arm64: Add support for hooks to handle undefined instructions

Add support to register hooks for undefined instructions. The handlers
will be called when the undefined instruction and the processor state
(as contained in pstate) match criteria used at registration.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 18 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 56a9e63..1bb0430 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -354,6 +354,8 @@ bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn);
 int aarch64_insn_patch_text_nosync(void *addr, u32 insn);
 int aarch64_insn_patch_text_sync(void *addrs[], u32 insns[], int cnt);
 int aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt);
+
+bool aarch32_insn_is_wide(u32 insn);
 #endif /* __ASSEMBLY__ */
 
 #endif	/* __ASM_INSN_H */
diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h
index 10ca8ff..232e4ba 100644
--- a/arch/arm64/include/asm/traps.h
+++ b/arch/arm64/include/asm/traps.h
@@ -18,6 +18,22 @@
 #ifndef __ASM_TRAP_H
 #define __ASM_TRAP_H
 
+#include <linux/list.h>
+
+struct pt_regs;
+
+struct undef_hook {
+	struct list_head node;
+	u32 instr_mask;
+	u32 instr_val;
+	u64 pstate_mask;
+	u64 pstate_val;
+	int (*fn)(struct pt_regs *regs, u32 instr);
+};
+
+void register_undef_hook(struct undef_hook *hook);
+void unregister_undef_hook(struct undef_hook *hook);
+
 static inline int in_exception_text(unsigned long ptr)
 {
 	extern char __exception_text_start[];