arm64: kprobes: Drop ID map text from kprobes blacklist

The ID mapped text region is never accessed via the normal kernel
mapping of text, and so it was moved into .rodata instead. This means it
is no longer considered as a suitable place for kprobes by default, and
the explicit blacklist is unnecessary, and actually results in an error
message at boot:

  kprobes: Failed to populate blacklist (error -22), kprobes not restricted, be careful using them!

So stop blacklisting the ID map text explicitly.

Fixes: af7249b ("arm64: kernel: move identity map out of .text mapping")
Reported-by: Nathan Chancellor <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>
Tested-by: Nathan Chancellor <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

Author: ardbiesheuvel

arch/arm64/kernel/probes/kprobes.c

@@ -387,10 +387,6 @@ int __init arch_populate_kprobe_blacklist(void)
 					(unsigned long)__irqentry_text_end);
 	if (ret)
 		return ret;
-	ret = kprobe_add_area_blacklist((unsigned long)__idmap_text_start,
-					(unsigned long)__idmap_text_end);
-	if (ret)
-		return ret;
 	ret = kprobe_add_area_blacklist((unsigned long)__hyp_text_start,
 					(unsigned long)__hyp_text_end);
 	if (ret || is_kernel_in_hyp_mode())