4 files changed, 45 insertions, 32 deletions

diff --git a/arch/s390/include/asm/asm-extable.h b/arch/s390/include/asm/asm-extable.h
index 620390f17f0c..61484a5f1209 100644
--- a/arch/s390/include/asm/asm-extable.h
+++ b/arch/s390/include/asm/asm-extable.h
@@ -5,17 +5,22 @@
 #include <linux/stringify.h>
 #include <asm/asm-const.h>
 
-#define __EX_TABLE(_section, _fault, _target)				\
+#define EX_TYPE_NONE	0
+#define EX_TYPE_FIXUP	1
+#define EX_TYPE_BPF	2
+
+#define __EX_TABLE(_section, _fault, _target, _type)			\
 	stringify_in_c(.section	_section,"a";)				\
-	stringify_in_c(.align	8;)					\
+	stringify_in_c(.align	4;)					\
 	stringify_in_c(.long	(_fault) - .;)				\
 	stringify_in_c(.long	(_target) - .;)				\
-	stringify_in_c(.quad	0;)					\
+	stringify_in_c(.short	(_type);)				\
+	stringify_in_c(.short	0;)					\
 	stringify_in_c(.previous)
 
 #define EX_TABLE(_fault, _target)					\
-	__EX_TABLE(__ex_table, _fault, _target)
+	__EX_TABLE(__ex_table, _fault, _target, EX_TYPE_FIXUP)
 #define EX_TABLE_AMODE31(_fault, _target)				\
-	__EX_TABLE(.amode31.ex_table, _fault, _target)
+	__EX_TABLE(.amode31.ex_table, _fault, _target, EX_TYPE_FIXUP)
 
 #endif /* __ASM_EXTABLE_H */
diff --git a/arch/s390/include/asm/extable.h b/arch/s390/include/asm/extable.h
index d39d7159832a..af6ba52743e9 100644
--- a/arch/s390/include/asm/extable.h
+++ b/arch/s390/include/asm/extable.h
@@ -25,7 +25,7 @@
 struct exception_table_entry
 {
 	int insn, fixup;
-	long handler;
+	short type, data;
 };
 
 extern struct exception_table_entry *__start_amode31_ex_table;
@@ -38,17 +38,6 @@ static inline unsigned long extable_fixup(const struct exception_table_entry *x)
 	return (unsigned long)&x->fixup + x->fixup;
 }
 
-typedef bool (*ex_handler_t)(const struct exception_table_entry *,
-			     struct pt_regs *);
-
-static inline ex_handler_t
-ex_fixup_handler(const struct exception_table_entry *x)
-{
-	if (likely(!x->handler))
-		return NULL;
-	return (ex_handler_t)((unsigned long)&x->handler + x->handler);
-}
-
 #define ARCH_HAS_RELATIVE_EXTABLE
 
 static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
@@ -58,15 +47,26 @@ static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
 {
 	a->fixup = b->fixup + delta;
 	b->fixup = tmp.fixup - delta;
-	a->handler = b->handler;
-	if (a->handler)
-		a->handler += delta;
-	b->handler = tmp.handler;
-	if (b->handler)
-		b->handler -= delta;
+	a->type = b->type;
+	b->type = tmp.type;
+	a->data = b->data;
+	b->data = tmp.data;
 }
 #define swap_ex_entry_fixup swap_ex_entry_fixup
 
+#ifdef CONFIG_BPF_JIT
+
+bool ex_handler_bpf(const struct exception_table_entry *ex, struct pt_regs *regs);
+
+#else /* !CONFIG_BPF_JIT */
+
+static inline bool ex_handler_bpf(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	return false;
+}
+
+#endif /* CONFIG_BPF_JIT */
+
 bool fixup_exception(struct pt_regs *regs);
 
 #endif
diff --git a/arch/s390/mm/extable.c b/arch/s390/mm/extable.c
index d6ca75570dcf..ac6b736ac883 100644
--- a/arch/s390/mm/extable.c
+++ b/arch/s390/mm/extable.c
@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/extable.h>
+#include <linux/panic.h>
+#include <asm/asm-extable.h>
 #include <asm/extable.h>
 
 const struct exception_table_entry *s390_search_extables(unsigned long addr)
@@ -15,17 +17,24 @@ const struct exception_table_entry *s390_search_extables(unsigned long addr)
 	return search_extable(__start_amode31_ex_table, num, addr);
 }
 
+static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
 bool fixup_exception(struct pt_regs *regs)
 {
 	const struct exception_table_entry *ex;
-	ex_handler_t handler;
 
 	ex = s390_search_extables(instruction_pointer(regs));
 	if (!ex)
 		return false;
-	handler = ex_fixup_handler(ex);
-	if (unlikely(handler))
-		return handler(ex, regs);
-	regs->psw.addr = extable_fixup(ex);
-	return true;
+	switch (ex->type) {
+	case EX_TYPE_FIXUP:
+		return ex_handler_fixup(ex, regs);
+	case EX_TYPE_BPF:
+		return ex_handler_bpf(ex, regs);
+	}
+	panic("invalid exception table entry");
 }
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index f884d1b9ca79..a1a3a10c514c 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -622,8 +622,7 @@ static int get_probe_mem_regno(const u8 *insn)
 	return insn[1] >> 4;
 }
 
-static bool ex_handler_bpf(const struct exception_table_entry *x,
-			   struct pt_regs *regs)
+bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs)
 {
 	int regno;
 	u8 *insn;
@@ -678,7 +677,7 @@ static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp,
 			/* JIT bug - landing pad and extable must be close. */
 			return -1;
 		ex->fixup = delta;
-		ex->handler = (u8 *)ex_handler_bpf - (u8 *)&ex->handler;
+		ex->type = EX_TYPE_BPF;
 		jit->excnt++;
 	}
 	return 0;