On Tue, 23 Nov 2021 12:39:15 +0100 (CET)
Miroslav Benes <mbenes@xxxxxxx> wrote:
> +++ b/kernel/livepatch/patch.c
> @@ -127,15 +127,18 @@ static void notrace klp_ftrace_handler(unsigned long ip,
> /*
> * Convert a function address into the appropriate ftrace location.
> *
> - * Usually this is just the address of the function, but on some architectures
> - * it's more complicated so allow them to provide a custom behaviour.
> + * Usually this is just the address of the function, but there are some
> + * exceptions.
> + *
> + * * PPC - live patch works only with -mprofile-kernel. In this case,
> + * the ftrace location is always within the first 16 bytes.
> + * * x86_64 with CET/IBT enabled - there is ENDBR instruction at +0 offset.
> + * __fentry__ follows it.
> */
> -#ifndef klp_get_ftrace_location
> -static unsigned long klp_get_ftrace_location(unsigned long faddr)
> +static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
Why make this the default function? It should only do this for powerpc and
x86 *if* CET/IBT is enabled.
-- Steve
> {
> - return faddr;
> + return ftrace_location_range(faddr, faddr + 16);
> }
> -#endif
>
