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

[Christophe Leroy]

Le 22/09/2023 à 10:55, Song Liu a écrit :
> 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?
> 

In fact I may have misunderstood patch 9. I'll provide a response there.

Christophe