kernel/linux.git/arch/arc/Kconfig, branch linux-5.9.y

Merge tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

2020-08-04T21:47:45+00:00

Pull fork cleanups from Christian Brauner: "This is cleanup series from when we reworked a chunk of the process creation paths in the kernel and switched to struct {kernel_}clone_args. High-level this does two main things: - Remove the double export of both do_fork() and _do_fork() where do_fork() used the incosistent legacy clone calling convention. Now we only export _do_fork() which is based on struct kernel_clone_args. - Remove the copy_thread_tls()/copy_thread() split making the architecture specific HAVE_COYP_THREAD_TLS config option obsolete. This switches all remaining architectures to select HAVE_COPY_THREAD_TLS and thus to the copy_thread_tls() calling convention. The current split makes the process creation codepaths more convoluted than they need to be. Each architecture has their own copy_thread() function unless it selects HAVE_COPY_THREAD_TLS then it has a copy_thread_tls() function. The split is not needed anymore nowadays, all architectures support CLONE_SETTLS but quite a few of them never bothered to select HAVE_COPY_THREAD_TLS and instead simply continued to use copy_thread() and use the old calling convention. Removing this split cleans up the process creation codepaths and paves the way for implementing clone3() on such architectures since it requires the copy_thread_tls() calling convention. After having made each architectures support copy_thread_tls() this series simply renames that function back to copy_thread(). It also switches all architectures that call do_fork() directly over to _do_fork() and the struct kernel_clone_args calling convention. This is a corollary of switching the architectures that did not yet support it over to copy_thread_tls() since do_fork() is conditional on not supporting copy_thread_tls() (Mostly because it lacks a separate argument for tls which is trivial to fix but there's no need for this function to exist.). The do_fork() removal is in itself already useful as it allows to to remove the export of both do_fork() and _do_fork() we currently have in favor of only _do_fork(). This has already been discussed back when we added clone3(). The legacy clone() calling convention is - as is probably well-known - somewhat odd: # # ABI hall of shame # config CLONE_BACKWARDS config CLONE_BACKWARDS2 config CLONE_BACKWARDS3 that is aggravated by the fact that some architectures such as sparc follow the CLONE_BACKWARDSx calling convention but don't really select the corresponding config option since they call do_fork() directly. So do_fork() enforces a somewhat arbitrary calling convention in the first place that doesn't really help the individual architectures that deviate from it. They can thus simply be switched to _do_fork() enforcing a single calling convention. (I really hope that any new architectures will __not__ try to implement their own calling conventions...) Most architectures already have made a similar switch (m68k comes to mind). Overall this removes more code than it adds even with a good portion of added comments. It simplifies a chunk of arch specific assembly either by moving the code into C or by simply rewriting the assembly. Architectures that have been touched in non-trivial ways have all been actually boot and stress tested: sparc and ia64 have been tested with Debian 9 images. They are the two architectures which have been touched the most. All non-trivial changes to architectures have seen acks from the relevant maintainers. nios2 with a custom built buildroot image. h8300 I couldn't get something bootable to test on but the changes have been fairly automatic and I'm sure we'll hear people yell if I broke something there. All other architectures that have been touched in trivial ways have been compile tested for each single patch of the series via git rebase -x "make ..." v5.8-rc2. arm{64} and x86{_64} have been boot tested even though they have just been trivially touched (removal of the HAVE_COPY_THREAD_TLS macro from their Kconfig) because well they are basically "core architectures" and since it is trivial to get your hands on a useable image" * tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: arch: rename copy_thread_tls() back to copy_thread() arch: remove HAVE_COPY_THREAD_TLS unicore: switch to copy_thread_tls() sh: switch to copy_thread_tls() nds32: switch to copy_thread_tls() microblaze: switch to copy_thread_tls() hexagon: switch to copy_thread_tls() c6x: switch to copy_thread_tls() alpha: switch to copy_thread_tls() fork: remove do_fork() h8300: select HAVE_COPY_THREAD_TLS, switch to kernel_clone_args nios2: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args ia64: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args sparc: unconditionally enable HAVE_COPY_THREAD_TLS sparc: share process creation helpers between sparc and sparc64 sparc64: enable HAVE_COPY_THREAD_TLS fork: fold legacy_clone_args_valid() into _do_fork()

arch: remove HAVE_COPY_THREAD_TLS

2020-07-04T21:41:37+00:00

All architectures support copy_thread_tls() now, so remove the legacy copy_thread() function and the HAVE_COPY_THREAD_TLS config option. Everyone uses the same process creation calling convention based on copy_thread_tls() and struct kernel_clone_args. This will make it easier to maintain the core process creation code under kernel/, simplifies the callpaths and makes the identical for all architectures. Cc: linux-arch@vger.kernel.org Acked-by: Thomas Bogendoerfer Acked-by: Greentime Hu Acked-by: Geert Uytterhoeven Reviewed-by: Kees Cook Signed-off-by: Christian Brauner

ARCv2: support loop buffer (LPB) disabling

2020-06-18T20:07:24+00:00

On HS cores, loop buffer (LPB) is programmable in runtime and can be optionally disabled. Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta

ARC: build: allow users to specify -mcpu

2020-06-16T22:07:23+00:00

kernel build system used to add -mcpu for each ARC ISA as default. These days there are versions and varaints of ARC HS cores some of which have specific -mcpu options to fine tune / optimize generated code. So allow users/external build systems to specify their own -mcpu This will be used in future patches for HSDK-4xD board support which uses specific -mcpu to utilize dual issue scheduling of the core. Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta [abrodkin/vgupta: rewrote changelog]

treewide: replace '---help---' in Kconfig files with 'help'

2020-06-13T16:57:21+00:00

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over '---help---'"), the number of '---help---' has been gradually decreasing, but there are still more than 2400 instances. This commit finishes the conversion. While I touched the lines, I also fixed the indentation. There are a variety of indentation styles found. a) 4 spaces + '---help---' b) 7 spaces + '---help---' c) 8 spaces + '---help---' d) 1 space + 1 tab + '---help---' e) 1 tab + '---help---' (correct indentation) f) 1 tab + 1 space + '---help---' g) 1 tab + 2 spaces + '---help---' In order to convert all of them to 1 tab + 'help', I ran the following commend: $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/' Signed-off-by: Masahiro Yamada

mm/debug: add tests validating architecture page table helpers

2020-06-05T02:06:21+00:00

This adds tests which will validate architecture page table helpers and other accessors in their compliance with expected generic MM semantics. This will help various architectures in validating changes to existing page table helpers or addition of new ones. This test covers basic page table entry transformations including but not limited to old, young, dirty, clean, write, write protect etc at various level along with populating intermediate entries with next page table page and validating them. Test page table pages are allocated from system memory with required size and alignments. The mapped pfns at page table levels are derived from a real pfn representing a valid kernel text symbol. This test gets called via late_initcall(). This test gets built and run when CONFIG_DEBUG_VM_PGTABLE is selected. Any architecture, which is willing to subscribe this test will need to select ARCH_HAS_DEBUG_VM_PGTABLE. For now this is limited to arc, arm64, x86, s390 and powerpc platforms where the test is known to build and run successfully Going forward, other architectures too can subscribe the test after fixing any build or runtime problems with their page table helpers. Folks interested in making sure that a given platform's page table helpers conform to expected generic MM semantics should enable the above config which will just trigger this test during boot. Any non conformity here will be reported as an warning which would need to be fixed. This test will help catch any changes to the agreed upon semantics expected from generic MM and enable platforms to accommodate it thereafter. [anshuman.khandual@arm.com: v17] Link: http://lkml.kernel.org/r/1587436495-22033-3-git-send-email-anshuman.khandual@arm.com [anshuman.khandual@arm.com: v18] Link: http://lkml.kernel.org/r/1588564865-31160-3-git-send-email-anshuman.khandual@arm.com Suggested-by: Catalin Marinas Signed-off-by: Anshuman Khandual Signed-off-by: Christophe Leroy Signed-off-by: Qian Cai Signed-off-by: Andrew Morton Tested-by: Gerald Schaefer [s390] Tested-by: Christophe Leroy [ppc32] Reviewed-by: Ingo Molnar Cc: Mike Rapoport Cc: Vineet Gupta Cc: Catalin Marinas Cc: Will Deacon Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Kirill A. Shutemov Cc: Paul Walmsley Cc: Palmer Dabbelt Link: http://lkml.kernel.org/r/1583919272-24178-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds

ARC: allow userspace DSP applications to use AGU extensions

2020-03-16T17:30:49+00:00

To be able to run DSP-enabled userspace applications with AGU (address generation unit) extensions we additionally need to save and restore following registers at context switch: * AGU_AP* * AGU_OS* * AGU_MOD* Reviewed-by: Vineet Gupta Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta

ARC: add support for DSP-enabled userspace applications

2020-03-16T17:30:49+00:00

To be able to run DSP-enabled userspace applications we need to save and restore following DSP-related registers: At IRQ/exception entry/exit: * DSP_CTRL (save it and reset to value suitable for kernel) * ACC0_LO, ACC0_HI (we already save them as r58, r59 pair) At context switch: * ACC0_GLO, ACC0_GHI * DSP_BFLY0, DSP_FFT_CTRL Reviewed-by: Vineet Gupta Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta

ARC: handle DSP presence in HW

2020-03-16T17:23:44+00:00

When DSP extensions are present, some of the regular integer instructions such as DIV, MACD etc are executed in the DSP unit with semantics alterable by flags in DSP_CTRL aux register. This register is writable by userspace and thus can potentially affect corresponding instructions in kernel code, intentionally or otherwise. So safegaurd kernel by effectively disabling DSP_CTRL upon bootup and every entry to kernel. Do note that for this config we simply zero out the DSP_CTRL reg assuming userspace doesn't really care about DSP. The next patch caters to the DSP aware userspace where this reg is saved/restored upon kernel entry/exit. Reviewed-by: Vineet Gupta Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta

ARC: fix some Kconfig typos

2020-02-10T06:17:22+00:00

Fix language typos in arch/arc/Kconfig. Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Randy Dunlap Signed-off-by: Vineet Gupta