arm64: Add more test functions to insn.c

Certain instructions are hard to execute correctly out-of-line (as in
kprobes).  Test functions are added to insn.[hc] to identify these.  The
instructions include any that use PC-relative addressing, change the PC,
or change interrupt masking. For efficiency and simplicity test
functions are also added for small collections of related instructions.

Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index 368c08290dd8..28c6110ffcbb 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -162,6 +162,32 @@ static bool __kprobes __aarch64_insn_hotpatch_safe(u32 insn)
 		aarch64_insn_is_nop(insn);
 }
 
+bool __kprobes aarch64_insn_uses_literal(u32 insn)
+{
+	/* ldr/ldrsw (literal), prfm */
+
+	return aarch64_insn_is_ldr_lit(insn) ||
+		aarch64_insn_is_ldrsw_lit(insn) ||
+		aarch64_insn_is_adr_adrp(insn) ||
+		aarch64_insn_is_prfm_lit(insn);
+}
+
+bool __kprobes aarch64_insn_is_branch(u32 insn)
+{
+	/* b, bl, cb*, tb*, b.cond, br, blr */
+
+	return aarch64_insn_is_b(insn) ||
+		aarch64_insn_is_bl(insn) ||
+		aarch64_insn_is_cbz(insn) ||
+		aarch64_insn_is_cbnz(insn) ||
+		aarch64_insn_is_tbz(insn) ||
+		aarch64_insn_is_tbnz(insn) ||
+		aarch64_insn_is_ret(insn) ||
+		aarch64_insn_is_br(insn) ||
+		aarch64_insn_is_blr(insn) ||
+		aarch64_insn_is_bcond(insn);
+}
+
 /*
  * ARM Architecture Reference Manual for ARMv8 Profile-A, Issue A.a
  * Section B2.6.5 "Concurrent modification and execution of instructions":
@@ -1175,6 +1201,14 @@ u32 aarch64_set_branch_offset(u32 insn, s32 offset)
 	BUG();
 }
 
+/*
+ * Extract the Op/CR data from a msr/mrs instruction.
+ */
+u32 aarch64_insn_extract_system_reg(u32 insn)
+{
+	return (insn & 0x1FFFE0) >> 5;
+}
+
 bool aarch32_insn_is_wide(u32 insn)
 {
 	return insn >= 0xe800;