| Message ID | 20170601154819.18831-3-drjones@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2017-06-01 17:48+0200, Andrew Jones: > Signed-off-by: Andrew Jones <drjones@redhat.com> > --- > diff --git a/lib/x86/smp.c b/lib/x86/smp.c > @@ -1,5 +1,6 @@ > @@ -91,6 +95,21 @@ void on_cpu_async(int cpu, void (*function)(void *data), void *data) > __on_cpu(cpu, function, data, 0); > } > (I'm sorry the review took so long.) > +void on_cpus(void (*func)(void)) > +{ > + int cpu; > + > + for (cpu = cpu_count() - 1; cpu >= 0; --cpu) > + on_cpu_async(cpu, (ipi_function_type)func, NULL); Calling a casted function pointer is undefined behavior in C and I think that keeping the argument is better anyway -- the API is consistent that way and you don't need to introduce a global in some patches. > + > + while (cpus_active()) > + ; Add a pause() here, Thanks.
On Wed, Jun 07, 2017 at 04:48:34PM +0200, Radim Krčmář wrote: > 2017-06-01 17:48+0200, Andrew Jones: > > Signed-off-by: Andrew Jones <drjones@redhat.com> > > --- > > diff --git a/lib/x86/smp.c b/lib/x86/smp.c > > @@ -1,5 +1,6 @@ > > @@ -91,6 +95,21 @@ void on_cpu_async(int cpu, void (*function)(void *data), void *data) > > __on_cpu(cpu, function, data, 0); > > } > > > > (I'm sorry the review took so long.) > > > +void on_cpus(void (*func)(void)) > > +{ > > + int cpu; > > + > > + for (cpu = cpu_count() - 1; cpu >= 0; --cpu) > > + on_cpu_async(cpu, (ipi_function_type)func, NULL); > > Calling a casted function pointer is undefined behavior in C and I think > that keeping the argument is better anyway -- the API is consistent that > way and you don't need to introduce a global in some patches. I agree I shouldn't use undefined behavior and I have no strong preference on the API, so I 'll change this, and I'll fix ARM too. > > > + > > + while (cpus_active()) > > + ; > > Add a pause() here, Will do. Thanks, drew
diff --git a/lib/x86/smp.c b/lib/x86/smp.c index 4bdbeaeb8b68..b16c98c02ad2 100644 --- a/lib/x86/smp.c +++ b/lib/x86/smp.c @@ -1,5 +1,6 @@ #include <libcflat.h> +#include "atomic.h" #include "smp.h" #include "apic.h" #include "fwcfg.h" @@ -15,6 +16,7 @@ static void *volatile ipi_data; static volatile int ipi_done; static volatile bool ipi_wait; static int _cpu_count; +static atomic_t active_cpus; static __attribute__((used)) void ipi() { @@ -27,6 +29,7 @@ static __attribute__((used)) void ipi() apic_write(APIC_EOI, 0); } function(data); + atomic_dec(&active_cpus); if (wait) { ipi_done = 1; apic_write(APIC_EOI, 0); @@ -68,6 +71,7 @@ static void __on_cpu(int cpu, void (*function)(void *data), void *data, if (cpu == smp_id()) function(data); else { + atomic_inc(&active_cpus); ipi_done = 0; ipi_function = function; ipi_data = data; @@ -91,6 +95,21 @@ void on_cpu_async(int cpu, void (*function)(void *data), void *data) __on_cpu(cpu, function, data, 0); } +void on_cpus(void (*func)(void)) +{ + int cpu; + + for (cpu = cpu_count() - 1; cpu >= 0; --cpu) + on_cpu_async(cpu, (ipi_function_type)func, NULL); + + while (cpus_active()) + ; +} + +int cpus_active(void) +{ + return atomic_read(&active_cpus) > 1; +} void smp_init(void) { @@ -106,4 +125,5 @@ void smp_init(void) for (i = 1; i < cpu_count(); ++i) on_cpu(i, setup_smp_id, 0); + atomic_inc(&active_cpus); } diff --git a/lib/x86/smp.h b/lib/x86/smp.h index afabac8495f1..5b8deb4a185e 100644 --- a/lib/x86/smp.h +++ b/lib/x86/smp.h @@ -6,7 +6,9 @@ void smp_init(void); int cpu_count(void); int smp_id(void); +int cpus_active(void); void on_cpu(int cpu, void (*function)(void *data), void *data); void on_cpu_async(int cpu, void (*function)(void *data), void *data); +void on_cpus(void (*func)(void)); #endif
Signed-off-by: Andrew Jones <drjones@redhat.com> --- lib/x86/smp.c | 20 ++++++++++++++++++++ lib/x86/smp.h | 2 ++ 2 files changed, 22 insertions(+)