powerpc/powernv: Return secondary CPUs to firmware before FW update

Firmware update on PowerNV platform takes several minutes. During this time one CPU is stuck in FW and the kernel complains about "soft lockups". This patch returns all secondary CPUs to firmware before starting firmware update process. [ Reworked a bit and cleaned up -- BenH ] Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/powernv: Return secondary CPUs to firmware before FW update
Firmware update on PowerNV platform takes several minutes. During this time one CPU is stuck in FW and the kernel complains about "soft lockups". This patch returns all secondary CPUs to firmware before starting firmware update process. [ Reworked a bit and cleaned up -- BenH ] Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Vasant Hegde · Benjamin Herrenschmidt
1 parent 654837e8fe
Showing 3 changed files with 66 additions and 7 deletions Side-by-side Diff
arch/powerpc/include/asm/opal.h
arch/powerpc/platforms/powernv/opal-flash.c
arch/powerpc/platforms/powernv/setup.c
@@ -916,6 +916,7 @@
 extern unsigned long opal_get_boot_time(void);
 extern void opal_nvram_init(void);
 extern void opal_flash_init(void);
+extern void opal_flash_term_callback(void);
 extern int opal_elog_init(void);
 extern void opal_platform_dump_init(void);
 extern void opal_sys_param_init(void);
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
+#include <linux/delay.h>
  
 #include <asm/opal.h>
  
  
@@ -290,16 +291,52 @@
 	/* First entry address */
 	addr = __pa(list);
  
-	pr_alert("FLASH: Image is %u bytes\n", image_data.size);
-	pr_alert("FLASH: Image update requested\n");
-	pr_alert("FLASH: Image will be updated during system reboot\n");
-	pr_alert("FLASH: This will take several minutes. Do not power off!\n");
-
 flash:
 	rc = opal_update_flash(addr);
  
 invalid_img:
 	return rc;
+}
+
+/* Return CPUs to OPAL before starting FW update */
+static void flash_return_cpu(void *info)
+{
+	int cpu = smp_processor_id();
+
+	if (!cpu_online(cpu))
+		return;
+
+	/* Disable IRQ */
+	hard_irq_disable();
+
+	/* Return the CPU to OPAL */
+	opal_return_cpu();
+}
+
+/* This gets called just before system reboots */
+void opal_flash_term_callback(void)
+{
+	struct cpumask mask;
+
+	if (update_flash_data.status != FLASH_IMG_READY)
+		return;
+
+	pr_alert("FLASH: Flashing new firmware\n");
+	pr_alert("FLASH: Image is %u bytes\n", image_data.size);
+	pr_alert("FLASH: Performing flash and reboot/shutdown\n");
+	pr_alert("FLASH: This will take several minutes. Do not power off!\n");
+
+	/* Small delay to help getting the above message out */
+	msleep(500);
+
+	/* Return secondary CPUs to firmware */
+	cpumask_copy(&mask, cpu_online_mask);
+	cpumask_clear_cpu(smp_processor_id(), &mask);
+	if (!cpumask_empty(&mask))
+		smp_call_function_many(&mask,
+				       flash_return_cpu, NULL, false);
+	/* Hard disable interrupts */
+	hard_irq_disable();
 }
  
 /*
@@ -98,11 +98,32 @@
 	of_node_put(root);
 }
  
+static void pnv_prepare_going_down(void)
+{
+	/*
+	 * Disable all notifiers from OPAL, we can't
+	 * service interrupts anymore anyway
+	 */
+	opal_notifier_disable();
+
+	/* Soft disable interrupts */
+	local_irq_disable();
+
+	/*
+	 * Return secondary CPUs to firwmare if a flash update
+	 * is pending otherwise we will get all sort of error
+	 * messages about CPU being stuck etc.. This will also
+	 * have the side effect of hard disabling interrupts so
+	 * past this point, the kernel is effectively dead.
+	 */
+	opal_flash_term_callback();
+}
+
 static void  __noreturn pnv_restart(char *cmd)
 {
 	long rc = OPAL_BUSY;
  
-	opal_notifier_disable();
+	pnv_prepare_going_down();
  
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_cec_reboot();
@@ -119,7 +140,7 @@
 {
 	long rc = OPAL_BUSY;
  
-	opal_notifier_disable();
+	pnv_prepare_going_down();
  
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_cec_power_down(0);
...	...	@@ -916,6 +916,7 @@
916	916	extern unsigned long opal_get_boot_time(void);
917	917	extern void opal_nvram_init(void);
918	918	extern void opal_flash_init(void);
	919	+extern void opal_flash_term_callback(void);
919	920	extern int opal_elog_init(void);
920	921	extern void opal_platform_dump_init(void);
921	922	extern void opal_sys_param_init(void);
...	...	@@ -20,6 +20,7 @@
20	20	#include <linux/mm.h>
21	21	#include <linux/vmalloc.h>
22	22	#include <linux/pagemap.h>
	23	+#include <linux/delay.h>
23	24
24	25	#include <asm/opal.h>
25	26
26	27
...	...	@@ -290,16 +291,52 @@
290	291	/* First entry address */
291	292	addr = __pa(list);
292	293
293		- pr_alert("FLASH: Image is %u bytes\n", image_data.size);
294		- pr_alert("FLASH: Image update requested\n");
295		- pr_alert("FLASH: Image will be updated during system reboot\n");
296		- pr_alert("FLASH: This will take several minutes. Do not power off!\n");
297		-
298	294	flash:
299	295	rc = opal_update_flash(addr);
300	296
301	297	invalid_img:
302	298	return rc;
	299	+}
	300	+
	301	+/* Return CPUs to OPAL before starting FW update */
	302	+static void flash_return_cpu(void *info)
	303	+{
	304	+ int cpu = smp_processor_id();
	305	+
	306	+ if (!cpu_online(cpu))
	307	+ return;
	308	+
	309	+ /* Disable IRQ */
	310	+ hard_irq_disable();
	311	+
	312	+ /* Return the CPU to OPAL */
	313	+ opal_return_cpu();
	314	+}
	315	+
	316	+/* This gets called just before system reboots */
	317	+void opal_flash_term_callback(void)
	318	+{
	319	+ struct cpumask mask;
	320	+
	321	+ if (update_flash_data.status != FLASH_IMG_READY)
	322	+ return;
	323	+
	324	+ pr_alert("FLASH: Flashing new firmware\n");
	325	+ pr_alert("FLASH: Image is %u bytes\n", image_data.size);
	326	+ pr_alert("FLASH: Performing flash and reboot/shutdown\n");
	327	+ pr_alert("FLASH: This will take several minutes. Do not power off!\n");
	328	+
	329	+ /* Small delay to help getting the above message out */
	330	+ msleep(500);
	331	+
	332	+ /* Return secondary CPUs to firmware */
	333	+ cpumask_copy(&mask, cpu_online_mask);
	334	+ cpumask_clear_cpu(smp_processor_id(), &mask);
	335	+ if (!cpumask_empty(&mask))
	336	+ smp_call_function_many(&mask,
	337	+ flash_return_cpu, NULL, false);
	338	+ /* Hard disable interrupts */
	339	+ hard_irq_disable();
303	340	}
304	341
305	342	/*
...	...	@@ -98,11 +98,32 @@
98	98	of_node_put(root);
99	99	}
100	100
	101	+static void pnv_prepare_going_down(void)
	102	+{
	103	+ /*
	104	+ * Disable all notifiers from OPAL, we can't
	105	+ * service interrupts anymore anyway
	106	+ */
	107	+ opal_notifier_disable();
	108	+
	109	+ /* Soft disable interrupts */
	110	+ local_irq_disable();
	111	+
	112	+ /*
	113	+ * Return secondary CPUs to firwmare if a flash update
	114	+ * is pending otherwise we will get all sort of error
	115	+ * messages about CPU being stuck etc.. This will also
	116	+ * have the side effect of hard disabling interrupts so
	117	+ * past this point, the kernel is effectively dead.
	118	+ */
	119	+ opal_flash_term_callback();
	120	+}
	121	+
101	122	static void __noreturn pnv_restart(char *cmd)
102	123	{
103	124	long rc = OPAL_BUSY;
104	125
105		- opal_notifier_disable();
	126	+ pnv_prepare_going_down();
106	127
107	128	while (rc == OPAL_BUSY \|\| rc == OPAL_BUSY_EVENT) {
108	129	rc = opal_cec_reboot();
...	...	@@ -119,7 +140,7 @@
119	140	{
120	141	long rc = OPAL_BUSY;
121	142
122		- opal_notifier_disable();
	143	+ pnv_prepare_going_down();
123	144
124	145	while (rc == OPAL_BUSY \|\| rc == OPAL_BUSY_EVENT) {
125	146	rc = opal_cec_power_down(0);