1 files changed, 18 insertions, 30 deletions

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 9527a4c6cbc2..0618aa61b26a 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -822,9 +822,6 @@ static void do_nothing(void *unused)
 
 void rfi_flush_enable(bool enable)
 {
-	if (rfi_flush == enable)
-		return;
-
 	if (enable) {
 		do_rfi_flush_fixups(enabled_flush_types);
 		on_each_cpu(do_nothing, NULL, 1);
@@ -834,11 +831,15 @@ void rfi_flush_enable(bool enable)
 	rfi_flush = enable;
 }
 
-static void init_fallback_flush(void)
+static void __ref init_fallback_flush(void)
 {
 	u64 l1d_size, limit;
 	int cpu;
 
+	/* Only allocate the fallback flush area once (at boot time). */
+	if (l1d_flush_fallback_area)
+		return;
+
 	l1d_size = ppc64_caches.l1d.size;
 	limit = min(safe_stack_limit(), ppc64_rma_size);
 
@@ -851,34 +852,23 @@ static void init_fallback_flush(void)
 	memset(l1d_flush_fallback_area, 0, l1d_size * 2);
 
 	for_each_possible_cpu(cpu) {
-		/*
-		 * The fallback flush is currently coded for 8-way
-		 * associativity. Different associativity is possible, but it
-		 * will be treated as 8-way and may not evict the lines as
-		 * effectively.
-		 *
-		 * 128 byte lines are mandatory.
-		 */
-		u64 c = l1d_size / 8;
-
 		paca[cpu].rfi_flush_fallback_area = l1d_flush_fallback_area;
-		paca[cpu].l1d_flush_congruence = c;
-		paca[cpu].l1d_flush_sets = c / 128;
+		paca[cpu].l1d_flush_size = l1d_size;
 	}
 }
 
-void __init setup_rfi_flush(enum l1d_flush_type types, bool enable)
+void setup_rfi_flush(enum l1d_flush_type types, bool enable)
 {
 	if (types & L1D_FLUSH_FALLBACK) {
-		pr_info("rfi-flush: Using fallback displacement flush\n");
+		pr_info("rfi-flush: fallback displacement flush available\n");
 		init_fallback_flush();
 	}
 
 	if (types & L1D_FLUSH_ORI)
-		pr_info("rfi-flush: Using ori type flush\n");
+		pr_info("rfi-flush: ori type flush available\n");
 
 	if (types & L1D_FLUSH_MTTRIG)
-		pr_info("rfi-flush: Using mttrig type flush\n");
+		pr_info("rfi-flush: mttrig type flush available\n");
 
 	enabled_flush_types = types;
 
@@ -889,13 +879,19 @@ void __init setup_rfi_flush(enum l1d_flush_type types, bool enable)
 #ifdef CONFIG_DEBUG_FS
 static int rfi_flush_set(void *data, u64 val)
 {
+	bool enable;
+
 	if (val == 1)
-		rfi_flush_enable(true);
+		enable = true;
 	else if (val == 0)
-		rfi_flush_enable(false);
+		enable = false;
 	else
 		return -EINVAL;
 
+	/* Only do anything if we're changing state */
+	if (enable != rfi_flush)
+		rfi_flush_enable(enable);
+
 	return 0;
 }
 
@@ -914,12 +910,4 @@ static __init int rfi_flush_debugfs_init(void)
 }
 device_initcall(rfi_flush_debugfs_init);
 #endif
-
-ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
-{
-	if (rfi_flush)
-		return sprintf(buf, "Mitigation: RFI Flush\n");
-
-	return sprintf(buf, "Vulnerable\n");
-}
 #endif /* CONFIG_PPC_BOOK3S_64 */