On Tue, Jun 11, 2019 at 01:41:21AM +0200, Hauke Mehrtens wrote:
> On 5/28/19 7:05 PM, Paul Burton wrote:
> > ---
> >
> > arch/mips/mm/mmap.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
> > index 2f616ebeb7e0..7755a1fad05a 100644
> > --- a/arch/mips/mm/mmap.c
> > +++ b/arch/mips/mm/mmap.c
> > @@ -203,6 +203,11 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
> >
> > int __virt_addr_valid(const volatile void *kaddr)
> > {
> > + unsigned long vaddr = (unsigned long)vaddr;
the second vaddr should be better kaddr
> > +
> > + if ((vaddr < PAGE_OFFSET) || (vaddr >= MAP_BASE))
> > + return 0;
> > +
> > return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
> > }
> > EXPORT_SYMBOL_GPL(__virt_addr_valid);
> >
>
> Someone complained that this compiled to a constant "return 0" for him:
> https://bugs.openwrt.org/index.php?do=details&task_id=2305#comment6554
>
> I just checked this on a unmodified 5.2-rc4 with the xway_defconfig and
> I get this:
>
> 0001915c <__virt_addr_valid>:
> 1915c: 03e00008 jr ra
> 19160: 00001025 move v0,zero
>
> Is this intended?
I don't think so. Interesting what the compiler decides to do here.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
