linux.git/arch, branch bh1745

arm64: dts: rpi3, rpi4: Add BH1745 device tree node

2023-03-08T21:35:36+00:00

This way the bh1745.ko driver will be loaded. Signed-off-by: Andi Shyti Co-developed-by: Corentin Teissier Signed-off-by: Corentin Teissier

x86/resctl: fix scheduler confusion with 'current'

2023-03-08T19:48:11+00:00

The implementation of 'current' on x86 is very intentionally special: it is a very common thing to look up, and it uses 'this_cpu_read_stable()' to get the current thread pointer efficiently from per-cpu storage. And the keyword in there is 'stable': the current thread pointer never changes as far as a single thread is concerned. Even if when a thread is preempted, or moved to another CPU, or even across an explicit call 'schedule()' that thread will still have the same value for 'current'. It is, after all, the kernel base pointer to thread-local storage. That's why it's stable to begin with, but it's also why it's important enough that we have that special 'this_cpu_read_stable()' access for it. So this is all done very intentionally to allow the compiler to treat 'current' as a value that never visibly changes, so that the compiler can do CSE and combine multiple different 'current' accesses into one. However, there is obviously one very special situation when the currently running thread does actually change: inside the scheduler itself. So the scheduler code paths are special, and do not have a 'current' thread at all. Instead there are _two_ threads: the previous and the next thread - typically called 'prev' and 'next' (or prev_p/next_p) internally. So this is all actually quite straightforward and simple, and not all that complicated. Except for when you then have special code that is run in scheduler context, that code then has to be aware that 'current' isn't really a valid thing. Did you mean 'prev'? Did you mean 'next'? In fact, even if then look at the code, and you use 'current' after the new value has been assigned to the percpu variable, we have explicitly told the compiler that 'current' is magical and always stable. So the compiler is quite free to use an older (or newer) value of 'current', and the actual assignment to the percpu storage is not relevant even if it might look that way. Which is exactly what happened in the resctl code, that blithely used 'current' in '__resctrl_sched_in()' when it really wanted the new process state (as implied by the name: we're scheduling 'into' that new resctl state). And clang would end up just using the old thread pointer value at least in some configurations. This could have happened with gcc too, and purely depends on random compiler details. Clang just seems to have been more aggressive about moving the read of the per-cpu current_task pointer around. The fix is trivial: just make the resctl code adhere to the scheduler rules of using the prev/next thread pointer explicitly, instead of using 'current' in a situation where it just wasn't valid. That same code is then also used outside of the scheduler context (when a thread resctl state is explicitly changed), and then we will just pass in 'current' as that pointer, of course. There is no ambiguity in that case. The fix may be trivial, but noticing and figuring out what went wrong was not. The credit for that goes to Stephane Eranian. Reported-by: Stephane Eranian Link: https://lore.kernel.org/lkml/20230303231133.1486085-1-eranian@google.com/ Link: https://lore.kernel.org/lkml/alpine.LFD.2.01.0908011214330.3304@localhost.localdomain/ Reviewed-by: Nick Desaulniers Tested-by: Tony Luck Tested-by: Stephane Eranian Tested-by: Babu Moger Cc: stable@kernel.org Signed-off-by: Linus Torvalds

cpumask: fix incorrect cpumask scanning result checks

2023-03-06T20:15:13+00:00

It turns out that commit 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask optimizations") exposed a number of cases of drivers not checking the result of "cpumask_next()" and friends correctly. The documented correct check for "no more cpus in the cpumask" is to check for the result being equal or larger than the number of possible CPU ids, exactly _because_ we've always done those constant-sized cpumask scans using a widened type before. So the return value of a cpumask scan should be checked with if (cpu >= nr_cpu_ids) ... because the cpumask scan did not necessarily stop exactly *at* that maximum CPU id. But a few cases ended up instead using checks like if (cpu == nr_cpumask_bits) ... which used that internal "widened" number of bits. And that used to work pretty much by accident (ok, in this case "by accident" is simply because it matched the historical internal implementation of the cpumask scanning, so it was more of a "intentionally using implementation details rather than an accident"). But the extended constant-sized optimizations then did that internal implementation differently, and now that code that did things wrong but matched the old implementation no longer worked at all. Which then causes subsequent odd problems due to using what ends up being an invalid CPU ID. Most of these cases require either unusual hardware or special uses to hit, but the random.c one triggers quite easily. All you really need is to have a sufficiently small CONFIG_NR_CPUS value for the bit scanning optimization to be triggered, but not enough CPUs to then actually fill that widened cpumask. At that point, the cpumask scanning will return the NR_CPUS constant, which is _not_ the same as nr_cpumask_bits. This just does the mindless fix with sed -i 's/== nr_cpumask_bits/>= nr_cpu_ids/' to fix the incorrect uses. The ones in the SCSI lpfc driver in particular could probably be fixed more cleanly by just removing that repeated pattern entirely, but I am not emptionally invested enough in that driver to care. Reported-and-tested-by: Guenter Roeck Link: https://lore.kernel.org/lkml/481b19b5-83a0-4793-b4fd-194ad7b978c3@roeck-us.net/ Reported-and-tested-by: Geert Uytterhoeven Link: https://lore.kernel.org/lkml/CAMuHMdUKo_Sf7TjKzcNDa8Ve+6QrK+P8nSQrSQ=6LTRmcBKNww@mail.gmail.com/ Reported-by: Vernon Yang Link: https://lore.kernel.org/lkml/20230306160651.2016767-1-vernon2gm@gmail.com/ Cc: Yury Norov Cc: Jason A. Donenfeld Signed-off-by: Linus Torvalds

cpumask: re-introduce constant-sized cpumask optimizations

2023-03-05T22:30:34+00:00

Commit aa47a7c215e7 ("lib/cpumask: deprecate nr_cpumask_bits") resulted in the cpumask operations potentially becoming hugely less efficient, because suddenly the cpumask was always considered to be variable-sized. The optimization was then later added back in a limited form by commit 6f9c07be9d02 ("lib/cpumask: add FORCE_NR_CPUS config option"), but that FORCE_NR_CPUS option is not useful in a generic kernel and more of a special case for embedded situations with fixed hardware. Instead, just re-introduce the optimization, with some changes. Instead of depending on CPUMASK_OFFSTACK being false, and then always using the full constant cpumask width, this introduces three different cpumask "sizes": - the exact size (nr_cpumask_bits) remains identical to nr_cpu_ids. This is used for situations where we should use the exact size. - the "small" size (small_cpumask_bits) is the NR_CPUS constant if it fits in a single word and the bitmap operations thus end up able to trigger the "small_const_nbits()" optimizations. This is used for the operations that have optimized single-word cases that get inlined, notably the bit find and scanning functions. - the "large" size (large_cpumask_bits) is the NR_CPUS constant if it is an sufficiently small constant that makes simple "copy" and "clear" operations more efficient. This is arbitrarily set at four words or less. As a an example of this situation, without this fixed size optimization, cpumask_clear() will generate code like movl nr_cpu_ids(%rip), %edx addq $63, %rdx shrq $3, %rdx andl $-8, %edx callq memset@PLT on x86-64, because it would calculate the "exact" number of longwords that need to be cleared. In contrast, with this patch, using a MAX_CPU of 64 (which is quite a reasonable value to use), the above becomes a single movq $0,cpumask instruction instead, because instead of caring to figure out exactly how many CPU's the system has, it just knows that the cpumask will be a single word and can just clear it all. Note that this does end up tightening the rules a bit from the original version in another way: operations that set bits in the cpumask are now limited to the actual nr_cpu_ids limit, whereas we used to do the nr_cpumask_bits thing almost everywhere in the cpumask code. But if you just clear bits, or scan for bits, we can use the simpler compile-time constants. In the process, remove 'cpumask_complement()' and 'for_each_cpu_not()' which were not useful, and which fundamentally have to be limited to 'nr_cpu_ids'. Better remove them now than have somebody introduce use of them later. Of course, on x86-64 with MAXSMP there is no sane small compile-time constant for the cpumask sizes, and we end up using the actual CPU bits, and will generate the above kind of horrors regardless. Please don't use MAXSMP unless you really expect to have machines with thousands of cores. Signed-off-by: Linus Torvalds

Merge tag 'x86-urgent-2023-03-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-03-05T19:27:48+00:00

Pull x86 updates from Thomas Gleixner: "A small set of updates for x86: - Return -EIO instead of success when the certificate buffer for SEV guests is not large enough - Allow STIPB to be enabled with legacy IBSR. Legacy IBRS is cleared on return to userspace for performance reasons, but the leaves user space vulnerable to cross-thread attacks which STIBP prevents. Update the documentation accordingly" * tag 'x86-urgent-2023-03-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: virt/sev-guest: Return -EIO if certificate buffer is not large enough Documentation/hw-vuln: Document the interaction between IBRS and STIBP x86/speculation: Allow enabling STIBP with legacy IBRS

Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2023-03-05T19:07:58+00:00

Pull VM_FAULT_RETRY fixes from Al Viro: "Some of the page fault handlers do not deal with the following case correctly: - handle_mm_fault() has returned VM_FAULT_RETRY - there is a pending fatal signal - fault had happened in kernel mode Correct action in such case is not "return unconditionally" - fatal signals are handled only upon return to userland and something like copy_to_user() would end up retrying the faulting instruction and triggering the same fault again and again. What we need to do in such case is to make the caller to treat that as failed uaccess attempt - handle exception if there is an exception handler for faulting instruction or oops if there isn't one. Over the years some architectures had been fixed and now are handling that case properly; some still do not. This series should fix the remaining ones. Status: - m68k, riscv, hexagon, parisc: tested/acked by maintainers. - alpha, sparc32, sparc64: tested locally - bug has been reproduced on the unpatched kernel and verified to be fixed by this series. - ia64, microblaze, nios2, openrisc: build, but otherwise completely untested" * tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: openrisc: fix livelock in uaccess nios2: fix livelock in uaccess microblaze: fix livelock in uaccess ia64: fix livelock in uaccess sparc: fix livelock in uaccess alpha: fix livelock in uaccess parisc: fix livelock in uaccess hexagon: fix livelock in uaccess riscv: fix livelock in uaccess m68k: fix livelock in uaccess

Remove Intel compiler support

2023-03-05T18:49:37+00:00

include/linux/compiler-intel.h had no update in the past 3 years. We often forget about the third C compiler to build the kernel. For example, commit a0a12c3ed057 ("asm goto: eradicate CC_HAS_ASM_GOTO") only mentioned GCC and Clang. init/Kconfig defines CC_IS_GCC and CC_IS_CLANG but not CC_IS_ICC, and nobody has reported any issue. I guess the Intel Compiler support is broken, and nobody is caring about it. Harald Arnesen pointed out ICC (classic Intel C/C++ compiler) is deprecated: $ icc -v icc: remark #10441: The Intel(R) C++ Compiler Classic (ICC) is deprecated and will be removed from product release in the second half of 2023. The Intel(R) oneAPI DPC++/C++ Compiler (ICX) is the recommended compiler moving forward. Please transition to use this compiler. Use '-diag-disable=10441' to disable this message. icc version 2021.7.0 (gcc version 12.1.0 compatibility) Arnd Bergmann provided a link to the article, "Intel C/C++ compilers complete adoption of LLVM". lib/zstd/common/compiler.h and lib/zstd/compress/zstd_fast.c were kept untouched for better sync with https://github.com/facebook/zstd Link: https://www.intel.com/content/www/us/en/developer/articles/technical/adoption-of-llvm-complete-icx.html Signed-off-by: Masahiro Yamada Acked-by: Arnd Bergmann Reviewed-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Reviewed-by: Miguel Ojeda Signed-off-by: Linus Torvalds

Merge tag 'mm-hotfixes-stable-2023-03-04-13-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-03-04T21:32:50+00:00

Pull misc fixes from Andrew Morton: "17 hotfixes. Eight are for MM and seven are for other parts of the kernel. Seven are cc:stable and eight address post-6.3 issues or were judged unsuitable for -stable backporting" * tag 'mm-hotfixes-stable-2023-03-04-13-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mailmap: map Dikshita Agarwal's old address to his current one mailmap: map Vikash Garodia's old address to his current one fs/cramfs/inode.c: initialize file_ra_state fs: hfsplus: fix UAF issue in hfsplus_put_super panic: fix the panic_print NMI backtrace setting lib: parser: update documentation for match_NUMBER functions kasan, x86: don't rename memintrinsics in uninstrumented files kasan: test: fix test for new meminstrinsic instrumentation kasan: treat meminstrinsic as builtins in uninstrumented files kasan: emit different calls for instrumentable memintrinsics ocfs2: fix non-auto defrag path not working issue ocfs2: fix defrag path triggering jbd2 ASSERT mailmap: map Georgi Djakov's old Linaro address to his current one mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON lib/zlib: DFLTCC deflate does not write all available bits for Z_NO_FLUSH mm/damon/paddr: fix missing folio_put() mm/mremap: fix dup_anon_vma() in vma_merge() case 4

Merge tag 'powerpc-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2023-03-04T19:20:42+00:00

Pull powerpc fixes from Michael Ellerman: - Drop orphaned VAS MAINTAINERS entry - Fix build errors with clang and KCSAN - Avoid build errors seen with LD_DEAD_CODE_DATA_ELIMINATION together with recordmcount Thanks to Nathan Chancellor. * tag 'powerpc-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc: Avoid dead code/data elimination when using recordmcount powerpc/vmlinux.lds: Add .text.asan/tsan sections powerpc: Drop orphaned VAS MAINTAINERS entry

Merge tag 's390-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2023-03-03T17:38:01+00:00

Pull more s390 updates from Heiko Carstens: - Add empty command line parameter handling stubs to kernel for all command line parameters which are handled in the decompressor. This avoids invalid "Unknown kernel command line parameters" messages from the kernel, and also avoids that these will be incorrectly passed to user space. This caused already confusion, therefore add the empty stubs - Add missing phys_to_virt() handling to machine check handler - Introduce and use a union to be used for zcrypt inline assemblies. This makes sure that only a register wide member of the union is passed as input and output parameter to inline assemblies, while usual C code uses other members of the union to access bit fields of it - Add and use a READ_ONCE_ALIGNED_128() macro, which can be used to atomically read a 128-bit value from memory. This replaces the (mis-)use of the 128-bit cmpxchg operation to do the same in cpum_sf code. Currently gcc does not generate the used lpq instruction if __READ_ONCE() is used for aligned 128-bit accesses, therefore use this s390 specific helper - Simplify machine check handler code if a task needs to be killed because of e.g. register corruption due to a machine malfunction - Perform CPU reset to clear pending interrupts and TLB entries on an already stopped target CPU before delegating work to it - Generate arch/s390/boot/vmlinux.map link map for the decompressor, when CONFIG_VMLINUX_MAP is enabled for debugging purposes - Fix segment type handling for dcssblk devices. It incorrectly always returned type "READ/WRITE" even for read-only segements, which can result in a kernel panic if somebody tries to write to a read-only device - Sort config S390 select list again - Fix two kprobe reenter bugs revealed by a recently added kprobe kunit test * tag 's390-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/kprobes: fix current_kprobe never cleared after kprobes reenter s390/kprobes: fix irq mask clobbering on kprobe reenter from post_handler s390/Kconfig: sort config S390 select list again s390/extmem: return correct segment type in __segment_load() s390/decompressor: add link map saving s390/smp: perform cpu reset before delegating work to target cpu s390/mcck: cleanup user process termination path s390/cpum_sf: use READ_ONCE_ALIGNED_128() instead of 128-bit cmpxchg s390/rwonce: add READ_ONCE_ALIGNED_128() macro s390/ap,zcrypt,vfio: introduce and use ap_queue_status_reg union s390/nmi: fix virtual-physical address confusion s390/setup: do not complain about parameters handled in decompressor