kernel.git/arch/arm/boot/compressed/Makefile, branch linux-5.10.y

ARM: 9105/1: atags_to_fdt: don't warn about stack size

2021-09-18T11:40:09Z

commit b30d0289de72c62516df03fdad8d53f552c69839 upstream. The merge_fdt_bootargs() function by definition consumes more than 1024 bytes of stack because it has a 1024 byte command line on the stack, meaning that we always get a warning when building this file: arch/arm/boot/compressed/atags_to_fdt.c: In function 'merge_fdt_bootargs': arch/arm/boot/compressed/atags_to_fdt.c:98:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=] However, as this is the decompressor and we know that it has a very shallow call chain, and we do not actually risk overflowing the kernel stack at runtime here. This just shuts up the warning by disabling the warning flag for this file. Tested on Nexus 7 2012 builds. Acked-by: Nicolas Pitre Signed-off-by: David Heidelberg Signed-off-by: Arnd Bergmann Cc: Signed-off-by: Russell King (Oracle) Signed-off-by: Greg Kroah-Hartman

ARM: 9056/1: decompressor: fix BSS size calculation for LLVM ld.lld

2021-05-11T12:47:12Z

commit c4e792d1acce31c2eb7b9193ab06ab94de05bf42 upstream. The LLVM ld.lld linker uses a different symbol type for __bss_start, resulting in the calculation of KBSS_SZ to be thrown off. Up until now, this has gone unnoticed as it only affects the appended DTB case, but pending changes for ARM in the way the decompressed kernel is cleaned from the caches has uncovered this problem. On a ld.lld build: $ nm vmlinux |grep bss_ c1c22034 D __bss_start c1c86e98 B __bss_stop resulting in $ readelf -s arch/arm/boot/compressed/vmlinux | grep bss_size 433: c1c86e98 0 NOTYPE GLOBAL DEFAULT ABS _kernel_bss_size which is obviously incorrect, and may cause the cache clean to access unmapped memory, or cause the size calculation to wrap, resulting in no cache clean to be performed at all. Fix this by updating the sed regex to take D type symbols into account. Link: https://lore.kernel.org/linux-arm-kernel/6c65bcef-d4e7-25fa-43cf-2c435bb61bb9@collabora.com/ Link: https://lore.kernel.org/linux-arm-kernel/20210205085220.31232-1-ardb@kernel.org/ Cc: # v4.19+ Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Reported-by: Guillaume Tucker Reported-by: "kernelci.org bot" Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman

kbuild: Hoist '--orphan-handling' into Kconfig

2020-12-01T13:45:36Z

Currently, '--orphan-handling=warn' is spread out across four different architectures in their respective Makefiles, which makes it a little unruly to deal with in case it needs to be disabled for a specific linker version (in this case, ld.lld 10.0.1). To make it easier to control this, hoist this warning into Kconfig and the main Makefile so that disabling it is simpler, as the warning will only be enabled in a couple places (main Makefile and a couple of compressed boot folders that blow away LDFLAGS_vmlinx) and making it conditional is easier due to Kconfig syntax. One small additional benefit of this is saving a call to ld-option on incremental builds because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN. To keep the list of supported architectures the same, introduce CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to gain this automatically after all of the sections are specified and size asserted. A special thanks to Kees Cook for the help text on this config. Link: https://github.com/ClangBuiltLinux/linux/issues/1187 Acked-by: Kees Cook Acked-by: Michael Ellerman (powerpc) Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada

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

2020-10-20T16:18:31Z

Pull ARM updates from Russell King: - handle inexact watchpoint addresses (Douglas Anderson) - decompressor serial debug cleanups (Linus Walleij) - update L2 cache prefetch bits (Guillaume Tucker) - add text offset and malloc size to the decompressor kexec data * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: add malloc size to decompressor kexec size structure ARM: add TEXT_OFFSET to decompressor kexec image structure ARM: 9007/1: l2c: fix prefetch bits init in L2X0_AUX_CTRL using DT values ARM: 9010/1: uncompress: Print the location of appended DTB ARM: 9009/1: uncompress: Enable debug in head.S ARM: 9008/1: uncompress: Drop excess whitespace print ARM: 9006/1: uncompress: Wait for ready and busy in debug prints ARM: 9005/1: debug: Select flow control for all debug UARTs ARM: 9004/1: debug: Split waituart to CTS and TXRDY ARM: 9003/1: uncompress: Delete unused debug macros ARM: 8997/2: hw_breakpoint: Handle inexact watchpoint addresses

ARM: add malloc size to decompressor kexec size structure

2020-09-15T13:36:26Z

Add the required malloc size to the decompressor kexec size structure. Signed-off-by: Russell King

ARM: add TEXT_OFFSET to decompressor kexec image structure

2020-09-15T13:36:25Z

Add the TEXT_OFFSET to the decompressor's kexec image structure to kexec knows what offset to use. Signed-off-by: Russell King

ARM: 9009/1: uncompress: Enable debug in head.S

2020-09-15T13:35:31Z

The assembly file head.S includes some debug code that does not get enabled when we select CONFIG_DEBUG_UNCOMPRESS. The debug in head.S relies on the user tagging on -DDEBUG on the compilation command line. To simplify debugging, tag on -DDEBUG so that we also get these debug messages when selecting CONFIG_DEBUG_UNCOMPRESS. Signed-off-by: Linus Walleij Signed-off-by: Russell King

arm/boot: Warn on orphan section placement

2020-09-03T08:28:35Z

We don't want to depend on the linker's orphan section placement heuristics as these can vary between linkers, and may change between versions. All sections need to be explicitly handled in the linker script. With all sections now handled, enable orphan section warning. Signed-off-by: Kees Cook Signed-off-by: Ingo Molnar Reviewed-by: Nick Desaulniers Link: https://lore.kernel.org/r/20200902025347.2504702-4-keescook@chromium.org

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

2020-08-09T16:32:59Z

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

2020-07-07T02:13:10Z

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