1-1/+1
preserve_pci_rom_image() was accessing the romsize field in efi_pci_io_protocol_t directly instead of using the efi_table_attr() helper. This prevents the ROM image from being saved correctly during a mixed mode boot. Fixes: 2c3625cb9fa2 ("efi/x86: Fold __setup_efi_pci32() and __setup_efi_pci64() into one function") Signed-off-by: Mikel Rychliski <mikel@mikelr.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-22efi/runtime-wrappers: Clean up white space and add __init annotationArd Biesheuvel1-22/+19
Some cosmetic changes as well as a missing __init annotation. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-22acpi/prmt: Use EFI runtime sandbox to invoke PRM handlersArd Biesheuvel1-0/+31
Instead of bypassing the kernel's adaptation layer for performing EFI runtime calls, wire up ACPI PRM handling into it. This means these calls can no longer occur concurrently with EFI runtime calls, and will be made from the EFI runtime workqueue. It also means any page faults occurring during PRM handling will be identified correctly as originating in firmware code. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-22efi/runtime-wrappers: Don't duplicate setup/teardown codeArd Biesheuvel1-8/+18
Avoid duplicating the EFI arch setup and teardown routine calls numerous times in efi_call_rts(). Instead, expand the efi_call_virt_pointer() macro into efi_call_rts(), taking the pre and post parts out of the switch. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-22efi/runtime-wrappers: Remove duplicated macro for service returning voidArd Biesheuvel1-3/+6
__efi_call_virt() exists as an alternative for efi_call_virt() for the sole reason that ResetSystem() returns void, and so we cannot use a call to it in the RHS of an assignment. Given that there is only a single user, let's drop the macro, and expand it into the caller. That way, the remaining macro can be tightened somewhat in terms of type safety too. Note that the use of typeof() on the runtime service invocation does not result in an actual call being made, but it does require a few pointer types to be fixed up and converted into the proper function pointer prototypes. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-21efi/runtime-wrapper: Move workqueue manipulation out of lineArd Biesheuvel1-28/+33
efi_queue_work() is a macro that implements the non-trivial manipulation of the EFI runtime workqueue and completion data structure, most of which is generic, and could be shared between all the users of the macro. So move it out of the macro and into a new helper function. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-21efi/runtime-wrappers: Use type safe encapsulation of call argumentsArd Biesheuvel1-66/+130
The current code that marshalls the EFI runtime call arguments to hand them off to a async helper does so in a type unsafe and slightly messy manner - everything is cast to void* except for some integral types that are passed by reference and dereferenced on the receiver end. Let's clean this up a bit, and record the arguments of each runtime service invocation exactly as they are issued, in a manner that permits the compiler to check the types of the arguments at both ends. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-21efi/riscv: Move EFI runtime call setup/teardown helpers out of lineArd Biesheuvel1-2/+13
Only the arch_efi_call_virt() macro that some architectures override needs to be a macro, given that it is variadic and encapsulates calls via function pointers that have different prototypes. The associated setup and teardown code are not special in this regard, and don't need to be instantiated at each call site. So turn them into ordinary C functions and move them out of line. Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-07x86/efistub: Avoid legacy decompressor when doing EFI bootArd Biesheuvel1-94/+72
The bare metal decompressor code was never really intended to run in a hosted environment such as the EFI boot services, and does a few things that are becoming problematic in the context of EFI boot now that the logo requirements are getting tighter: EFI executables will no longer be allowed to consist of a single executable section that is mapped with read, write and execute permissions if they are intended for use in a context where Secure Boot is enabled (and where Microsoft's set of certificates is used, i.e., every x86 PC built to run Windows). To avoid stepping on reserved memory before having inspected the E820 tables, and to ensure the correct placement when running a kernel build that is non-relocatable, the bare metal decompressor moves its own executable image to the end of the allocation that was reserved for it, in order to perform the decompression in place. This means the region in question requires both write and execute permissions, which either need to be given upfront (which EFI will no longer permit), or need to be applied on demand using the existing page fault handling framework. However, the physical placement of the kernel is usually randomized anyway, and even if it isn't, a dedicated decompression output buffer can be allocated anywhere in memory using EFI APIs when still running in the boot services, given that EFI support already implies a relocatable kernel. This means that decompression in place is never necessary, nor is moving the compressed image from one end to the other. Since EFI already maps all of memory 1:1, it is also unnecessary to create new page tables or handle page faults when decompressing the kernel. That means there is also no need to replace the special exception handlers for SEV. Generally, there is little need to do any of the things that the decompressor does beyond - initialize SEV encryption, if needed, - perform the 4/5 level paging switch, if needed, - decompress the kernel - relocate the kernel So do all of this from the EFI stub code, and avoid the bare metal decompressor altogether. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-24-ardb@kernel.org
2023-08-07x86/efistub: Perform SNP feature test while running in the firmwareArd Biesheuvel1-0/+17
Before refactoring the EFI stub boot flow to avoid the legacy bare metal decompressor, duplicate the SNP feature check in the EFI stub before handing over to the kernel proper. The SNP feature check can be performed while running under the EFI boot services, which means it can force the boot to fail gracefully and return an error to the bootloader if the loaded kernel does not implement support for all the features that the hypervisor enabled. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-23-ardb@kernel.org
2023-08-07efi/libstub: Add limit argument to efi_random_alloc()Ard Biesheuvel4-7/+9
x86 will need to limit the kernel memory allocation to the lowest 512 MiB of memory, to match the behavior of the existing bare metal KASLR physical randomization logic. So in preparation for that, add a limit parameter to efi_random_alloc() and wire it up. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-22-ardb@kernel.org
2023-08-07x86/efistub: Prefer EFI memory attributes protocol over DXE servicesArd Biesheuvel1-8/+21
Currently, the EFI stub relies on DXE services in some cases to clear non-execute restrictions from page allocations that need to be executable. This is dodgy, because DXE services are not specified by UEFI but by PI, and they are not intended for consumption by OS loaders. However, no alternative existed at the time. Now, there is a new UEFI protocol that should be used instead, so if it exists, prefer it over the DXE services calls. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-18-ardb@kernel.org
2023-08-07x86/efistub: Perform 4/5 level paging switch from the stubArd Biesheuvel6-26/+130
In preparation for updating the EFI stub boot flow to avoid the bare metal decompressor code altogether, implement the support code for switching between 4 and 5 levels of paging before jumping to the kernel proper. Reuse the newly refactored trampoline that the bare metal decompressor uses, but relies on EFI APIs to allocate 32-bit addressable memory and remap it with the appropriate permissions. Given that the bare metal decompressor will no longer call into the trampoline if the number of paging levels is already set correctly, it is no longer needed to remove NX restrictions from the memory range where this trampoline may end up. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lore.kernel.org/r/20230807162720.545787-17-ardb@kernel.org
2023-08-07x86/efistub: Clear BSS in EFI handover protocol entrypointArd Biesheuvel1-2/+11
The so-called EFI handover protocol is value-add from the distros that permits a loader to simply copy a PE kernel image into memory and call an alternative entrypoint that is described by an embedded boot_params structure. Most implementations of this protocol do not bother to check the PE header for minimum alignment, section placement, etc, and therefore also don't clear the image's BSS, or even allocate enough memory for it. Allocating more memory on the fly is rather difficult, but at least clear the BSS region explicitly when entering in this manner, so that the EFI stub code does not get confused by global variables that were not zero-initialized correctly. When booting in mixed mode, this BSS clearing must occur before any global state is created, so clear it in the 32-bit asm entry point. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-7-ardb@kernel.org
2023-08-07x86/efistub: Simplify and clean up handover entry codeArd Biesheuvel1-4/+16
Now that the EFI entry code in assembler is only used by the optional and deprecated EFI handover protocol, and given that the EFI stub C code no longer returns to it, most of it can simply be dropped. While at it, clarify the symbol naming, by merging efi_main() and efi_stub_entry(), making the latter the shared entry point for all different boot modes that enter via the EFI stub. The efi32_stub_entry() and efi64_stub_entry() names are referenced explicitly by the tooling that populates the setup header, so these must be retained, but can be emitted as aliases of efi_stub_entry() where appropriate. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-5-ardb@kernel.org
2023-08-07x86/efistub: Branch straight to kernel entry point from C codeArd Biesheuvel1-5/+17
Instead of returning to the calling code in assembler that does nothing more than perform an indirect call with the boot_params pointer in register ESI/RSI, perform the jump directly from the EFI stub C code. This will allow the asm entrypoint code to be dropped entirely in subsequent patches. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-4-ardb@kernel.org