Re: [PATCH v2 3/3] ARM: Support KFENCE for ARM

[Kefeng Wang]

On 2021/11/4 0:22, Alexander Potapenko wrote:
> On Wed, Nov 3, 2021 at 2:26 PM Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
> > Add architecture specific implementation details for KFENCE and enable
> > KFENCE on ARM. In particular, this implements the required interface in
> >   <asm/kfence.h>.
> >
> > KFENCE requires that attributes for pages from its memory pool can
> > individually be set. Therefore, force the kfence pool to be mapped
> > at page granularity.
> >
> > Testing this patch using the testcases in kfence_test.c and all passed
> > with or without ARM_LPAE.
> >
> > Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
...
> > diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
> > index f7ab6dabe89f..49148b675b43 100644
> > --- a/arch/arm/mm/fault.c
> > +++ b/arch/arm/mm/fault.c
> > @@ -17,6 +17,7 @@
> >   #include <linux/sched/debug.h>
> >   #include <linux/highmem.h>
> >   #include <linux/perf_event.h>
> > +#include <linux/kfence.h>
> >
> >   #include <asm/system_misc.h>
> >   #include <asm/system_info.h>
> > @@ -99,6 +100,11 @@ void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr)
> >   { }
> >   #endif                                 /* CONFIG_MMU */
> >
> > +static inline bool is_write_fault(unsigned int fsr)
> > +{
> > +       return (fsr & FSR_WRITE) && !(fsr & FSR_CM);
> > +}
>
> Please don't increase the diff by moving the code around. Consider
> putting is_write_fault() in the right place in "ARM: mm: Provide
> is_write_fault()" instead.
Sure. Let's wait some time to see whether there are any other comments,
and resend, thanks.
> .