kernel/arch/xtensa/include/asm/futex.h, branch linux-rolling-stable

futex: Fix additional regressions

2021-12-11T22:31:51Z

Naresh reported another architecture that was broken by the same typo that was already fixed for three architectures: mips also refers to the futex_atomic_op_inuser_local() function by the wrong name and runs into a missing closing '}' as well. Going through the source tree the same typo was found in the documentation as well as in the xtensa code, both of which ended up escaping the regression testing so far. In the case of xtensa, it appears that the broken code path is only used when building for platforms that are not supported by the default gcc configuration, so they are impossible to test for with default setups. After going through these more carefully and fixing up the typos, all architectures have been build-tested again to ensure that this is now complete. Fixes: 4e0d84634445 ("futex: Fix sparc32/m68k/nds32 build regression") Fixes: 3f2bedabb62c ("futex: Ensure futex_atomic_cmpxchg_inatomic() is present") Reported-by: Linux Kernel Functional Testing Reported-by: Naresh Kamboju Signed-off-by: Arnd Bergmann Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20211203080823.2938839-1-arnd@kernel.org

futex: Ensure futex_atomic_cmpxchg_inatomic() is present

2021-11-24T23:02:28Z

The boot-time detection of futex_atomic_cmpxchg_inatomic() has a bug on some 32-bit arm builds, and Thomas Gleixner suggested that setting CONFIG_HAVE_FUTEX_CMPXCHG would avoid the problem, as it is always present anyway. Looking into which other architectures could do the same showed that almost all architectures have it, the exceptions being: - some old 32-bit MIPS uniprocessor cores without ll/sc - one xtensa variant with no SMP - 32-bit SPARC when built for SMP Fix MIPS And Xtensa by rearranging the generic code to let it be used as a fallback. For SPARC, the SMP definition just ends up turning off futex anyway, so this can be done at Kconfig time instead. Note that sparc32 glibc requires the CASA instruction for its mutexes anyway, which is only available when running on SPARCv9 or LEON CPUs, but needs to be implemented in the sparc32 kernel for those. Signed-off-by: Arnd Bergmann Signed-off-by: Thomas Gleixner Acked-by: Max Filippov Acked-by: Geert Uytterhoeven Acked-by: Rich Felker Link: https://lore.kernel.org/r/20211026100432.1730393-1-arnd@kernel.org

futex: arch_futex_atomic_op_inuser() calling conventions change

2020-03-28T03:58:51Z

Move access_ok() in and pagefault_enable()/pagefault_disable() out. Mechanical conversion only - some instances don't really need a separate access_ok() at all (e.g. the ones only using get_user()/put_user(), or architectures where access_ok() is always true); we'll deal with that in followups. Signed-off-by: Al Viro

xtensa: use "m" constraint instead of "r" in futex.h assembly

2019-11-26T19:33:39Z

Use "m" constraint instead of "r" for the address, as "m" allows compiler to access adjacent locations using base + offset, while "r" requires updating the base register every time. Signed-off-by: Max Filippov

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55Z

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

xtensa: add exclusive atomics support

2019-05-07T17:36:31Z

Implement atomic primitives using exclusive access opcodes available in the recent xtensa cores. Since l32ex/s32ex don't have any memory ordering guarantees don't define __smp_mb__before_atomic/__smp_mb__after_atomic to make them use memw. Signed-off-by: Max Filippov

xtensa: clean up inline assembly in futex.h

2019-05-07T17:30:39Z

Replace numeric inline assembly parameters with named parameters. Drop unused parameters from the futex_atomic_cmpxchg_inatomic. Use new temporary variable to hold target address in the fixup code in futex_atomic_cmpxchg_inatomic. Conditionalize function bodies so that only 'return -ENOSYS' is left in configurations without futex support. Signed-off-by: Max Filippov

xtensa: drop ifdef KERNEL from kernel-only headers

2019-05-07T00:48:54Z

These headers are not exported to userspace, so they're never used without __KERNEL__ defined. Drop these ifdef statements. Signed-off-by: Max Filippov

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57Z

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds

xtensa: don't use l32r opcode directly

2018-12-05T20:53:07Z

xtensa assembler is capable of representing register loads with either movi + addmi, l32r or const16, depending on the core configuration. Don't use '.literal' and 'l32r' directly in the code, use 'movi' and let the assembler relax them. Signed-off-by: Max Filippov