From: Thomas Tai <thomas.tai@oracle.com>
Date: Thu, 27 Oct 2016 19:48:50 +0000 (-0700)
Subject: sparc64: allocate sufficient space for machine description
X-Git-Tag: v4.1.12-104.0.20170618_1145~239
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7ebef2e9ff5dc4c29a105a7c9d9a73788f1c7e5b;p=users%2Fjedix%2Flinux-maple.git

sparc64: allocate sufficient space for machine description

Machine description size can changed at runtime. If the
required MD size changes during allocating the space, retry
until the space is large enough.

Orabug: 23082240

Signed-off-by: Thomas Tai <thomas.tai@oracle.com>
Reviewed-by: Chris Hyser <chris.hyser@oracle.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
---

diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c
index 665b24fa20800..603e30f2e6f65 100644
--- a/arch/sparc/kernel/mdesc.c
+++ b/arch/sparc/kernel/mdesc.c
@@ -24,6 +24,8 @@
 #include <asm/mmu_64.h>
 #include <asm/adi.h>
 
+#define MDESC_RETRIES 1000
+
 /* Unlike the OBP device tree, the machine description is a full-on
  * DAG.  An arbitrary number of ARCs are possible from one
  * node to other nodes and thus we can't use the OBP device_node
@@ -516,39 +518,48 @@ void mdesc_update(void)
 	unsigned long len, real_len, status;
 	struct mdesc_handle *hp, *orig_hp;
 	unsigned long flags;
+	int i;
 
 	mutex_lock(&mdesc_mutex);
 
-	(void) sun4v_mach_desc(0UL, 0UL, &len);
+	for (i = 0; i < MDESC_RETRIES; ++i) {
+		(void)sun4v_mach_desc(0UL, 0UL, &len);
 
-	hp = mdesc_alloc(len, &kmalloc_mdesc_memops);
-	if (!hp) {
-		printk(KERN_ERR "MD: mdesc alloc fails\n");
-		goto out;
-	}
+		hp = mdesc_alloc(len, &kmalloc_mdesc_memops);
+		if (!hp) {
+			pr_err("MD: mdesc alloc fails\n");
+			goto out;
+		}
 
-	status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
-	if (status != HV_EOK || real_len > len) {
-		printk(KERN_ERR "MD: mdesc reread fails with %lu\n",
-		       status);
-		atomic_dec(&hp->refcnt);
-		mdesc_free(hp);
-		goto out;
-	}
+		status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
+		if (status != HV_EOK || real_len > len) {
+			/* retry reading the mdesc */
+			atomic_dec(&hp->refcnt);
+			mdesc_free(hp);
+			hp = NULL;
+			continue;
+		}
 
-	spin_lock_irqsave(&mdesc_lock, flags);
-	orig_hp = cur_mdesc;
-	cur_mdesc = hp;
-	spin_unlock_irqrestore(&mdesc_lock, flags);
+		spin_lock_irqsave(&mdesc_lock, flags);
+		orig_hp = cur_mdesc;
+		cur_mdesc = hp;
+		spin_unlock_irqrestore(&mdesc_lock, flags);
 
-	mdesc_notify_clients(orig_hp, hp);
+		mdesc_notify_clients(orig_hp, hp);
 
-	spin_lock_irqsave(&mdesc_lock, flags);
-	if (atomic_dec_and_test(&orig_hp->refcnt))
-		mdesc_free(orig_hp);
-	else
-		list_add(&orig_hp->list, &mdesc_zombie_list);
-	spin_unlock_irqrestore(&mdesc_lock, flags);
+		spin_lock_irqsave(&mdesc_lock, flags);
+		if (atomic_dec_and_test(&orig_hp->refcnt))
+			mdesc_free(orig_hp);
+		else
+			list_add(&orig_hp->list, &mdesc_zombie_list);
+		spin_unlock_irqrestore(&mdesc_lock, flags);
+
+		/* successfully read the mdesc, break out of the loop */
+		break;
+	}
+
+	if  (i >= MDESC_RETRIES)
+		pr_err("MD: mdesc reread fails with %lu\n", status);
 
 out:
 	mutex_unlock(&mdesc_mutex);
@@ -1394,30 +1405,44 @@ void __init sun4v_mdesc_init(void)
 {
 	struct mdesc_handle *hp;
 	unsigned long len, real_len, status;
+	int i;
 
-	(void) sun4v_mach_desc(0UL, 0UL, &len);
+	for (i = 0; i < MDESC_RETRIES; ++i) {
 
-	printk("MDESC: Size is %lu bytes.\n", len);
+		(void)sun4v_mach_desc(0UL, 0UL, &len);
 
-	hp = mdesc_alloc(len, &memblock_mdesc_ops);
-	if (hp == NULL) {
-		prom_printf("MDESC: alloc of %lu bytes failed.\n", len);
-		prom_halt();
+		hp = mdesc_alloc(len, &memblock_mdesc_ops);
+		if (!hp) {
+			prom_printf("MDESC: alloc of %lu bytes failed.\n", len);
+			prom_halt();
+			break;
+		}
+
+		status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
+		if (status != HV_EOK || real_len > len) {
+			mdesc_free(hp);
+			hp = NULL;
+			continue;
+		}
+
+		/* current 'mops' pointers are dangerous if not __init code */
+		hp->mops = NULL;
+		cur_mdesc = hp;
+
+#ifdef CONFIG_SPARC64
+	        mdesc_adi_init();
+#endif
+		report_platform_properties();
+
+		/* successfully read mdesc, break out of the loop */
+		break;
 	}
 
-	status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
-	if (status != HV_EOK || real_len > len) {
+	if  (i >= MDESC_RETRIES) {
 		prom_printf("sun4v_mach_desc fails, err(%lu), "
 			    "len(%lu), real_len(%lu)\n",
 			    status, len, real_len);
-		mdesc_free(hp);
 		prom_halt();
 	}
-
-	/* current 'mops' pointers are dangerous if not __init code */
-	hp->mops = NULL;
-	cur_mdesc = hp;
-
-	mdesc_adi_init();
-	report_platform_properties();
+	pr_info("MDESC: Size is %lu bytes.\n", len);
 }