[coreboot-gerrit] [M] Change in coreboot[main]: cpu/x86/mp_init: Add code to restart APs

[Filip Lewiński (Code Review)]

Attention is currently required from: Michał Żygowski.

Hello Michał Żygowski,

I'd like you to do a code review.
Please visit

https://review.coreboot.org/c/coreboot/+/82696?usp=email

to review the following change.

Change subject: cpu/x86/mp_init: Add code to restart APs
......................................................................

cpu/x86/mp_init: Add code to restart APs

Change-Id: Ief2a7629d3075de29b363d05330e3a76cef48971
Signed-off-by: Michał Żygowski 
---
M src/cpu/x86/mp_init.c
M src/include/cpu/x86/mp.h
2 files changed, 50 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/96/82696/1

diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c
index bb51697..750a669 100644
--- a/src/cpu/x86/mp_init.c
+++ b/src/cpu/x86/mp_init.c
@@ -1177,3 +1177,46 @@

return ret;
 }
+
+
+/* AP restart code */
+
+static struct mp_flight_record ap_restart_steps[] = {
+	/* Wait for APs to finish then optionally start looking for work. */
+	MP_FR_BLOCK_APS(ap_wait_for_instruction, NULL),
+};
+
+enum cb_err restart_aps(void)
+{
+	struct mp_params mp_params;
+	atomic_t *ap_count;
+
+	if (!CONFIG(PARALLEL_MP_AP_WORK))
+		return CB_ERR_NOT_IMPLEMENTED;
+
+	mp_params.num_cpus = mp_state.cpu_count;
+	mp_params.num_records = ARRAY_SIZE(ap_restart_steps);
+	mp_params.flight_plan = &ap_restart_steps[0];
+
+	mp_info.num_records = ARRAY_SIZE(ap_restart_steps);
+	mp_info.records = &ap_restart_steps[0];
+
+	/* Load the SIPI vector. */
+	ap_count = load_sipi_vector(&mp_params);
+	if (ap_count == NULL)
+		return CB_ERR;
+
+	/* Make sure SIPI data hits RAM so the APs that come up will see
+	 * the startup code even if the caches are disabled.  */
+	wbinvd();
+
+	if (start_aps(NULL, global_num_aps, ap_count) != CB_SUCCESS) {
+		mdelay(1000);
+		printk(BIOS_DEBUG, "%d/%d eventually checked in?\n",
+		       atomic_read(ap_count), global_num_aps);
+		return CB_ERR;
+	}
+
+	/* Walk the flight plan for the BSP. */
+	return bsp_do_flight_plan(&mp_params);
+}
diff --git a/src/include/cpu/x86/mp.h b/src/include/cpu/x86/mp.h
index dd86dce..f80d309 100644
--- a/src/include/cpu/x86/mp.h
+++ b/src/include/cpu/x86/mp.h
@@ -136,6 +136,13 @@
 enum cb_err mp_park_aps(void);

/*
+ * Restart APs after they have been parked. Used by Intel TXT, which requires
+ * parking APs before running ACM , to restart APs and let coreboot program
+ * MTRRs on APs. For use only after mp_init.
+ */
+enum cb_err restart_aps(void);
+
+/*
  * SMM helpers to use with initializing CPUs.
  */