arm64: kprobes: call set_memory_rox() for kprobe page

The kprobe page is allocated by execmem allocator with ROX permission.
It needs to call set_memory_rox() to set proper permission for the
direct map too. It was missed.

Fixes: 10d5e97 ("arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page")
Cc: <stable@vger.kernel.org>
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

Author: Yang Shi

arch/arm64/kernel/probes/kprobes.c

@@ -10,6 +10,7 @@
 
 #define pr_fmt(fmt) "kprobes: " fmt
 
+#include <linux/execmem.h>
 #include <linux/extable.h>
 #include <linux/kasan.h>
 #include <linux/kernel.h>
@@ -41,6 +42,17 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 static void __kprobes
 post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
 
+void *alloc_insn_page(void)
+{
+	void *addr;
+
+	addr = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
+	if (!addr)
+		return NULL;
+	set_memory_rox((unsigned long)addr, 1);
+	return addr;
+}
+
 static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
 {
 	kprobe_opcode_t *addr = p->ainsn.xol_insn;