Linux kernel documentation tree maintained by Jonathan Corbet http://mirrors.hust.edu.cn/git/lwn.git/atom?h=docs-6.1 2022-09-29T19:20:53+00:00 2022-09-29T19:20:53+00:00 David Hildenbrand david@redhat.com 2022-09-23T11:34:25+00:00 urn:sha1:69d517e6e21099f81efbd39e47874649ae575804 checkpatch does not point out that VM_BUG_ON() and friends should be avoided, however, Linus notes: VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally no different, the only difference is "we can make the code smaller because these are less important". [1] So let's warn on VM_BUG_ON() and other BUG variants as well. While at it, make it clearer that the kernel really shouldn't be crashed. As there are some subsystem BUG macros that actually don't end up crashing the kernel -- for example, KVM_BUG_ON() -- exclude these manually. [1] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20220923113426.52871-3-david@redhat.com Signed-off-by: Jonathan Corbet <corbet@lwn.net> 2022-09-29T18:55:06+00:00 Jonathan Corbet corbet@lwn.net 2022-09-27T16:05:57+00:00 urn:sha1:f4bf1cd4ac9c8c4610b687e49a1ba691ab286235 This one file should not really be in the top-level documentation directory. core-api/ may not be a perfect fit but seems to be best, so move it there. Adjust a couple of internal document references to make them location-independent, and point checkpatch.pl at the new location. Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Joe Perches <joe@perches.com> Reviewed-by: David Vernet <void@manifault.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20220927160559.97154-6-corbet@lwn.net Signed-off-by: Jonathan Corbet <corbet@lwn.net> 2022-08-13T01:39:43+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-08-13T01:39:43+00:00 urn:sha1:69dac8e431af26173ca0a1ebc87054e01c585bcc Pull more RISC-V updates from Palmer Dabbelt: "There's still a handful of new features in here, but there are a lot of fixes/cleanups as well: - Support for the Zicbom extension for explicit cache-block management, along with the necessary bits to make the non-standard cache management ops on the Allwinner D1 function - Support for the Zihintpause extension, which codifies a go-slow instruction used for cpu_relax() - Support for the Sstc extension for supervisor-mode timer/counter management - Many device tree fixes and cleanups, including a large set for the Canaan device trees - A handful of fixes and cleanups for the PMU driver" * tag 'riscv-for-linus-5.20-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (43 commits) dt-bindings: gpio: sifive: add gpio-line-names wireguard: selftests: set CONFIG_NONPORTABLE on riscv32 RISC-V: KVM: Support sstc extension RISC-V: Improve SBI definitions RISC-V: Move counter info definition to sbi header file RISC-V: Fix SBI PMU calls for RV32 RISC-V: Update user page mapping only once during start RISC-V: Fix counter restart during overflow for RV32 RISC-V: Prefer sstc extension if available RISC-V: Enable sstc extension parsing from DT RISC-V: Add SSTC extension CSR details riscv:uprobe fix SR_SPIE set/clear handling dt-bindings: riscv: fix SiFive l2-cache's cache-sets riscv: ensure cpu_ops_sbi is declared RISC-V: cpu_ops_spinwait.c should include head.h RISC-V: Declare cpu_ops_spinwait in <asm/cpu_ops.h> riscv: dts: starfive: correct number of external interrupts riscv: dts: sifive unmatched: Add PWM controlled LEDs riscv/purgatory: Omit use of bin2c riscv/purgatory: hard-code obj-y in Makefile ... 2022-08-11T16:32:34+00:00 Masahiro Yamada masahiroy@kernel.org 2022-06-25T22:34:37+00:00 urn:sha1:d8357e3bf8f7aabd98bf4dc2709ee877b741cefc The .incbin assembler directive is much faster than bin2c + $(CC). Do similar refactoring as in commit 4c0f032d4963 ("s390/purgatory: Omit use of bin2c"). Please note the .quad directive matches to size_t in C (both 8 byte) because the purgatory is compiled only for the 64-bit kernel. (KEXEC_FILE depends on 64BIT). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/r/20220625223438.835408-2-masahiroy@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> 2022-08-11T15:40:01+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-08-11T15:40:01+00:00 urn:sha1:21f9c8a13bb2a0c24d9c6b86bc0896542a28c197 This reverts commit 258fafcd0683d9ccfa524129d489948ab3ddc24c. The clang -Wformat warning is terminally broken, and the clang people can't seem to get their act together. This test program causes a warning with clang: #include <stdio.h> int main(int argc, char **argv) { printf("%hhu\n", 'a'); } resulting in t.c:5:19: warning: format specifies type 'unsigned char' but the argument has type 'int' [-Wformat] printf("%hhu\n", 'a'); ~~~~ ^~~ %d and apparently clang people consider that a feature, because they don't want to face the reality of how either C character constants, C arithmetic, and C varargs functions work. The rest of the world just shakes their head at that kind of incompetence, and turns off -Wformat for clang again. And no, the "you should use a pointless cast to shut this up" is not a valid answer. That warning should not exist in the first place, or at least be optinal with some "-Wformat-me-harder" kind of option. [ Admittedly, there's also very little reason to *ever* use '%hh[ud]' in C, but what little reason there is is entirely about 'I want to see only the low 8 bits of the argument'. So I would suggest nobody ever use that format in the first place, but if they do, the clang behavious is simply always wrong. Because '%hhu' takes an 'int'. It's that simple. ] Reported-by: Sudip Mukherjee (Codethink) <sudipm.mukherjee@gmail.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 2022-08-10T17:40:41+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-08-10T17:40:41+00:00 urn:sha1:0af5cb349a2c97fbabb3cede96efcde9d54b7940 Pull Kbuild updates from Masahiro Yamada: - Remove the support for -O3 (CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3) - Fix error of rpm-pkg cross-builds - Support riscv for checkstack tool - Re-enable -Wformwat warnings for Clang - Clean up modpost, Makefiles, and misc scripts * tag 'kbuild-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits) modpost: remove .symbol_white_list field entirely modpost: remove unneeded .symbol_white_list initializers modpost: add PATTERNS() helper macro modpost: shorten warning messages in report_sec_mismatch() Revert "Kbuild, lto, workaround: Don't warn for initcall_reference in modpost" modpost: use more reliable way to get fromsec in section_rel(a)() modpost: add array range check to sec_name() modpost: refactor get_secindex() kbuild: set EXIT trap before creating temporary directory modpost: remove unused Elf_Sword macro Makefile.extrawarn: re-enable -Wformat for clang kbuild: add dtbs_prepare target kconfig: Qt5: tell the user which packages are required modpost: use sym_get_data() to get module device_table data modpost: drop executable ELF support checkstack: add riscv support for scripts/checkstack.pl kconfig: shorten the temporary directory name for cc-option scripts: headers_install.sh: Update config leak ignore entries kbuild: error out if $(INSTALL_MOD_PATH) contains % or : kbuild: error out if $(KBUILD_EXTMOD) contains % or : ... 2022-08-08T21:12:19+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-08-08T21:12:19+00:00 urn:sha1:e74acdf55da6649dd30be5b621a93b71cbe7f3f9 Pull module updates from Luis Chamberlain: "For the 6.0 merge window the modules code shifts to cleanup and minor fixes effort. This becomes much easier to do and review now due to the code split to its own directory from effort on the last kernel release. I expect to see more of this with time and as we expand on test coverage in the future. The cleanups and fixes come from usual suspects such as Christophe Leroy and Aaron Tomlin but there are also some other contributors. One particular minor fix worth mentioning is from Helge Deller, where he spotted a *forever* incorrect natural alignment on both ELF section header tables: * .altinstructions * __bug_table sections A lot of back and forth went on in trying to determine the ill effects of this misalignment being present for years and it has been determined there should be no real ill effects unless you have a buggy exception handler. Helge actually hit one of these buggy exception handlers on parisc which is how he ended up spotting this issue. When implemented correctly these paths with incorrect misalignment would just mean a performance penalty, but given that we are dealing with alternatives on modules and with the __bug_table (where info regardign BUG()/WARN() file/line information associated with it is stored) this really shouldn't be a big deal. The only other change with mentioning is the kmap() with kmap_local_page() and my only concern with that was on what is done after preemption, but the virtual addresses are restored after preemption. This is only used on module decompression. This all has sit on linux-next for a while except the kmap stuff which has been there for 3 weeks" * tag 'modules-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: module: Replace kmap() with kmap_local_page() module: Show the last unloaded module's taint flag(s) module: Use strscpy() for last_unloaded_module module: Modify module_flags() to accept show_state argument module: Move module's Kconfig items in kernel/module/ MAINTAINERS: Update file list for module maintainers module: Use vzalloc() instead of vmalloc()/memset(0) modules: Ensure natural alignment for .altinstructions and __bug_table sections module: Increase readability of module_kallsyms_lookup_name() module: Fix ERRORs reported by checkpatch.pl module: Add support for default value for module async_probe 2022-08-08T16:42:04+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-08-08T16:42:04+00:00 urn:sha1:cab9de71694de738323e30c2d1a1eb51a03f6265 Pull coccinelle semantic patch updates from Julia Lawall: - Update the semantic patches in the kernel that contain a URL for Coccinelle with a URL that is currently valid (from myself). - Add a semantic patch checking for unnecessary NULL tests on dev_{put, hold} functions (from Ziyang Xuan, followed bt a modification from myself). - Drop a semantic patch that replaces 0/1 by booleans, as this change was considered to be not worthwhile by some maintainers (from Steve Rostedt). - Extend an existing semantic patch with more checks for useless tests on variables addresses (from Jérémy Lefaure). * tag 'coccinelle-for-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/jlawall/linux: update Coccinelle URL coccinelle: free: add version constraint scripts/coccinelle/free: add NULL test before dev_{put, hold} functions coccinelle: Remove script that checks replacing 0/1 with false/true in functions returning bool coccinelle: Extend address test from ifaddr semantic patch to test expressions 2022-08-07T19:30:36+00:00 Julia Lawall Julia.Lawall@inria.fr 2022-08-07T16:19:54+00:00 urn:sha1:f01701cec8cbb94df209e9705b97abd01c151ba1 Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> 2022-08-07T19:30:24+00:00 Julia Lawall Julia.Lawall@inria.fr 2022-07-16T13:28:10+00:00 urn:sha1:18c06cf868bc4e37b9766a91be02453c38f89745 The various functions contain a NULL check starting in v5.15. Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>