| Message ID | 20221018130456.1356081-1-pierre.gondois@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] firmware: arm_sdei: Fix sleep from invalid context BUG | expand |
The changelog was removed: v2: - Don't use a raw spin_lock, but move the CPUHP_AP_ARM_SDEI_ cpuhp state to the _ONLINE section. On 10/18/22 15:04, Pierre Gondois wrote: > On an Ampere Altra, > Running a preemp_rt kernel based on v5.19-rc3-rt5 on an > Ampere Altra triggers: > [ 15.683141] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 > [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0 > [ 15.683157] preempt_count: 0, expected: 0 > [ 15.683159] RCU nest depth: 0, expected: 0 > [ 15.683163] 3 locks held by cpuhp/0/24: > [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130 > [ 15.683224] irq event stamp: 36 > [ 15.683226] hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0 > [ 15.683236] hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248 > [ 15.683238] softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0 > [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] > [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 > [ 15.683268] Call trace: > [ 15.683271] dump_backtrace+0x114/0x120 > [ 15.683277] show_stack+0x20/0x70 > [ 15.683279] dump_stack_lvl+0x9c/0xd8 > [ 15.683288] dump_stack+0x18/0x34 > [ 15.683289] __might_resched+0x188/0x228 > [ 15.683292] rt_spin_lock+0x70/0x120 > [ 15.683301] sdei_cpuhp_up+0x3c/0x130 > [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 > [ 15.683305] cpuhp_thread_fun+0x120/0x248 > [ 15.683308] smpboot_thread_fn+0x280/0x320 > [ 15.683315] kthread+0x130/0x140 > [ 15.683321] ret_from_fork+0x10/0x20 > > sdei_cpuhp_up() is called in the STARTING hotplug section, > which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ > state to the _ONLINE section to execute the cpuhp cb with > preemption enabled. > > Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the > calling CPU. It is checked that preemption is disabled for them. > _ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'. > Preemption is enabled in those threads, but their cpumask is limited > to 1 CPU. > Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb > don't trigger them. This means that no check will be done for some > cases, e.g. sdei_mask_local_cpu() invocations. > > Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call > which acts on the calling CPU. > > Suggested-by: James Morse <james.morse@arm.com> > Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> > --- > drivers/firmware/arm_sdei.c | 28 ++++++++++++++-------------- > include/linux/cpuhotplug.h | 2 +- > 2 files changed, 15 insertions(+), 15 deletions(-) > > diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c > index 1e1a51510e83..9b03e164a37a 100644 > --- a/drivers/firmware/arm_sdei.c > +++ b/drivers/firmware/arm_sdei.c > @@ -301,8 +301,6 @@ int sdei_mask_local_cpu(void) > { > int err; > > - WARN_ON_ONCE(preemptible()); > - > err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL); > if (err && err != -EIO) { > pr_warn_once("failed to mask CPU[%u]: %d\n", > @@ -315,6 +313,7 @@ int sdei_mask_local_cpu(void) > > static void _ipi_mask_cpu(void *ignored) > { > + WARN_ON_ONCE(preemptible()); > sdei_mask_local_cpu(); > } > > @@ -322,8 +321,6 @@ int sdei_unmask_local_cpu(void) > { > int err; > > - WARN_ON_ONCE(preemptible()); > - > err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL); > if (err && err != -EIO) { > pr_warn_once("failed to unmask CPU[%u]: %d\n", > @@ -336,6 +333,7 @@ int sdei_unmask_local_cpu(void) > > static void _ipi_unmask_cpu(void *ignored) > { > + WARN_ON_ONCE(preemptible()); > sdei_unmask_local_cpu(); > } > > @@ -343,6 +341,8 @@ static void _ipi_private_reset(void *ignored) > { > int err; > > + WARN_ON_ONCE(preemptible()); > + > err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0, > NULL); > if (err && err != -EIO) > @@ -389,8 +389,6 @@ static void _local_event_enable(void *data) > int err; > struct sdei_crosscall_args *arg = data; > > - WARN_ON_ONCE(preemptible()); > - > err = sdei_api_event_enable(arg->event->event_num); > > sdei_cross_call_return(arg, err); > @@ -401,6 +399,8 @@ int sdei_event_enable(u32 event_num) > int err = -EINVAL; > struct sdei_event *event; > > + WARN_ON_ONCE(preemptible()); > + > mutex_lock(&sdei_events_lock); > event = sdei_event_find(event_num); > if (!event) { > @@ -479,8 +479,6 @@ static void _local_event_unregister(void *data) > int err; > struct sdei_crosscall_args *arg = data; > > - WARN_ON_ONCE(preemptible()); > - > err = sdei_api_event_unregister(arg->event->event_num); > > sdei_cross_call_return(arg, err); > @@ -492,6 +490,7 @@ int sdei_event_unregister(u32 event_num) > struct sdei_event *event; > > WARN_ON(in_nmi()); > + WARN_ON_ONCE(preemptible()); > > mutex_lock(&sdei_events_lock); > event = sdei_event_find(event_num); > @@ -561,8 +560,6 @@ static void _local_event_register(void *data) > struct sdei_registered_event *reg; > struct sdei_crosscall_args *arg = data; > > - WARN_ON(preemptible()); > - > reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id()); > err = sdei_api_event_register(arg->event->event_num, sdei_entry_point, > reg, 0, 0); > @@ -576,6 +573,7 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) > struct sdei_event *event; > > WARN_ON(in_nmi()); > + WARN_ON_ONCE(preemptible()); > > mutex_lock(&sdei_events_lock); > if (sdei_event_find(event_num)) { > @@ -717,6 +715,8 @@ static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action, > { > int rv; > > + WARN_ON_ONCE(preemptible()); > + > switch (action) { > case CPU_PM_ENTER: > rv = sdei_mask_local_cpu(); > @@ -765,7 +765,7 @@ static int sdei_device_freeze(struct device *dev) > int err; > > /* unregister private events */ > - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); > + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); > > err = sdei_unregister_shared(); > if (err) > @@ -786,7 +786,7 @@ static int sdei_device_thaw(struct device *dev) > return err; > } > > - err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", > + err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", > &sdei_cpuhp_up, &sdei_cpuhp_down); > if (err) > pr_warn("Failed to re-register CPU hotplug notifier...\n"); > @@ -823,7 +823,7 @@ static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action, > * We are going to reset the interface, after this there is no point > * doing work when we take CPUs offline. > */ > - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); > + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); > > sdei_platform_reset(); > > @@ -1003,7 +1003,7 @@ static int sdei_probe(struct platform_device *pdev) > goto remove_cpupm; > } > > - err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", > + err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", > &sdei_cpuhp_up, &sdei_cpuhp_down); > if (err) { > pr_warn("Failed to register CPU hotplug notifier...\n"); > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h > index f61447913db9..63b89e00a4c3 100644 > --- a/include/linux/cpuhotplug.h > +++ b/include/linux/cpuhotplug.h > @@ -161,7 +161,6 @@ enum cpuhp_state { > CPUHP_AP_PERF_X86_CSTATE_STARTING, > CPUHP_AP_PERF_XTENSA_STARTING, > CPUHP_AP_MIPS_OP_LOONGSON3_STARTING, > - CPUHP_AP_ARM_SDEI_STARTING, > CPUHP_AP_ARM_VFP_STARTING, > CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING, > CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING, > @@ -209,6 +208,7 @@ enum cpuhp_state { > CPUHP_AP_IRQ_AFFINITY_ONLINE, > CPUHP_AP_BLK_MQ_ONLINE, > CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS, > + CPUHP_AP_ARM_SDEI_ONLINE, > CPUHP_AP_X86_INTEL_EPB_ONLINE, > CPUHP_AP_PERF_ONLINE, > CPUHP_AP_PERF_X86_ONLINE,
On Tue, Oct 18, 2022 at 03:04:53PM +0200, Pierre Gondois wrote: > On an Ampere Altra, > Running a preemp_rt kernel based on v5.19-rc3-rt5 on an > Ampere Altra triggers: > [ 15.683141] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 > [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0 > [ 15.683157] preempt_count: 0, expected: 0 > [ 15.683159] RCU nest depth: 0, expected: 0 > [ 15.683163] 3 locks held by cpuhp/0/24: > [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130 > [ 15.683224] irq event stamp: 36 > [ 15.683226] hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0 > [ 15.683236] hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248 > [ 15.683238] softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0 > [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] > [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 > [ 15.683268] Call trace: > [ 15.683271] dump_backtrace+0x114/0x120 > [ 15.683277] show_stack+0x20/0x70 > [ 15.683279] dump_stack_lvl+0x9c/0xd8 > [ 15.683288] dump_stack+0x18/0x34 > [ 15.683289] __might_resched+0x188/0x228 > [ 15.683292] rt_spin_lock+0x70/0x120 > [ 15.683301] sdei_cpuhp_up+0x3c/0x130 > [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 > [ 15.683305] cpuhp_thread_fun+0x120/0x248 > [ 15.683308] smpboot_thread_fn+0x280/0x320 > [ 15.683315] kthread+0x130/0x140 > [ 15.683321] ret_from_fork+0x10/0x20 > > sdei_cpuhp_up() is called in the STARTING hotplug section, > which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ > state to the _ONLINE section to execute the cpuhp cb with > preemption enabled. > > Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the > calling CPU. It is checked that preemption is disabled for them. > _ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'. > Preemption is enabled in those threads, but their cpumask is limited > to 1 CPU. > Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb > don't trigger them. This means that no check will be done for some > cases, e.g. sdei_mask_local_cpu() invocations. > > Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call > which acts on the calling CPU. > > Suggested-by: James Morse <james.morse@arm.com> > Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> > --- > drivers/firmware/arm_sdei.c | 28 ++++++++++++++-------------- > include/linux/cpuhotplug.h | 2 +- > 2 files changed, 15 insertions(+), 15 deletions(-) James -- are you taking care of this one, or should I queue it via arm64? Will
Hello James, Just a ping in case this was forgotten, Regards, Pierre On 10/18/22 15:07, Pierre Gondois wrote: > The changelog was removed: > > v2: > - Don't use a raw spin_lock, but move the CPUHP_AP_ARM_SDEI_ > cpuhp state to the _ONLINE section. > > > On 10/18/22 15:04, Pierre Gondois wrote: >> On an Ampere Altra, >> Running a preemp_rt kernel based on v5.19-rc3-rt5 on an >> Ampere Altra triggers: >> [ 15.683141] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 >> [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0 >> [ 15.683157] preempt_count: 0, expected: 0 >> [ 15.683159] RCU nest depth: 0, expected: 0 >> [ 15.683163] 3 locks held by cpuhp/0/24: >> [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 >> [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 >> [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130 >> [ 15.683224] irq event stamp: 36 >> [ 15.683226] hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0 >> [ 15.683236] hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248 >> [ 15.683238] softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0 >> [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 >> [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] >> [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 >> [ 15.683268] Call trace: >> [ 15.683271] dump_backtrace+0x114/0x120 >> [ 15.683277] show_stack+0x20/0x70 >> [ 15.683279] dump_stack_lvl+0x9c/0xd8 >> [ 15.683288] dump_stack+0x18/0x34 >> [ 15.683289] __might_resched+0x188/0x228 >> [ 15.683292] rt_spin_lock+0x70/0x120 >> [ 15.683301] sdei_cpuhp_up+0x3c/0x130 >> [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 >> [ 15.683305] cpuhp_thread_fun+0x120/0x248 >> [ 15.683308] smpboot_thread_fn+0x280/0x320 >> [ 15.683315] kthread+0x130/0x140 >> [ 15.683321] ret_from_fork+0x10/0x20 >> >> sdei_cpuhp_up() is called in the STARTING hotplug section, >> which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ >> state to the _ONLINE section to execute the cpuhp cb with >> preemption enabled. >> >> Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the >> calling CPU. It is checked that preemption is disabled for them. >> _ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'. >> Preemption is enabled in those threads, but their cpumask is limited >> to 1 CPU. >> Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb >> don't trigger them. This means that no check will be done for some >> cases, e.g. sdei_mask_local_cpu() invocations. >> >> Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call >> which acts on the calling CPU. >> >> Suggested-by: James Morse <james.morse@arm.com> >> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> >> --- >> drivers/firmware/arm_sdei.c | 28 ++++++++++++++-------------- >> include/linux/cpuhotplug.h | 2 +- >> 2 files changed, 15 insertions(+), 15 deletions(-) >> >> diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c >> index 1e1a51510e83..9b03e164a37a 100644 >> --- a/drivers/firmware/arm_sdei.c >> +++ b/drivers/firmware/arm_sdei.c >> @@ -301,8 +301,6 @@ int sdei_mask_local_cpu(void) >> { >> int err; >> >> - WARN_ON_ONCE(preemptible()); >> - >> err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL); >> if (err && err != -EIO) { >> pr_warn_once("failed to mask CPU[%u]: %d\n", >> @@ -315,6 +313,7 @@ int sdei_mask_local_cpu(void) >> >> static void _ipi_mask_cpu(void *ignored) >> { >> + WARN_ON_ONCE(preemptible()); >> sdei_mask_local_cpu(); >> } >> >> @@ -322,8 +321,6 @@ int sdei_unmask_local_cpu(void) >> { >> int err; >> >> - WARN_ON_ONCE(preemptible()); >> - >> err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL); >> if (err && err != -EIO) { >> pr_warn_once("failed to unmask CPU[%u]: %d\n", >> @@ -336,6 +333,7 @@ int sdei_unmask_local_cpu(void) >> >> static void _ipi_unmask_cpu(void *ignored) >> { >> + WARN_ON_ONCE(preemptible()); >> sdei_unmask_local_cpu(); >> } >> >> @@ -343,6 +341,8 @@ static void _ipi_private_reset(void *ignored) >> { >> int err; >> >> + WARN_ON_ONCE(preemptible()); >> + >> err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0, >> NULL); >> if (err && err != -EIO) >> @@ -389,8 +389,6 @@ static void _local_event_enable(void *data) >> int err; >> struct sdei_crosscall_args *arg = data; >> >> - WARN_ON_ONCE(preemptible()); >> - >> err = sdei_api_event_enable(arg->event->event_num); >> >> sdei_cross_call_return(arg, err); >> @@ -401,6 +399,8 @@ int sdei_event_enable(u32 event_num) >> int err = -EINVAL; >> struct sdei_event *event; >> >> + WARN_ON_ONCE(preemptible()); >> + >> mutex_lock(&sdei_events_lock); >> event = sdei_event_find(event_num); >> if (!event) { >> @@ -479,8 +479,6 @@ static void _local_event_unregister(void *data) >> int err; >> struct sdei_crosscall_args *arg = data; >> >> - WARN_ON_ONCE(preemptible()); >> - >> err = sdei_api_event_unregister(arg->event->event_num); >> >> sdei_cross_call_return(arg, err); >> @@ -492,6 +490,7 @@ int sdei_event_unregister(u32 event_num) >> struct sdei_event *event; >> >> WARN_ON(in_nmi()); >> + WARN_ON_ONCE(preemptible()); >> >> mutex_lock(&sdei_events_lock); >> event = sdei_event_find(event_num); >> @@ -561,8 +560,6 @@ static void _local_event_register(void *data) >> struct sdei_registered_event *reg; >> struct sdei_crosscall_args *arg = data; >> >> - WARN_ON(preemptible()); >> - >> reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id()); >> err = sdei_api_event_register(arg->event->event_num, sdei_entry_point, >> reg, 0, 0); >> @@ -576,6 +573,7 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) >> struct sdei_event *event; >> >> WARN_ON(in_nmi()); >> + WARN_ON_ONCE(preemptible()); >> >> mutex_lock(&sdei_events_lock); >> if (sdei_event_find(event_num)) { >> @@ -717,6 +715,8 @@ static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action, >> { >> int rv; >> >> + WARN_ON_ONCE(preemptible()); >> + >> switch (action) { >> case CPU_PM_ENTER: >> rv = sdei_mask_local_cpu(); >> @@ -765,7 +765,7 @@ static int sdei_device_freeze(struct device *dev) >> int err; >> >> /* unregister private events */ >> - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); >> + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); >> >> err = sdei_unregister_shared(); >> if (err) >> @@ -786,7 +786,7 @@ static int sdei_device_thaw(struct device *dev) >> return err; >> } >> >> - err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", >> + err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", >> &sdei_cpuhp_up, &sdei_cpuhp_down); >> if (err) >> pr_warn("Failed to re-register CPU hotplug notifier...\n"); >> @@ -823,7 +823,7 @@ static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action, >> * We are going to reset the interface, after this there is no point >> * doing work when we take CPUs offline. >> */ >> - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); >> + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); >> >> sdei_platform_reset(); >> >> @@ -1003,7 +1003,7 @@ static int sdei_probe(struct platform_device *pdev) >> goto remove_cpupm; >> } >> >> - err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", >> + err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", >> &sdei_cpuhp_up, &sdei_cpuhp_down); >> if (err) { >> pr_warn("Failed to register CPU hotplug notifier...\n"); >> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h >> index f61447913db9..63b89e00a4c3 100644 >> --- a/include/linux/cpuhotplug.h >> +++ b/include/linux/cpuhotplug.h >> @@ -161,7 +161,6 @@ enum cpuhp_state { >> CPUHP_AP_PERF_X86_CSTATE_STARTING, >> CPUHP_AP_PERF_XTENSA_STARTING, >> CPUHP_AP_MIPS_OP_LOONGSON3_STARTING, >> - CPUHP_AP_ARM_SDEI_STARTING, >> CPUHP_AP_ARM_VFP_STARTING, >> CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING, >> CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING, >> @@ -209,6 +208,7 @@ enum cpuhp_state { >> CPUHP_AP_IRQ_AFFINITY_ONLINE, >> CPUHP_AP_BLK_MQ_ONLINE, >> CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS, >> + CPUHP_AP_ARM_SDEI_ONLINE, >> CPUHP_AP_X86_INTEL_EPB_ONLINE, >> CPUHP_AP_PERF_ONLINE, >> CPUHP_AP_PERF_X86_ONLINE,
Hi Pierre, Sorry its taken so long for me to catch up with this ... On 18/10/2022 14:04, Pierre Gondois wrote: > On an Ampere Altra, > Running a preemp_rt kernel based on v5.19-rc3-rt5 on an > Ampere Altra triggers: > [ 15.683141] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 > [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0 > [ 15.683157] preempt_count: 0, expected: 0 > [ 15.683159] RCU nest depth: 0, expected: 0 > [ 15.683163] 3 locks held by cpuhp/0/24: > [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130 > [ 15.683224] irq event stamp: 36 > [ 15.683226] hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0 > [ 15.683236] hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248 > [ 15.683238] softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0 > [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] > [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 > [ 15.683268] Call trace: > [ 15.683271] dump_backtrace+0x114/0x120 > [ 15.683277] show_stack+0x20/0x70 > [ 15.683279] dump_stack_lvl+0x9c/0xd8 > [ 15.683288] dump_stack+0x18/0x34 > [ 15.683289] __might_resched+0x188/0x228 > [ 15.683292] rt_spin_lock+0x70/0x120 > [ 15.683301] sdei_cpuhp_up+0x3c/0x130 > [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 > [ 15.683305] cpuhp_thread_fun+0x120/0x248 > [ 15.683308] smpboot_thread_fn+0x280/0x320 > [ 15.683315] kthread+0x130/0x140 > [ 15.683321] ret_from_fork+0x10/0x20 > sdei_cpuhp_up() is called in the STARTING hotplug section, > which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ > state to the _ONLINE section to execute the cpuhp cb with > preemption enabled. The background to this is SDEI got its own cpuhp slot because 'perf NMI' support was one of the use-cases, but this got superseded by pNMI. Without an interaction with perf, the slot doesn't need to be that early. > Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the > calling CPU. It is checked that preemption is disabled for them. > _ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'. > Preemption is enabled in those threads, but their cpumask is limited > to 1 CPU. > Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb > don't trigger them. This means that no check will be done for some > cases, e.g. sdei_mask_local_cpu() invocations. (these things are documentation anyway) > Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call > which acts on the calling CPU. > diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c > index 1e1a51510e83..9b03e164a37a 100644 > --- a/drivers/firmware/arm_sdei.c > +++ b/drivers/firmware/arm_sdei.c > @@ -401,6 +399,8 @@ int sdei_event_enable(u32 event_num) > int err = -EINVAL; > struct sdei_event *event; > > + WARN_ON_ONCE(preemptible()); > + > mutex_lock(&sdei_events_lock); > event = sdei_event_find(event_num); > if (!event) { This doesn't look right. How can this code take a mutex if its in a non-preemptable context? > @@ -492,6 +490,7 @@ int sdei_event_unregister(u32 event_num) > struct sdei_event *event; > > WARN_ON(in_nmi()); > + WARN_ON_ONCE(preemptible()); > > mutex_lock(&sdei_events_lock); > event = sdei_event_find(event_num); Same again. > @@ -576,6 +573,7 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) > struct sdei_event *event; > > WARN_ON(in_nmi()); > + WARN_ON_ONCE(preemptible()); > > mutex_lock(&sdei_events_lock); > if (sdei_event_find(event_num)) { Same again. I think you've copied these here because they called _local_event_unregister(), but they did that via on_each_cpu(), which is what made _local_event_unregister() non-preemtable. You can just remove these three, the original warnings were mostly documentation, and to catch myself out. (before RT moved the goal posts). With that: Reviewed-by: James Morse <james.morse@arm.com> (could you trim the [timestamps] out of the commit log?) > @@ -765,7 +765,7 @@ static int sdei_device_freeze(struct device *dev) > int err; > > /* unregister private events */ > - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); > + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); Is there any mileage in making this CPUHP_AP_ONLINE_DYN ? Perf really was the only reason that this needed to happen in any particular order. Thanks, James
Hello James, On 2/10/23 18:42, James Morse wrote: > Hi Pierre, > > Sorry its taken so long for me to catch up with this ... No worries. > > On 18/10/2022 14:04, Pierre Gondois wrote: >> On an Ampere Altra, >> Running a preemp_rt kernel based on v5.19-rc3-rt5 on an >> Ampere Altra triggers: >> [ 15.683141] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 >> [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0 >> [ 15.683157] preempt_count: 0, expected: 0 >> [ 15.683159] RCU nest depth: 0, expected: 0 >> [ 15.683163] 3 locks held by cpuhp/0/24: >> [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 >> [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 >> [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130 >> [ 15.683224] irq event stamp: 36 >> [ 15.683226] hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0 >> [ 15.683236] hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248 >> [ 15.683238] softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0 >> [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 >> [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] >> [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 >> [ 15.683268] Call trace: >> [ 15.683271] dump_backtrace+0x114/0x120 >> [ 15.683277] show_stack+0x20/0x70 >> [ 15.683279] dump_stack_lvl+0x9c/0xd8 >> [ 15.683288] dump_stack+0x18/0x34 >> [ 15.683289] __might_resched+0x188/0x228 >> [ 15.683292] rt_spin_lock+0x70/0x120 >> [ 15.683301] sdei_cpuhp_up+0x3c/0x130 >> [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 >> [ 15.683305] cpuhp_thread_fun+0x120/0x248 >> [ 15.683308] smpboot_thread_fn+0x280/0x320 >> [ 15.683315] kthread+0x130/0x140 >> [ 15.683321] ret_from_fork+0x10/0x20 > >> sdei_cpuhp_up() is called in the STARTING hotplug section, >> which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ >> state to the _ONLINE section to execute the cpuhp cb with >> preemption enabled. > > The background to this is SDEI got its own cpuhp slot because 'perf NMI' support > was one of the use-cases, but this got superseded by pNMI. Without an interaction with > perf, the slot doesn't need to be that early. > > >> Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the >> calling CPU. It is checked that preemption is disabled for them. >> _ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'. >> Preemption is enabled in those threads, but their cpumask is limited >> to 1 CPU. > >> Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb >> don't trigger them. This means that no check will be done for some >> cases, e.g. sdei_mask_local_cpu() invocations. > > (these things are documentation anyway) > > >> Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call >> which acts on the calling CPU. > >> diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c >> index 1e1a51510e83..9b03e164a37a 100644 >> --- a/drivers/firmware/arm_sdei.c >> +++ b/drivers/firmware/arm_sdei.c > >> @@ -401,6 +399,8 @@ int sdei_event_enable(u32 event_num) >> int err = -EINVAL; >> struct sdei_event *event; >> >> + WARN_ON_ONCE(preemptible()); >> + >> mutex_lock(&sdei_events_lock); >> event = sdei_event_find(event_num); >> if (!event) { > > This doesn't look right. How can this code take a mutex if its in a non-preemptable context? > >> @@ -492,6 +490,7 @@ int sdei_event_unregister(u32 event_num) >> struct sdei_event *event; >> >> WARN_ON(in_nmi()); >> + WARN_ON_ONCE(preemptible()); >> >> mutex_lock(&sdei_events_lock); >> event = sdei_event_find(event_num); > > Same again. > >> @@ -576,6 +573,7 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) >> struct sdei_event *event; >> >> WARN_ON(in_nmi()); >> + WARN_ON_ONCE(preemptible()); >> >> mutex_lock(&sdei_events_lock); >> if (sdei_event_find(event_num)) { > > Same again. > > I think you've copied these here because they called _local_event_unregister(), but they > did that via on_each_cpu(), which is what made _local_event_unregister() non-preemtable. Yes right, these 3 warnings don't really make sense. They will be removed. > > You can just remove these three, the original warnings were mostly documentation, and to > catch myself out. (before RT moved the goal posts). > > With that: > Reviewed-by: James Morse <james.morse@arm.com> > > (could you trim the [timestamps] out of the commit log?) Yes sure. > > >> @@ -765,7 +765,7 @@ static int sdei_device_freeze(struct device *dev) >> int err; >> >> /* unregister private events */ >> - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); >> + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); > > Is there any mileage in making this CPUHP_AP_ONLINE_DYN ? > Perf really was the only reason that this needed to happen in any particular order. Ok I will do that. Thanks for the review, Regards, Pierre > > > Thanks, > > James
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c index 1e1a51510e83..9b03e164a37a 100644 --- a/drivers/firmware/arm_sdei.c +++ b/drivers/firmware/arm_sdei.c @@ -301,8 +301,6 @@ int sdei_mask_local_cpu(void) { int err; - WARN_ON_ONCE(preemptible()); - err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL); if (err && err != -EIO) { pr_warn_once("failed to mask CPU[%u]: %d\n", @@ -315,6 +313,7 @@ int sdei_mask_local_cpu(void) static void _ipi_mask_cpu(void *ignored) { + WARN_ON_ONCE(preemptible()); sdei_mask_local_cpu(); } @@ -322,8 +321,6 @@ int sdei_unmask_local_cpu(void) { int err; - WARN_ON_ONCE(preemptible()); - err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL); if (err && err != -EIO) { pr_warn_once("failed to unmask CPU[%u]: %d\n", @@ -336,6 +333,7 @@ int sdei_unmask_local_cpu(void) static void _ipi_unmask_cpu(void *ignored) { + WARN_ON_ONCE(preemptible()); sdei_unmask_local_cpu(); } @@ -343,6 +341,8 @@ static void _ipi_private_reset(void *ignored) { int err; + WARN_ON_ONCE(preemptible()); + err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0, NULL); if (err && err != -EIO) @@ -389,8 +389,6 @@ static void _local_event_enable(void *data) int err; struct sdei_crosscall_args *arg = data; - WARN_ON_ONCE(preemptible()); - err = sdei_api_event_enable(arg->event->event_num); sdei_cross_call_return(arg, err); @@ -401,6 +399,8 @@ int sdei_event_enable(u32 event_num) int err = -EINVAL; struct sdei_event *event; + WARN_ON_ONCE(preemptible()); + mutex_lock(&sdei_events_lock); event = sdei_event_find(event_num); if (!event) { @@ -479,8 +479,6 @@ static void _local_event_unregister(void *data) int err; struct sdei_crosscall_args *arg = data; - WARN_ON_ONCE(preemptible()); - err = sdei_api_event_unregister(arg->event->event_num); sdei_cross_call_return(arg, err); @@ -492,6 +490,7 @@ int sdei_event_unregister(u32 event_num) struct sdei_event *event; WARN_ON(in_nmi()); + WARN_ON_ONCE(preemptible()); mutex_lock(&sdei_events_lock); event = sdei_event_find(event_num); @@ -561,8 +560,6 @@ static void _local_event_register(void *data) struct sdei_registered_event *reg; struct sdei_crosscall_args *arg = data; - WARN_ON(preemptible()); - reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id()); err = sdei_api_event_register(arg->event->event_num, sdei_entry_point, reg, 0, 0); @@ -576,6 +573,7 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) struct sdei_event *event; WARN_ON(in_nmi()); + WARN_ON_ONCE(preemptible()); mutex_lock(&sdei_events_lock); if (sdei_event_find(event_num)) { @@ -717,6 +715,8 @@ static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action, { int rv; + WARN_ON_ONCE(preemptible()); + switch (action) { case CPU_PM_ENTER: rv = sdei_mask_local_cpu(); @@ -765,7 +765,7 @@ static int sdei_device_freeze(struct device *dev) int err; /* unregister private events */ - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); err = sdei_unregister_shared(); if (err) @@ -786,7 +786,7 @@ static int sdei_device_thaw(struct device *dev) return err; } - err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", + err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", &sdei_cpuhp_up, &sdei_cpuhp_down); if (err) pr_warn("Failed to re-register CPU hotplug notifier...\n"); @@ -823,7 +823,7 @@ static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action, * We are going to reset the interface, after this there is no point * doing work when we take CPUs offline. */ - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); sdei_platform_reset(); @@ -1003,7 +1003,7 @@ static int sdei_probe(struct platform_device *pdev) goto remove_cpupm; } - err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", + err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", &sdei_cpuhp_up, &sdei_cpuhp_down); if (err) { pr_warn("Failed to register CPU hotplug notifier...\n"); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index f61447913db9..63b89e00a4c3 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -161,7 +161,6 @@ enum cpuhp_state { CPUHP_AP_PERF_X86_CSTATE_STARTING, CPUHP_AP_PERF_XTENSA_STARTING, CPUHP_AP_MIPS_OP_LOONGSON3_STARTING, - CPUHP_AP_ARM_SDEI_STARTING, CPUHP_AP_ARM_VFP_STARTING, CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING, CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING, @@ -209,6 +208,7 @@ enum cpuhp_state { CPUHP_AP_IRQ_AFFINITY_ONLINE, CPUHP_AP_BLK_MQ_ONLINE, CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS, + CPUHP_AP_ARM_SDEI_ONLINE, CPUHP_AP_X86_INTEL_EPB_ONLINE, CPUHP_AP_PERF_ONLINE, CPUHP_AP_PERF_X86_ONLINE,
On an Ampere Altra, Running a preemp_rt kernel based on v5.19-rc3-rt5 on an Ampere Altra triggers: [ 15.683141] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0 [ 15.683157] preempt_count: 0, expected: 0 [ 15.683159] RCU nest depth: 0, expected: 0 [ 15.683163] 3 locks held by cpuhp/0/24: [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130 [ 15.683224] irq event stamp: 36 [ 15.683226] hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0 [ 15.683236] hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248 [ 15.683238] softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0 [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 [ 15.683268] Call trace: [ 15.683271] dump_backtrace+0x114/0x120 [ 15.683277] show_stack+0x20/0x70 [ 15.683279] dump_stack_lvl+0x9c/0xd8 [ 15.683288] dump_stack+0x18/0x34 [ 15.683289] __might_resched+0x188/0x228 [ 15.683292] rt_spin_lock+0x70/0x120 [ 15.683301] sdei_cpuhp_up+0x3c/0x130 [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 [ 15.683305] cpuhp_thread_fun+0x120/0x248 [ 15.683308] smpboot_thread_fn+0x280/0x320 [ 15.683315] kthread+0x130/0x140 [ 15.683321] ret_from_fork+0x10/0x20 sdei_cpuhp_up() is called in the STARTING hotplug section, which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ state to the _ONLINE section to execute the cpuhp cb with preemption enabled. Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the calling CPU. It is checked that preemption is disabled for them. _ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'. Preemption is enabled in those threads, but their cpumask is limited to 1 CPU. Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb don't trigger them. This means that no check will be done for some cases, e.g. sdei_mask_local_cpu() invocations. Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call which acts on the calling CPU. Suggested-by: James Morse <james.morse@arm.com> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> --- drivers/firmware/arm_sdei.c | 28 ++++++++++++++-------------- include/linux/cpuhotplug.h | 2 +- 2 files changed, 15 insertions(+), 15 deletions(-)