+/*
+ * Check if the target PC is within an alternative block.
+ */
+static bool branch_insn_requires_update(struct alt_instr *alt, unsigned long pc)
+{
+ unsigned long replptr;
+
+ if (kernel_text_address(pc))
+ return 1;
+
+ replptr = (unsigned long)ALT_REPL_PTR(alt);
+ if (pc >= replptr && pc <= (replptr + alt->alt_len))
+ return 0;
+
+ /*
+ * Branching into *another* alternate sequence is doomed, and
+ * we're not even trying to fix it up.
+ */
+ BUG();
+}
+
+static u32 get_alt_insn(struct alt_instr *alt, u32 *insnptr, u32 *altinsnptr)
+{
+ u32 insn;
+
+ insn = le32_to_cpu(*altinsnptr);
+
+ if (aarch64_insn_is_branch_imm(insn)) {
+ s32 offset = aarch64_get_branch_offset(insn);
+ unsigned long target;
+
+ target = (unsigned long)altinsnptr + offset;
+
+ /*
+ * If we're branching inside the alternate sequence,
+ * do not rewrite the instruction, as it is already
+ * correct. Otherwise, generate the new instruction.
+ */
+ if (branch_insn_requires_update(alt, target)) {
+ offset = target - (unsigned long)insnptr;
+ insn = aarch64_set_branch_offset(insn, offset);
+ }
+ }
+
+ return insn;
+}
+