Re: [PATCH v2] lib: Use PFN_PHYS() in devmem_is_allowed()

[Palmer Dabbelt]

On Fri, 30 Jul 2021 00:04:05 PDT (-0700), wangkefeng.wang@xxxxxxxxxx wrote:
> On 2021/7/30 14:49, Liang Wang wrote:
> > The physical address may exceed 32 bits on ARM(when ARM_LPAE enabled),
> > use PFN_PHYS() in devmem_is_allowed(), or the physical address may
> > overflow and be truncated.
> >
> > This bug was initially introduced from v2.6.37, and the function was moved
> > to lib when v5.10.
> >
> > Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
> > Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
> > Cc: stable@xxxxxxxxxxxxxxx # v2.6.37
> > Signed-off-by: Liang Wang <wangliang101@xxxxxxxxxx>
> Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> > ---
> > v2: update subject and changelog
> >   lib/devmem_is_allowed.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/devmem_is_allowed.c b/lib/devmem_is_allowed.c
> > index c0d67c541849..60be9e24bd57 100644
> > --- a/lib/devmem_is_allowed.c
> > +++ b/lib/devmem_is_allowed.c
> > @@ -19,7 +19,7 @@
> >    */
> >   int devmem_is_allowed(unsigned long pfn)
> >   {
> > -	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
> > +	if (iomem_is_exclusive(PFN_PHYS(pfn)))
> >   		return 0;
> >   	if (!page_is_ram(pfn))
> >   		return 1;

Acked-by: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>

I only see the reply so I'm assuming this is going in through some other 
tree, but LMK if you want it via the RISC-V tree as IIRC we're using it 
too.

Thanks!