user/sven/linux.git/init/Makefile, branch v6.5.3

kbuild: Fix CFI failures with GCOV

2023-06-25T14:12:20Z

With GCOV_PROFILE_ALL, Clang injects __llvm_gcov_* functions to each object file, and the functions are indirectly called during boot. However, when code is injected to object files that are not part of vmlinux.o, it's also not processed by objtool, which breaks CFI hash randomization as the hashes in these files won't be included in the .cfi_sites section and thus won't be randomized. Similarly to commit 42633ed852de ("kbuild: Fix CFI hash randomization with KASAN"), disable GCOV for .vmlinux.export.o and init/version-timestamp.o to avoid emitting unnecessary functions to object files that don't otherwise have executable code. Fixes: 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization") Reported-by: Joe Fradley Signed-off-by: Sami Tolvanen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada

kbuild: Fix CFI hash randomization with KASAN

2023-01-13T23:22:03Z

Clang emits a asan.module_ctor constructor to each object file when KASAN is enabled, and these functions are indirectly called in do_ctors. With CONFIG_CFI_CLANG, the compiler also emits a CFI type hash before each address-taken global function so they can pass indirect call checks. However, in commit 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization"), x86 implemented boot time hash randomization, which relies on the .cfi_sites section generated by objtool. As objtool is run against vmlinux.o instead of individual object files with X86_KERNEL_IBT (enabled by default), CFI types in object files that are not part of vmlinux.o end up not being included in .cfi_sites, and thus won't get randomized and trip CFI when called. Only .vmlinux.export.o and init/version-timestamp.o are linked into vmlinux separately from vmlinux.o. As these files don't contain any functions, disable KASAN for both of them to avoid breaking hash randomization. Link: https://github.com/ClangBuiltLinux/linux/issues/1742 Fixes: 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization") Signed-off-by: Sami Tolvanen Acked-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230112224948.1479453-2-samitolvanen@google.com

kbuild: generate include/generated/compile.h in top Makefile

2022-09-28T19:40:15Z

Now that UTS_VERSION was separated out, this header can be generated much earlier, and probably the top Makefile is a better place to do it than init/Makefile. Signed-off-by: Masahiro Yamada

kbuild: build init/built-in.a just once

2022-09-28T19:40:15Z

Kbuild builds init/built-in.a twice; first during the ordinary directory descending, second from scripts/link-vmlinux.sh. We do this because UTS_VERSION contains the build version and the timestamp. We cannot update it during the normal directory traversal since we do not yet know if we need to update vmlinux. UTS_VERSION is temporarily calculated, but omitted from the update check. Otherwise, vmlinux would be rebuilt every time. When Kbuild results in running link-vmlinux.sh, it increments the version number in the .version file and takes the timestamp at that time to really fix UTS_VERSION. However, updating the same file twice is a footgun. To avoid nasty timestamp issues, all build artifacts that depend on init/built-in.a are atomically generated in link-vmlinux.sh, where some of them do not need rebuilding. To fix this issue, this commit changes as follows: [1] Split UTS_VERSION out to include/generated/utsversion.h from include/generated/compile.h include/generated/utsversion.h is generated just before the vmlinux link. It is generated under include/generated/ because some decompressors (s390, x86) use UTS_VERSION. [2] Split init_uts_ns and linux_banner out to init/version-timestamp.c from init/version.c init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary directory descending, they are compiled with __weak and used to determine if vmlinux needs relinking. Just before the vmlinux link, they are compiled without __weak to embed the real version and timestamp. Signed-off-by: Masahiro Yamada

sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers

2022-03-11T14:36:35Z

Displaying "PREEMPT" on kernel headers when CONFIG_PREEMPT_DYNAMIC=y can be misleading for anybody involved in remote debugging because it is then not guaranteed that there is an actual preemption behaviour. It depends on default Kconfig or boot defined choices. Therefore, tell about PREEMPT_DYNAMIC on static kernel headers and leave the search for the actual preemption behaviour to browsing dmesg. Reviewed-by: Valentin Schneider Signed-off-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220217111240.GA742892@lothringen

kbuild: do not quote string values in include/config/auto.conf

2022-01-08T09:03:57Z

The previous commit fixed up all shell scripts to not include include/config/auto.conf. Now that include/config/auto.conf is only included by Makefiles, we can change it into a more Make-friendly form. Previously, Kconfig output string values enclosed with double-quotes (both in the .config and include/config/auto.conf): CONFIG_X="foo bar" Unlike shell, Make handles double-quotes (and single-quotes as well) verbatim. We must rip them off when used. There are some patterns: [1] $(patsubst "%",%,$(CONFIG_X)) [2] $(CONFIG_X:"%"=%) [3] $(subst ",,$(CONFIG_X)) [4] $(shell echo $(CONFIG_X)) These are not only ugly, but also fragile. [1] and [2] do not work if the value contains spaces, like CONFIG_X=" foo bar " [3] does not work correctly if the value contains double-quotes like CONFIG_X="foo\"bar" [4] seems to work better, but has a cost of forking a process. Anyway, quoted strings were always PITA for our Makefiles. This commit changes Kconfig to stop quoting in include/config/auto.conf. These are the string type symbols referenced in Makefiles or scripts: ACPI_CUSTOM_DSDT_FILE ARC_BUILTIN_DTB_NAME ARC_TUNE_MCPU BUILTIN_DTB_SOURCE CC_IMPLICIT_FALLTHROUGH CC_VERSION_TEXT CFG80211_EXTRA_REGDB_KEYDIR EXTRA_FIRMWARE EXTRA_FIRMWARE_DIR EXTRA_TARGETS H8300_BUILTIN_DTB INITRAMFS_SOURCE LOCALVERSION MODULE_SIG_HASH MODULE_SIG_KEY NDS32_BUILTIN_DTB NIOS2_DTB_SOURCE OPENRISC_BUILTIN_DTB SOC_CANAAN_K210_DTB_SOURCE SYSTEM_BLACKLIST_HASH_LIST SYSTEM_REVOCATION_KEYS SYSTEM_TRUSTED_KEYS TARGET_CPU UNUSED_KSYMS_WHITELIST XILINX_MICROBLAZE0_FAMILY XILINX_MICROBLAZE0_HW_VER XTENSA_VARIANT_NAME I checked them one by one, and fixed up the code where necessary. Signed-off-by: Masahiro Yamada

preempt: Restore preemption model selection configs

2021-11-11T12:09:33Z

Commit c597bfddc9e9 ("sched: Provide Kconfig support for default dynamic preempt mode") changed the selectable config names for the preemption model. This means a config file must now select CONFIG_PREEMPT_BEHAVIOUR=y rather than CONFIG_PREEMPT=y to get a preemptible kernel. This means all arch config files would need to be updated - right now they'll all end up with the default CONFIG_PREEMPT_NONE_BEHAVIOUR. Rather than touch a good hundred of config files, restore usage of CONFIG_PREEMPT{_NONE, _VOLUNTARY}. Make them configure: o The build-time preemption model when !PREEMPT_DYNAMIC o The default boot-time preemption model when PREEMPT_DYNAMIC Add siblings of those configs with the _BUILD suffix to unconditionally designate the build-time preemption model (PREEMPT_DYNAMIC is built with the "highest" preemption model it supports, aka PREEMPT). Downstream configs should by now all be depending / selected by CONFIG_PREEMPTION rather than CONFIG_PREEMPT, so only a few sites need patching up. Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Acked-by: Marco Elver Link: https://lore.kernel.org/r/20211110202448.4054153-2-valentin.schneider@arm.com

init: use $(call cmd,) for generating include/generated/compile.h

2021-05-26T19:01:50Z

The 'cmd' macro shows the short log only when $(quiet) is quiet_. Do not do it manually. Signed-off-by: Masahiro Yamada

md: move the early init autodetect code to drivers/md/

2020-07-16T13:34:47Z

Just like the NFS and CIFS root code this better lives with the driver it is tightly integrated with. Signed-off-by: Christoph Hellwig Acked-by: Song Liu Acked-by: Linus Torvalds

kbuild: use CONFIG_CC_VERSION_TEXT to construct LINUX_COMPILER macro

2020-05-12T04:28:33Z

scripts/mkcompile_h runs $(CC) just for getting the version string. Reuse CONFIG_CC_VERSION_TEXT for optimization. For GCC, this slightly changes the version string. I do not think it is a big deal as we do not have the defined format for LINUX_COMPILER. In fact, the recent commit 4dcc9a88448a ("kbuild: mkcompile_h: Include $LD version in /proc/version") added the linker version. Signed-off-by: Masahiro Yamada