| Message ID | 20231204172646.2541916-3-jthoughton@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: hugetlb: Fix page fault loop for sw-dirty/hw-clean contiguous PTEs | expand |
On 04/12/2023 17:26, James Houghton wrote: > Make it impossible to create a sw-dirty, hw-clean PTE with pte_modify. > Such a PTE should be impossible to create, and there may be places that > assume that pte_dirty() implies pte_hw_dirty(). > > Signed-off-by: James Houghton <jthoughton@google.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index b19a8aee684c..79ce70fbb751 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -834,6 +834,12 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > pte = set_pte_bit(pte, __pgprot(PTE_DIRTY)); > > pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); > + /* > + * If we end up clearing hw dirtiness for a sw-dirty PTE, set hardware > + * dirtiness again. > + */ > + if (pte_sw_dirty(pte)) > + pte = pte_mkdirty(pte); > return pte; > } >
On Mon, Dec 04, 2023 at 05:26:46PM +0000, James Houghton wrote: > Make it impossible to create a sw-dirty, hw-clean PTE with pte_modify. > Such a PTE should be impossible to create, and there may be places that > assume that pte_dirty() implies pte_hw_dirty(). > > Signed-off-by: James Houghton <jthoughton@google.com> I'm not sure how, but you seem to be missing the '---' separator and the diffstat here, so I suspect this might confuse tools such as b4 which try to apply the patch directly. > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index b19a8aee684c..79ce70fbb751 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -834,6 +834,12 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > pte = set_pte_bit(pte, __pgprot(PTE_DIRTY)); > > pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); > + /* > + * If we end up clearing hw dirtiness for a sw-dirty PTE, set hardware > + * dirtiness again. > + */ > + if (pte_sw_dirty(pte)) > + pte = pte_mkdirty(pte); > return pte; Looks like this is a fix for Catalin to pick up (patch #1 isn't necessary afaict). Will
On Mon, Dec 11, 2023 at 10:42 AM Will Deacon <will@kernel.org> wrote: > > On Mon, Dec 04, 2023 at 05:26:46PM +0000, James Houghton wrote: > > Make it impossible to create a sw-dirty, hw-clean PTE with pte_modify. > > Such a PTE should be impossible to create, and there may be places that > > assume that pte_dirty() implies pte_hw_dirty(). > > > > Signed-off-by: James Houghton <jthoughton@google.com> > > I'm not sure how, but you seem to be missing the '---' separator and the > diffstat here, so I suspect this might confuse tools such as b4 which try > to apply the patch directly. Thanks for pointing that out. Looks like it came from using `--summary` in git format-patch. :/ > > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > > index b19a8aee684c..79ce70fbb751 100644 > > --- a/arch/arm64/include/asm/pgtable.h > > +++ b/arch/arm64/include/asm/pgtable.h > > @@ -834,6 +834,12 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > > pte = set_pte_bit(pte, __pgprot(PTE_DIRTY)); > > > > pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); > > + /* > > + * If we end up clearing hw dirtiness for a sw-dirty PTE, set hardware > > + * dirtiness again. > > + */ > > + if (pte_sw_dirty(pte)) > > + pte = pte_mkdirty(pte); > > return pte; > > Looks like this is a fix for Catalin to pick up (patch #1 isn't necessary > afaict). If only this patch is taken, make sure to add cc:stable and the fixes tag from patch #1. Thank you!
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index b19a8aee684c..79ce70fbb751 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -834,6 +834,12 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) pte = set_pte_bit(pte, __pgprot(PTE_DIRTY)); pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); + /* + * If we end up clearing hw dirtiness for a sw-dirty PTE, set hardware + * dirtiness again. + */ + if (pte_sw_dirty(pte)) + pte = pte_mkdirty(pte); return pte; }
Make it impossible to create a sw-dirty, hw-clean PTE with pte_modify. Such a PTE should be impossible to create, and there may be places that assume that pte_dirty() implies pte_hw_dirty(). Signed-off-by: James Houghton <jthoughton@google.com>