kernel/linux.git/drivers/firmware/efi, branch v5.15.201

efi/cper: Fix cper_bits_to_str buffer handling and return value

2026-01-19T12:10:19+00:00

commit d7f1b4bdc7108be1b178e1617b5f45c8918e88d7 upstream. The return value calculation was incorrect: `return len - buf_size;` Initially `len = buf_size`, then `len` decreases with each operation. This results in a negative return value on success. Fix by returning `buf_size - len` which correctly calculates the actual number of bytes written. Fixes: a976d790f494 ("efi/cper: Add a new helper function to print bitmasks") Signed-off-by: Morduan Zang Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi/cper: align ARM CPER type with UEFI 2.9A/2.10 specs

2026-01-19T12:09:40+00:00

[ Upstream commit 96b010536ee020e716d28d9b359a4bcd18800aeb ] Up to UEFI spec 2.9, the type byte of CPER struct for ARM processor was defined simply as: Type at byte offset 4: - Cache error - TLB Error - Bus Error - Micro-architectural Error All other values are reserved Yet, there was no information about how this would be encoded. Spec 2.9A errata corrected it by defining: - Bit 1 - Cache Error - Bit 2 - TLB Error - Bit 3 - Bus Error - Bit 4 - Micro-architectural Error All other values are reserved That actually aligns with the values already defined on older versions at N.2.4.1. Generic Processor Error Section. Spec 2.10 also preserve the same encoding as 2.9A. Adjust CPER and GHES handling code for both generic and ARM processors to properly handle UEFI 2.9A and 2.10 encoding. Link: https://uefi.org/specs/UEFI/2.10/Apx_N_Common_Platform_Error_Record.html#arm-processor-error-information Signed-off-by: Mauro Carvalho Chehab Reviewed-by: Jonathan Cameron Acked-by: Borislav Petkov (AMD) Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

efi/cper: Adjust infopfx size to accept an extra space

2026-01-19T12:09:39+00:00

[ Upstream commit 8ad2c72e21efb3dc76c5b14089fa7984cdd87898 ] Compiling with W=1 with werror enabled produces an error: drivers/firmware/efi/cper-arm.c: In function ‘cper_print_proc_arm’: drivers/firmware/efi/cper-arm.c:298:64: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=] 298 | snprintf(infopfx, sizeof(infopfx), "%s ", newpfx); | ^ drivers/firmware/efi/cper-arm.c:298:25: note: ‘snprintf’ output between 2 and 65 bytes into a destination of size 64 298 | snprintf(infopfx, sizeof(infopfx), "%s ", newpfx); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ As the logic there adds an space at the end of infopx buffer. Add an extra space to avoid such warning. Signed-off-by: Mauro Carvalho Chehab Reviewed-by: Jonathan Cameron Acked-by: Borislav Petkov (AMD) Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

efi/cper: Add a new helper function to print bitmasks

2026-01-19T12:09:39+00:00

[ Upstream commit a976d790f49499ccaa0f991788ad8ebf92e7fd5c ] Add a helper function to print a string with names associated to each bit field. A typical example is: const char * const bits[] = { "bit 3 name", "bit 4 name", "bit 5 name", }; char str[120]; unsigned int bitmask = BIT(3) | BIT(5); #define MASK GENMASK(5,3) cper_bits_to_str(str, sizeof(str), FIELD_GET(MASK, bitmask), bits, ARRAY_SIZE(bits)); The above code fills string "str" with "bit 3 name|bit 5 name". Reviewed-by: Jonathan Cameron Signed-off-by: Mauro Carvalho Chehab Acked-by: Borislav Petkov (AMD) Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

arch: back to -std=gnu89 in < v5.18

2025-12-06T21:09:15+00:00

Recent fixes have been backported to < v5.18 to fix build issues with GCC 5.15. They all force -std=gnu11 in the CFLAGS, "because [the kernel] requests the gnu11 standard via '-std=' in the main Makefile". This is true for >= 5.18 versions, but not before. This switch to -std=gnu11 has been done in commit e8c07082a810 ("Kbuild: move to -std=gnu11"). For a question of uniformity, force -std=gnu89, similar to what is done in the main Makefile. Note: the fixes tags below refers to upstream commits, but this fix is only for kernels not having commit e8c07082a810 ("Kbuild: move to -std=gnu11"). Fixes: 7cbb015e2d3d ("parisc: fix building with gcc-15") Fixes: 3b8b80e99376 ("s390: Add '-std=gnu11' to decompressor and purgatory CFLAGS") Fixes: b3bee1e7c3f2 ("x86/boot: Compile boot code with -std=gnu11 too") Fixes: ee2ab467bddf ("x86/boot: Use '-std=gnu11' to fix build with GCC 15") Fixes: 8ba14d9f490a ("efi: libstub: Use '-std=gnu11' to fix build with GCC 15") Signed-off-by: Matthieu Baerts (NGI0) Cc: Nathan Chancellor Cc: Ard Biesheuvel Cc: Alexey Dobriyan Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

efi: Avoid cold plugged memory for placing the kernel

2025-03-13T11:50:40+00:00

commit ba69e0750b0362870294adab09339a0c39c3beaf upstream. 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 Signed-off-by: Greg Kroah-Hartman

efi: libstub: Use '-std=gnu11' to fix build with GCC 15

2025-03-13T11:50:26+00:00

commit 8ba14d9f490aef9fd535c04e9e62e1169eb7a055 upstream. GCC 15 changed the default C standard version to C23, which should not have impacted the kernel because it requests the gnu11 standard via '-std=' in the main Makefile. However, the EFI libstub Makefile uses its own set of KBUILD_CFLAGS for x86 without a '-std=' value (i.e., using the default), resulting in errors from the kernel's definitions of bool, true, and false in stddef.h, which are reserved keywords under C23. ./include/linux/stddef.h:11:9: error: expected identifier before ‘false’ 11 | false = 0, ./include/linux/types.h:35:33: error: two or more data types in declaration specifiers 35 | typedef _Bool bool; Set '-std=gnu11' in the x86 cflags to resolve the error and consistently use the same C standard version for the entire kernel. All other architectures reuse KBUILD_CFLAGS from the rest of the kernel, so this issue is not visible for them. Cc: stable@vger.kernel.org Reported-by: Kostadin Shishmanov Closes: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvduultkgfAIRZI3vQpZylu7Gl929HaYFRGeMEalWCpeMzCIIhLxxRhq4U-Y=@protonmail.com/ Reported-by: Jakub Jelinek Closes: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/ Signed-off-by: Nathan Chancellor Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi: sysfb_efi: fix W=1 warnings when EFI is not set

2025-03-13T11:50:08+00:00

[ Upstream commit 19fdc68aa7b90b1d3d600e873a3e050a39e7663d ] A build with W=1 fails because there are code and data that are not needed or used when CONFIG_EFI is not set. Move the "#ifdef CONFIG_EFI" block to earlier in the source file so that the unused code/data are not built. drivers/firmware/efi/sysfb_efi.c:345:39: warning: ‘efifb_fwnode_ops’ defined but not used [-Wunused-const-variable=] 345 | static const struct fwnode_operations efifb_fwnode_ops = { | ^~~~~~~~~~~~~~~~ drivers/firmware/efi/sysfb_efi.c:238:35: warning: ‘efifb_dmi_swap_width_height’ defined but not used [-Wunused-const-variable=] 238 | static const struct dmi_system_id efifb_dmi_swap_width_height[] __initconst = { | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/firmware/efi/sysfb_efi.c:188:35: warning: ‘efifb_dmi_system_table’ defined but not used [-Wunused-const-variable=] 188 | static const struct dmi_system_id efifb_dmi_system_table[] __initconst = { | ^~~~~~~~~~~~~~~~~~~~~~ Fixes: 15d27b15de96 ("efi: sysfb_efi: fix build when EFI is not set") Signed-off-by: Randy Dunlap Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202501071933.20nlmJJt-lkp@intel.com/ Cc: David Rheinsberg Cc: Hans de Goede Cc: Javier Martinez Canillas Cc: Peter Jones Cc: Simona Vetter Cc: linux-fbdev@vger.kernel.org Cc: Ard Biesheuvel Cc: linux-efi@vger.kernel.org Reviewed-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

tpm: fix signed/unsigned bug when checking event logs

2024-12-14T18:50:47+00:00

[ Upstream commit e6d654e9f5a97742cfe794b1c4bb5d3fb2d25e98 ] A prior bugfix that fixes a signed/unsigned error causes another signed unsigned error. A situation where log_tbl->size is invalid can cause the size passed to memblock_reserve to become negative. log_size from the main event log is an unsigned int, and the code reduces to the following u64 value = (int)unsigned_value; This results in sign extension, and the value sent to memblock_reserve becomes effectively negative. Fixes: be59d57f9806 ("efi/tpm: Fix sanity check of unsigned tbl_size being less than zero") Signed-off-by: Gregory Price Reviewed-by: Ilias Apalodimas Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption

2024-10-17T13:11:14+00:00

commit 77d48d39e99170b528e4f2e9fc5d1d64cdedd386 upstream. The TPM event log table is a Linux specific construct, where the data produced by the GetEventLog() boot service is cached in memory, and passed on to the OS using an EFI configuration table. The use of EFI_LOADER_DATA here results in the region being left unreserved in the E820 memory map constructed by the EFI stub, and this is the memory description that is passed on to the incoming kernel by kexec, which is therefore unaware that the region should be reserved. Even though the utility of the TPM2 event log after a kexec is questionable, any corruption might send the parsing code off into the weeds and crash the kernel. So let's use EFI_ACPI_RECLAIM_MEMORY instead, which is always treated as reserved by the E820 conversion logic. Cc: Reported-by: Breno Leitao Tested-by: Usama Arif Reviewed-by: Ilias Apalodimas Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman