On Mon, Apr 20, 2020 at 02:40:05PM -0700, Mike Kravetz wrote:
> On 4/20/20 1:29 PM, Anders Roxell wrote:
> > On Mon, 20 Apr 2020 at 20:23, Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote:
> >> On 4/20/20 8:34 AM, Qian Cai wrote:
> >>>
> >>> Reverted this series fixed many undefined behaviors on arm64 with the config,
> >> While rearranging the code (patch 3 in series), I made the incorrect
> >> assumption that CONT_XXX_SIZE == (1UL << CONT_XXX_SHIFT). However,
> >> this is not the case. Does the following patch fix these issues?
> >>
> >> From b75cb4a0852e208bee8c4eb347dc076fcaa88859 Mon Sep 17 00:00:00 2001
> >> From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> >> Date: Mon, 20 Apr 2020 10:41:18 -0700
> >> Subject: [PATCH] arm64/hugetlb: fix hugetlb initialization
> >>
> >> When calling hugetlb_add_hstate() to initialize a new hugetlb size,
> >> be sure to use correct huge pages size order.
> >>
> >> Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> >> ---
> >> arch/arm64/mm/hugetlbpage.c | 8 ++++----
> >> 1 file changed, 4 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> >> index 9ca840527296..a02411a1f19a 100644
> >> --- a/arch/arm64/mm/hugetlbpage.c
> >> +++ b/arch/arm64/mm/hugetlbpage.c
> >> @@ -453,11 +453,11 @@ void huge_ptep_clear_flush(struct vm_area_struct *vma,
> >> static int __init hugetlbpage_init(void)
> >> {
> >> #ifdef CONFIG_ARM64_4K_PAGES
> >> - hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
> >> + hugetlb_add_hstate(ilog2(PUD_SIZE) - PAGE_SHIFT);
> >> #endif
> >> - hugetlb_add_hstate(CONT_PMD_SHIFT - PAGE_SHIFT);
> >> - hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
> >> - hugetlb_add_hstate(CONT_PTE_SHIFT - PAGE_SHIFT);
> >> + hugetlb_add_hstate(ilog2(CONT_PMD_SIZE) - PAGE_SHIFT);
> >> + hugetlb_add_hstate(ilog2(PMD_SIZE) - PAGE_SHIFT);
> >> + hugetlb_add_hstate(ilog2(CONT_PTE_SIZE) - PAGE_SHIFT);
> >>
> >> return 0;
> >> }
> >
> > I build this for an arm64 kernel and ran it in qemu and it worked.
>
> Thanks for testing Anders!
>
> Will, here is an updated version of the patch based on your suggestion.
> I added the () for emphasis but that may just be noise for some. Also,
> the naming differences and values for CONT_PTE may make some people
> look twice. Not sure if being consistent here helps?
Cheers, thanks for this. I think being consistent is worthwhile, as it's
the definitions themselves that are weird and we can conceivably clean
that up as a separate patch.
So,
Acked-by: Will Deacon <will@xxxxxxxxxx>
Looks like Andrew already picked it up (thanks!)
Thanks,
Will
