linux/arch/tile/kernel/traps.c, branch v4.9

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

arch/tile: move user_exit() to early kernel entry sequence

2016-01-18T19:49:30Z

This ensures that we always notify context tracking that we have exited from user space no matter how we enter the kernel. It is similar to how arm64 handles context tracking, for example. This allows the removal of all the exception_enter() calls that were added in commit 49e4e15619cd ("tile: support CONTEXT_TRACKING and thus NOHZ_FULL"). Signed-off-by: Chris Metcalf

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: 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

tile: Use the more common pr_warn instead of pr_warning

2014-11-11T20:51:42Z

And other message logging neatening. Other miscellanea: o coalesce formats o realign arguments o standardize a couple of macros o use __func__ instead of embedding the function name Signed-off-by: Joe Perches Signed-off-by: Chris Metcalf

tile: use ARRAY_SIZE

2014-10-02T14:19:32Z

ARRAY_SIZE is more concise to use when the size of an array is divided by the size of its type or the size of its first element. The semantic patch that makes this change is as follows: // @i@ @@ @@ type T; T[] E; @@ - (sizeof(E)/sizeof(T)) + ARRAY_SIZE(E) // Signed-off-by: Himangi Saraogi Acked-by: Julia Lawall Signed-off-by: Chris Metcalf

replace strict_strto* call with kstrto*

2014-05-28T19:47:16Z

remove obsolete calls to strict_strto* and replace them with kstrto* calls accordingly. Signed-off-by: Daniel Walter Signed-off-by: Chris Metcalf

tile: use standard tile_bundle_bits type in traps.c

2013-09-03T18:53:22Z

We were rolling our own bundle_bits, which is unnecessary. Signed-off-by: Chris Metcalf

tilegx: support KGDB

2013-09-03T18:51:26Z

Enter kernel debugger at boot with: --hvd UART_1=1 --hvx kgdbwait --hvx kgdboc=ttyS1,115200 or at runtime with: echo ttyS1,115200 > /sys/module/kgdboc/parameters/kgdboc echo g > /proc/sysrq-trigger Signed-off-by: Chris Metcalf