Re: [PATCH v2 11/20] x86/jump-label: remove support for custom poker

Borislav Petkov
2019-02-11T18:37:59Z

On Mon, Jan 28, 2019 at 04:34:13PM -0800, Rick Edgecombe wrote:
> From: Nadav Amit <namit@vmware.com>
>
> There are only two types of poking: early and breakpoint based. The use
> of a function pointer to perform poking complicates the code and is
> probably inefficient due to the use of indirect branches.
>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Signed-off-by: Nadav Amit <namit@vmware.com>
> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> ---
> arch/x86/kernel/jump_label.c | 24 ++++++++----------------
> 1 file changed, 8 insertions(+), 16 deletions(-)

...

> @@ -80,16 +71,17 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
> bug_at((void *)jump_entry_code(entry), line);
>
> /*
> - * Make text_poke_bp() a default fallback poker.
> + * As long as we're UP and not yet marked RO, we can use
> + * text_poke_early; SYSTEM_BOOTING guarantees both, as we switch to
> + * SYSTEM_SCHEDULING before going either.

s/going/doing/ ?

--
Regards/Gruss,
Boris.

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