kernel/linux.git/init/Kconfig, branch v5.10.158

init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash

2022-12-02T16:40:03+00:00

[ Upstream commit 534bd70374d646f17e2cebe0e6e4cdd478ce4f0c ] When using dash as /bin/sh, the CC_HAS_ASM_GOTO_TIED_OUTPUT test fails with a syntax error which is not the one we are looking for: : In function ‘foo’: :1:29: warning: missing terminating " character :1:29: error: missing terminating " character :2:5: error: expected ‘:’ before ‘+’ token :2:7: warning: missing terminating " character :2:7: error: missing terminating " character :2:5: error: expected declaration or statement at end of input Removing '\n' solves this. Fixes: 1aa0e8b144b6 ("Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug") Signed-off-by: Alexandre Belloni Reviewed-by: Sean Christopherson Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug

2022-06-09T08:21:25+00:00

commit 1aa0e8b144b6474c4914439d232d15bfe883636b upstream. Add a config option to guard (future) usage of asm_volatile_goto() that includes "tied outputs", i.e. "+" constraints that specify both an input and output parameter. clang-13 has a bug[1] that causes compilation of such inline asm to fail, and KVM wants to use a "+m" constraint to implement a uaccess form of CMPXCHG[2]. E.g. the test code fails with :1:29: error: invalid operand in inline asm: '.long (${1:l}) - .' int foo(int *x) { asm goto (".long (%l[bar]) - .\n": "+m"(*x) ::: bar); return *x; bar: return 0; } ^ :1:29: error: unknown token in expression :1:9: note: instantiated into assembly here .long () - . ^ 2 errors generated. on clang-13, but passes on gcc (with appropriate asm goto support). The bug is fixed in clang-14, but won't be backported to clang-13 as the changes are too invasive/risky. gcc also had a similar bug[3], fixed in gcc-11, where gcc failed to account for its behavior of assigning two numbers to tied outputs (one for input, one for output) when evaluating symbolic references. [1] https://github.com/ClangBuiltLinux/linux/issues/1512 [2] https://lore.kernel.org/all/YfMruK8%2F1izZ2VHS@google.com [3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98096 Suggested-by: Nick Desaulniers Reviewed-by: Nick Desaulniers Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-Id: <20220202004945.2540433-2-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

bpf: Add kconfig knob for disabling unpriv bpf by default

2022-01-05T11:40:34+00:00

commit 08389d888287c3823f80b0216766b71e17f0aba5 upstream. Add a kconfig knob which allows for unprivileged bpf to be disabled by default. If set, the knob sets /proc/sys/kernel/unprivileged_bpf_disabled to value of 2. This still allows a transition of 2 -> {0,1} through an admin. Similarly, this also still keeps 1 -> {1} behavior intact, so that once set to permanently disabled, it cannot be undone aside from a reboot. We've also added extra2 with max of 2 for the procfs handler, so that an admin still has a chance to toggle between 0 <-> 2. Either way, as an additional alternative, applications can make use of CAP_BPF that we added a while ago. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/74ec548079189e4e4dffaeb42b8987bb3c852eee.1620765074.git.daniel@iogearbox.net Cc: Salvatore Bonaccorso Signed-off-by: Greg Kroah-Hartman

init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM

2021-04-10T11:36:11+00:00

commit ea29b20a828511de3348334e529a3d046a180416 upstream. I read the commit log of the following two: - bc083a64b6c0 ("init/Kconfig: make COMPILE_TEST depend on !UML") - 334ef6ed06fa ("init/Kconfig: make COMPILE_TEST depend on !S390") Both are talking about HAS_IOMEM dependency missing in many drivers. So, 'depends on HAS_IOMEM' seems the direct, sensible solution to me. This does not change the behavior of UML. UML still cannot enable COMPILE_TEST because it does not provide HAS_IOMEM. The current dependency for S390 is too strong. Under the condition of CONFIG_PCI=y, S390 provides HAS_IOMEM, hence can enable COMPILE_TEST. I also removed the meaningless 'default n'. Link: https://lkml.kernel.org/r/20210224140809.1067582-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada Cc: Heiko Carstens Cc: Guenter Roeck Cc: Arnd Bergmann Cc: Kees Cook Cc: Daniel Borkmann Cc: Johannes Weiner Cc: KP Singh Cc: Nathan Chancellor Cc: Nick Terrell Cc: Quentin Perret Cc: Valentin Schneider Cc: "Enrico Weigelt, metux IT consult" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

init/Kconfig: make COMPILE_TEST depend on !S390

2021-04-10T11:36:11+00:00

commit 334ef6ed06fa1a54e35296b77b693bcf6d63ee9e upstream. While allmodconfig and allyesconfig build for s390 there are also various bots running compile tests with randconfig, where PCI is disabled. This reveals that a lot of drivers should actually depend on HAS_IOMEM. Adding this to each device driver would be a never ending story, therefore just disable COMPILE_TEST for s390. The reasoning is more or less the same as described in commit bc083a64b6c0 ("init/Kconfig: make COMPILE_TEST depend on !UML"). Reported-by: kernel test robot Suggested-by: Arnd Bergmann Signed-off-by: Heiko Carstens Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE

2021-03-04T10:38:41+00:00

commit bfe3911a91047557eb0e620f95a370aee6a248c7 upstream. Userspace has discovered the functionality offered by SYS_kcmp and has started to depend upon it. In particular, Mesa uses SYS_kcmp for os_same_file_description() in order to identify when two fd (e.g. device or dmabuf) point to the same struct file. Since they depend on it for core functionality, lift SYS_kcmp out of the non-default CONFIG_CHECKPOINT_RESTORE into the selectable syscall category. Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to deduplicate the per-service file descriptor store. Note that some distributions such as Ubuntu are already enabling CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp. References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046 Signed-off-by: Chris Wilson Cc: Kees Cook Cc: Andy Lutomirski Cc: Will Drewry Cc: Andrew Morton Cc: Dave Airlie Cc: Daniel Vetter Cc: Lucas Stach Cc: Rasmus Villemoes Cc: Cyrill Gorcunov Cc: stable@vger.kernel.org Acked-by: Daniel Vetter # DRM depends on kcmp Acked-by: Rasmus Villemoes # systemd uses kcmp Reviewed-by: Cyrill Gorcunov Reviewed-by: Kees Cook Acked-by: Thomas Zimmermann Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@chris-wilson.co.uk Signed-off-by: Greg Kroah-Hartman

Merge tag 'kbuild-fixes-v5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2020-12-06T18:31:39+00:00

Pull Kbuild fixes from Masahiro Yamada: - Move -Wcast-align to W=3, which tends to be false-positive and there is no tree-wide solution. - Pass -fmacro-prefix-map to KBUILD_CPPFLAGS because it is a preprocessor option and makes sense for .S files as well. - Disable -gdwarf-2 for Clang's integrated assembler to avoid warnings. - Disable --orphan-handling=warn for LLD 10.0.1 to avoid warnings. - Fix undesirable line breaks in *.mod files. * tag 'kbuild-fixes-v5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: avoid split lines in .mod files kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1 kbuild: Hoist '--orphan-handling' into Kconfig Kbuild: do not emit debug info for assembly with LLVM_IAS=1 kbuild: use -fmacro-prefix-map for .S sources Makefile.extrawarn: move -Wcast-align to W=3

kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1

2020-12-01T13:46:06+00:00

ld.lld 10.0.1 spews a bunch of various warnings about .rela sections, along with a few others. Newer versions of ld.lld do not have these warnings. As a result, do not add '--orphan-handling=warn' to LDFLAGS_vmlinux if ld.lld's version is not new enough. Link: https://github.com/ClangBuiltLinux/linux/issues/1187 Link: https://github.com/ClangBuiltLinux/linux/issues/1193 Reported-by: Arvind Sankar Reported-by: kernelci.org bot Reported-by: Mark Brown Reviewed-by: Kees Cook Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada

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

2020-12-01T13:45:36+00:00

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

init/Kconfig: Fix CPU number in LOG_CPU_MAX_BUF_SHIFT description

2020-11-03T08:34:40+00:00

Currently, LOG_BUF_SHIFT defaults to 17, which is 2 ^ 17 bytes = 128 KB, and LOG_CPU_MAX_BUF_SHIFT defaults to 12, which is 2 ^ 12 bytes = 4 KB. Half of 128 KB is 64 KB, so more than 16 CPUs are required for the value to be used, as then the sum of contributions is greater than 64 KB for the first time. My guess is, that the description was written with the configuration values used in the SUSE in mind. Fixes: 23b2899f7f194f06e ("printk: allow increasing the ring buffer depending on the number of CPUs") Cc: Luis R. Rodriguez Cc: linux-kernel@vger.kernel.org Signed-off-by: Paul Menzel Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20200811092924.6256-1-pmenzel@molgen.mpg.de