diff options
author | Juergen Gross <jgross@suse.com> | 2016-08-29 08:48:44 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2016-09-05 13:52:39 +0200 |
commit | df8ce9d78a4e7fbe7ddfd8ccee3ecaaa0013e883 (patch) | |
tree | a9d0a3e96a445aefe77de0dfadbd521df2499f5a | |
parent | 47ae4b05d0fa2f2a998ebaf34d2dcbffca56a9db (diff) |
smp: Add function to execute a function synchronously on a CPU
On some hardware models (e.g. Dell Studio 1555 laptop) some hardware
related functions (e.g. SMIs) are to be executed on physical CPU 0
only. Instead of open coding such a functionality multiple times in
the kernel add a service function for this purpose. This will enable
the possibility to take special measures in virtualized environments
like Xen, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Douglas_Warzecha@dell.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akataria@vmware.com
Cc: boris.ostrovsky@oracle.com
Cc: chrisw@sous-sol.org
Cc: david.vrabel@citrix.com
Cc: hpa@zytor.com
Cc: jdelvare@suse.com
Cc: jeremy@goop.org
Cc: linux@roeck-us.net
Cc: pali.rohar@gmail.com
Cc: rusty@rustcorp.com.au
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1472453327-19050-4-git-send-email-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r-- | include/linux/smp.h | 3 | ||||
-rw-r--r-- | kernel/smp.c | 50 | ||||
-rw-r--r-- | kernel/up.c | 17 |
3 files changed, 70 insertions, 0 deletions
diff --git a/include/linux/smp.h b/include/linux/smp.h index eccae4690f41..8e0cb7a0f836 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -196,6 +196,9 @@ extern void arch_enable_nonboot_cpus_end(void); void smp_setup_processor_id(void); +int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, + bool phys); + /* SMP core functions */ int smpcfd_prepare_cpu(unsigned int cpu); int smpcfd_dead_cpu(unsigned int cpu); diff --git a/kernel/smp.c b/kernel/smp.c index 4274ca5f3bbc..f4f6137941cb 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -725,3 +725,53 @@ void wake_up_all_idle_cpus(void) preempt_enable(); } EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); + +/** + * smp_call_on_cpu - Call a function on a specific cpu + * + * Used to call a function on a specific cpu and wait for it to return. + * Optionally make sure the call is done on a specified physical cpu via vcpu + * pinning in order to support virtualized environments. + */ +struct smp_call_on_cpu_struct { + struct work_struct work; + struct completion done; + int (*func)(void *); + void *data; + int ret; + int cpu; +}; + +static void smp_call_on_cpu_callback(struct work_struct *work) +{ + struct smp_call_on_cpu_struct *sscs; + + sscs = container_of(work, struct smp_call_on_cpu_struct, work); + if (sscs->cpu >= 0) + hypervisor_pin_vcpu(sscs->cpu); + sscs->ret = sscs->func(sscs->data); + if (sscs->cpu >= 0) + hypervisor_pin_vcpu(-1); + + complete(&sscs->done); +} + +int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) +{ + struct smp_call_on_cpu_struct sscs = { + .work = __WORK_INITIALIZER(sscs.work, smp_call_on_cpu_callback), + .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done), + .func = func, + .data = par, + .cpu = phys ? cpu : -1, + }; + + if (cpu >= nr_cpu_ids || !cpu_online(cpu)) + return -ENXIO; + + queue_work_on(cpu, system_wq, &sscs.work); + wait_for_completion(&sscs.done); + + return sscs.ret; +} +EXPORT_SYMBOL_GPL(smp_call_on_cpu); diff --git a/kernel/up.c b/kernel/up.c index 3ccee2bd13ba..ee81ac9af4ca 100644 --- a/kernel/up.c +++ b/kernel/up.c @@ -83,3 +83,20 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), preempt_enable(); } EXPORT_SYMBOL(on_each_cpu_cond); + +int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) +{ + int ret; + + if (cpu != 0) + return -ENXIO; + + if (phys) + hypervisor_pin_vcpu(0); + ret = func(par); + if (phys) + hypervisor_pin_vcpu(-1); + + return ret; +} +EXPORT_SYMBOL_GPL(smp_call_on_cpu); |