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2023-09-05Merge tag 'kbuild-v6.6' of ↵Linus Torvalds1-4/+0
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Enable -Wenum-conversion warning option - Refactor the rpm-pkg target - Fix scripts/setlocalversion to consider annotated tags for rt-kernel - Add a jump key feature for the search menu of 'make nconfig' - Support Qt6 for 'make xconfig' - Enable -Wformat-overflow, -Wformat-truncation, -Wstringop-overflow, and -Wrestrict warnings for W=1 builds - Replace <asm/export.h> with <linux/export.h> for alpha, ia64, and sparc - Support DEB_BUILD_OPTIONS=parallel=N for the debian source package - Refactor scripts/Makefile.modinst and fix some modules_sign issues - Add a new Kconfig env variable to warn symbols that are not defined anywhere - Show help messages of config fragments in 'make help' * tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (62 commits) kconfig: fix possible buffer overflow kbuild: Show marked Kconfig fragments in "help" kconfig: add warn-unknown-symbols sanity check kbuild: dummy-tools: make MPROFILE_KERNEL checks work on BE Documentation/llvm: refresh docs modpost: Skip .llvm.call-graph-profile section check kbuild: support modules_sign for external modules as well kbuild: support 'make modules_sign' with CONFIG_MODULE_SIG_ALL=n kbuild: move more module installation code to scripts/Makefile.modinst kbuild: reduce the number of mkdir calls during modules_install kbuild: remove $(MODLIB)/source symlink kbuild: move depmod rule to scripts/Makefile.modinst kbuild: add modules_sign to no-{compiler,sync-config}-targets kbuild: do not run depmod for 'make modules_sign' kbuild: deb-pkg: support DEB_BUILD_OPTIONS=parallel=N in debian/rules alpha: remove <asm/export.h> alpha: replace #include <asm/export.h> with #include <linux/export.h> ia64: remove <asm/export.h> ia64: replace #include <asm/export.h> with #include <linux/export.h> sparc: remove <asm/export.h> ...
2023-09-03kbuild: Show marked Kconfig fragments in "help"Kees Cook1-4/+0
Currently the Kconfig fragments in kernel/configs and arch/*/configs that aren't used internally aren't discoverable through "make help", which consists of hard-coded lists of config fragments. Instead, list all the fragment targets that have a "# Help: " comment prefix so the targets can be generated dynamically. Add logic to the Makefile to search for and display the fragment and comment. Add comments to fragments that are intended to be direct targets. Signed-off-by: Kees Cook <keescook@chromium.org> Co-developed-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-07-24Merge drm/drm-next into drm-misc-nextThomas Zimmermann1-0/+12
Backmerging to get v6.5-rc2. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
2023-07-22fbdev: Split frame buffer support in FB and FB_CORE symbolsJavier Martinez Canillas1-1/+1
Currently the CONFIG_FB option has to be enabled even if no legacy fbdev drivers are needed (e.g: only to have support for framebuffer consoles). The DRM subsystem has a fbdev emulation layer, but depends on CONFIG_FB and so it can only be enabled if that dependency is enabled as well. That means fbdev drivers have to be explicitly disabled if users want to enable CONFIG_FB, only to use fbcon and/or the DRM fbdev emulation layer. This patch introduces a non-visible CONFIG_FB_CORE symbol that could be enabled just to have core support needed for CONFIG_DRM_FBDEV_EMULATION, allowing CONFIG_FB to be disabled (and automatically disabling all the fbdev drivers). Nothing from fb_backlight.o and fbmon.o is used by the DRM fbdev emulation layer so these two objects can be compiled out when CONFIG_FB is disabled. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Tested-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Helge Deller <deller@gmx.de> Link: https://patchwork.freedesktop.org/patch/msgid/20230719081544.741051-4-javierm@redhat.com
2023-06-16x86/unwind/orc: Add ELF section with ORC version identifierOmar Sandoval1-0/+12
Commits ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata") and fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in two") changed the ORC format. Although ORC is internal to the kernel, it's the only way for external tools to get reliable kernel stack traces on x86-64. In particular, the drgn debugger [1] uses ORC for stack unwinding, and these format changes broke it [2]. As the drgn maintainer, I don't care how often or how much the kernel changes the ORC format as long as I have a way to detect the change. It suffices to store a version identifier in the vmlinux and kernel module ELF files (to use when parsing ORC sections from ELF), and in kernel memory (to use when parsing ORC from a core dump+symbol table). Rather than hard-coding a version number that needs to be manually bumped, Peterz suggested hashing the definitions from orc_types.h. If there is a format change that isn't caught by this, the hashing script can be updated. This patch adds an .orc_header allocated ELF section containing the 20-byte hash to vmlinux and kernel modules, along with the corresponding __start_orc_header and __stop_orc_header symbols in vmlinux. 1: https://github.com/osandov/drgn 2: https://github.com/osandov/drgn/issues/303 Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata") Fixes: fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in two") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lkml.kernel.org/r/aef9c8dc43915b886a8c48509a12ec1b006ca1ca.1686690801.git.osandov@osandov.com
2023-02-15x86/build: Make 64-bit defconfig the defaultArnd Bergmann1-3/+3
Running 'make ARCH=x86 defconfig' on anything other than an x86_64 machine currently results in a 32-bit build, which is rarely what anyone wants these days. Change the default so that the 64-bit config gets used unless the user asks for i386_defconfig, uses ARCH=i386 or runs on a system that "uname -m" identifies as i386/i486/i586/i686. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230215091706.1623070-1-arnd@kernel.org
2023-01-22x86/build: Move '-mindirect-branch-cs-prefix' out of GCC-only blockNathan Chancellor1-1/+1
LLVM 16 will have support for this flag so move it out of the GCC-only block to allow LLVM builds to take advantage of it. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://github.com/ClangBuiltLinux/linux/issues/1665 Link: https://github.com/llvm/llvm-project/commit/6f867f9102838ebe314c1f3661fdf95700386e5a Link: https://lore.kernel.org/r/20230120165826.2469302-1-nathan@kernel.org
2022-12-19Merge tag 'kbuild-v6.2' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Support zstd-compressed debug info - Allow W=1 builds to detect objects shared among multiple modules - Add srcrpm-pkg target to generate a source RPM package - Make the -s option detection work for future GNU Make versions - Add -Werror to KBUILD_CPPFLAGS when CONFIG_WERROR=y - Allow W=1 builds to detect -Wundef warnings in any preprocessed files - Raise the minimum supported version of binutils to 2.25 - Use $(intcmp ...) to compare integers if GNU Make >= 4.4 is used - Use $(file ...) to read a file if GNU Make >= 4.2 is used - Print error if GNU Make older than 3.82 is used - Allow modpost to detect section mismatches with Clang LTO - Include vmlinuz.efi into kernel tarballs for arm64 CONFIG_EFI_ZBOOT=y * tag 'kbuild-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits) buildtar: fix tarballs with EFI_ZBOOT enabled modpost: Include '.text.*' in TEXT_SECTIONS padata: Mark padata_work_init() as __ref kbuild: ensure Make >= 3.82 is used kbuild: refactor the prerequisites of the modpost rule kbuild: change module.order to list *.o instead of *.ko kbuild: use .NOTINTERMEDIATE for future GNU Make versions kconfig: refactor Makefile to reduce process forks kbuild: add read-file macro kbuild: do not sort after reading modules.order kbuild: add test-{ge,gt,le,lt} macros Documentation: raise minimum supported version of binutils to 2.25 kbuild: add -Wundef to KBUILD_CPPFLAGS for W=1 builds kbuild: move -Werror from KBUILD_CFLAGS to KBUILD_CPPFLAGS kbuild: Port silent mode detection to future gnu make. init/version.c: remove #include <generated/utsrelease.h> firmware_loader: remove #include <generated/utsrelease.h> modpost: Mark uuid_le type to be suitable only for MEI kbuild: add ability to make source rpm buildable using koji kbuild: warn objects shared among multiple modules ...
2022-12-13kbuild: add test-{ge,gt,le,lt} macrosMasahiro Yamada1-1/+1
GNU Make 4.4 introduced $(intcmp ...), which is useful to compare two integers without forking a new process. Add test-{ge,gt,le,lt} macros, which work more efficiently with GNU Make >= 4.4. For older Make versions, they fall back to the 'test' shell command. The first two parameters to $(intcmp ...) must not be empty. To avoid the syntax error, I appended '0' to them. Fortunately, '00' is treated as '0'. This is needed because CONFIG options may expand to an empty string when the kernel configuration is not included. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> # RISC-V Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-11-01x86/ibt: Implement FineIBTPeter Zijlstra1-1/+1
Implement an alternative CFI scheme that merges both the fine-grained nature of kCFI but also takes full advantage of the coarse grained hardware CFI as provided by IBT. To contrast: kCFI is a pure software CFI scheme and relies on being able to read text -- specifically the instruction *before* the target symbol, and does the hash validation *before* doing the call (otherwise control flow is compromised already). FineIBT is a software and hardware hybrid scheme; by ensuring every branch target starts with a hash validation it is possible to place the hash validation after the branch. This has several advantages: o the (hash) load is avoided; no memop; no RX requirement. o IBT WAIT-FOR-ENDBR state is a speculation stop; by placing the hash validation in the immediate instruction after the branch target there is a minimal speculation window and the whole is a viable defence against SpectreBHB. o Kees feels obliged to mention it is slightly more vulnerable when the attacker can write code. Obviously this patch relies on kCFI, but additionally it also relies on the padding from the call-depth-tracking patches. It uses this padding to place the hash-validation while the call-sites are re-written to modify the indirect target to be 16 bytes in front of the original target, thus hitting this new preamble. Notably, there is no hardware that needs call-depth-tracking (Skylake) and supports IBT (Tigerlake and onwards). Suggested-by: Joao Moreira (Intel) <joao@overdrivepizza.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221027092842.634714496@infradead.org
2022-10-17x86/Kconfig: Introduce function paddingThomas Gleixner1-0/+6
Now that all functions are 16 byte aligned, add 16 bytes of NOP padding in front of each function. This prepares things for software call stack tracking and kCFI/FineIBT. This significantly increases kernel .text size, around 5.1% on a x86_64-defconfig-ish build. However, per the random access argument used for alignment, these 16 extra bytes are code that wouldn't be used. Performance measurements back this up by showing no significant performance regressions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220915111146.950884492@infradead.org
2022-10-10Merge tag 'kbuild-v6.1' of ↵Linus Torvalds1-5/+0
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Remove potentially incomplete targets when Kbuid is interrupted by SIGINT etc in case GNU Make may miss to do that when stderr is piped to another program. - Rewrite the single target build so it works more correctly. - Fix rpm-pkg builds with V=1. - List top-level subdirectories in ./Kbuild. - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in kallsyms. - Avoid two different modules in lib/zstd/ having shared code, which potentially causes building the common code as build-in and modular back-and-forth. - Unify two modpost invocations to optimize the build process. - Remove head-y syntax in favor of linker scripts for placing particular sections in the head of vmlinux. - Bump the minimal GNU Make version to 3.82. - Clean up misc Makefiles and scripts. * tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits) docs: bump minimal GNU Make version to 3.82 ia64: simplify esi object addition in Makefile Revert "kbuild: Check if linker supports the -X option" kbuild: rebuild .vmlinux.export.o when its prerequisite is updated kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o zstd: Fixing mixed module-builtin objects kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols kallsyms: take the input file instead of reading stdin kallsyms: drop duplicated ignore patterns from kallsyms.c kbuild: reuse mksysmap output for kallsyms mksysmap: update comment about __crc_* kbuild: remove head-y syntax kbuild: use obj-y instead extra-y for objects placed at the head kbuild: hide error checker logs for V=1 builds kbuild: re-run modpost when it is updated kbuild: unify two modpost invocations kbuild: move vmlinux.o rule to the top Makefile kbuild: move .vmlinux.objs rule to Makefile.modpost kbuild: list sub-directories in ./Kbuild Makefile.compiler: replace cc-ifversion with compiler-specific macros ...
2022-10-02kbuild: remove head-y syntaxMasahiro Yamada1-5/+0
Kbuild puts the objects listed in head-y at the head of vmlinux. Conventionally, we do this for head*.S, which contains the kernel entry point. A counter approach is to control the section order by the linker script. Actually, the code marked as __HEAD goes into the ".head.text" section, which is placed before the normal ".text" section. I do not know if both of them are needed. From the build system perspective, head-y is not mandatory. If you can achieve the proper code placement by the linker script only, it would be cleaner. I collected the current head-y objects into head-object-list.txt. It is a whitelist. My hope is it will be reduced in the long run. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-09-28x86: enable initial Rust supportMiguel Ojeda1-0/+10
Note that only x86_64 is covered and not all features nor mitigations are handled, but it is enough as a starting point and showcases the basics needed to add Rust support for a new architecture. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: David Gow <davidgow@google.com> Signed-off-by: David Gow <davidgow@google.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-08-21asm goto: eradicate CC_HAS_ASM_GOTONick Desaulniers1-4/+0
GCC has supported asm goto since 4.5, and Clang has since version 9.0.0. The minimum supported versions of these tools for the build according to Documentation/process/changes.rst are 5.1 and 11.0.0 respectively. Remove the feature detection script, Kconfig option, and clean up some fallback code that is no longer supported. The removed script was also testing for a GCC specific bug that was fixed in the 4.7 release. Also remove workarounds for bpftrace using clang older than 9.0.0, since other BPF backend fixes are required at this point. Link: https://lore.kernel.org/lkml/CAK7LNATSr=BXKfkdW8f-H5VT_w=xBpT2ZQcZ7rm6JfkdE+QnmA@mail.gmail.com/ Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48637 Acked-by: Borislav Petkov <bp@suse.de> Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-07-20lkdtm: Disable return thunks in rodata.cJosh Poimboeuf1-0/+1
The following warning was seen: WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:557 apply_returns (arch/x86/kernel/alternative.c:557 (discriminator 1)) Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc4-00008-gee88d363d156 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014 RIP: 0010:apply_returns (arch/x86/kernel/alternative.c:557 (discriminator 1)) Code: ff ff 74 cb 48 83 c5 04 49 39 ee 0f 87 81 fe ff ff e9 22 ff ff ff 0f 0b 48 83 c5 04 49 39 ee 0f 87 6d fe ff ff e9 0e ff ff ff <0f> 0b 48 83 c5 04 49 39 ee 0f 87 59 fe ff ff e9 fa fe ff ff 48 89 The warning happened when apply_returns() failed to convert "JMP __x86_return_thunk" to RET. It was instead a JMP to nowhere, due to the thunk relocation not getting resolved. That rodata.o code is objcopy'd to .rodata, and later memcpy'd, so relocations don't work (and are apparently silently ignored). LKDTM is only used for testing, so the naked RET should be fine. So just disable return thunks for that file. While at it, disable objtool and KCSAN for the file. Fixes: 0b53c374b9ef ("x86/retpoline: Use -mfunction-return") Reported-by: kernel test robot <oliver.sang@intel.com> Debugged-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/lkml/Ys58BxHxoDZ7rfpr@xsang-OptiPlex-9020/
2022-06-29x86/retbleed: Add fine grained Kconfig knobsPeter Zijlstra1-2/+6
Do fine-grained Kconfig for all the various retbleed parts. NOTE: if your compiler doesn't support return thunks this will silently 'upgrade' your mitigation to IBPB, you might not like this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86/retpoline: Use -mfunction-returnPeter Zijlstra1-0/+2
Utilize -mfunction-return=thunk-extern when available to have the compiler replace RET instructions with direct JMPs to the symbol __x86_return_thunk. This does not affect assembler (.S) sources, only C sources. -mfunction-return=thunk-extern has been available since gcc 7.3 and clang 15. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-05-26Merge tag 'kbuild-v5.19' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add HOSTPKG_CONFIG env variable to allow users to override pkg-config - Support W=e as a shorthand for KCFLAGS=-Werror - Fix CONFIG_IKHEADERS build to support toybox cpio - Add scripts/dummy-tools/pahole to ease distro packagers' life - Suppress false-positive warnings from checksyscalls.sh for W=2 build - Factor out the common code of arch/*/boot/install.sh into scripts/install.sh - Support 'kernel-install' tool in scripts/prune-kernel - Refactor module-versioning to link the symbol versions at the final link of vmlinux and modules - Remove CONFIG_MODULE_REL_CRCS because module-versioning now works in an arch-agnostic way - Refactor modpost, Makefiles * tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (56 commits) genksyms: adjust the output format to modpost kbuild: stop merging *.symversions kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS modpost: extract symbol versions from *.cmd files modpost: add sym_find_with_module() helper modpost: change the license of EXPORT_SYMBOL to bool type modpost: remove left-over cross_compile declaration kbuild: record symbol versions in *.cmd files kbuild: generate a list of objects in vmlinux modpost: move *.mod.c generation to write_mod_c_files() modpost: merge add_{intree_flag,retpoline,staging_flag} to add_header scripts/prune-kernel: Use kernel-install if available kbuild: factor out the common installation code into scripts/install.sh modpost: split new_symbol() to symbol allocation and hash table addition modpost: make sym_add_exported() always allocate a new symbol modpost: make multiple export error modpost: dump Module.symvers in the same order of modules.order modpost: traverse the namespace_list in order modpost: use doubly linked list for dump_lists modpost: traverse unresolved symbols in order ...
2022-05-11kbuild: factor out the common installation code into scripts/install.shMasahiro Yamada1-2/+1
Many architectures have similar install.sh scripts. The first half is really generic; it verifies that the kernel image and System.map exist, then executes ~/bin/${INSTALLKERNEL} or /sbin/${INSTALLKERNEL} if available. The second half is kind of arch-specific; it copies the kernel image and System.map to the destination, but the code is slightly different. Factor out the generic part into scripts/install.sh. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2022-04-06x86/configs: Add x86 debugging Kconfig fragment plus docsDave Hansen1-0/+1
The kernel has a wide variety of debugging options to help catch and squash bugs. However, new debugging is added all the time and the existing options can be hard to find. Add a Kconfig fragment with the debugging options which tip maintainers expect to be used to test contributions. This should make it easier for contributors to test their code and find issues before submission. [ bp: Add to "make help" output, fix DEBUG_INFO selection as pointed out by Nathan Chancellor <nathan@kernel.org>. ] Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220331175728.299103A0@davehans-spike.ostc.intel.com
2022-03-15x86: Remove toolchain check for X32 ABI capabilityMasahiro Yamada1-16/+0
Commit 0bf6276392e9 ("x32: Warn and disable rather than error if binutils too old") added a small test in arch/x86/Makefile because binutils 2.22 or newer is needed to properly support elf32-x86-64. This check is no longer necessary, as the minimum supported version of binutils is 2.23, which is enforced at configuration time with scripts/min-tool-version.sh. Remove this check and replace all uses of CONFIG_X86_X32 with CONFIG_X86_X32_ABI, as two symbols are no longer necessary. [nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still used, and simplify commit message to satisfy -tip requirements] Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220314194842.3452-2-nathan@kernel.org
2022-03-15x86/ibt: Base IBT bitsPeter Zijlstra1-2/+14
Add Kconfig, Makefile and basic instruction support for x86 IBT. (Ab)use __DISABLE_EXPORTS to disable IBT since it's already employed to mark compressed and purgatory. Additionally mark realmode with it as well to avoid inserting ENDBR instructions there. While ENDBR is technically a NOP, inserting them was causing some grief due to code growth. There's also a problem with using __noendbr in code compiled without -fcf-protection=branch. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154317.519875203@infradead.org
2021-12-09x86: Add straight-line-speculation mitigationPeter Zijlstra1-0/+4
Make use of an upcoming GCC feature to mitigate straight-line-speculation for x86: https://gcc.gnu.org/g:53a643f8568067d7700a9f2facc8ba39974973d3 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952 https://bugs.llvm.org/show_bug.cgi?id=52323 It's built tested on x86_64-allyesconfig using GCC-12 and GCC-11. Maintenance overhead of this should be fairly low due to objtool validation. Size overhead of all these additional int3 instructions comes to: text data bss dec hex filename 22267751 6933356 2011368 31212475 1dc43bb defconfig-build/vmlinux 22804126 6933356 1470696 31208178 1dc32f2 defconfig-build/vmlinux.sls Or roughly 2.4% additional text. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211204134908.140103474@infradead.org
2021-12-08x86: Use -mindirect-branch-cs-prefix for RETPOLINE buildsPeter Zijlstra1-0/+1
In order to further enable commit: bbe2df3f6b6d ("x86/alternative: Try inline spectre_v2=retpoline,amd") add the new GCC flag -mindirect-branch-cs-prefix: https://gcc.gnu.org/g:2196a681d7810ad8b227bf983f38ba716620545e https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952 https://bugs.llvm.org/show_bug.cgi?id=52323 to RETPOLINE=y builds. This should allow fully inlining retpoline,amd for GCC builds. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20211119165630.276205624@infradead.org
2021-12-08x86: Move RETPOLINE*_CFLAGS to arch MakefilePeter Zijlstra1-0/+11
Currently, RETPOLINE*_CFLAGS are defined in the top-level Makefile but only x86 makes use of them. Move them there. If ever another architecture finds the need, it can be reconsidered. [ bp: Massage a bit. ] Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20211119165630.219152765@infradead.org
2021-11-08Merge tag 'kbuild-v5.16' of ↵Linus Torvalds1-2/+0
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Remove the global -isystem compiler flag, which was made possible by the introduction of <linux/stdarg.h> - Improve the Kconfig help to print the location in the top menu level - Fix "FORCE prerequisite is missing" build warning for sparc - Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which generate a zstd-compressed tarball - Prevent gen_init_cpio tool from generating a corrupted cpio when KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later - Misc cleanups * tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits) kbuild: use more subdir- for visiting subdirectories while cleaning sh: remove meaningless archclean line initramfs: Check timestamp to prevent broken cpio archive kbuild: split DEBUG_CFLAGS out to scripts/Makefile.debug gen_init_cpio: add static const qualifiers kbuild: Add make tarzst-pkg build option scripts: update the comments of kallsyms support sparc: Add missing "FORCE" target when using if_changed kconfig: refactor conf_touch_dep() kconfig: refactor conf_write_dep() kconfig: refactor conf_write_autoconf() kconfig: add conf_get_autoheader_name() kconfig: move sym_escape_string_value() to confdata.c kconfig: refactor listnewconfig code kconfig: refactor conf_write_symbol() kconfig: refactor conf_write_heading() kconfig: remove 'const' from the return type of sym_escape_string_value() kconfig: rename a variable in the lexer to a clearer name kconfig: narrow the scope of variables in the lexer kconfig: Create links to main menu items in search ...
2021-10-28x86/Makefile: Remove unneeded whitespaces before tabsElyes HAOUAS1-1/+1
Align the FDINITRD line to the FDARGS one with tabs. [ bp: Commit message. ] Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20211028121021.10384-1-ehaouas@noos.fr
2021-10-24kbuild: use more subdir- for visiting subdirectories while cleaningMasahiro Yamada1-2/+0
Documentation/kbuild/makefiles.rst suggests to use "archclean" for cleaning arch/$(SRCARCH)/boot/, but it is not a hard requirement. Since commit d92cc4d51643 ("kbuild: require all architectures to have arch/$(SRCARCH)/Kbuild"), we can use the "subdir- += boot" trick for all architectures. This can take advantage of the parallel option (-j) for "make clean". I also cleaned up the comments in arch/$(SRCARCH)/Makefile. The "archdep" target no longer exists. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
2021-09-04Merge tag 'kbuild-v5.15' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add -s option (strict mode) to merge_config.sh to make it fail when any symbol is redefined. - Show a warning if a different compiler is used for building external modules. - Infer --target from ARCH for CC=clang to let you cross-compile the kernel without CROSS_COMPILE. - Make the integrated assembler default (LLVM_IAS=1) for CC=clang. - Add <linux/stdarg.h> to the kernel source instead of borrowing <stdarg.h> from the compiler. - Add Nick Desaulniers as a Kbuild reviewer. - Drop stale cc-option tests. - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG to handle symbols in inline assembly. - Show a warning if 'FORCE' is missing for if_changed rules. - Various cleanups * tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits) kbuild: redo fake deps at include/ksym/*.h kbuild: clean up objtool_args slightly modpost: get the *.mod file path more simply checkkconfigsymbols.py: Fix the '--ignore' option kbuild: merge vmlinux_link() between ARCH=um and other architectures kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh kbuild: merge vmlinux_link() between the ordinary link and Clang LTO kbuild: remove stale *.symversions kbuild: remove unused quiet_cmd_update_lto_symversions gen_compile_commands: extract compiler command from a series of commands x86: remove cc-option-yn test for -mtune= arc: replace cc-option-yn uses with cc-option s390: replace cc-option-yn uses with cc-option ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild sparc: move the install rule to arch/sparc/Makefile security: remove unneeded subdir-$(CONFIG_...) kbuild: sh: remove unused install script kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y kbuild: Switch to 'f' variants of integrated assembler flag kbuild: Shuffle blank line to improve comment meaning ...
2021-08-25x86/build: Move the install rule to arch/x86/MakefileMasahiro Yamada1-1/+2
Currently, the install target in arch/x86/Makefile descends into arch/x86/boot/Makefile to invoke the shell script, but there is no good reason to do so. arch/x86/Makefile can run the shell script directly. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210729140023.442101-2-masahiroy@kernel.org
2021-08-25x86/build: Remove the left-over bzlilo targetMasahiro Yamada1-2/+2
Commit f279b49f13bd ("x86/boot: Modernize genimage script; hdimage+EFI support") removed the bzlilo target from arch/x86/boot/Makefile. Remove the left-over from arch/x86/Makefile. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210729140023.442101-1-masahiroy@kernel.org
2021-08-22x86/build: Remove stale cc-option checksNick Desaulniers1-32/+14
cc-option, __cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, __cc-option, and cc-option-yn tests. -Wno-address-of-packed-member -mno-avx -m32 -mno-80387 -march=k8 -march=nocona -march=core2 -march=atom -mtune=generic -mfentry [ mingo: Fixed regression on GCC, via partial revert of the stack-boundary changes. ] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Link: https://lkml.kernel.org/r/20210812183848.1519994-1-ndesaulniers@google.com
2021-08-10kbuild: do not require sub-make for separate output tree buildsMasahiro Yamada1-1/+1
As explained in commit 3204a7fb98a3 ("kbuild: prefix $(srctree)/ to some included Makefiles"), I want to stop using --include-dir some day. I already fixed up the top Makefile, but some arch Makefiles (mips, um, x86) still include check-in Makefiles without $(srctree)/. Fix them up so 'need-sub-make := 1' can go away for this case. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-07-10Merge tag 'kbuild-v5.14' of ↵Linus Torvalds1-3/+0
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Increase the -falign-functions alignment for the debug option. - Remove ugly libelf checks from the top Makefile. - Make the silent build (-s) more silent. - Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified. - Various script cleanups * tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits) scripts: add generic syscallnr.sh scripts: check duplicated syscall number in syscall table sparc: syscalls: use pattern rules to generate syscall headers parisc: syscalls: use pattern rules to generate syscall headers nds32: add arch/nds32/boot/.gitignore kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set kbuild: modpost: Explicitly warn about unprototyped symbols kbuild: remove trailing slashes from $(KBUILD_EXTMOD) kconfig.h: explain IS_MODULE(), IS_ENABLED() kconfig: constify long_opts scripts/setlocalversion: simplify the short version part scripts/setlocalversion: factor out 12-chars hash construction scripts/setlocalversion: add more comments to -dirty flag detection scripts/setlocalversion: remove workaround for old make-kpkg scripts/setlocalversion: remove mercurial, svn and git-svn supports kbuild: clean up ${quiet} checks in shell scripts kbuild: sink stdout from cmd for silent build init: use $(call cmd,) for generating include/generated/compile.h kbuild: merge scripts/mkmakefile to top Makefile sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild ...
2021-06-28Merge tag 'x86-boot-2021-06-28' of ↵Linus Torvalds1-2/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot update from Ingo Molnar: "Modernize the genimage.sh script, add a 'hdimage' target and EFI support" * tag 'x86-boot-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Modernize genimage script; hdimage+EFI support
2021-06-11x86, lto: Pass -stack-alignment only on LLD < 13.0.0Tor Vic1-2/+3
Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1], leading to the following error message when building a LTO kernel with Clang-13 and LLD-13: ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument '-stack-alignment=8'. Try 'ld.lld --help' ld.lld: Did you mean '--stackrealign=8'? It also appears that the '-code-model' flag is not necessary anymore starting with LLVM-9 [2]. Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0. These flags were necessary because these flags were not encoded in the IR properly, so the link would restart optimizations without them. Now there are properly encoded in the IR, and these flags exposing implementation details are no longer necessary. [1] https://reviews.llvm.org/D103048 [2] https://reviews.llvm.org/D52322 Cc: stable@vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/1377 Signed-off-by: Tor Vic <torvic9@mailbox.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/f2c018ee-5999-741e-58d4-e482d5246067@mailbox.org
2021-05-26kbuild: require all architectures to have arch/$(SRCARCH)/KbuildMasahiro Yamada1-3/+0
arch/$(SRCARCH)/Kbuild is useful for Makefile cleanups because you can use the obj-y syntax. Add an empty file if it is missing in arch/$(SRCARCH)/. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-19x86/build: Fix location of '-plugin-opt=' flagsNathan Chancellor1-6/+6
Commit b33fff07e3e3 ("x86, build: allow LTO to be selected") added a couple of '-plugin-opt=' flags to KBUILD_LDFLAGS because the code model and stack alignment are not stored in LLVM bitcode. However, these flags were added to KBUILD_LDFLAGS prior to the emulation flag assignment, which uses ':=', so they were overwritten and never added to $(LD) invocations. The absence of these flags caused misalignment issues in the AMDGPU driver when compiling with CONFIG_LTO_CLANG, resulting in general protection faults. Shuffle the assignment below the initial one so that the flags are properly passed along and all of the linker flags stay together. At the same time, avoid any future issues with clobbering flags by changing the emulation flag assignment to '+=' since KBUILD_LDFLAGS is already defined with ':=' in the main Makefile before being exported for modification here as a result of commit: ce99d0bf312d ("kbuild: clear LDFLAGS in the top Makefile") Fixes: b33fff07e3e3 ("x86, build: allow LTO to be selected") Reported-by: Anthony Ruhier <aruhier@mailbox.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Anthony Ruhier <aruhier@mailbox.org> Cc: stable@vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/1374 Link: https://lore.kernel.org/r/20210518190106.60935-1-nathan@kernel.org
2021-05-10x86/boot: Modernize genimage script; hdimage+EFI supportH. Peter Anvin (Intel)1-2/+3
The image generation scripts in arch/x86/boot are pretty out of date, except for the isoimage target. Update and clean up the genimage.sh script, and make it support an arbitrary number of initramfs files in the image. Add a "hdimage" target, which can be booted by either BIOS or EFI (if the kernel is compiled with the EFI stub.) For EFI to be able to pass the command line to the kernel, we need the EFI shell, but the firmware builtin EFI shell, if it even exists, is pretty much always the last resort boot option, so search for OVMF or EDK2 and explicitly include a copy of the EFI shell. To make this all work, use bash features in the script. Furthermore, this version of the script makes use of some mtools features, especially mpartition, that might not exist in very old version of mtools, but given all the other dependencies on this script this doesn't seem such a big deal. Finally, put a volume label ("LINUX_BOOT") on all generated images. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210510082840.628372-1-hpa@zytor.com
2021-04-30Merge tag 'kbuild-v5.13' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Evaluate $(call cc-option,...) etc. only for build targets - Add CONFIG_VMLINUX_MAP to generate .map file when linking vmlinux - Remove unnecessary --gcc-toolchains Clang flag because the --prefix flag finds the toolchains - Do not pass Clang's --prefix flag when using the integrated as - Check the assembler version in Kconfig time - Add new CONFIG options, AS_VERSION, AS_IS_GNU, AS_IS_LLVM to clean up some dependencies in Kconfig - Fix invalid Module.symvers creation when building only modules without vmlinux - Fix false-positive modpost warnings when CONFIG_TRIM_UNUSED_KSYMS is set, but there is no module to build - Refactor module installation Makefile - Support zstd for module compression - Convert alpha and ia64 to use generic shell scripts to generate the syscall headers - Add a new elfnote to indicate if the kernel was built with LTO, which will be used by pahole - Flatten the directory structure under include/config/ so CONFIG options and filenames match - Change the deb source package name from linux-$(KERNELRELEASE) to linux-upstream * tag 'kbuild-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (42 commits) kbuild: Add $(KBUILD_HOSTLDFLAGS) to 'has_libelf' test kbuild: deb-pkg: change the source package name to linux-upstream tools: do not include scripts/Kbuild.include kbuild: redo fake deps at include/config/*.h kbuild: remove TMPO from try-run MAINTAINERS: add pattern for dummy-tools kbuild: add an elfnote for whether vmlinux is built with lto ia64: syscalls: switch to generic syscallhdr.sh ia64: syscalls: switch to generic syscalltbl.sh alpha: syscalls: switch to generic syscallhdr.sh alpha: syscalls: switch to generic syscalltbl.sh sysctl: use min() helper for namecmp() kbuild: add support for zstd compressed modules kbuild: remove CONFIG_MODULE_COMPRESS kbuild: merge scripts/Makefile.modsign to scripts/Makefile.modinst kbuild: move module strip/compression code into scripts/Makefile.modinst kbuild: refactor scripts/Makefile.modinst kbuild: rename extmod-prefix to extmod_prefix kbuild: check module name conflict for external modules as well kbuild: show the target directory for depmod log ...
2021-04-28Merge tag 'x86_core_for_v5.13' of ↵Linus Torvalds1-0/+8
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 updates from Borislav Petkov: - Turn the stack canary into a normal __percpu variable on 32-bit which gets rid of the LAZY_GS stuff and a lot of code. - Add an insn_decode() API which all users of the instruction decoder should preferrably use. Its goal is to keep the details of the instruction decoder away from its users and simplify and streamline how one decodes insns in the kernel. Convert its users to it. - kprobes improvements and fixes - Set the maximum DIE per package variable on Hygon - Rip out the dynamic NOP selection and simplify all the machinery around selecting NOPs. Use the simplified NOPs in objtool now too. - Add Xeon Sapphire Rapids to list of CPUs that support PPIN - Simplify the retpolines by folding the entire thing into an alternative now that objtool can handle alternatives with stack ops. Then, have objtool rewrite the call to the retpoline with the alternative which then will get patched at boot time. - Document Intel uarch per models in intel-family.h - Make Sub-NUMA Clustering topology the default and Cluster-on-Die the exception on Intel. * tag 'x86_core_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits) x86, sched: Treat Intel SNC topology as default, COD as exception x86/cpu: Comment Skylake server stepping too x86/cpu: Resort and comment Intel models objtool/x86: Rewrite retpoline thunk calls objtool: Skip magical retpoline .altinstr_replacement objtool: Cache instruction relocs objtool: Keep track of retpoline call sites objtool: Add elf_create_undef_symbol() objtool: Extract elf_symbol_add() objtool: Extract elf_strtab_concat() objtool: Create reloc sections implicitly objtool: Add elf_create_reloc() helper objtool: Rework the elf_rebuild_reloc_section() logic objtool: Fix static_call list generation objtool: Handle per arch retpoline naming objtool: Correctly handle retpoline thunk calls x86/retpoline: Simplify retpolines x86/alternatives: Optimize optimize_nops() x86: Add insn_decode_kernel() x86/kprobes: Move 'inline' to the beginning of the kprobe_is_ss() declaration ...
2021-04-26Merge tag 'x86_build_for_v5.13' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build updates from Borislav Petkov: "A bunch of clang build fixes and a Kconfig highmem selection fix for 486SX" * tag 'x86_build_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/build: Disable HIGHMEM64G selection for M486SX efi/libstub: Add $(CLANG_FLAGS) to x86 flags x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS)
2021-04-24kbuild: remove TMPO from try-runMasahiro Yamada1-2/+2
TMPO is only used by arch/x86/Makefile. Change arch/x86/Makefile to use $$TMPO.o and remove TMPO from scripts/Makefile.compiler. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-02Merge tag 'v5.12-rc5' into WIP.x86/core, to pick up recent NOP related changesIngo Molnar1-1/+1
In particular we want to have this upstream commit: b90829704780: ("bpf: Use NOP_ATOMIC5 instead of emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG") ... before merging in x86/cpu changes and the removal of the NOP optimizations, and applying PeterZ's !retpoline objtool series. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-03-26x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS)John Millikin1-0/+1
When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable contains additional flags needed to build C and assembly sources for the target platform. Normally this variable is automatically included in `$(KBUILD_CFLAGS)' via the top-level Makefile. The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a plain assignment and therefore drops the Clang flags. This causes Clang to not recognize x86-specific assembler directives:   arch/x86/realmode/rm/header.S:36:1: error: unknown directive   .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header   ^ Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)', which is inherited by real-mode make rules, fixes cross-compilation with Clang for x86 targets. Relevant flags: * `--target' sets the target architecture when cross-compiling. This   flag must be set for both compilation and assembly (`KBUILD_AFLAGS')   to support architecture-specific assembler directives. * `-no-integrated-as' tells clang to assemble with GNU Assembler   instead of its built-in LLVM assembler. This flag is set by default   unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet   parse certain GNU extensions. Signed-off-by: John Millikin <john@john-millikin.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Link: https://lkml.kernel.org/r/20210326000435.4785-2-nathan@kernel.org
2021-03-23x86/build: Turn off -fcf-protection for realmode targetsArnd Bergmann1-1/+1
The new Ubuntu GCC packages turn on -fcf-protection globally, which causes a build failure in the x86 realmode code: cc1: error: ‘-fcf-protection’ is not compatible with this target Turn it off explicitly on compilers that understand this option. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210323124846.1584944-1-arnd@kernel.org
2021-03-08x86/stackprotector/32: Make the canary into a regular percpu variableAndy Lutomirski1-0/+8
On 32-bit kernels, the stackprotector canary is quite nasty -- it is stored at %gs:(20), which is nasty because 32-bit kernels use %fs for percpu storage. It's even nastier because it means that whether %gs contains userspace state or kernel state while running kernel code depends on whether stackprotector is enabled (this is CONFIG_X86_32_LAZY_GS), and this setting radically changes the way that segment selectors work. Supporting both variants is a maintenance and testing mess. Merely rearranging so that percpu and the stack canary share the same segment would be messy as the 32-bit percpu address layout isn't currently compatible with putting a variable at a fixed offset. Fortunately, GCC 8.1 added options that allow the stack canary to be accessed as %fs:__stack_chk_guard, effectively turning it into an ordinary percpu variable. This lets us get rid of all of the code to manage the stack canary GDT descriptor and the CONFIG_X86_32_LAZY_GS mess. (That name is special. We could use any symbol we want for the %fs-relative mode, but for CONFIG_SMP=n, gcc refuses to let us use any name other than __stack_chk_guard.) Forcibly disable stackprotector on older compilers that don't support the new options and turn the stack canary into a percpu variable. The "lazy GS" approach is now used for all 32-bit configurations. Also makes load_gs_index() work on 32-bit kernels. On 64-bit kernels, it loads the GS selector and updates the user GSBASE accordingly. (This is unchanged.) On 32-bit kernels, it loads the GS selector and updates GSBASE, which is now always the user base. This means that the overall effect is the same on 32-bit and 64-bit, which avoids some ifdeffery. [ bp: Massage commit message. ] Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/c0ff7dba14041c7e5d1cae5d4df052f03759bef3.1613243844.git.luto@kernel.org
2021-02-24Merge tag 'clang-lto-v5.12-rc1-part2' of ↵Linus Torvalds1-0/+5
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull more clang LTO updates from Kees Cook: "Clang LTO x86 enablement. Full disclosure: while this has _not_ been in linux-next (since it initially looked like the objtool dependencies weren't going to make v5.12), it has been under daily build and runtime testing by Sami for quite some time. These x86 portions have been discussed on lkml, with Peter, Josh, and others helping nail things down. The bulk of the changes are to get objtool working happily. The rest of the x86 enablement is very small. Summary: - Generate __mcount_loc in objtool (Peter Zijlstra) - Support running objtool against vmlinux.o (Sami Tolvanen) - Clang LTO enablement for x86 (Sami Tolvanen)" Link: https://lore.kernel.org/lkml/20201013003203.4168817-26-samitolvanen@google.com/ Link: https://lore.kernel.org/lkml/cover.1611263461.git.jpoimboe@redhat.com/ * tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: kbuild: lto: force rebuilds when switching CONFIG_LTO x86, build: allow LTO to be selected x86, cpu: disable LTO for cpu.c x86, vdso: disable LTO only for vDSO kbuild: lto: postpone objtool objtool: Split noinstr validation from --vmlinux x86, build: use objtool mcount tracing: add support for objtool mcount objtool: Don't autodetect vmlinux.o objtool: Fix __mcount_loc generation with Clang's assembler objtool: Add a pass for generating __mcount_loc
2021-02-23x86, build: allow LTO to be selectedSami Tolvanen1-0/+5
Pass code model and stack alignment to the linker as these are not stored in LLVM bitcode, and allow CONFIG_LTO_CLANG* to be enabled. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-26 19:33:33 +0300