linux/init/Kconfig, branch v6.8

init/Kconfig: lower GCC version check for -Warray-bounds

2024-03-05T00:40:33Z

We continue to see false positives from -Warray-bounds even in GCC 10, which is getting reported in a few places[1] still: security/security.c:811:2: warning: `memcpy' offset 32 is out of the bounds [0, 0] [-Warray-bounds] Lower the GCC version check from 11 to 10. Link: https://lkml.kernel.org/r/20240223170824.work.768-kees@kernel.org Reported-by: Lu Yao Closes: https://lore.kernel.org/lkml/20240117014541.8887-1-yaolu@kylinos.cn/ Link: https://lore.kernel.org/linux-next/65d84438.620a0220.7d171.81a7@mx.google.com [1] Signed-off-by: Kees Cook Reviewed-by: Paul Moore Cc: Ard Biesheuvel Cc: Christophe Leroy Cc: Greg Kroah-Hartman Cc: "Gustavo A. R. Silva" Cc: Johannes Weiner Cc: Marc Aurèle La France Cc: Masahiro Yamada Cc: Nathan Chancellor Cc: Nhat Pham Cc: Petr Mladek Cc: Randy Dunlap Cc: Suren Baghdasaryan Cc: Signed-off-by: Andrew Morton

update workarounds for gcc "asm goto" issue

2024-02-15T19:14:33Z

In commit 4356e9f841f7 ("work around gcc bugs with 'asm goto' with outputs") I did the gcc workaround unconditionally, because the cause of the bad code generation wasn't entirely clear. In the meantime, Jakub Jelinek debugged the issue, and has come up with a fix in gcc [2], which also got backported to the still maintained branches of gcc-11, gcc-12 and gcc-13. Note that while the fix technically wasn't in the original gcc-14 branch, Jakub says: "while it is true that no GCC 14 snapshots until today (or whenever the fix will be committed) have the fix, for GCC trunk it is up to the distros to use the latest snapshot if they use it at all and would allow better testing of the kernel code without the workaround, so that if there are other issues they won't be discovered years later. Most userland code doesn't actually use asm goto with outputs..." so we will consider gcc-14 to be fixed - if somebody is using gcc snapshots of the gcc-14 before the fix, they should upgrade. Note that while the bug goes back to gcc-11, in practice other gcc changes seem to have effectively hidden it since gcc-12.1 as per a bisect by Jakub. So even a gcc-14 snapshot without the fix likely doesn't show actual problems. Also, make the default 'asm_goto_output()' macro mark the asm as volatile by hand, because of an unrelated gcc issue [1] where it doesn't match the documented behavior ("asm goto is always volatile"). Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103979 [1] Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 [2] Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Requested-by: Jakub Jelinek Cc: Uros Bizjak Cc: Nick Desaulniers Cc: Sean Christopherson Cc: Andrew Pinski Signed-off-by: Linus Torvalds

Kconfig: Disable -Wstringop-overflow for GCC globally

2024-02-01T22:57:17Z

It turns out it was never just gcc-11 that was broken. Apparently it just happens to work on x86-64 with other gcc versions. On arm64, I see warnings with gcc version 13.2.1, and the kernel test robot reports the same problem on s390 with gcc 13.2.0. Admittedly it seems to be just the new Xe drm driver, but this is keeping me from doing my normal arm64 build testing. So it gets reverted until somebody figures out what causes the problem (and why it doesn't show on x86-64, which is what makes me suspect it was never just about gcc-11, and more about just random happenstance). This also changes the Kconfig naming a bit - just make the "disable this for GCC" conditional be one simple Kconfig entry, and we can put the gcc version dependencies in that entry once we figure out what the correct rules are. The version dependency _may_ still end up being "gcc version larger than 11" if the issue is purely in the Xe driver, but even if that ends up the case, let's make that all part of the "GCC_NO_STRINGOP_OVERFLOW" logic. For now, we just disable it for all gcc versions while the exact cause is unknown. Link: https://lore.kernel.org/all/202401161031.hjGJHMiJ-lkp@intel.com/T/ Cc: Gustavo A. R. Silva Cc: Kees Cook Signed-off-by: Linus Torvalds

init: Kconfig: Disable -Wstringop-overflow for GCC-11

2024-01-21T23:45:31Z

-Wstringop-overflow is buggy in GCC-11. Therefore, we should disable this option specifically for that compiler version. To achieve this, we introduce a new configuration option: GCC11_NO_STRINGOP_OVERFLOW. The compiler option related to string operation overflow is now managed under configuration CC_STRINGOP_OVERFLOW. This option is enabled by default for all other versions of GCC that support it. Link: https://lore.kernel.org/lkml/b3c99290-40bc-426f-b3d2-1aa903f95c4e@embeddedor.com/ Link: https://lore.kernel.org/lkml/20231128091351.2bfb38dd@canb.auug.org.au/ Reviewed-by: Kees Cook Link: https://lore.kernel.org/linux-hardening/ZWj1+jkweEDWbmAR@work/ Signed-off-by: Gustavo A. R. Silva

init/Kconfig: move more items into the EXPERT menu

2023-12-20T23:02:58Z

KCMP, RSEQ, CACHESTAT_SYSCALL, and PC104 depend on EXPERT but not shown in the EXPERT menu. Move some lines around so that they are displayed in the EXPERT menu. Drop one useless comment. Change "enabled" to "enable" for DEBUG_RSEQ. Link: https://lkml.kernel.org/r/20231208045819.2922-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Reviewed-by: Mathieu Desnoyers Cc: Peter Zijlstra Cc: "Paul E. McKenney" Cc: Boqun Feng Signed-off-by: Andrew Morton

arch: Remove Itanium (IA-64) architecture

2023-09-11T08:13:17Z

The Itanium architecture is obsolete, and an informal survey [0] reveals that any residual use of Itanium hardware in production is mostly HP-UX or OpenVMS based. The use of Linux on Itanium appears to be limited to enthusiasts that occasionally boot a fresh Linux kernel to see whether things are still working as intended, and perhaps to churn out some distro packages that are rarely used in practice. None of the original companies behind Itanium still produce or support any hardware or software for the architecture, and it is listed as 'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers that contributed on behalf of those companies (nor anyone else, for that matter) have been willing to support or maintain the architecture upstream or even be responsible for applying the odd fix. The Intel firmware team removed all IA-64 support from the Tianocore/EDK2 reference implementation of EFI in 2018. (Itanium is the original architecture for which EFI was developed, and the way Linux supports it deviates significantly from other architectures.) Some distros, such as Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have dropped support years ago. While the argument is being made [1] that there is a 'for the common good' angle to being able to build and run existing projects such as the Grid Community Toolkit [2] on Itanium for interoperability testing, the fact remains that none of those projects are known to be deployed on Linux/ia64, and very few people actually have access to such a system in the first place. Even if there were ways imaginable in which Linux/ia64 could be put to good use today, what matters is whether anyone is actually doing that, and this does not appear to be the case. There are no emulators widely available, and so boot testing Itanium is generally infeasible for ordinary contributors. GCC still supports IA-64 but its compile farm [3] no longer has any IA-64 machines. GLIBC would like to get rid of IA-64 [4] too because it would permit some overdue code cleanups. In summary, the benefits to the ecosystem of having IA-64 be part of it are mostly theoretical, whereas the maintenance overhead of keeping it supported is real. So let's rip off the band aid, and remove the IA-64 arch code entirely. This follows the timeline proposed by the Debian/ia64 maintainer [5], which removes support in a controlled manner, leaving IA-64 in a known good state in the most recent LTS release. Other projects will follow once the kernel support is removed. [0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/ [1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/ [2] https://gridcf.org/gct-docs/latest/index.html [3] https://cfarm.tetaneutral.net/machines/list/ [4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/ [5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/ Acked-by: Tony Luck Signed-off-by: Ard Biesheuvel

Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-29T21:53:51Z

Pull non-MM updates from Andrew Morton: - An extensive rework of kexec and crash Kconfig from Eric DeVolder ("refactor Kconfig to consolidate KEXEC and CRASH options") - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a couple of macros to args.h") - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper commands") - vsprintf inclusion rationalization from Andy Shevchenko ("lib/vsprintf: Rework header inclusions") - Switch the handling of kdump from a udev scheme to in-kernel handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory hot un/plug") - Many singleton patches to various parts of the tree * tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits) document while_each_thread(), change first_tid() to use for_each_thread() drivers/char/mem.c: shrink character device's devlist[] array x86/crash: optimize CPU changes crash: change crash_prepare_elf64_headers() to for_each_possible_cpu() crash: hotplug support for kexec_load() x86/crash: add x86 crash hotplug support crash: memory and CPU hotplug sysfs attributes kexec: exclude elfcorehdr from the segment digest crash: add generic infrastructure for crash hotplug support crash: move a few code bits to setup support of crash hotplug kstrtox: consistently use _tolower() kill do_each_thread() nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse scripts/bloat-o-meter: count weak symbol sizes treewide: drop CONFIG_EMBEDDED lockdep: fix static memory detection even more lib/vsprintf: declare no_hash_pointers in sprintf.h lib/vsprintf: split out sprintf() and friends kernel/fork: stop playing lockless games for exe_file replacement adfs: delete unused "union adfs_dirtail" definition ...

treewide: drop CONFIG_EMBEDDED

2023-08-21T20:46:25Z

There is only one Kconfig user of CONFIG_EMBEDDED and it can be switched to EXPERT or "if !ARCH_MULTIPLATFORM" (suggested by Arnd). Link: https://lkml.kernel.org/r/20230816055010.31534-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Acked-by: Geert Uytterhoeven Acked-by: Arnd Bergmann Acked-by: Palmer Dabbelt [RISC-V] Acked-by: Greg Ungerer Acked-by: Jason A. Donenfeld Acked-by: Michael Ellerman [powerpc] Cc: Russell King Cc: Vineet Gupta Cc: Brian Cain Cc: Michal Simek Cc: Thomas Bogendoerfer Cc: Dinh Nguyen Cc: Jonas Bonn Cc: Stefan Kristiansson Cc: Stafford Horne Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Paul Walmsley Cc: Albert Ou Cc: Yoshinori Sato Cc: Rich Felker Cc: John Paul Adrian Glaubitz Cc: Max Filippov Cc: Josh Triplett Cc: Masahiro Yamada Signed-off-by: Andrew Morton

kexec: consolidate kexec and crash options into kernel/Kconfig.kexec

2023-08-18T17:18:51Z

Patch series "refactor Kconfig to consolidate KEXEC and CRASH options", v6. The Kconfig is refactored to consolidate KEXEC and CRASH options from various arch//Kconfig files into new file kernel/Kconfig.kexec. The Kconfig.kexec is now a submenu titled "Kexec and crash features" located under "General Setup". The following options are impacted: - KEXEC - KEXEC_FILE - KEXEC_SIG - KEXEC_SIG_FORCE - KEXEC_IMAGE_VERIFY_SIG - KEXEC_BZIMAGE_VERIFY_SIG - KEXEC_JUMP - CRASH_DUMP Over time, these options have been copied between Kconfig files and are very similar to one another, but with slight differences. The following architectures are impacted by the refactor (because of use of one or more KEXEC/CRASH options): - arm - arm64 - ia64 - loongarch - m68k - mips - parisc - powerpc - riscv - s390 - sh - x86 More information: In the patch series "crash: Kernel handling of CPU and memory hot un/plug" https://lore.kernel.org/lkml/20230503224145.7405-1-eric.devolder@oracle.com/ the new kernel feature introduces the config option CRASH_HOTPLUG. In reviewing, Thomas Gleixner requested that the new config option not be placed in x86 Kconfig. Rather the option needs a generic/common home. To Thomas' point, the KEXEC and CRASH options have largely been duplicated in the various arch//Kconfig files, with minor differences. This kind of proliferation is to be avoid/stopped. https://lore.kernel.org/lkml/875y91yv63.ffs@tglx/ To that end, I have refactored the arch Kconfigs so as to consolidate the various KEXEC and CRASH options. Generally speaking, this work has the following themes: - KEXEC and CRASH options are moved into new file kernel/Kconfig.kexec - These items from arch/Kconfig: CRASH_CORE KEXEC_CORE KEXEC_ELF HAVE_IMA_KEXEC - These items from arch/x86/Kconfig form the common options: KEXEC KEXEC_FILE KEXEC_SIG KEXEC_SIG_FORCE KEXEC_BZIMAGE_VERIFY_SIG KEXEC_JUMP CRASH_DUMP - These items from arch/arm64/Kconfig form the common options: KEXEC_IMAGE_VERIFY_SIG - The crash hotplug series appends CRASH_HOTPLUG to Kconfig.kexec - The Kconfig.kexec is now a submenu titled "Kexec and crash features" and is now listed in "General Setup" submenu from init/Kconfig. - To control the common options, each has a new ARCH_SUPPORTS_

sched/psi: Select KERNFS as needed

2023-08-02T14:19:25Z

Users of KERNFS should select it to enforce its being built, so do this to prevent a build error. In file included from ../kernel/sched/build_utility.c:97: ../kernel/sched/psi.c: In function 'psi_trigger_poll': ../kernel/sched/psi.c:1479:17: error: implicit declaration of function 'kernfs_generic_poll' [-Werror=implicit-function-declaration] 1479 | kernfs_generic_poll(t->of, wait); Fixes: aff037078eca ("sched/psi: use kernfs polling functions for PSI trigger polling") Reported-by: kernel test robot Signed-off-by: Randy Dunlap Signed-off-by: Peter Zijlstra (Intel) Acked-by: Suren Baghdasaryan Link: lore.kernel.org/r/202307310732.r65EQFY0-lkp@intel.com