A common pattern is
- run a function on all cpus
- signal each cpu's completion with a cpumask
- halt the secondaries when they're complete
- have the primary wait on the cpumask for all to complete
smp_run is a wrapper for that pattern. Also, we were allowing
secondaries to go off in the weeds if they returned from their
secondary entry function, which can be difficult to debug. A
nice side-effect of adding this wrapper is we don't do that
anymore, and can even know when a secondary has halted with the
new cpu_halted_mask.
Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
---
arm/cstart.S | 3 ++-
arm/cstart64.S | 3 ++-
lib/arm/asm/smp.h | 2 ++
lib/arm/smp.c | 26 ++++++++++++++++++++++++++
4 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/arm/cstart.S b/arm/cstart.S
index 12461d104dad..b3176b274933 100644
--- a/arm/cstart.S
+++ b/arm/cstart.S
@@ -118,7 +118,8 @@ secondary_entry:
bl secondary_cinit
/* r0 is now the entry function, run it */
- mov pc, r0
+ blx r0
+ b secondary_halt
.globl halt
halt:
diff --git a/arm/cstart64.S b/arm/cstart64.S
index 7738babc4109..30f732f1e99b 100644
--- a/arm/cstart64.S
+++ b/arm/cstart64.S
@@ -79,7 +79,8 @@ secondary_entry:
bl secondary_cinit
/* x0 is now the entry function, run it */
- br x0
+ blr x0
+ b secondary_halt
.globl halt
halt:
diff --git a/lib/arm/asm/smp.h b/lib/arm/asm/smp.h
index 4cb86b6ce342..1d1cd7a29991 100644
--- a/lib/arm/asm/smp.h
+++ b/lib/arm/asm/smp.h
@@ -14,6 +14,7 @@ extern void halt(void);
extern cpumask_t cpu_present_mask;
extern cpumask_t cpu_online_mask;
+extern cpumask_t cpu_halted_mask;
#define cpu_present(cpu) cpumask_test_cpu(cpu, &cpu_present_mask)
#define cpu_online(cpu) cpumask_test_cpu(cpu, &cpu_online_mask)
#define for_each_present_cpu(cpu) for_each_cpu(cpu, &cpu_present_mask)
@@ -45,5 +46,6 @@ struct secondary_data {
extern struct secondary_data secondary_data;
extern void smp_boot_secondary(int cpu, secondary_entry_fn entry);
+extern void smp_run(void (*func)(void));
#endif /* _ASMARM_SMP_H_ */
diff --git a/lib/arm/smp.c b/lib/arm/smp.c
index bbaf9e60e950..8528aa454108 100644
--- a/lib/arm/smp.c
+++ b/lib/arm/smp.c
@@ -15,6 +15,7 @@
cpumask_t cpu_present_mask;
cpumask_t cpu_online_mask;
+cpumask_t cpu_halted_mask;
struct secondary_data secondary_data;
secondary_entry_fn secondary_cinit(void)
@@ -53,3 +54,28 @@ void smp_boot_secondary(int cpu, secondary_entry_fn entry)
while (!cpu_online(cpu))
wfe();
}
+
+void secondary_halt(void)
+{
+ struct thread_info *ti = current_thread_info();
+
+ cpumask_set_cpu(ti->cpu, &cpu_halted_mask);
+ halt();
+}
+
+void smp_run(void (*func)(void))
+{
+ int cpu;
+
+ for_each_present_cpu(cpu) {
+ if (cpu == 0)
+ continue;
+ smp_boot_secondary(cpu, func);
+ }
+ func();
+
+ cpumask_set_cpu(0, &cpu_halted_mask);
+ while (!cpumask_full(&cpu_halted_mask))
+ cpu_relax();
+ cpumask_clear_cpu(0, &cpu_halted_mask);
+}
--
2.9.4
