kernel/linux.git/arch/powerpc/include/asm/nmi.h, branch linux-7.0.y

powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h

2023-06-24T00:04:04+00:00

The powerpc architecture was the only one that defined arch_trigger_cpumask_backtrace() in asm/nmi.h instead of asm/irq.h. Move it to be consistent. This fixes compile time errors introduced by commit 7ca8fe94aa92 ("watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH"). That commit caused to stop being included if the hardlockup detector wasn't enabled. The specific errors were: error: implicit declaration of function `nmi_cpu_backtrace' error: implicit declaration of function `nmi_trigger_cpumask_backtrace' NOTE: when moving this into irq.h, we also change the guards from just checking if "CONFIG_NMI_IPI" is defined to also checking if "CONFIG_PPC_BOOK3S_64" is defined. This matches the code in arch/powerpc/kernel/stacktrace.c. Previously this worked because was included if "CONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH" was defined. For powerpc that's only selected if "CONFIG_PPC_BOOK3S_64" is defined. [dianders@chromium.org: change the guards to include CONFIG_PPC_BOOK3S_64] Link: https://lkml.kernel.org/r/20230622202816.v2.1.Ice67126857506712559078e7de26d32d26e64631@changeid Link: https://lkml.kernel.org/r/20230621164809.1.Ice67126857506712559078e7de26d32d26e64631@changeid Fixes: 7ca8fe94aa92 ("watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH") Signed-off-by: Douglas Anderson Reported-by: Michael Ellerman Closes: https://lore.kernel.org/r/871qi5otdh.fsf@mail.lhotse Reviewed-by: Petr Mladek Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Douglas Anderson Cc: Laurent Dufour Cc: Nicholas Piggin Cc: Stephen Rothwell Cc: Tom Rix Signed-off-by: Andrew Morton

watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h

2023-06-19T23:25:29+00:00

arch_touch_nmi_watchdog() needs a different implementation for various hardlockup detector implementations. And it does nothing when any hardlockup detector is not built at all. arch_touch_nmi_watchdog() is declared via linux/nmi.h. And it must be defined as an empty function when there is no hardlockup detector. It is done directly in this header file for the perf and buddy detectors. And it is done in the included asm/linux.h for arch specific detectors. The reason probably is that the arch specific variants build the code using another conditions. For example, powerpc64/sparc64 builds the code when CONFIG_PPC_WATCHDOG is enabled. Another reason might be that these architectures define more functions in asm/nmi.h anyway. However the generic code actually knows when the function will be implemented. It happens when some full featured or the sparc64-specific hardlockup detector is built. In particular, CONFIG_HARDLOCKUP_DETECTOR can be enabled only when a generic or arch-specific full featured hardlockup detector is available. The only exception is sparc64 which can be built even when the global HARDLOCKUP_DETECTOR switch is disabled. The information about sparc64 is a bit complicated. The hardlockup detector is built there when CONFIG_HAVE_NMI_WATCHDOG is set and CONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH is not set. People might wonder whether this change really makes things easier. The motivation is: + The current logic in linux/nmi.h is far from obvious. For example, arch_touch_nmi_watchdog() is defined as {} when neither CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER nor CONFIG_HAVE_NMI_WATCHDOG is defined. + The change synchronizes the checks in lib/Kconfig.debug and in the generic code. + It is a step that will help cleaning HAVE_NMI_WATCHDOG related checks. The change should not change the existing behavior. Link: https://lkml.kernel.org/r/20230616150618.6073-4-pmladek@suse.com Signed-off-by: Petr Mladek Reviewed-by: Douglas Anderson Cc: Christophe Leroy Cc: "David S. Miller" Cc: Michael Ellerman Cc: Nicholas Piggin Signed-off-by: Andrew Morton

watchdog/hardlockup: rename some "NMI watchdog" constants/function

2023-06-10T00:44:20+00:00

Do a search and replace of: - NMI_WATCHDOG_ENABLED => WATCHDOG_HARDLOCKUP_ENABLED - SOFT_WATCHDOG_ENABLED => WATCHDOG_SOFTOCKUP_ENABLED - watchdog_nmi_ => watchdog_hardlockup_ - nmi_watchdog_available => watchdog_hardlockup_available - nmi_watchdog_user_enabled => watchdog_hardlockup_user_enabled - soft_watchdog_user_enabled => watchdog_softlockup_user_enabled - NMI_WATCHDOG_DEFAULT => WATCHDOG_HARDLOCKUP_DEFAULT Then update a few comments near where names were changed. This is specifically to make it less confusing when we want to introduce the buddy hardlockup detector, which isn't using NMIs. As part of this, we sanitized a few names for consistency. [trix@redhat.com: make variables static] Link: https://lkml.kernel.org/r/20230525162822.1.I0fb41d138d158c9230573eaa37dc56afa2fb14ee@changeid Link: https://lkml.kernel.org/r/20230519101840.v5.12.I91f7277bab4bf8c0cb238732ed92e7ce7bbd71a6@changeid Signed-off-by: Douglas Anderson Signed-off-by: Tom Rix Reviewed-by: Tom Rix Cc: Andi Kleen Cc: Catalin Marinas Cc: Chen-Yu Tsai Cc: Christophe Leroy Cc: Colin Cross Cc: Daniel Thompson Cc: "David S. Miller" Cc: Guenter Roeck Cc: Ian Rogers Cc: Lecopzer Chen Cc: Marc Zyngier Cc: Mark Rutland Cc: Masayoshi Mizuma Cc: Matthias Kaehlcke Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Petr Mladek Cc: Pingfan Liu Cc: Randy Dunlap Cc: "Ravi V. Shankar" Cc: Ricardo Neri Cc: Stephane Eranian Cc: Stephen Boyd Cc: Sumit Garg Cc: Tzung-Bi Shih Cc: Will Deacon Signed-off-by: Andrew Morton

powerpc/watchdog: introduce a NMI watchdog's factor

2022-07-27T11:36:02+00:00

Introduce a factor which would apply to the NMI watchdog timeout. This factor is a percentage added to the watchdog_tresh value. The value is set under the watchdog_mutex protection and lockup_detector_reconfigure() is called to recompute wd_panic_timeout_tb. Once the factor is set, it remains until it is set back to 0, which means no impact. Signed-off-by: Laurent Dufour Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220713154729.80789-4-ldufour@linux.ibm.com

powerpc: Fix STACKTRACE=n build

2022-03-06T23:26:20+00:00

Our skiroot_defconfig doesn't enable FTRACE, and so doesn't get STACKTRACE enabled either. That leads to a build failure since commit 1614b2b11fab ("arch: Make ARCH_STACKWALK independent of STACKTRACE") made stacktrace.c build even when STACKTRACE=n. arch/powerpc/kernel/stacktrace.c: In function ‘handle_backtrace_ipi’: arch/powerpc/kernel/stacktrace.c:171:2: error: implicit declaration of function ‘nmi_cpu_backtrace’ 171 | nmi_cpu_backtrace(regs); | ^~~~~~~~~~~~~~~~~ arch/powerpc/kernel/stacktrace.c: In function ‘arch_trigger_cpumask_backtrace’: arch/powerpc/kernel/stacktrace.c:226:2: error: implicit declaration of function ‘nmi_trigger_cpumask_backtrace’ 226 | nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace_ipi); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This happens because our headers haven't defined arch_trigger_cpumask_backtrace, which causes lib/nmi_backtrace.c not to build nmi_cpu_backtrace(). The code in question doesn't actually depend on STACKTRACE=y, that was just added because arch_trigger_cpumask_backtrace() lived in stacktrace.c for convenience. So drop the dependency on CONFIG_STACKTRACE, that causes lib/nmi_backtrace.c to build nmi_cpu_backtrace() etc. and fixes the build. Fixes: 1614b2b11fab ("arch: Make ARCH_STACKWALK independent of STACKTRACE") [mpe: Cherry pick of 5a72345e6a78 from next into fixes] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220212111349.2806972-1-mpe@ellerman.id.au

powerpc: convert interrupt handlers to use wrappers

2021-02-08T13:02:12+00:00

Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210130130852.2952424-29-npiggin@gmail.com

powerpc/watchdog: Declare soft_nmi_interrupt() prototype

2021-01-30T00:39:30+00:00

soft_nmi_interrupt() usage requires PPC_WATCHDOG to be configured. Check the CONFIG definition to declare the prototype. It fixes this W=1 compile error : ../arch/powerpc/kernel/watchdog.c:250:6: error: no previous prototype for ‘soft_nmi_interrupt’ [-Werror=missing-prototypes] 250 | void soft_nmi_interrupt(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~ Signed-off-by: Cédric Le Goater Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210104143206.695198-18-clg@kaod.org

powerpc/64s: Fix HV NMI vs HV interrupt recoverability test

2019-02-26T12:28:24+00:00

HV interrupts that use HSRR registers do not enter with MSR[RI] clear, but their entry code is not recoverable vs NMI, due to shared use of HSPRG1 as a scratch register to save r13. This means that a system reset or machine check that hits in HSRR interrupt entry can cause r13 to be silently corrupted. Fix this by marking NMIs non-recoverable if they land in HV interrupt ranges. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

powerpc/64s: Fix build failures with CONFIG_NMI_IPI=n

2018-06-19T13:03:50+00:00

I broke the build when CONFIG_NMI_IPI=n with my recent commit to add arch_trigger_cpumask_backtrace(), eg: stacktrace.c:(.text+0x1b0): undefined reference to `.smp_send_safe_nmi_ipi' We should rework the CONFIG symbols here in future to avoid these double barrelled ifdefs but for now they fix the build. Fixes: 5cc05910f26e ("powerpc/64s: Wire up arch_trigger_cpumask_backtrace()") Reported-by: Christophe LEROY Signed-off-by: Michael Ellerman

powerpc/64s: Wire up arch_trigger_cpumask_backtrace()

2018-06-03T10:43:43+00:00

This allows eg. the RCU stall detector, or the soft/hardlockup detectors to trigger a backtrace on all CPUs. We implement this by sending a "safe" NMI, which will actually only send an IPI. Unfortunately the generic code prints "NMI", so that's a little confusing but we can probably live with it. If one of the CPUs doesn't respond to the IPI, we then print some info from it's paca and do a backtrace based on its saved_r1. Example output: INFO: rcu_sched detected stalls on CPUs/tasks: 2-...0: (0 ticks this GP) idle=1be/1/4611686018427387904 softirq=1055/1055 fqs=25735 (detected by 4, t=58847 jiffies, g=58, c=57, q=1258) Sending NMI from CPU 4 to CPUs 2: CPU 2 didn't respond to backtrace IPI, inspecting paca. irq_soft_mask: 0x01 in_mce: 0 in_nmi: 0 current: 3623 (bash) Back trace of paca->saved_r1 (0xc0000000e1c83ba0) (possibly stale): Call Trace: [c0000000e1c83ba0] [0000000000000014] 0x14 (unreliable) [c0000000e1c83bc0] [c000000000765798] lkdtm_do_action+0x48/0x80 [c0000000e1c83bf0] [c000000000765a40] direct_entry+0x110/0x1b0 [c0000000e1c83c90] [c00000000058e650] full_proxy_write+0x90/0xe0 [c0000000e1c83ce0] [c0000000003aae3c] __vfs_write+0x6c/0x1f0 [c0000000e1c83d80] [c0000000003ab214] vfs_write+0xd4/0x240 [c0000000e1c83dd0] [c0000000003ab5cc] ksys_write+0x6c/0x110 [c0000000e1c83e30] [c00000000000b860] system_call+0x58/0x6c Signed-off-by: Michael Ellerman Reviewed-by: Nicholas Piggin