Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755920AbaLHQBG (ORCPT ); Mon, 8 Dec 2014 11:01:06 -0500 Received: from mail-wg0-f52.google.com ([74.125.82.52]:39529 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755202AbaLHQBD (ORCPT ); Mon, 8 Dec 2014 11:01:03 -0500 Message-ID: <5485CB37.7050609@linaro.org> Date: Mon, 08 Dec 2014 16:00:55 +0000 From: Daniel Thompson User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Thomas Gleixner , Jason Cooper CC: Russell King , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, patches@linaro.org, linaro-kernel@lists.linaro.org, John Stultz , Sumit Semwal , Dirk Behme , Daniel Drake , Dmitry Pervushin , Tim Sander , Stephen Boyd Subject: Re: [PATCH 3.18-rc4 v12 0/5] arm: Implement arch_trigger_all_cpu_backtrace References: <1415968543-29469-1-git-send-email-daniel.thompson@linaro.org> <1417191374-26719-1-git-send-email-daniel.thompson@linaro.org> In-Reply-To: <1417191374-26719-1-git-send-email-daniel.thompson@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/11/14 16:16, Daniel Thompson wrote: > Hi Thomas, Hi Jason: Patches 1 to 3 are for you. > > This patchset modifies the GIC driver to allow it, on supported > platforms, to route IPI interrupts to FIQ and uses this feature to > implement arch_trigger_all_cpu_backtrace for arm. Are the irq parts of this patchset looking OK now? Daniel. > > On platforms not capable of supporting FIQ the signal to generate a > backtrace we fall back to using IRQ for propagation instead (relying on > a timeout to avoid wedging the CPU requesting the backtrace if other > CPUs are not responsive). > > It has been tested on two systems capable of supporting grouping > (Freescale i.MX6 and STiH416) and two that do not (vexpress-a9 and > Qualcomm Snapdragon 600). > > v12: > > * Squash first two patches into a single one and re-describe > (Thomas Gleixner). > > * Improve description of "irqchip: gic: Make gic_raise_softirq FIQ-safe" > (Thomas Gleixner). > > v11: > > * Optimized gic_raise_softirq() by replacing a register read with > a memory read (Jason Cooper). > > v10: > > * Add a further patch to optimize away some of the locking on systems > where CONFIG_BL_SWITCHER is not set (Marc Zyngier). Compiles OK with > exynos_defconfig (which is the only defconfig to set this option). > > * Whitespace fixes in patch 4. That patch previously used spaces for > alignment of new constants but the rest of the file used tabs. > > v9: > > * Improved documentation and structure of initial patch (now initial > two patches) to make gic_raise_softirq() safe to call from FIQ > (Thomas Gleixner). > > * Avoid masking interrupts during gic_raise_softirq(). The use of the > read lock makes this redundant (because we can safely re-enter the > function). > > v8: > > * Fixed build on arm64 causes by a spurious include file in irq-gic.c. > > v7-2 (accidentally released twice with same number): > > * Fixed boot regression on vexpress-a9 (reported by Russell King). > > * Rebased on v3.18-rc3; removed one patch from set that is already > included in mainline. > > * Dropped arm64/fiq.h patch from the set (still useful but not related > to issuing backtraces). > > v7: > > * Re-arranged code within the patch series to fix a regression > introduced midway through the series and corrected by a later patch > (testing by Olof's autobuilder). Tested offending patch in isolation > using defconfig identified by the autobuilder. > > v6: > > * Renamed svc_entry's call_trace argument to just trace (example code > from Russell King). > > * Fixed mismatched ENDPROC() in __fiq_abt (example code from Russell > King). > > * Modified usr_entry to optional avoid calling into the trace code and > used this in FIQ entry from usr path. Modified corresponding exit code > to avoid calling into trace code and the scheduler (example code from > Russell King). > > * Ensured the default FIQ register state is restored when the default > FIQ handler is reinstalled (example code from Russell King). > > * Renamed no_fiq_insn to dfl_fiq_insn to reflect the effect of adopting > a default FIQ handler. > > * Re-instated fiq_safe_migration_lock and associated logic in > gic_raise_softirq(). gic_raise_softirq() is called by wake_up_klogd() > in the console unlock logic. > > v5: > > * Rebased on 3.17-rc4. > > * Removed a spurious line from the final "glue it together" patch > that broke the build. > > v4: > > * Replaced push/pop with stmfd/ldmfd respectively (review of Nicolas > Pitre). > > * Really fix bad pt_regs pointer generation in __fiq_abt. > > * Remove fiq_safe_migration_lock and associated logic in > gic_raise_softirq() (review of Russell King) > > * Restructured to introduce the default FIQ handler first, before the > new features (review of Russell King). > > v3: > > * Removed redundant header guards from arch/arm64/include/asm/fiq.h > (review of Catalin Marinas). > > * Moved svc_exit_via_fiq macro to entry-header.S (review of Nicolas > Pitre). > > v2: > > * Restructured to sit nicely on a similar FYI patchset from Russell > King. It now effectively replaces the work in progress final patch > with something much more complete. > > * Implemented (and tested) a Thumb-2 implementation of svc_exit_via_fiq > (review of Nicolas Pitre) > > * Dropped the GIC group 0 workaround patch. The issue of FIQ interrupts > being acknowledged by the IRQ handler does still exist but should be > harmless because the IRQ handler will still wind up calling > ipi_cpu_backtrace(). > > * Removed any dependency on CONFIG_FIQ; all cpu backtrace effectively > becomes a platform feature (although the use of non-maskable > interrupts to implement it is best effort rather than guaranteed). > > * Better comments highlighting usage of RAZ/WI registers (and parts of > registers) in the GIC code. > > Changes *before* v1: > > * This patchset is a hugely cut-down successor to "[PATCH v11 00/19] > arm: KGDB NMI/FIQ support". Thanks to Thomas Gleixner for suggesting > the new structure. For historic details see: > https://lkml.org/lkml/2014/9/2/227 > > * Fix bug in __fiq_abt (no longer passes a bad struct pt_regs value). > In fixing this we also remove the useless indirection previously > found in the fiq_handler macro. > > * Make default fiq handler "always on" by migrating from fiq.c to > traps.c and replace do_unexp_fiq with the new handler (review > of Russell King). > > * Add arm64 version of fiq.h (review of Russell King) > > * Removed conditional branching and code from irq-gic.c, this is > replaced by much simpler code that relies on the GIC specification's > heavy use of read-as-zero/write-ignored (review of Russell King) > > > Daniel Thompson (5): > irqchip: gic: Optimize locking in gic_raise_softirq > irqchip: gic: Make gic_raise_softirq FIQ-safe > irqchip: gic: Introduce plumbing for IPI FIQ > ARM: add basic support for on-demand backtrace of other CPUs > arm: smp: Handle ipi_cpu_backtrace() using FIQ (if available) > > arch/arm/include/asm/irq.h | 5 + > arch/arm/include/asm/smp.h | 3 + > arch/arm/kernel/smp.c | 64 +++++++++++++ > arch/arm/kernel/traps.c | 8 +- > drivers/irqchip/irq-gic.c | 203 +++++++++++++++++++++++++++++++++++++--- > include/linux/irqchip/arm-gic.h | 8 ++ > 6 files changed, 275 insertions(+), 16 deletions(-) > > -- > 1.9.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/