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2021-10-03Linux 5.15-rc4Linus Torvalds
2021-09-26Linux 5.15-rc3Linus Torvalds
2021-09-19Linux 5.15-rc2Linus Torvalds
2021-09-13Merge branch 'gcc-min-version-5.1' (make gcc-5.1 the minimum version)Linus Torvalds
Merge patch series from Nick Desaulniers to update the minimum gcc version to 5.1. This is some of the left-overs from the merge window that I didn't want to deal with yesterday, so it comes in after -rc1 but was sent before. Gcc-4.9 support has been an annoyance for some time, and with -Werror I had the choice of applying a fairly big patch from Kees Cook to remove a fair number of initializer warnings (still leaving some), or this patch series from Nick that just removes the source of the problem. The initializer cleanups might still be worth it regardless, but honestly, I preferred just tackling the problem with gcc-4.9 head-on. We've been more aggressiuve about no longer having to care about compilers that were released a long time ago, and I think it's been a good thing. I added a couple of patches on top to sort out a few left-overs now that we no longer support gcc-4.x. As noted by Arnd, as a result of this minimum compiler version upgrade we can probably change our use of '--std=gnu89' to '--std=gnu11', and finally start using local loop declarations etc. But this series does _not_ yet do that. Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/ Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/1438 * emailed patches from Nick Desaulniers <ndesaulniers@google.com>: Drop some straggling mentions of gcc-4.9 as being stale compiler_attributes.h: drop __has_attribute() support for gcc4 vmlinux.lds.h: remove old check for GCC 4.9 compiler-gcc.h: drop checks for older GCC versions Makefile: drop GCC < 5 -fno-var-tracking-assignments workaround arm64: remove GCC version check for ARCH_SUPPORTS_INT128 powerpc: remove GCC version check for UPD_CONSTR riscv: remove Kconfig check for GCC version for ARCH_RV64I Kconfig.debug: drop GCC 5+ version check for DWARF5 mm/ksm: remove old GCC 4.9+ check compiler.h: drop fallback overflow checkers Documentation: raise minimum supported version of GCC to 5.1
2021-09-13Makefile: drop GCC < 5 -fno-var-tracking-assignments workaroundNick Desaulniers
Now that GCC 5.1 is the minimally supported version, we can drop this workaround for older versions of GCC. Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-12Linux 5.15-rc1Linus Torvalds
2021-09-08Makefile: use -Wno-main in the full kernel treeRandy Dunlap
When using gcc (SUSE Linux) 7.5.0 (on openSUSE 15.3), I see a build warning: kernel/trace/trace_osnoise.c: In function 'start_kthread': kernel/trace/trace_osnoise.c:1461:8: warning: 'main' is usually a function [-Wmain] void *main = osnoise_main; ^~~~ Quieten that warning by using "-Wno-main". It's OK to use "main" as a declaration name in the kernel. Build-tested on most ARCHes. [ v2: only do it for gcc, since clang doesn't have that particular warning ] Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/lkml/20210813224131.25803-1-rdunlap@infradead.org/ Suggested-by: Steven Rostedt <rostedt@goodmis.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: linux-kbuild@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-05Enable '-Werror' by default for all kernel buildsLinus Torvalds
... but make it a config option so that broken environments can disable it when required. We really should always have a clean build, and will disable specific over-eager warnings as required, if we can't fix them. But while I fairly religiously enforce that in my own tree, it doesn't get enforced by various build robots that don't necessarily report warnings. So this just makes '-Werror' a default compiler flag, but allows people to disable it for their configuration if they have some particular issues. Occasionally, new compiler versions end up enabling new warnings, and it can take a while before we have them fixed (or the warnings disabled if that is what it takes), so the config option allows for that situation. Hopefully this will mean that I get fewer pull requests that have new warnings that were not noticed by various automation we have in place. Knock wood. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-03Merge tag 'kbuild-v5.15' of ↵Linus Torvalds
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 ...
2021-09-03kbuild: Shuffle blank line to improve comment meaningNathan Chancellor
-Wunused-but-set-variable and -Wunused-const-variable are both disabled for the same reason but there is a blank line between them and no blank line between -Wno-unused-const-variable and the block. Shuffle the new line so that it is clear that the comment applied to both flags and the next block is separate from them. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-03kbuild: Add a comment above -Wno-gnuNathan Chancellor
Whenever a warning is disabled, it is helpful for future travelers to understand why the warning is disabled and why it is acceptable to do so. Add a comment for -Wno-gnu so that people understand why it is disabled. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-03kbuild: Remove -Wno-format-invalid-specifier from clang blockNathan Chancellor
Turning on -Wformat does not reveal any instances of this warning across several different builds so remove this line to keep the number of disabled warnings as slim as possible. This has been disabled since commit 61163efae020 ("kbuild: LLVMLinux: Add Kbuild support for building kernel with Clang"), which does not explain exactly why it was turned off but since it was so long ago in terms of both the kernel and LLVM so it is possible that some bug got fixed along the way. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-03Makefile: remove stale cc-option checksNick Desaulniers
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 GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-02Merge tag 'for-5.15/parisc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc architecture updates from Helge Deller: - Fix a kernel crash when a signal is delivered to bad userspace stack - Fix fall-through warnings in math-emu code - Increase size of gcc stack frame check - Switch coding from 'pci_' to 'dma_' API - Make struct parisc_driver::remove() return void - Some parisc related Makefile changes - Minor cleanups, e.g. change to octal permissions, fix macro collisions, fix PMD_ORDER collision, replace spaces with tabs * tag 'for-5.15/parisc' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: math-emu: Fix fall-through warnings parisc: fix crash with signals and alloca parisc: Fix compile failure when building 64-bit kernel natively parisc: ccio-dma.c: Added tab instead of spaces parisc/parport_gsc: switch from 'pci_' to 'dma_' API parisc: move core-y in arch/parisc/Makefile to arch/parisc/Kbuild parisc: switch from 'pci_' to 'dma_' API parisc: Make struct parisc_driver::remove() return void parisc: remove unused arch/parisc/boot/install.sh and its phony target parisc: Rename PMD_ORDER to PMD_TABLE_ORDER parisc: math-emu: Avoid "fmt" macro collision parisc: Increase size of gcc stack frame check parisc: Replace symbolic permissions with octal permissions
2021-09-02Merge tag 'hardening-v5.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: - Expand lib/test_stackinit to include more initialization styles - Improve Kconfig for CLang's auto-var-init feature - Introduce support for GCC's zero-call-used-regs feature * tag 'hardening-v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: lib/test_stackinit: Add assigned initializers lib/test_stackinit: Allow building stand-alone lib/test_stackinit: Fix static initializer test hardening: Clarify Kconfig text for auto-var-init hardening: Introduce CONFIG_ZERO_CALL_USED_REGS
2021-09-01parisc: Fix compile failure when building 64-bit kernel nativelyMasahiro Yamada
Commit 23243c1ace9f ("arch: use cross_compiling to check whether it is a cross build or not") broke 64-bit parisc builds on 32-bit parisc systems. Helge mentioned: - 64-bit parisc userspace is not supported yet [1] - hppa gcc does not support "-m64" flag [2] That means, parisc developers working on a 32-bit parisc machine need to use hppa64-linux-gnu-gcc (cross compiler) for building the 64-bit parisc kernel. After the offending commit, gcc is used in such a case because both $(SRCARCH) and $(SUBARCH) are 'parisc', hence cross_compiling is unset. A correct way is to introduce ARCH=parisc64 because building the 64-bit parisc kernel on a 32-bit parisc system is not exactly a native build, but rather a semi-cross build. [1]: https://lore.kernel.org/linux-parisc/5dfd81eb-c8ca-b7f5-e80e-8632767c022d@gmx.de/#t [2]: https://lore.kernel.org/linux-parisc/89515325-fc21-31da-d238-6f7a9abbf9a0@gmx.de/ Fixes: 23243c1ace9f ("arch: use cross_compiling to check whether it is a cross build or not") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reported-by: Meelis Roos <mroos@linux.ee> Tested-by: Meelis Roos <mroos@linux.ee> Cc: <stable@vger.kernel.org> # v5.13+ Signed-off-by: Helge Deller <deller@gmx.de>
2021-08-29Linux 5.14Linus Torvalds
2021-08-22Linux 5.14-rc7Linus Torvalds
2021-08-15Linux 5.14-rc6Linus Torvalds
2021-08-10kbuild: check CONFIG_AS_IS_LLVM instead of LLVM_IASMasahiro Yamada
LLVM_IAS is the user interface to set the -(no-)integrated-as flag, and it should be used only for that purpose. LLVM_IAS is checked in some places to determine the assembler type, but it is not precise. For example, $ make CC=gcc LLVM_IAS=1 ... will use the GNU assembler (i.e. binutils) since LLVM_IAS=1 is effective only when $(CC) is clang. Of course, 'CC=gcc LLVM_IAS=1' is an odd combination, but the build system can be more robust against such insane input. Commit ba64beb17493a ("kbuild: check the minimum assembler version in Kconfig") introduced CONFIG_AS_IS_GNU/LLVM, which is more precise because Kconfig checks the version string from the assembler in use. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
2021-08-10Makefile: move initial clang flag handling into scripts/Makefile.clangNick Desaulniers
With some of the changes we'd like to make to CROSS_COMPILE, the initial block of clang flag handling which controls things like the target triple, whether or not to use the integrated assembler and how to find GAS, and erroring on unknown warnings is becoming unwieldy. Move it into its own file under scripts/. Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-10kbuild: warn if a different compiler is used for external module buildsMasahiro Yamada
It is always safe to use the same compiler for the kernel and external modules, but in reality, some distributions such as Fedora release a different version of GCC from the one used for building the kernel. There was a long discussion about mixing different compilers [1]. I do not repeat it here, but at least, showing a heads up in that case is better than nothing. Linus suggested [2]: And a warning might be more palatable even if different compiler version work fine together. Just a heads up on "it looks like you might be mixing compiler versions" is a valid note, and isn't necessarily wrong. Even when they work well together, maybe you want to have people at least _aware_ of it. This commit shows a warning unless the compiler is exactly the same. warning: the compiler differs from the one used to build the kernel The kernel was built by: gcc (GCC) 11.1.1 20210531 (Red Hat 11.1.1-3) You are using: gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1) Check the difference, and if it is OK with you, please proceed at your risk. To avoid the locale issue as in commit bcbcf50f5218 ("kbuild: fix ld-version.sh to not be affected by locale"), pass LC_ALL=C to "$(CC) --version". [1] https://lore.kernel.org/linux-hardening/efe6b039a544da8215d5e54aa7c4b6d1986fc2b0.1611607264.git.jpoimboe@redhat.com/ [2] https://lore.kernel.org/lkml/CAHk-=wgjwhDy-y4mQh34L+2aF=n6BjzHdqAW2=8wri5x7O04pA@mail.gmail.com/ Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-10kbuild: do not require sub-make for separate output tree buildsMasahiro Yamada
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>
2021-08-08Linux 5.14-rc5Linus Torvalds
2021-08-07Merge tag 'kbuild-fixes-v5.14-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - Correct the Extended Regular Expressions in tools - Adjust scripts/checkversion.pl for the current Kbuild - Unset sub_make_done for 'make install' to make DKMS work again * tag 'kbuild-fixes-v5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: cancel sub_make_done for the install target to fix DKMS scripts: checkversion: modernize linux/version.h search strings mips: Fix non-POSIX regexp x86/tools/relocs: Fix non-POSIX regexp
2021-08-05Merge tag 'trace-v5.14-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Various tracing fixes: - Fix NULL pointer dereference caused by an error path - Give histogram calculation fields a size, otherwise it breaks synthetic creation based on them. - Reject strings being used for number calculations. - Fix recordmcount.pl warning on llvm building RISC-V allmodconfig - Fix the draw_functrace.py script to handle the new trace output - Fix warning of smp_processor_id() in preemptible code" * tag 'trace-v5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Quiet smp_processor_id() use in preemptable warning in hwlat scripts/tracing: fix the bug that can't parse raw_trace_func scripts/recordmcount.pl: Remove check_objcopy() and $can_use_local tracing: Reject string operand in the histogram expression tracing / histogram: Give calculation hist_fields a size tracing: Fix NULL pointer dereference in start_creating
2021-08-05kbuild: cancel sub_make_done for the install target to fix DKMSMasahiro Yamada
Since commit bcf637f54f6d ("kbuild: parse C= and M= before changing the working directory"), external module builds invoked by DKMS fail because M= option is not parsed. I wanted to add 'unset sub_make_done' in install.sh but similar scripts, arch/*/boot/install.sh, are duplicated, so I set sub_make_done empty in the top Makefile. Fixes: bcf637f54f6d ("kbuild: parse C= and M= before changing the working directory") Reported-by: John S Gruber <johnsgruber@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: John S Gruber <johnsgruber@gmail.com>
2021-08-04scripts/recordmcount.pl: Remove check_objcopy() and $can_use_localNathan Chancellor
When building ARCH=riscv allmodconfig with llvm-objcopy, the objcopy version warning from this script appears: WARNING: could not find objcopy version or version is less than 2.17. Local function references are disabled. The check_objcopy() function in scripts/recordmcount.pl is set up to parse GNU objcopy's version string, not llvm-objcopy's, which triggers the warning. Commit 799c43415442 ("kbuild: thin archives make default for all archs") made binutils 2.20 mandatory and commit ba64beb17493 ("kbuild: check the minimum assembler version in Kconfig") enforces this at configuration time so just remove check_objcopy() and $can_use_local instead, assuming --globalize-symbol is always available. llvm-objcopy has supported --globalize-symbol since LLVM 7.0.0 in 2018 and the minimum version for building the kernel with LLVM is 10.0.1 so there is no issue introduced: Link: https://github.com/llvm/llvm-project/commit/ee5be798dae30d5f9414b01f76ff807edbc881aa Link: https://lkml.kernel.org/r/20210802210307.3202472-1-nathan@kernel.org Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-08-01Linux 5.14-rc4Linus Torvalds
2021-07-25Linux 5.14-rc3Linus Torvalds
2021-07-20hardening: Introduce CONFIG_ZERO_CALL_USED_REGSKees Cook
When CONFIG_ZERO_CALL_USED_REGS is enabled, build the kernel with "-fzero-call-used-regs=used-gpr" (in GCC 11). This option will zero any caller-used register contents just before returning from a function, ensuring that temporary values are not leaked beyond the function boundary. This means that register contents are less likely to be available for side channel attacks and information exposures. Additionally this helps reduce the number of useful ROP gadgets in the kernel image by about 20%: $ ROPgadget.py --nosys --nojop --binary vmlinux.stock | tail -n1 Unique gadgets found: 337245 $ ROPgadget.py --nosys --nojop --binary vmlinux.zero-call-regs | tail -n1 Unique gadgets found: 267175 and more notably removes simple "write-what-where" gadgets: $ ROPgadget.py --ropchain --binary vmlinux.stock | sed -n '/Step 1/,/Step 2/p' - Step 1 -- Write-what-where gadgets [+] Gadget found: 0xffffffff8102d76c mov qword ptr [rsi], rdx ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff8104d7c8 pop rdx ; ret [-] Can't find the 'xor rdx, rdx' gadget. Try with another 'mov [reg], reg' [+] Gadget found: 0xffffffff814c2b4c mov qword ptr [rsi], rdi ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff81001e51 pop rdi ; ret [-] Can't find the 'xor rdi, rdi' gadget. Try with another 'mov [reg], reg' [+] Gadget found: 0xffffffff81540d61 mov qword ptr [rsi], rdi ; pop rbx ; pop rbp ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff81001e51 pop rdi ; ret [-] Can't find the 'xor rdi, rdi' gadget. Try with another 'mov [reg], reg' [+] Gadget found: 0xffffffff8105341e mov qword ptr [rsi], rax ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff81029a11 pop rax ; ret [+] Gadget found: 0xffffffff811f1c3b xor rax, rax ; ret - Step 2 -- Init syscall number gadgets $ ROPgadget.py --ropchain --binary vmlinux.zero* | sed -n '/Step 1/,/Step 2/p' - Step 1 -- Write-what-where gadgets [-] Can't find the 'mov qword ptr [r64], r64' gadget For an x86_64 parallel build tests, this has a less than 1% performance impact, and grows the image size less than 1%: $ size vmlinux.stock vmlinux.zero-call-regs text data bss dec hex filename 22437676 8559152 14127340 45124168 2b08a48 vmlinux.stock 22453184 8563248 14110956 45127388 2b096dc vmlinux.zero-call-regs Impact for other architectures may vary. For example, arm64 sees a 5.5% image size growth, mainly due to needing to always clear x16 and x17: https://lore.kernel.org/lkml/20210510134503.GA88495@C02TD0UTHF1T.local/ Signed-off-by: Kees Cook <keescook@chromium.org>
2021-07-18Linux 5.14-rc2Linus Torvalds
2021-07-18Merge tag 'kbuild-fixes-v5.14' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - Restore the original behavior of scripts/setlocalversion when LOCALVERSION is set to empty. - Show Kconfig prompts even for 'make -s' - Fix the combination of COFNIG_LTO_CLANG=y and CONFIG_MODVERSIONS=y for older GNU Make versions * tag 'kbuild-fixes-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: Documentation: Fix intiramfs script name Kbuild: lto: fix module versionings mismatch in GNU make 3.X kbuild: do not suppress Kconfig prompts for silent build scripts/setlocalversion: fix a bug when LOCALVERSION is empty
2021-07-18kbuild: do not suppress Kconfig prompts for silent buildMasahiro Yamada
When a new CONFIG option is available, Kbuild shows a prompt to get the user input. $ make [ snip ] Core Scheduling for SMT (SCHED_CORE) [N/y/?] (NEW) This is the only interactive place in the build process. Commit 174a1dcc9642 ("kbuild: sink stdout from cmd for silent build") suppressed Kconfig prompts as well because syncconfig is invoked by the 'cmd' macro. You cannot notice the fact that Kconfig is waiting for the user input. Use 'kecho' to show the equivalent short log without suppressing stdout from sub-make. Fixes: 174a1dcc9642 ("kbuild: sink stdout from cmd for silent build") Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
2021-07-15Revert "Makefile: Enable -Wimplicit-fallthrough for Clang"Linus Torvalds
This reverts commit b7eb335e26a9c7f258c96b3962c283c379d3ede0. It turns out that the problem with the clang -Wimplicit-fallthrough warning is not about the kernel source code, but about clang itself, and that the warning is unusable until clang fixes its broken ways. In particular, when you enable this warning for clang, you not only get warnings about implicit fallthroughs. You also get this: warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough] which is completely broken becasue it (a) doesn't even tell you where the problem is (seriously: no line numbers, no filename, no nothing). (b) is fundamentally broken anyway, because there are perfectly valid reasons to have a fallthrough statement even if it turns out that it can perhaps not be reached. In the kernel, an example of that second case is code in the scheduler: switch (state) { case cpuset: if (IS_ENABLED(CONFIG_CPUSETS)) { cpuset_cpus_allowed_fallback(p); state = possible; break; } fallthrough; case possible: where if CONFIG_CPUSETS is enabled you actually never hit the fallthrough case at all. But that in no way makes the fallthrough wrong. So the warning is completely broken, and enabling it for clang is a very bad idea. In the meantime, we can keep the gcc option enabled, and make the gcc build use -Wimplicit-fallthrough=5 which means that we will at least continue to require a proper fallthrough statement, and that gcc won't silently accept the magic comment versions. Because gcc does this all correctly, and while the odd "=5" part is kind of obscure, it's documented in [1]: "-Wimplicit-fallthrough=5 doesn’t recognize any comments as fallthrough comments, only attributes disable the warning" so if clang ever fixes its bad behavior we can try enabling it there again. Link: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html [1] Cc: Kees Cook <keescook@chromium.org> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-14Makefile: Enable -Wimplicit-fallthrough for ClangGustavo A. R. Silva
With the recent fixes for fallthrough warnings, it is now possible to enable -Wimplicit-fallthrough for Clang. It's important to mention that since we have adopted the use of the pseudo-keyword macro fallthrough; we also want to avoid having more /* fall through */ comments being introduced. Notice that contrary to GCC, Clang doesn't recognize any comments as implicit fall-through markings when the -Wimplicit-fallthrough option is enabled. So, in order to avoid having more comments being introduced, we have to use the option -Wimplicit-fallthrough=5 for GCC, which similar to Clang, will cause a warning in case a code comment is intended to be used as a fall-through marking. Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2021-07-11Linux 5.14-rc1Linus Torvalds
2021-07-10Merge tag 'kbuild-v5.14' of ↵Linus Torvalds
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 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: "There's a reasonable amount here and the juicy details are all below. It's worth noting that the MTE/KASAN changes strayed outside of our usual directories due to core mm changes and some associated changes to some other architectures; Andrew asked for us to carry these [1] rather that take them via the -mm tree. Summary: - Optimise SVE switching for CPUs with 128-bit implementations. - Fix output format from SVE selftest. - Add support for versions v1.2 and 1.3 of the SMC calling convention. - Allow Pointer Authentication to be configured independently for kernel and userspace. - PMU driver cleanups for managing IRQ affinity and exposing event attributes via sysfs. - KASAN optimisations for both hardware tagging (MTE) and out-of-line software tagging implementations. - Relax frame record alignment requirements to facilitate 8-byte alignment with KASAN and Clang. - Cleanup of page-table definitions and removal of unused memory types. - Reduction of ARCH_DMA_MINALIGN back to 64 bytes. - Refactoring of our instruction decoding routines and addition of some missing encodings. - Move entry code moved into C and hardened against harmful compiler instrumentation. - Update booting requirements for the FEAT_HCX feature, added to v8.7 of the architecture. - Fix resume from idle when pNMI is being used. - Additional CPU sanity checks for MTE and preparatory changes for systems where not all of the CPUs support 32-bit EL0. - Update our kernel string routines to the latest Cortex Strings implementation. - Big cleanup of our cache maintenance routines, which were confusingly named and inconsistent in their implementations. - Tweak linker flags so that GDB can understand vmlinux when using RELR relocations. - Boot path cleanups to enable early initialisation of per-cpu operations needed by KCSAN. - Non-critical fixes and miscellaneous cleanup" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (150 commits) arm64: tlb: fix the TTL value of tlb_get_level arm64: Restrict undef hook for cpufeature registers arm64/mm: Rename ARM64_SWAPPER_USES_SECTION_MAPS arm64: insn: avoid circular include dependency arm64: smp: Bump debugging information print down to KERN_DEBUG drivers/perf: fix the missed ida_simple_remove() in ddr_perf_probe() perf/arm-cmn: Fix invalid pointer when access dtc object sharing the same IRQ number arm64: suspend: Use cpuidle context helpers in cpu_suspend() PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter() arm64: Convert cpu_do_idle() to using cpuidle context helpers arm64: Add cpuidle context save/restore helpers arm64: head: fix code comments in set_cpu_boot_mode_flag arm64: mm: drop unused __pa(__idmap_text_start) arm64: mm: fix the count comments in compute_indices arm64/mm: Fix ttbr0 values stored in struct thread_info for software-pan arm64: mm: Pass original fault address to handle_mm_fault() arm64/mm: Drop SECTION_[SHIFT|SIZE|MASK] arm64/mm: Use CONT_PMD_SHIFT for ARM64_MEMSTART_SHIFT arm64/mm: Drop SWAPPER_INIT_MAP_SIZE arm64: Conditionally configure PTR_AUTH key of the kernel. ...
2021-06-27Linux 5.13Linus Torvalds
2021-06-20Linux 5.13-rc7Linus Torvalds
2021-06-17kbuild: remove trailing slashes from $(KBUILD_EXTMOD)Masahiro Yamada
M= (or KBUILD_EXTMOD) generally expects a directory path without any trailing slashes, like M=a/b/c. If you add a trailing slash, like M=a/b/c/, you will get ugly build logs (two slashes in a series), but it still works fine as long as it is consistent between 'make modules' and 'make modules_install'. The following commands correctly build and install the modules. $ make M=a/b/c/ modules $ sudo make M=a/b/c/ modules_install Since commit ccae4cfa7bfb ("kbuild: refactor scripts/Makefile.modinst"), a problem happens if you add a trailing slash only for modules_install. $ make M=a/b/c modules $ sudo make M=a/b/c/ modules_install No module is installed in this case, Johannes Berg reported. [1] Trim any trailing slashes from $(KBUILD_EXTMOD). I used the 'dirname' command to remove all the trailing slashes in case someone adds more slashes like M=a/b/c/////. The Make's built-in function, $(dir ...) cannot take care of such a case. [1]: https://lore.kernel.org/lkml/10cc8522b27a051e6a9c3e158a4c4b6414fd04a0.camel@sipsolutions.net/ Fixes: ccae4cfa7bfb ("kbuild: refactor scripts/Makefile.modinst") Reported-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-06-16Merge tag 'clang-features-v5.13-rc7' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull clang LTO fix from Kees Cook: "It seems Clang has been scrubbing through the missing LTO IR flags for Clang 13, and the last of these 'only with LTO' flags is fixed now. I've asked that they please consider making these changes in a less 'break all the Clang kernel builds' kind of way in the future. :P Summary: - The '-warn-stack-size' option under LTO has moved in Clang 13 (Tor Vic)" * tag 'clang-features-v5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: Makefile: lto: Pass -warn-stack-size only on LLD < 13.0.0
2021-06-14Makefile: lto: Pass -warn-stack-size only on LLD < 13.0.0Tor Vic
Since LLVM commit fc018eb, the '-warn-stack-size' flag has been dropped [1], leading to the following error message when building with Clang-13 and LLD-13: ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument '-warn-stack-size=2048'. Try: 'ld.lld --help' ld.lld: Did you mean '--asan-stack=2048'? In the same way as with commit 2398ce80152a ("x86, lto: Pass -stack-alignment only on LLD < 13.0.0") , make '-warn-stack-size' conditional on LLD < 13.0.0. [1] https://reviews.llvm.org/D103928 Fixes: 24845dcb170e ("Makefile: LTO: have linker check -Wframe-larger-than") 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> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/7631bab7-a8ab-f884-ab54-f4198976125c@mailbox.org
2021-06-13Linux 5.13-rc6Linus Torvalds
2021-06-08Makefile: fix GDB warning with CONFIG_RELRNick Desaulniers
GDB produces the following warning when debugging kernels built with CONFIG_RELR: BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn' when loading a kernel built with CONFIG_RELR into GDB. It can also prevent debugging symbols using such relocations. Peter sugguests: [That flag] means that lld will use dynamic tags and section type numbers in the OS-specific range rather than the generic range. The kernel itself doesn't care about these numbers; it determines the location of the RELR section using symbols defined by a linker script. Link: https://github.com/ClangBuiltLinux/linux/issues/1057 Suggested-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20210522012626.2811297-1-ndesaulniers@google.com Signed-off-by: Will Deacon <will@kernel.org>
2021-06-06Linux 5.13-rc5Linus Torvalds
2021-05-30Linux 5.13-rc4Linus Torvalds
2021-05-28Merge tag 'clang-features-v5.13-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull clang feature fixes from Kees Cook: - Correctly pass stack frame size checking under LTO (Nick Desaulniers) - Avoid CFI mismatches by checking initcall_t types (Marco Elver) * tag 'clang-features-v5.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: Makefile: LTO: have linker check -Wframe-larger-than init: verify that function is initcall_t at compile-time
2021-05-27kbuild: merge scripts/mkmakefile to top MakefileMasahiro Yamada
scripts/mkmakefile is simple enough to be merged in the Makefile. Use $(call cmd,...) to show the log instead of doing it in the shell script. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>