kernel.git/arch/powerpc/platforms/pseries, branch linux-5.13.y

powerpc/pseries: Fix update of LPAR security flavor after LPM

2021-08-18T07:07:06Z

commit c18956e6e0b95f78dad2773ecc8c61a9e41f6405 upstream. After LPM, when migrating from a system with security mitigation enabled to a system with mitigation disabled, the security flavor exposed in /proc is not correctly set back to 0. Do not assume the value of the security flavor is set to 0 when entering init_cpu_char_feature_flags(), so when called after a LPM, the value is set correctly even if the mitigation are not turned off. Fixes: 6ce56e1ac380 ("powerpc/pseries: export LPAR security flavor in lparcfg") Cc: stable@vger.kernel.org # v5.13+ Signed-off-by: Laurent Dufour Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210805152308.33988-1-ldufour@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: Fix regression while building external modules

2021-08-04T10:47:56Z

commit 333cf507465fbebb3727f5b53e77538467df312a upstream. With commit c9f3401313a5 ("powerpc: Always enable queued spinlocks for 64s, disable for others") CONFIG_PPC_QUEUED_SPINLOCKS is always enabled on ppc64le, external modules that use spinlock APIs are failing. ERROR: modpost: GPL-incompatible module XXX.ko uses GPL-only symbol 'shared_processor' Before the above commit, modules were able to build without any issues. Also this problem is not seen on other architectures. This problem can be workaround if CONFIG_UNINLINE_SPIN_UNLOCK is enabled in the config. However CONFIG_UNINLINE_SPIN_UNLOCK is not enabled by default and only enabled in certain conditions like CONFIG_DEBUG_SPINLOCKS is set in the kernel config. #include spinlock_t spLock; static int __init spinlock_test_init(void) { spin_lock_init(&spLock); spin_lock(&spLock); spin_unlock(&spLock); return 0; } static void __exit spinlock_test_exit(void) { printk("spinlock_test unloaded\n"); } module_init(spinlock_test_init); module_exit(spinlock_test_exit); MODULE_DESCRIPTION ("spinlock_test"); MODULE_LICENSE ("non-GPL"); MODULE_AUTHOR ("Srikar Dronamraju"); Given that spin locks are one of the basic facilities for module code, this effectively makes it impossible to build/load almost any non GPL modules on ppc64le. This was first reported at https://github.com/openzfs/zfs/issues/11172 Currently shared_processor is exported as GPL only symbol. Fix this for parity with other architectures by exposing shared_processor to non-GPL modules too. Fixes: 14c73bd344da ("powerpc/vcpu: Assume dedicated processors as non-preempt") Cc: stable@vger.kernel.org # v5.5+ Reported-by: marc.c.dionne@gmail.com Signed-off-by: Srikar Dronamraju Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210729060449.292780-1-srikar@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman

powerpc/preempt: Don't touch the idle task's preempt_count during hotplug

2021-07-14T15:07:52Z

commit 2c669ef6979c370f98d4b876e54f19613c81e075 upstream. Powerpc currently resets a CPU's idle task preempt_count to 0 before said task starts executing the secondary startup routine (and becomes an idle task proper). This conflicts with commit f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled"). which initializes all of the idle tasks' preempt_count to PREEMPT_DISABLED during smp_init(). Note that this was superfluous before said commit, as back then the hotplug machinery would invoke init_idle() via idle_thread_get(), which would have already reset the CPU's idle task's preempt_count to PREEMPT_ENABLED. Get rid of this preempt_count write. Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled") Reported-by: Bharata B Rao Signed-off-by: Valentin Schneider Tested-by: Guenter Roeck Tested-by: Bharata B Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210707183831.2106509-1-valentin.schneider@arm.com Signed-off-by: Greg Kroah-Hartman

powerpc: Fix is_kvm_guest() / kvm_para_available()

2021-07-14T15:07:45Z

[ Upstream commit 95839225639ba7c3d8d7231b542728dcf222bf2d ] Commit a21d1becaa3f ("powerpc: Reintroduce is_kvm_guest() as a fast-path check") added is_kvm_guest() and changed kvm_para_available() to use it. is_kvm_guest() checks a static key, kvm_guest, and that static key is set in check_kvm_guest(). The problem is check_kvm_guest() is only called on pseries, and even then only in some configurations. That means is_kvm_guest() always returns false on all non-pseries and some pseries depending on configuration. That's a bug. For PR KVM guests this is noticable because they no longer do live patching of themselves, which can be detected by the omission of a message in dmesg such as: KVM: Live patching for a fast VM worked To fix it make check_kvm_guest() an initcall, to ensure it's always called at boot. It needs to be core so that it runs before kvm_guest_init() which is postcore. To be an initcall it needs to return int, where 0 means success, so update that. We still call it manually in pSeries_smp_probe(), because that runs before init calls are run. Fixes: a21d1becaa3f ("powerpc: Reintroduce is_kvm_guest() as a fast-path check") Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210623130514.2543232-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable

2021-07-14T15:07:45Z

[ Upstream commit ed78f56e1271f108e8af61baeba383dcd77adbec ] In case performance stats for an nvdimm are not available, reading the 'perf_stats' sysfs file returns an -ENOENT error. A better approach is to make the 'perf_stats' file entirely invisible to indicate that performance stats for an nvdimm are unavailable. So this patch updates 'papr_nd_attribute_group' to add a 'is_visible' callback implemented as newly introduced 'papr_nd_attribute_visible()' that returns an appropriate mode in case performance stats aren't supported in a given nvdimm. Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is available when 'papr_nd_attribute_visible()' is called during nvdimm initialization. Even though 'perf_stats' attribute is available since v5.9, there are no known user-space tools/scripts that are dependent on presence of its sysfs file. Hence I dont expect any user-space breakage with this patch. Fixes: 2d02bf835e57 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP") Signed-off-by: Vaibhav Jain Reviewed-by: Dan Williams Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210513092349.285021-1-vaibhav@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/papr_scm: Properly handle UUID types and API

2021-07-14T15:07:45Z

[ Upstream commit 0e8554b5d7801b0aebc6c348a0a9f7706aa17b3b ] Parse to and export from UUID own type, before dereferencing. This also fixes wrong comment (Little Endian UUID is something else) and should eliminate the direct strict types assignments. Fixes: 43001c52b603 ("powerpc/papr_scm: Use ibm,unit-guid as the iset cookie") Fixes: 259a948c4ba1 ("powerpc/pseries/scm: Use a specific endian format for storing uuid from the device tree") Signed-off-by: Andy Shevchenko Reviewed-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210616134303.58185-1-andriy.shevchenko@linux.intel.com Signed-off-by: Sasha Levin

powerpc/pseries: warn if recursing into the hcall tracing code

2021-05-12T01:07:39Z

The hcall tracing code has a recursion check built in, which skips tracing if we are already tracing an hcall. However if the tracing code has problems with recursion, this check may not catch all cases because the tracing code could be invoked from a different tracepoint first, then make an hcall that gets traced, then recurse. Add an explicit warning if recursion is detected here, which might help to notice tracing code making hcalls. Really the core trace code should have its own recursion checking and warnings though. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210508101455.1578318-5-npiggin@gmail.com

powerpc/pseries: use notrace hcall variant for H_CEDE idle

2021-05-12T01:07:38Z

Rather than special-case H_CEDE in the hcall trace wrappers, make the idle H_CEDE call use plpar_hcall_norets_notrace(). Signed-off-by: Nicholas Piggin Reviewed-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210508101455.1578318-4-npiggin@gmail.com

powerpc/pseries: Don't trace hcall tracing wrapper

2021-05-12T01:07:38Z

This doesn't seem very useful to trace before the recursion check, even if the ftrace code has any recursion checks of its own. Be on the safe side and don't trace the hcall trace wrappers. Reported-by: Naveen N. Rao Signed-off-by: Nicholas Piggin Reviewed-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210508101455.1578318-3-npiggin@gmail.com

powerpc/pseries: Fix hcall tracing recursion in pv queued spinlocks

2021-05-12T01:07:38Z

The paravit queued spinlock slow path adds itself to the queue then calls pv_wait to wait for the lock to become free. This is implemented by calling H_CONFER to donate cycles. When hcall tracing is enabled, this H_CONFER call can lead to a spin lock being taken in the tracing code, which will result in the lock to be taken again, which will also go to the slow path because it queues behind itself and so won't ever make progress. An example trace of a deadlock: __pv_queued_spin_lock_slowpath trace_clock_global ring_buffer_lock_reserve trace_event_buffer_lock_reserve trace_event_buffer_reserve trace_event_raw_event_hcall_exit __trace_hcall_exit plpar_hcall_norets_trace __pv_queued_spin_lock_slowpath trace_clock_global ring_buffer_lock_reserve trace_event_buffer_lock_reserve trace_event_buffer_reserve trace_event_raw_event_rcu_dyntick rcu_irq_exit irq_exit __do_irq call_do_irq do_IRQ hardware_interrupt_common_virt Fix this by introducing plpar_hcall_norets_notrace(), and using that to make SPLPAR virtual processor dispatching hcalls by the paravirt spinlock code. Signed-off-by: Nicholas Piggin Reviewed-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210508101455.1578318-2-npiggin@gmail.com