kernel/linux.git/arch/h8300, branch linux-5.9.y

sched/idle: Fix arch_cpu_idle() vs tracing

2020-12-16T09:58:32+00:00

[ Upstream commit 58c644ba512cfbc2e39b758dd979edd1d6d00e27 ] We call arch_cpu_idle() with RCU disabled, but then use local_irq_{en,dis}able(), which invokes tracing, which relies on RCU. Switch all arch_cpu_idle() implementations to use raw_local_irq_{en,dis}able() and carefully manage the lockdep,rcu,tracing state like we do in entry. (XXX: we really should change arch_cpu_idle() to not return with interrupts enabled) Reported-by: Sven Schnelle Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Mark Rutland Tested-by: Mark Rutland Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org Signed-off-by: Sasha Levin

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

uaccess: remove segment_eq

2020-08-12T17:57:58+00:00

segment_eq is only used to implement uaccess_kernel. Just open code uaccess_kernel in the arch uaccess headers and remove one layer of indirection. Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Acked-by: Linus Torvalds Acked-by: Greentime Hu Acked-by: Geert Uytterhoeven Cc: Nick Hu Cc: Vincent Chen Cc: Paul Walmsley Cc: Palmer Dabbelt Link: http://lkml.kernel.org/r/20200710135706.537715-5-hch@lst.de Signed-off-by: Linus Torvalds

Merge branch 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2020-08-07T16:29:25+00:00

Pull ptrace regset updates from Al Viro: "Internal regset API changes: - regularize copy_regset_{to,from}_user() callers - switch to saner calling conventions for ->get() - kill user_regset_copyout() The ->put() side of things will have to wait for the next cycle, unfortunately. The balance is about -1KLoC and replacements for ->get() instances are a lot saner" * 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits) regset: kill user_regset_copyout{,_zero}() regset(): kill ->get_size() regset: kill ->get() csky: switch to ->regset_get() xtensa: switch to ->regset_get() parisc: switch to ->regset_get() nds32: switch to ->regset_get() nios2: switch to ->regset_get() hexagon: switch to ->regset_get() h8300: switch to ->regset_get() openrisc: switch to ->regset_get() riscv: switch to ->regset_get() c6x: switch to ->regset_get() ia64: switch to ->regset_get() arc: switch to ->regset_get() arm: switch to ->regset_get() sh: convert to ->regset_get() arm64: switch to ->regset_get() mips: switch to ->regset_get() sparc: switch to ->regset_get() ...

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()

locking/atomic: Move ATOMIC_INIT into linux/types.h

2020-07-29T14:14:18+00:00

This patch moves ATOMIC_INIT from asm/atomic.h into linux/types.h. This allows users of atomic_t to use ATOMIC_INIT without having to include atomic.h as that way may lead to header loops. Signed-off-by: Herbert Xu Signed-off-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Link: https://lkml.kernel.org/r/20200729123105.GB7047@gondor.apana.org.au

h8300: switch to ->regset_get()

2020-07-27T18:31:10+00:00

Signed-off-by: Al Viro

arch: rename copy_thread_tls() back to copy_thread()

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

Now that HAVE_COPY_THREAD_TLS has been removed, rename copy_thread_tls() back simply copy_thread(). It's a simpler name, and doesn't imply that only tls is copied here. This finishes an outstanding chunk of internal process creation work since we've added clone3(). Cc: linux-arch@vger.kernel.org Acked-by: Thomas Bogendoerfer A Acked-by: Stafford Horne Acked-by: Greentime Hu Acked-by: Geert Uytterhoeven A Reviewed-by: Kees Cook Signed-off-by: Christian Brauner

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

h8300: select HAVE_COPY_THREAD_TLS, switch to kernel_clone_args

2020-07-04T21:41:36+00:00

This is part of a larger series that aims at getting rid of the copy_thread()/copy_thread_tls() split that makes the process creation codepaths in the kernel more convoluted and error-prone than they need to be. I'm converting all the remaining arches that haven't yet switched and am collecting individual acks. Once I have them, I'll send the whole series removing the copy_thread()/copy_thread_tls() split, the HAVE_COPY_THREAD_TLS define and the legacy do_fork() helper. The only kernel-wide process creation entry point for anything not going directly through the syscall path will then be based on struct kernel_clone_args. No more danger of weird process creation abi quirks between architectures hopefully, and easier to maintain overall. It also unblocks implementing clone3() on architectures not support copy_thread_tls(). Any architecture that wants to implement clone3() will need to select HAVE_COPY_THREAD_TLS and thus need to implement copy_thread_tls(). So both goals are connected but independently beneficial. HAVE_COPY_THREAD_TLS means that a given architecture supports CLONE_SETTLS and not setting it should usually mean that the architectures doesn't implement it but that's not how things are. In fact all architectures support CLONE_TLS it's just that they don't follow the calling convention that HAVE_COPY_THREAD_TLS implies. That means all architectures can be switched over to select HAVE_COPY_THREAD_TLS. Once that is done we can remove that macro (yay, less code), the unnecessary do_fork() export in kernel/fork.c, and also rename copy_thread_tls() back to copy_thread(). At this point copy_thread() becomes the main architecture specific part of process creation but it will be the same layout and calling convention for all architectures. (Once that is done we can probably cleanup each copy_thread() function even more but that's for the future.) Though h8300 doesn't not suppor the CLONE_SETTLS flag there's no reason to not switch to the copy_thread_tls() calling convention. As before CLONE_SETTLS with legacy clone will just be ignored. This brings us one step closer to getting rid of the copy_thread()/copy_thread_tls() split we still have and ultimately the HAVE_COPY_THREAD_TLS define in general. A lot of architectures have already converted and h8300 is one of the few hat haven't yet. This also unblocks implementing the clone3() syscall on h8300. Once that is done we can get of another ARCH_WANTS_* macro. Once Any architecture that supports HAVE_COPY_THREAD_TLS cannot call the do_fork() helper anymore. This is fine and intended since it should be removed in favor of the new, cleaner _do_fork() calling convention based on struct kernel_clone_args. In fact, most architectures have already switched. With this patch, h8300 joins the other arches which can't use the fork(), vfork(), clone(), clone3() syscalls directly and who follow the new process creation calling convention that is based on struct kernel_clone_args which we introduced a while back. This means less custom assembly in the architectures entry path to set up the registers before calling into the process creation helper and it is easier to to support new features without having to adapt calling conventions. It also unifies all process creation paths between fork(), vfork(), clone(), and clone3(). (We can't fix the ABI nightmare that legacy clone() is but we can prevent stuff like this happening in the future.) For some more context, please see: commit 606e9ad20094f6d500166881d301f31a51bc8aa7 Merge: ac61145a725a 457677c70c76 Author: Linus Torvalds Date: Sat Jan 11 15:33:48 2020 -0800 Merge tag 'clone3-tls-v5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull thread fixes from Christian Brauner: "This contains a series of patches to fix CLONE_SETTLS when used with clone3(). The clone3() syscall passes the tls argument through struct clone_args instead of a register. This means, all architectures that do not implement copy_thread_tls() but still support CLONE_SETTLS via copy_thread() expecting the tls to be located in a register argument based on clone() are currently unfortunately broken. Their tls value will be garbage. The patch series fixes this on all architectures that currently define __ARCH_WANT_SYS_CLONE3. It also adds a compile-time check to ensure that any architecture that enables clone3() in the future is forced to also implement copy_thread_tls(). My ultimate goal is to get rid of the copy_thread()/copy_thread_tls() split and just have copy_thread_tls() at some point in the not too distant future (Maybe even renaming copy_thread_tls() back to simply copy_thread() once the old function is ripped from all arches). This is dependent now on all arches supporting clone3(). While all relevant arches do that now there are still four missing: ia64, m68k, sh and sparc. They have the system call reserved, but not implemented. Once they all implement clone3() we can get rid of ARCH_WANT_SYS_CLONE3 and HAVE_COPY_THREAD_TLS. Note that in the meantime, m68k has already switched to the new calling convention. And I've got sparc patches acked by Dave, patches for ia64, and nios2 have been sent out and are ready too. Cc: Yoshinori Sato Cc: uclinux-h8-devel@lists.sourceforge.jp Signed-off-by: Christian Brauner