kernel/linux.git/arch/arm/boot/compressed, branch linux-5.9.y

efi/arm: set HSCTLR Thumb2 bit correctly for HVC calls from HYP

2020-11-24T12:39:06+00:00

[ Upstream commit fbc81ec5b85d43a4b22e49ec0e643fa7dec2ea40 ] Commit db227c19e68db353 ("ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully") updated the EFI entry code to permit firmware to invoke the EFI stub loader in HYP mode, with the MMU either enabled or disabled, neither of which is permitted by the EFI spec, but which does happen in the field. In the MMU on case, we remain in HYP mode as configured by the firmware, and rely on the fact that any HVC instruction issued in this mode will be dispatched via the SVC slot in the HYP vector table. However, this slot will point to a Thumb2 symbol if the kernel is built in Thumb2 mode, and so we have to configure HSCTLR to ensure that the exception handlers are invoked in Thumb2 mode as well. Fixes: db227c19e68db353 ("ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully") Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

kbuild: introduce ccflags-remove-y and asflags-remove-y

2020-08-09T16:32:59+00:00

CFLAGS_REMOVE_.o filters out flags when compiling a particular object, but there is no convenient way to do that for every object in a directory. Add ccflags-remove-y and asflags-remove-y to make it easily. Use ccflags-remove-y to clean up some Makefiles. The add/remove order works as follows: [1] KBUILD_CFLAGS specifies compiler flags used globally [2] ccflags-y adds compiler flags for all objects in the current Makefile [3] ccflags-remove-y removes compiler flags for all objects in the current Makefile (New feature) [4] CFLAGS_ adds compiler flags per file. [5] CFLAGS_REMOVE_ removes compiler flags per file. Having [3] before [4] allows us to remove flags from most (but not all) objects in the current Makefile. For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE) from all objects in the directory, then adds it back to trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o The same applies to lib/livepatch/Makefile. Please note ccflags-remove-y has no effect to the sub-directories. In contrast, the previous notation got rid of compiler flags also from all the sub-directories. The following are not affected because they have no sub-directories: arch/arm/boot/compressed/ arch/powerpc/xmon/ arch/sh/ kernel/trace/ However, lib/ has several sub-directories. To keep the behavior, I added ccflags-remove-y to all Makefiles in subdirectories of lib/, except the following: lib/vdso/Makefile - Kbuild does not descend into this Makefile lib/raid/test/Makefile - This is not used for the kernel build I think commit 2464a609ded0 ("ftrace: do not trace library functions") excluded too much. In the next commit, I will remove ccflags-remove-y from the sub-directories of lib/. Suggested-by: Sami Tolvanen Signed-off-by: Masahiro Yamada Acked-by: Steven Rostedt (VMware) Acked-by: Michael Ellerman (powerpc) Acked-by: Brendan Higgins (KUnit) Tested-by: Anders Roxell

kbuild: remove cc-option test of -fno-stack-protector

2020-07-07T02:13:10+00:00

Some Makefiles already pass -fno-stack-protector unconditionally. For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile. No problem report so far about hard-coding this option. So, we can assume all supported compilers know -fno-stack-protector. GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN) Get rid of cc-option from -fno-stack-protector. Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'. Note: arch/mips/vdso/Makefile adds -fno-stack-protector twice, first unconditionally, and second conditionally. I removed the second one. Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Acked-by: Ard Biesheuvel Reviewed-by: Nick Desaulniers

ARM: 8985/1: efi/decompressor: deal with HYP mode boot gracefully

2020-06-13T10:11:18+00:00

EFI on ARM only supports short descriptors, and given that it mandates that the MMU and caches are on, it is implied that booting in HYP mode is not supported. However, implementations of EFI exist (i.e., U-Boot) that ignore this requirement, which is not entirely unreasonable, given that it makes HYP mode inaccessible to the operating system. So let's make sure that we can deal with this condition gracefully. We already tolerate booting the EFI stub with the caches off (even though this violates the EFI spec as well), and so we should deal with HYP mode boot with MMU and caches either on or off. - When the MMU and caches are on, we can ignore the HYP stub altogether, since we can carry on executing at HYP. We do need to ensure that we disable the MMU at HYP before entering the kernel proper. - When the MMU and caches are off, we have to drop to SVC mode so that we can set up the page tables using short descriptors. In this case, we need to install the HYP stub as usual, so that we can return to HYP mode before handing over to the kernel proper. Tested-by: Heinrich Schuchardt Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2020-06-01T22:36:32+00:00

Pull ARM updates from Russell King: - remove a now unnecessary usage of the KERNEL_DS for sys_oabi_epoll_ctl() - update my email address in a number of drivers - decompressor EFI updates from Ard Biesheuvel - module unwind section handling updates - sparsemem Kconfig cleanups - make act_mm macro respect THREAD_SIZE * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8980/1: Allow either FLATMEM or SPARSEMEM on the multiplatform build ARM: 8979/1: Remove redundant ARCH_SPARSEMEM_DEFAULT setting ARM: 8978/1: mm: make act_mm() respect THREAD_SIZE ARM: decompressor: run decompressor in place if loaded via UEFI ARM: decompressor: move GOT into .data for EFI enabled builds ARM: decompressor: defer loading of the contents of the LC0 structure ARM: decompressor: split off _edata and stack base into separate object ARM: decompressor: move headroom variable out of LC0 ARM: 8976/1: module: allow arch overrides for .init section names ARM: 8975/1: module: fix handling of unwind init sections ARM: 8974/1: use SPARSMEM_STATIC when SPARSEMEM is enabled ARM: 8971/1: replace the sole use of a symbol with its definition ARM: 8969/1: decompressor: simplify libfdt builds Update rmk's email address in various drivers ARM: compat: remove KERNEL_DS usage in sys_oabi_epoll_ctl()

Merge tag 'efi-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-06-01T20:35:27+00:00

Pull EFI updates from Ingo Molnar: "The EFI changes for this cycle are: - preliminary changes for RISC-V - Add support for setting the resolution on the EFI framebuffer - Simplify kernel image loading for arm64 - Move .bss into .data via the linker script instead of relying on symbol annotations. - Get rid of __pure getters to access global variables - Clean up the config table matching arrays - 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 - Simplify GDT handling in early mixed mode thunking code - Some other minor fixes and cleanups" * tag 'efi-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits) efi/x86: Don't blow away existing initrd efi/x86: Drop the special GDT for the EFI thunk efi/libstub: Add missing prototype for PE/COFF entry point efi/efivars: Add missing kobject_put() in sysfs entry creation error path efi/libstub: Use pool allocation for the command line efi/libstub: Don't parse overlong command lines efi/libstub: Use snprintf with %ls to convert the command line efi/libstub: Get the exact UTF-8 length efi/libstub: Use %ls for filename efi/libstub: Add UTF-8 decoding to efi_puts efi/printf: Add support for wchar_t (UTF-16) efi/gop: Add an option to list out the available GOP modes efi/libstub: Add definitions for console input and events efi/libstub: Implement printk-style logging efi/printf: Turn vsprintf into vsnprintf efi/printf: Abort on invalid format efi/printf: Refactor code to consolidate padding and output efi/printf: Handle null string input efi/printf: Factor out integer argument retrieval efi/printf: Factor out width/precision parsing ...

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2020-05-26T00:11:39+00:00

Pull ARM fixes from Russell King: - correct value of decompressor tag size in header - fix DACR value when we have nested exceptions - fix a missing newline on a kernel message - fix mask for ptrace thumb breakpoint hook * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8977/1: ptrace: Fix mask for thumb breakpoint hook ARM: 8973/1: Add missing newline terminator to kernel message ARM: uaccess: fix DACR mismatch with nested exceptions ARM: uaccess: integrate uaccess_save and uaccess_restore ARM: uaccess: consolidate uaccess asm to asm/uaccess-asm.h ARM: 8970/1: decompressor: increase tag size

efi/libstub: Add missing prototype for PE/COFF entry point

2020-05-23T09:01:57+00:00

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

ARM: decompressor: run decompressor in place if loaded via UEFI

2020-05-19T16:23:22+00:00

The decompressor can load from anywhere in memory, and the only reason the EFI stub code relocates it is to ensure it appears within the first 128 MiB of memory, so that the uncompressed kernel ends up at the right offset in memory. We can short circuit this, and simply jump into the decompressor startup code at the point where it knows where the base of memory lives. This also means there is no need to disable the MMU and caches, create new page tables and re-enable them. Signed-off-by: Ard Biesheuvel Reviewed-by: Nicolas Pitre

ARM: decompressor: move GOT into .data for EFI enabled builds

2020-05-19T16:23:22+00:00

We will be running the decompressor in place after a future patch, instead of copying it around first. This means we no longer have to disable and re-enable the MMU and caches either. However, this means we will be loaded with the restricted permissions set by the UEFI firmware, which means that we have to move the GOT table into the data section in order for the contents to be writable by the code itself. Signed-off-by: Ard Biesheuvel Reviewed-by: Nicolas Pitre