Change in coreboot[master]: cpu/x86/mp_init.c: Add wait_finished_mp_run_on_all_cpus

[Kane Chen (Code Review)]

Kane Chen has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/63566 )

Change subject: cpu/x86/mp_init.c: Add wait_finished_mp_run_on_all_cpus
......................................................................

cpu/x86/mp_init.c: Add wait_finished_mp_run_on_all_cpus

This patch adds a parameter wait_ap_complete in mp_callback to decide
when APs call store_callback to notify BSP it already takes jobs.
This can allow the caller to decide whether it should wait all APs to
continue or not.

Change-Id: I8d1d49bca410c821a3ad0347548afc42eb860594
Signed-off-by: Kane Chen 
Co-authored-by: Arthur Heymans 
---
M src/cpu/x86/mp_init.c
M src/include/cpu/x86/mp.h
2 files changed, 34 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/66/63566/1

diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c
index 81c987b..28febdc 100644
--- a/src/cpu/x86/mp_init.c
+++ b/src/cpu/x86/mp_init.c
@@ -33,6 +33,7 @@
    void (*func)(void *);
    void *arg;
    int logical_cpu_number;
+	bool wait_ap_complete;
 };

static char processor_name[49];
@@ -960,12 +961,15 @@
    	/* Copy to local variable before signaling consumption. */
    	memcpy(&lcb, cb, sizeof(lcb));
    	mfence();
-		store_callback(per_cpu_slot, NULL);
+		if (!lcb.wait_ap_complete)
+			store_callback(per_cpu_slot, NULL);
    	if (lcb.logical_cpu_number && (cur_cpu !=
    			lcb.logical_cpu_number))
    		continue;
    	else
    		lcb.func(lcb.arg);
+		if (lcb.wait_ap_complete)
+			store_callback(per_cpu_slot, NULL);
    }
 }

@@ -977,6 +981,15 @@
    return run_ap_work(&lcb, expire_us);
 }

+enum cb_err mp_run_on_aps_and_wait_for_complete(void (*func)(void *), void *arg,
+		int logical_cpu_num, long expire_us)
+{
+	struct mp_callback lcb = { .func = func, .arg = arg,
+				.logical_cpu_number = logical_cpu_num,
+				.wait_ap_complete = true};
+	return run_ap_work(&lcb, expire_us);
+}
+
 enum cb_err mp_run_on_all_aps(void (*func)(void *), void *arg, long expire_us,
    		      bool run_parallel)
 {
@@ -1009,6 +1022,16 @@
    return mp_run_on_aps(func, arg, MP_RUN_ON_ALL_CPUS, 1000 * USECS_PER_MSEC);
 }

+enum cb_err wait_finished_mp_run_on_all_cpus(void (*func)(void *), void *arg)
+{
+	/* Run on BSP first. */
+	func(arg);
+
+	/* For up to 1 second for AP to finish previous work. */
+	return mp_run_on_aps_and_wait_for_complete(func, arg, MP_RUN_ON_ALL_CPUS,
+												1000 * USECS_PER_MSEC);
+}
+
 enum cb_err mp_park_aps(void)
 {
    struct stopwatch sw;
diff --git a/src/include/cpu/x86/mp.h b/src/include/cpu/x86/mp.h
index 1b4c956..2324c48 100644
--- a/src/include/cpu/x86/mp.h
+++ b/src/include/cpu/x86/mp.h
@@ -106,6 +106,12 @@
  */
 enum cb_err mp_run_on_aps(void (*func)(void *), void *arg, int logical_cpu_num,
    	long expire_us);
+/*
+ * This function is similar to mp_run_on_aps but the BSP will wait for all APs
+ * to complete the assigned tasks and continue
+ */
+enum cb_err mp_run_on_aps_and_wait_for_complete(void (*func)(void *), void *arg,
+	int logical_cpu_num, long expire_us);

/*
  * Runs func on all APs excluding BSP, with a provision to run calls in parallel
@@ -117,6 +123,10 @@
 /* Like mp_run_on_aps() but also runs func on BSP. */
 enum cb_err mp_run_on_all_cpus(void (*func)(void *), void *arg);

+/* Like mp_run_on_all_cpus but make sure all APs finish executing the
+   function call. The time limit on a function call is 1 second. */
+enum cb_err wait_finished_mp_run_on_all_cpus(void (*func)(void *), void *arg);
+
 /*
  * Park all APs to prepare for OS boot. This is handled automatically
  * by the coreboot infrastructure.