Re: [PATCH v3 06/13] mm/execmem: introduce execmem_data_alloc()

[Song Liu]

On Fri, Sep 22, 2023 at 12:17 AM Christophe Leroy
<christophe.leroy@xxxxxxxxxx> wrote:
>
>
>
> Le 22/09/2023 à 00:52, Song Liu a écrit :
> > On Mon, Sep 18, 2023 at 12:31 AM Mike Rapoport <rppt@xxxxxxxxxx> wrote:
> >>
> > [...]
> >> diff --git a/include/linux/execmem.h b/include/linux/execmem.h
> >> index 519bdfdca595..09d45ac786e9 100644
> >> --- a/include/linux/execmem.h
> >> +++ b/include/linux/execmem.h
> >> @@ -29,6 +29,7 @@
> >>    * @EXECMEM_KPROBES: parameters for kprobes
> >>    * @EXECMEM_FTRACE: parameters for ftrace
> >>    * @EXECMEM_BPF: parameters for BPF
> >> + * @EXECMEM_MODULE_DATA: parameters for module data sections
> >>    * @EXECMEM_TYPE_MAX:
> >>    */
> >>   enum execmem_type {
> >> @@ -37,6 +38,7 @@ enum execmem_type {
> >>          EXECMEM_KPROBES,
> >>          EXECMEM_FTRACE,
> >
> > In longer term, I think we can improve the JITed code and merge
> > kprobe/ftrace/bpf. to use the same ranges. Also, do we need special
> > setting for FTRACE? If not, let's just remove it.
>
> How can we do that ? Some platforms like powerpc require executable
> memory for BPF and non-exec mem for KPROBE so it can't be in the same
> area/ranges.

Hmm... non-exec mem for kprobes?

       if (strict_module_rwx_enabled())
               execmem_params.ranges[EXECMEM_KPROBES].pgprot = PAGE_KERNEL_ROX;
       else
               execmem_params.ranges[EXECMEM_KPROBES].pgprot = PAGE_KERNEL_EXEC;

Do you mean the latter case?

Thanks,
Song