From a4e89ffb59235fd11d27107dea3efa4562ac0a12 Mon Sep 17 00:00:00 2001 From: Matt Weber Date: Wed, 28 Jun 2017 11:14:29 -0500 Subject: powerpc/e6500: Update machine check for L1D cache err This patch updates the machine check handler of Linux kernel to handle the e6500 architecture case. In e6500 core, L1 Data Cache Write Shadow Mode (DCWS) register is not implemented but L1 data cache always runs in write shadow mode. So, on L1 data cache parity errors, hardware will automatically invalidate the data cache but will still log a machine check interrupt. Signed-off-by: Ronak Desai Signed-off-by: Matthew Weber Signed-off-by: Scott Wood --- arch/powerpc/kernel/traps.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 675d5d2bfcde..410352acfa38 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -393,6 +393,7 @@ static inline int check_io_access(struct pt_regs *regs) int machine_check_e500mc(struct pt_regs *regs) { unsigned long mcsr = mfspr(SPRN_MCSR); + unsigned long pvr = mfspr(SPRN_PVR); unsigned long reason = mcsr; int recoverable = 1; @@ -434,8 +435,15 @@ int machine_check_e500mc(struct pt_regs *regs) * may still get logged and cause a machine check. We should * only treat the non-write shadow case as non-recoverable. */ - if (!(mfspr(SPRN_L1CSR2) & L1CSR2_DCWS)) - recoverable = 0; + /* On e6500 core, L1 DCWS (Data cache write shadow mode) bit + * is not implemented but L1 data cache always runs in write + * shadow mode. Hence on data cache parity errors HW will + * automatically invalidate the L1 Data Cache. + */ + if (PVR_VER(pvr) != PVR_VER_E6500) { + if (!(mfspr(SPRN_L1CSR2) & L1CSR2_DCWS)) + recoverable = 0; + } } if (reason & MCSR_L2MMU_MHIT) { -- cgit v1.2.3 From 5490125d77a43016b26f629d4b485e2c62172551 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 12 Sep 2017 21:36:59 +0200 Subject: watchdog/core: Remove broken suspend/resume interfaces This interface has several issues: - It's causing recursive locking of the hotplug lock. - It's complete overkill to teardown all threads and then recreate them The same can be achieved with the simple hardlockup_detector_perf_stop / restart() interfaces. The abuse from the busy looping poweroff() loop of PARISC has been solved as well. Remove the cruft. Signed-off-by: Thomas Gleixner Reviewed-by: Don Zickus Cc: Andrew Morton Cc: Borislav Petkov Cc: Chris Metcalf Cc: Linus Torvalds Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Sebastian Siewior Cc: Ulrich Obergfell Link: http://lkml.kernel.org/r/20170912194146.487537732@linutronix.de Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/watchdog.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index 2f6eadd9408d..5ded171f02d6 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -310,9 +310,6 @@ static int start_wd_on_cpu(unsigned int cpu) if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED)) return 0; - if (watchdog_suspended) - return 0; - if (!cpumask_test_cpu(cpu, &watchdog_cpumask)) return 0; -- cgit v1.2.3 From 6592ad2fcc8f15b4f99b36c1db7d9f65510c203b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 12 Sep 2017 21:37:16 +0200 Subject: watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage Both the perf reconfiguration and the powerpc watchdog_nmi_reconfigure() need to be done in two steps. 1) Stop all NMIs 2) Read the new parameters and start NMIs Right now watchdog_nmi_reconfigure() is a combination of both. To allow a clean reconfiguration add a 'run' argument and split the functionality in powerpc. Signed-off-by: Thomas Gleixner Reviewed-by: Don Zickus Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Chris Metcalf Cc: Linus Torvalds Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Sebastian Siewior Cc: Ulrich Obergfell Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20170912194147.862865570@linutronix.de Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/watchdog.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index 5ded171f02d6..291af79a9826 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -355,17 +355,18 @@ static void watchdog_calc_timeouts(void) wd_timer_period_ms = watchdog_thresh * 1000 * 2 / 5; } -void watchdog_nmi_reconfigure(void) +void watchdog_nmi_reconfigure(bool run) { int cpu; - watchdog_calc_timeouts(); - - for_each_cpu(cpu, &wd_cpus_enabled) - stop_wd_on_cpu(cpu); - - for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) - start_wd_on_cpu(cpu); + if (!run) { + for_each_cpu(cpu, &wd_cpus_enabled) + stop_wd_on_cpu(cpu); + } else { + watchdog_calc_timeouts(); + for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) + start_wd_on_cpu(cpu); + } } /* -- cgit v1.2.3 From ab5fe3ff38ff9653490910cc71dbbedc95a86e41 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 12 Sep 2017 21:37:23 +0200 Subject: watchdog/hardlockup: Clean up hotplug locking mess All watchdog thread related functions are delegated to the smpboot thread infrastructure, which handles serialization against CPU hotplug correctly. The sysctl interface is completely decoupled from anything which requires CPU hotplug protection. No need to protect the sysctl writes against cpu hotplug anymore. Remove it and add the now required protection to the powerpc arch_nmi_watchdog implementation. Signed-off-by: Thomas Gleixner Reviewed-by: Don Zickus Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Chris Metcalf Cc: Linus Torvalds Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Sebastian Siewior Cc: Ulrich Obergfell Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20170912194148.418497420@linutronix.de Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/watchdog.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index 291af79a9826..dfb067764480 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -359,6 +359,7 @@ void watchdog_nmi_reconfigure(bool run) { int cpu; + cpus_read_lock(); if (!run) { for_each_cpu(cpu, &wd_cpus_enabled) stop_wd_on_cpu(cpu); @@ -367,6 +368,7 @@ void watchdog_nmi_reconfigure(bool run) for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) start_wd_on_cpu(cpu); } + cpus_read_unlock(); } /* -- cgit v1.2.3 From c1fa0768a8713b135848f78fd43ffc208d8ded70 Mon Sep 17 00:00:00 2001 From: Gustavo Romero Date: Wed, 13 Sep 2017 22:13:48 -0400 Subject: powerpc/tm: Flush TM only if CPU has TM feature Commit cd63f3c ("powerpc/tm: Fix saving of TM SPRs in core dump") added code to access TM SPRs in flush_tmregs_to_thread(). However flush_tmregs_to_thread() does not check if TM feature is available on CPU before trying to access TM SPRs in order to copy live state to thread structures. flush_tmregs_to_thread() is indeed guarded by CONFIG_PPC_TRANSACTIONAL_MEM but it might be the case that kernel was compiled with CONFIG_PPC_TRANSACTIONAL_MEM enabled and ran on a CPU without TM feature available, thus rendering the execution of TM instructions that are treated by the CPU as illegal instructions. The fix is just to add proper checking in flush_tmregs_to_thread() if CPU has the TM feature before accessing any TM-specific resource, returning immediately if TM is no available on the CPU. Adding that checking in flush_tmregs_to_thread() instead of in places where it is called, like in vsr_get() and vsr_set(), is better because avoids the same problem cropping up elsewhere. Cc: stable@vger.kernel.org # v4.13+ Fixes: cd63f3c ("powerpc/tm: Fix saving of TM SPRs in core dump") Signed-off-by: Gustavo Romero Reviewed-by: Cyril Bur Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index 07cd22e35405..f52ad5bb7109 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -131,7 +131,7 @@ static void flush_tmregs_to_thread(struct task_struct *tsk) * in the appropriate thread structures from live. */ - if (tsk != current) + if ((!cpu_has_feature(CPU_FTR_TM)) || (tsk != current)) return; if (MSR_TM_SUSPENDED(mfmsr())) { -- cgit v1.2.3 From 8afafa6fba7809c0785018b77c95b19e58b35b94 Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Fri, 15 Sep 2017 15:38:21 +0530 Subject: powerpc/kprobes: Update optprobes to use emulate_update_regs() Optprobes depended on an updated regs->nip from analyse_instr() to identify the location to branch back from the optprobes trampoline. However, since commit 3cdfcbfd32b9d ("powerpc: Change analyse_instr so it doesn't modify *regs"), analyse_instr() doesn't update the registers anymore. Due to this, we end up branching back from the optprobes trampoline to the same branch into the trampoline resulting in a loop. Fix this by calling out to emulate_update_regs() before using the nip. Additionally, explicitly compare the return value from analyse_instr() to 1, rather than just checking for !0 so as to guard against any future changes to analyse_instr() that may result in -1 being returned in more scenarios. Fixes: 3cdfcbfd32b9d ("powerpc: Change analyse_instr so it doesn't modify *regs") Signed-off-by: Naveen N. Rao Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/optprobes.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c index 6f8273f5e988..91e037ab20a1 100644 --- a/arch/powerpc/kernel/optprobes.c +++ b/arch/powerpc/kernel/optprobes.c @@ -104,8 +104,10 @@ static unsigned long can_optimize(struct kprobe *p) * and that can be emulated. */ if (!is_conditional_branch(*p->ainsn.insn) && - analyse_instr(&op, ®s, *p->ainsn.insn)) + analyse_instr(&op, ®s, *p->ainsn.insn) == 1) { + emulate_update_regs(®s, &op); nip = regs.nip; + } return nip; } -- cgit v1.2.3 From 3e77adeea3c5393c9b624832f65441e92867f618 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Thu, 7 Sep 2017 16:35:40 +1000 Subject: powerpc/eeh: Create PHB PEs after EEH is initialized Otherwise we end up not yet having computed the right diag data size on powernv where EEH initialization is delayed, thus causing memory corruption later on when calling OPAL. Fixes: 5cb1f8fdddb7 ("powerpc/powernv/pci: Dynamically allocate PHB diag data") Cc: stable@vger.kernel.org # v4.13+ Signed-off-by: Benjamin Herrenschmidt Acked-by: Russell Currey Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/eeh.c | 4 ++++ arch/powerpc/kernel/eeh_dev.c | 18 ------------------ 2 files changed, 4 insertions(+), 18 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c index 9e816787c0d4..116000b45531 100644 --- a/arch/powerpc/kernel/eeh.c +++ b/arch/powerpc/kernel/eeh.c @@ -1019,6 +1019,10 @@ int eeh_init(void) } else if ((ret = eeh_ops->init())) return ret; + /* Initialize PHB PEs */ + list_for_each_entry_safe(hose, tmp, &hose_list, list_node) + eeh_dev_phb_init_dynamic(hose); + /* Initialize EEH event */ ret = eeh_event_init(); if (ret) diff --git a/arch/powerpc/kernel/eeh_dev.c b/arch/powerpc/kernel/eeh_dev.c index ad04ecd63c20..a34e6912c15e 100644 --- a/arch/powerpc/kernel/eeh_dev.c +++ b/arch/powerpc/kernel/eeh_dev.c @@ -78,21 +78,3 @@ void eeh_dev_phb_init_dynamic(struct pci_controller *phb) /* EEH PE for PHB */ eeh_phb_pe_create(phb); } - -/** - * eeh_dev_phb_init - Create EEH devices for devices included in existing PHBs - * - * Scan all the existing PHBs and create EEH devices for their OF - * nodes and their children OF nodes - */ -static int __init eeh_dev_phb_init(void) -{ - struct pci_controller *phb, *tmp; - - list_for_each_entry_safe(phb, tmp, &hose_list, list_node) - eeh_dev_phb_init_dynamic(phb); - - return 0; -} - -core_initcall(eeh_dev_phb_init); -- cgit v1.2.3 From d8bd9f3f0925d22726de159531bfe3774b5cacc6 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Fri, 22 Sep 2017 13:32:21 +1000 Subject: powerpc: Handle MCE on POWER9 with only DSISR bit 30 set On POWER9 DD2.1 and below, it's possible for a paste instruction to cause a Machine Check Exception (MCE) where only DSISR bit 30 (IBM 33) is set. This will result in the MCE handler seeing an unknown event, which triggers linux to crash. We change this by detecting unknown events caused by load/stores in the MCE handler and marking them as handled so that we no longer crash. An MCE that occurs like this is spurious, so we don't need to do anything in terms of servicing it. If there is something that needs to be serviced, the CPU will raise the MCE again with the correct DSISR so that it can be serviced properly. Signed-off-by: Michael Neuling Reviewed-by: Nicholas Piggin [mpe: Expand comment with details from change log, use normal bit #s] Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/mce_power.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c index b76ca198e09c..f523125b9d34 100644 --- a/arch/powerpc/kernel/mce_power.c +++ b/arch/powerpc/kernel/mce_power.c @@ -624,5 +624,18 @@ long __machine_check_early_realmode_p8(struct pt_regs *regs) long __machine_check_early_realmode_p9(struct pt_regs *regs) { + /* + * On POWER9 DD2.1 and below, it's possible to get a machine check + * caused by a paste instruction where only DSISR bit 30 is set. This + * will result in the MCE handler seeing an unknown event and the kernel + * crashing. An MCE that occurs like this is spurious, so we don't need + * to do anything in terms of servicing it. If there is something that + * needs to be serviced, the CPU will raise the MCE again with the + * correct DSISR so that it can be serviced properly. So detect this + * case and mark it as handled. + */ + if (SRR1_MC_LOADSTORE(regs->msr) && regs->dsisr == 0x40000000) + return 1; + return mce_handle_error(regs, mce_p9_derror_table, mce_p9_ierror_table); } -- cgit v1.2.3 From bca73f595a566f0262967535bb5b2ea9c4271d9a Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Thu, 28 Sep 2017 22:37:35 -0500 Subject: powerpc: Fix workaround for spurious MCE on POWER9 In the recent commit d8bd9f3f0925 ("powerpc: Handle MCE on POWER9 with only DSISR bit 30 set") I screwed up the bit number. It should be bit 25 (IBM bit 38). Fixes: d8bd9f3f0925 ("powerpc: Handle MCE on POWER9 with only DSISR bit 30 set") Signed-off-by: Michael Neuling Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/mce_power.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c index f523125b9d34..72f153c6f3fa 100644 --- a/arch/powerpc/kernel/mce_power.c +++ b/arch/powerpc/kernel/mce_power.c @@ -626,7 +626,7 @@ long __machine_check_early_realmode_p9(struct pt_regs *regs) { /* * On POWER9 DD2.1 and below, it's possible to get a machine check - * caused by a paste instruction where only DSISR bit 30 is set. This + * caused by a paste instruction where only DSISR bit 25 is set. This * will result in the MCE handler seeing an unknown event and the kernel * crashing. An MCE that occurs like this is spurious, so we don't need * to do anything in terms of servicing it. If there is something that @@ -634,7 +634,7 @@ long __machine_check_early_realmode_p9(struct pt_regs *regs) * correct DSISR so that it can be serviced properly. So detect this * case and mark it as handled. */ - if (SRR1_MC_LOADSTORE(regs->msr) && regs->dsisr == 0x40000000) + if (SRR1_MC_LOADSTORE(regs->msr) && regs->dsisr == 0x02000000) return 1; return mce_handle_error(regs, mce_p9_derror_table, mce_p9_ierror_table); -- cgit v1.2.3 From 3b7af5c0fd9631762d1c4d7b4cee76f571dd3c2c Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Wed, 27 Sep 2017 12:55:51 +0800 Subject: powerpc: Fix action argument for cpufeatures-based TLB flush Commit 41d0c2ecde19 ("powerpc/powernv: Fix local TLB flush for boot and MCE on POWER9") introduced calls to __flush_tlb_power[89] from the cpufeatures code, specifying the number of sets to flush. However, these functions take an action argument, not a number of sets. This means we hit the BUG() in __flush_tlb_{206,300} when using cpufeatures-style configuration. This change passes TLB_INVAL_SCOPE_GLOBAL instead. Fixes: 41d0c2ecde19 ("powerpc/powernv: Fix local TLB flush for boot and MCE on POWER9") Cc: stable@vger.kernel.org # v4.13+ Signed-off-by: Jeremy Kerr Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/dt_cpu_ftrs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c index 1df770e8cbe0..7275fed271af 100644 --- a/arch/powerpc/kernel/dt_cpu_ftrs.c +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c @@ -102,10 +102,10 @@ static void cpufeatures_flush_tlb(void) case PVR_POWER8: case PVR_POWER8E: case PVR_POWER8NVL: - __flush_tlb_power8(POWER8_TLB_SETS); + __flush_tlb_power8(TLB_INVAL_SCOPE_GLOBAL); break; case PVR_POWER9: - __flush_tlb_power9(POWER9_TLB_SETS_HASH); + __flush_tlb_power9(TLB_INVAL_SCOPE_GLOBAL); break; default: pr_err("unknown CPU version for boot TLB flush\n"); -- cgit v1.2.3 From 070e004912fed099263408bf2ff1bbc6926abe2e Mon Sep 17 00:00:00 2001 From: Christian Lamparter Date: Sun, 1 Oct 2017 16:33:03 +0200 Subject: powerpc/4xx: Fix compile error with 64K pages on 40x, 44x MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The mmu context on the 40x, 44x does not define pte_frag entry. This causes gcc abort the compilation due to: setup-common.c: In function ‘setup_arch’: setup-common.c:908: error: ‘mm_context_t’ has no ‘pte_frag’ This patch fixes the issue by removing the pte_frag initialization in setup-common.c. This is possible, because the compiler will do the initialization, since the mm_context is a sub struct of init_mm. init_mm is declared in mm_types.h as external linkage. According to C99 6.2.4.3: An object whose identifier is declared with external linkage [...] has static storage duration. C99 defines in 6.7.8.10 that: If an object that has static storage duration is not initialized explicitly, then: - if it has pointer type, it is initialized to a null pointer Fixes: b1923caa6e64 ("powerpc: Merge 32-bit and 64-bit setup_arch()") Signed-off-by: Christian Lamparter Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/setup-common.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 0ac741fae90e..2e3bc16d02b2 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -904,9 +904,6 @@ void __init setup_arch(char **cmdline_p) #endif #endif -#ifdef CONFIG_PPC_64K_PAGES - init_mm.context.pte_frag = NULL; -#endif #ifdef CONFIG_SPAPR_TCE_IOMMU mm_iommu_init(&init_mm); #endif -- cgit v1.2.3 From 6b9dc4806b28214a4a260517e59439e0ac12a15e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 2 Oct 2017 12:34:50 +0200 Subject: watchdog/core, powerpc: Replace watchdog_nmi_reconfigure() The recent cleanup of the watchdog code split watchdog_nmi_reconfigure() into two stages. One to stop the NMI and one to restart it after reconfiguration. That was done by adding a boolean 'run' argument to the code, which is functionally correct but not necessarily a piece of art. Replace it by two explicit functions: watchdog_nmi_stop() and watchdog_nmi_start(). Fixes: 6592ad2fcc8f ("watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage") Requested-by: Linus 'Nursing his pet-peeve' Torvalds Signed-off-by: Thomas 'Mopping up garbage' Gleixner Acked-by: Michael Ellerman Cc: Peter Zijlstra Cc: Don Zickus Cc: Benjamin Herrenschmidt Cc: Nicholas Piggin Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710021957480.2114@nanos --- arch/powerpc/kernel/watchdog.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index dfb067764480..2673ec8bec00 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -355,19 +355,24 @@ static void watchdog_calc_timeouts(void) wd_timer_period_ms = watchdog_thresh * 1000 * 2 / 5; } -void watchdog_nmi_reconfigure(bool run) +void watchdog_nmi_stop(void) { int cpu; cpus_read_lock(); - if (!run) { - for_each_cpu(cpu, &wd_cpus_enabled) - stop_wd_on_cpu(cpu); - } else { - watchdog_calc_timeouts(); - for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) - start_wd_on_cpu(cpu); - } + for_each_cpu(cpu, &wd_cpus_enabled) + stop_wd_on_cpu(cpu); + cpus_read_unlock(); +} + +void watchdog_nmi_start(void) +{ + int cpu; + + cpus_read_lock(); + watchdog_calc_timeouts(); + for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) + start_wd_on_cpu(cpu); cpus_read_unlock(); } -- cgit v1.2.3 From e31d6883f21c1cdfe5bc64e28411f8a92b783fde Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Oct 2017 16:37:53 +0200 Subject: watchdog/core, powerpc: Lock cpus across reconfiguration Instead of dropping the cpu hotplug lock after stopping NMI watchdog and threads and reaquiring for restart, the code and the protection rules become more obvious when holding cpu hotplug lock across the full reconfiguration. Suggested-by: Linus Torvalds Signed-off-by: Thomas Gleixner Acked-by: Michael Ellerman Cc: Peter Zijlstra Cc: Don Zickus Cc: Benjamin Herrenschmidt Cc: Nicholas Piggin Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710022105570.2114@nanos --- arch/powerpc/kernel/watchdog.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index 2673ec8bec00..f9b4c6352d24 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -359,21 +359,17 @@ void watchdog_nmi_stop(void) { int cpu; - cpus_read_lock(); for_each_cpu(cpu, &wd_cpus_enabled) stop_wd_on_cpu(cpu); - cpus_read_unlock(); } void watchdog_nmi_start(void) { int cpu; - cpus_read_lock(); watchdog_calc_timeouts(); for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) start_wd_on_cpu(cpu); - cpus_read_unlock(); } /* -- cgit v1.2.3 From 34ddaa3e5c0096fef52485186c7eb6cf56ddc686 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Oct 2017 16:39:02 +0200 Subject: powerpc/watchdog: Make use of watchdog_nmi_probe() The rework of the core hotplug code triggers the WARN_ON in start_wd_cpu() on powerpc because it is called multiple times for the boot CPU. The first call is via: start_wd_on_cpu+0x80/0x2f0 watchdog_nmi_reconfigure+0x124/0x170 softlockup_reconfigure_threads+0x110/0x130 lockup_detector_init+0xbc/0xe0 kernel_init_freeable+0x18c/0x37c kernel_init+0x2c/0x160 ret_from_kernel_thread+0x5c/0xbc And then again via the CPU hotplug registration: start_wd_on_cpu+0x80/0x2f0 cpuhp_invoke_callback+0x194/0x620 cpuhp_thread_fun+0x7c/0x1b0 smpboot_thread_fn+0x290/0x2a0 kthread+0x168/0x1b0 ret_from_kernel_thread+0x5c/0xbc This can be avoided by setting up the cpu hotplug state with nocalls and move the initialization to the watchdog_nmi_probe() function. That initializes the hotplug callbacks without invoking the callback and the following core initialization function then configures the watchdog for the online CPUs (in this case CPU0) via softlockup_reconfigure_threads(). Reported-and-tested-by: Michael Ellerman Signed-off-by: Thomas Gleixner Acked-by: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Nicholas Piggin Cc: linuxppc-dev@lists.ozlabs.org --- arch/powerpc/kernel/watchdog.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index f9b4c6352d24..c702a8981452 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -373,22 +373,21 @@ void watchdog_nmi_start(void) } /* - * This runs after lockup_detector_init() which sets up watchdog_cpumask. + * Invoked from core watchdog init. */ -static int __init powerpc_watchdog_init(void) +int __init watchdog_nmi_probe(void) { int err; - watchdog_calc_timeouts(); - - err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/watchdog:online", - start_wd_on_cpu, stop_wd_on_cpu); - if (err < 0) + err = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, + "powerpc/watchdog:online", + start_wd_on_cpu, stop_wd_on_cpu); + if (err < 0) { pr_warn("Watchdog could not be initialized"); - + return err; + } return 0; } -arch_initcall(powerpc_watchdog_init); static void handle_backtrace_ipi(struct pt_regs *regs) { -- cgit v1.2.3