1 files changed, 37 insertions, 19 deletions

diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h
index 6c32190dc73e..d9cbc18f6b2e 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -1,37 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_S390_JUMP_LABEL_H
 #define _ASM_S390_JUMP_LABEL_H
 
+#define HAVE_JUMP_LABEL_BATCH
+
+#ifndef __ASSEMBLER__
+
 #include <linux/types.h>
+#include <linux/stringify.h>
 
 #define JUMP_LABEL_NOP_SIZE 6
 
-#ifdef CONFIG_64BIT
-#define ASM_PTR ".quad"
-#define ASM_ALIGN ".balign 8"
+#ifdef CONFIG_CC_IS_CLANG
+#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "i"
+#elif __GNUC__ < 9
+#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "X"
 #else
-#define ASM_PTR ".long"
-#define ASM_ALIGN ".balign 4"
+#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "jdd"
 #endif
 
-static __always_inline bool arch_static_branch(struct static_key *key)
+/*
+ * We use a brcl 0,<offset> instruction for jump labels so it
+ * can be easily distinguished from a hotpatch generated instruction.
+ */
+static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
 {
-	asm goto("0:	brcl 0,0\n"
-		".pushsection __jump_table, \"aw\"\n"
-		ASM_ALIGN "\n"
-		ASM_PTR " 0b, %l[label], %0\n"
-		".popsection\n"
-		: : "X" (key) : : label);
+	asm goto("0:	brcl 0,%l[label]\n"
+			  ".pushsection __jump_table,\"aw\"\n"
+			  ".balign	8\n"
+			  ".long	0b-.,%l[label]-.\n"
+			  ".quad	%0+%1-.\n"
+			  ".popsection\n"
+			  : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
 	return false;
 label:
 	return true;
 }
 
-typedef unsigned long jump_label_t;
-
-struct jump_entry {
-	jump_label_t code;
-	jump_label_t target;
-	jump_label_t key;
-};
+static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
+{
+	asm goto("0:	brcl 15,%l[label]\n"
+			  ".pushsection __jump_table,\"aw\"\n"
+			  ".balign	8\n"
+			  ".long	0b-.,%l[label]-.\n"
+			  ".quad	%0+%1-.\n"
+			  ".popsection\n"
+			  : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
+	return false;
+label:
+	return true;
+}
 
+#endif  /* __ASSEMBLER__ */
 #endif