lwn.git/arch/tile/kernel/intvec_32.S, branch docs-fixes

arch: remove tile port

2018-03-16T09:56:03+00:00

The Tile architecture port was added by Chris Metcalf in 2010, and maintained until early 2018 when he orphaned it due to his departure from Mellanox, and nobody else stepped up to maintain it. The product line is still around in the form of the BlueField SoC, but no longer uses the Tile architecture. There are also still products for sale with Tile-GX SoCs, notably the Mikrotik CCR router family. The products all use old (linux-3.3) kernels with lots of patches and won't be upgraded by their manufacturers. There have been efforts to port both OpenWRT and Debian to these, but both projects have stalled and are very unlikely to be continued in the future. Given that we are reasonably sure that nobody is still using the port with an upstream kernel any more, it seems better to remove it now while the port is in a good shape than to let it bitrot for a few years first. Cc: Chris Metcalf Cc: John Paul Adrian Glaubitz Link: http://www.mellanox.com/page/npu_multicore_overview Link: https://jenkins.debian.net/view/rebootstrap/job/rebootstrap_tilegx_gcc7/ Signed-off-by: Arnd Bergmann

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

2016-01-18T19:49:30+00:00

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

arch/tile: adopt prepare_exit_to_usermode() model from x86

2016-01-18T19:49:09+00:00

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: enable full SECCOMP support

2015-07-30T16:32:16+00:00

Signed-off-by: Chris Metcalf

tile: Enable NMIs on return from handle_nmi() without errors

2014-03-07T16:19:48+00:00

NMI interrupts mask ALL interrupts before calling the handler, so we need to unmask NMIs according to the value handle_nmi() returns. If it returns zero, the NMIs should be re-enabled; if it returns a non-zero error, the NMIs should be disabled. Signed-off-by: Zhigang Lu Signed-off-by: Chris Metcalf

tile: Add support for handling PMC hardware

2014-03-07T16:19:47+00:00

The PMC module is used by perf_events, oprofile and watchdogs. Signed-off-by: Zhigang Lu Signed-off-by: Chris Metcalf

tile: ensure interrupts disabled for preempt_schedule_irq()

2013-09-27T20:09:43+00:00

When coming from a page fault (for example), interrupts might be enabled as we enter the code to return from interrupt. Cc: stable@vger.kernel.org Signed-off-by: Chris Metcalf

tile: remove support for TILE64

2013-09-03T18:53:29+00:00

This chip is no longer being actively developed for (it was superceded by the TILEPro64 in 2008), and in any case the existing compiler and toolchain in the community do not support it. It's unlikely that the kernel works with TILE64 at this point as the configuration has not been tested in years. The support is also awkward as it requires maintaining a significant number of ifdefs. So, just remove it altogether. Signed-off-by: Chris Metcalf

tile: parameterize VA and PA space more cleanly

2013-09-03T18:47:34+00:00

The existing code relied on the hardware definition () to specify how much VA and PA space was available. It's convenient to allow customizing this for some configurations, so provide symbols MAX_PA_WIDTH and MAX_VA_WIDTH in that can be modified if desired. Additionally, move away from the MEM_XX_INTRPT nomenclature to define the start of various regions within the VA space. In fact the cleaner symbol is, for example, MEM_SV_START, to indicate the start of the area used for supervisor code; the actual address of the interrupt vectors is not as important, and can be changed if desired. As part of this change, convert from "intrpt1" nomenclature (which built in the old privilege-level 1 model) to a simple "intrpt". Also strip out some tilepro-specific code supporting modifying the PL the kernel could run at, since we don't actually support using different PLs in tilepro, only tilegx. Signed-off-by: Chris Metcalf

tilegx: change how we find the kernel stack

2013-08-30T15:56:58+00:00

Previously, we used a special-purpose register (SPR_SYSTEM_SAVE_K_0) to hold the CPU number and the top of the current kernel stack by using the low bits to hold the CPU number, and using the high bits to hold the address of the page just above where we'd want the kernel stack to be. That way we could initialize a new SP when first entering the kernel by just masking the SPR value and subtracting a couple of words. However, it's actually more useful to be able to place an arbitrary kernel-top value in the SPR. This allows us to create a new stack context (e.g. for virtualization) with an arbitrary top-of-stack VA. To make this work, we now store the CPU number in the high bits, above the highest legal VA bit (42 bits in the current tilegx microarchitecture). The full 42 bits are thus available to store the top of stack value. Getting the current cpu (a relatively common operation) is still fast; it's now a shift rather than a mask. We make this change only for tilegx, since tilepro has too few SPR bits to do this, and we don't need this support on tilepro anyway. Signed-off-by: Chris Metcalf