user/sven/linux.git/arch/tile/kernel/process.c, branch v4.9.139

arch/tile: adopt the new nmi_backtrace framework

2016-10-08T01:46:30Z

Previously tile was rolling its own method of capturing backtrace data in the NMI handlers, but it was relying on running printk() from the NMI handler, which is not always safe. So adopt the nmi_backtrace model (with the new cpumask extension) instead. So we can call the nmi_backtrace code directly from the nmi handler, move the nmi_enter()/exit() into the top-level tile NMI handler. The semantics of the routine change slightly since it is now synchronous with the remote cores completing the backtraces. Previously it was asynchronous, but with protection to avoid starting a new remote backtrace if the old one was still in progress. Link: http://lkml.kernel.org/r/1472487169-14923-4-git-send-email-cmetcalf@mellanox.com Signed-off-by: Chris Metcalf Cc: Daniel Thompson [arm] Cc: Petr Mladek Cc: Aaron Tomlin Cc: Peter Zijlstra (Intel) Cc: "Rafael J. Wysocki" Cc: Russell King Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Clarify naming of thread info/stack allocators

2016-06-24T22:09:37Z

We've had the thread info allocated together with the thread stack for most architectures for a long time (since the thread_info was split off from the task struct), but that is about to change. But the patches that move the thread info to be off-stack (and a part of the task struct instead) made it clear how confused the allocator and freeing functions are. Because the common case was that we share an allocation with the thread stack and the thread_info, the two pointers were identical. That identity then meant that we would have things like ti = alloc_thread_info_node(tsk, node); ... tsk->stack = ti; which certainly _worked_ (since stack and thread_info have the same value), but is rather confusing: why are we assigning a thread_info to the stack? And if we move the thread_info away, the "confusing" code just gets to be entirely bogus. So remove all this confusion, and make it clear that we are doing the stack allocation by renaming and clarifying the function names to be about the stack. The fact that the thread_info then shares the allocation is an implementation detail, and not really about the allocation itself. This is a pure renaming and type fix: we pass in the same pointer, it's just that we clarify what the pointer means. The ia64 code that actually only has one single allocation (for all of task_struct, thread_info and kernel thread stack) now looks a bit odd, but since "tsk->stack" is actually not even used there, that oddity doesn't matter. It would be a separate thing to clean that up, I intentionally left the ia64 changes as a pure brute-force renaming and type change. Acked-by: Andy Lutomirski Signed-off-by: Linus Torvalds

exit_thread: accept a task parameter to be exited

2016-05-21T00:58:30Z

We need to call exit_thread from copy_process in a fail path. So make it accept task_struct as a parameter. [v2] * s390: exit_thread_runtime_instr doesn't make sense to be called for non-current tasks. * arm: fix the comment in vfp_thread_copy * change 'me' to 'tsk' for task_struct * now we can change only archs that actually have exit_thread [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jiri Slaby Cc: "David S. Miller" Cc: "H. Peter Anvin" Cc: "James E.J. Bottomley" Cc: Aurelien Jacquiot Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Chen Liqin Cc: Chris Metcalf Cc: Chris Zankel Cc: David Howells Cc: Fenghua Yu Cc: Geert Uytterhoeven Cc: Guan Xuetao Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: James Hogan Cc: Jeff Dike Cc: Jesper Nilsson Cc: Jiri Slaby Cc: Jonas Bonn Cc: Koichi Yasutake Cc: Lennox Wu Cc: Ley Foon Tan Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Mikael Starvik Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Rich Felker Cc: Richard Henderson Cc: Richard Kuo Cc: Richard Weinberger Cc: Russell King Cc: Steven Miao Cc: Thomas Gleixner Cc: Tony Luck Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arch/tile: adopt prepare_exit_to_usermode() model from x86

2016-01-18T19:49:09Z

This change is a prerequisite change for TASK_ISOLATION but also stands on its own for readability and maintainability. The existing tile do_work_pending() was called in a loop from assembly on the slow path; this change moves the loop into C code as well. For the x86 version see commit c5c46f59e4e7 ("x86/entry: Add new, comprehensible entry and exit handlers written in C"). This change exposes a pre-existing bug on the older tilepro platform; the singlestep processing is done last, but on tilepro (unlike tilegx) we enable interrupts while doing that processing, so we could in theory miss a signal or other asynchronous event. A future change could fix this by breaking the singlestep work into a "prepare" step done in the main loop, and a "trigger" step done after exiting the loop. Since this change is intended as purely a restructuring change, we call out the bug explicitly now, but don't yet fix it. Signed-off-by: Chris Metcalf

tile: Reorganize _switch_to()

2015-08-08T08:29:21Z

Move the simulator bits into finish_arch_post_lock_switch() and properly call __switch_to() from _switch_to(). Signed-off-by: Chris Metcalf Cc: Cc: Linus Torvalds Cc: Peter Zijlstra (Intel) Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1438783412-10990-1-git-send-email-cmetcalf@ezchip.com [ Made it a delta to: fe363adb9225 ("sched, tile: Remove finish_arch_switch"). ] Signed-off-by: Ingo Molnar

sched, tile: Remove finish_arch_switch

2015-08-04T07:38:18Z

Move the simulator bits into switch_to() and use finish_arch_post_lock_switch() for the homecache migration bits. Signed-off-by: Chris Metcalf Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

tile: improve stack backtrace

2015-05-11T15:22:40Z

This commit fixes a number of issues with the tile backtrace code. - Don't try to identify userspace shared object or executable paths if we are doing a backtrace from an interrupt; it's not legal, and also unlikely to be interesting. Likewise, don't try to do it for other address spaces, since d_path() assumes it is being called in "current" context. - Move "in_backtrace" from thread_struct to thread_info. This way we can access it even if our stack thread_info has been clobbered, which makes backtracing more robust. - Avoid using "current" directly when testing for is_sigreturn(). Since "current" may be corrupt, we're better off using kbt->task explicitly to look up the vdso_base for the current task. Conveniently, this simplifies the internal APIs (we only need one is_sigreturn() function now). - Avoid bogus "Odd fault" warning when pc/sp/ex1 are all zero, as is true for kernel threads above the last frame. - Hook into Tejun Heo's dump_stack() framework in lib/dump_stack.c. - Write last entry in save_stack_trace() as ULONG_MAX, not zero, since ftrace (at least) relies on finding that marker. - Implement save_stack_trace_regs() and save_strack_trace_user(), and set CONFIG_USER_STACKTRACE_SUPPORT. Signed-off-by: Chris Metcalf

tile: fix "odd fault" warning for stack backtraces

2015-05-11T15:22:37Z

We were setting ex1 in new kernel threads to KERNEL_PL. But since we just do a simple context-switch, not an iret, any value set here is ignored anyway, and its presence causes stack backtraces to end with a warning about an "odd fault". Signed-off-by: Chris Metcalf

tile: support delivering NMIs for multicore backtrace

2015-05-11T15:22:31Z

A new hypervisor service was added some time ago (MDE 4.2.1 or later, or MDE 4.3 or later) that allows cores to request NMIs to be delivered to other cores. Use this facility to deliver a request that causes a backtrace to be generated on each core, and hook it into the magic SysRq functionality. Signed-off-by: Chris Metcalf

tile: support CONTEXT_TRACKING and thus NOHZ_FULL

2015-04-17T18:01:10Z

Add the TIF_NOHZ flag appropriately. Add call to user_exit() on entry to do_work_pending() and on entry to syscalls via do_syscall_trace_enter(), and also the top of do_syscall_trace_exit() just because it's done in x86. Add call to user_enter() at the bottom of do_work_pending() once we have no more work to do before returning to userspace. Wrap all the trap code in exception_enter() / exception_exit(). Signed-off-by: Chris Metcalf Acked-by: Frederic Weisbecker