| Message ID | 20220329164329.208407-8-david@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages | expand |
Le 29/03/2022 à 18:43, David Hildenbrand a écrit : > The swap type is simply stored in bits 0x1f of the swap pte. Let's > simplify by just getting rid of _PAGE_BIT_SWAP_TYPE. It's not like that > we can simply change it: _PAGE_SWP_SOFT_DIRTY would suddenly fall into > _RPAGE_RSV1, which isn't possible and would make the > BUILD_BUG_ON(_PAGE_HPTEFLAGS & _PAGE_SWP_SOFT_DIRTY) angry. > > While at it, make it clearer which bit we're actually using for > _PAGE_SWP_SOFT_DIRTY by just using the proper define and introduce and > use SWP_TYPE_MASK. > > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > arch/powerpc/include/asm/book3s/64/pgtable.h | 12 +++++------- Why only BOOK3S ? Why not BOOK3E as well ? Christophe > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > index 875730d5af40..8e98375d5c4a 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -13,7 +13,6 @@ > /* > * Common bits between hash and Radix page table > */ > -#define _PAGE_BIT_SWAP_TYPE 0 > > #define _PAGE_EXEC 0x00001 /* execute permission */ > #define _PAGE_WRITE 0x00002 /* write access allowed */ > @@ -751,17 +750,16 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > * Don't have overlapping bits with _PAGE_HPTEFLAGS \ > * We filter HPTEFLAGS on set_pte. \ > */ \ > - BUILD_BUG_ON(_PAGE_HPTEFLAGS & (0x1f << _PAGE_BIT_SWAP_TYPE)); \ > + BUILD_BUG_ON(_PAGE_HPTEFLAGS & SWP_TYPE_MASK); \ > BUILD_BUG_ON(_PAGE_HPTEFLAGS & _PAGE_SWP_SOFT_DIRTY); \ > } while (0) > > #define SWP_TYPE_BITS 5 > -#define __swp_type(x) (((x).val >> _PAGE_BIT_SWAP_TYPE) \ > - & ((1UL << SWP_TYPE_BITS) - 1)) > +#define SWP_TYPE_MASK ((1UL << SWP_TYPE_BITS) - 1) > +#define __swp_type(x) ((x).val & SWP_TYPE_MASK) > #define __swp_offset(x) (((x).val & PTE_RPN_MASK) >> PAGE_SHIFT) > #define __swp_entry(type, offset) ((swp_entry_t) { \ > - ((type) << _PAGE_BIT_SWAP_TYPE) \ > - | (((offset) << PAGE_SHIFT) & PTE_RPN_MASK)}) > + (type) | (((offset) << PAGE_SHIFT) & PTE_RPN_MASK)}) > /* > * swp_entry_t must be independent of pte bits. We build a swp_entry_t from > * swap type and offset we get from swap and convert that to pte to find a > @@ -774,7 +772,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > #define __swp_entry_to_pmd(x) (pte_pmd(__swp_entry_to_pte(x))) > > #ifdef CONFIG_MEM_SOFT_DIRTY > -#define _PAGE_SWP_SOFT_DIRTY (1UL << (SWP_TYPE_BITS + _PAGE_BIT_SWAP_TYPE)) > +#define _PAGE_SWP_SOFT_DIRTY _PAGE_NON_IDEMPOTENT > #else > #define _PAGE_SWP_SOFT_DIRTY 0UL > #endif /* CONFIG_MEM_SOFT_DIRTY */
On 30.03.22 08:07, Christophe Leroy wrote: > > > Le 29/03/2022 à 18:43, David Hildenbrand a écrit : >> The swap type is simply stored in bits 0x1f of the swap pte. Let's >> simplify by just getting rid of _PAGE_BIT_SWAP_TYPE. It's not like that >> we can simply change it: _PAGE_SWP_SOFT_DIRTY would suddenly fall into >> _RPAGE_RSV1, which isn't possible and would make the >> BUILD_BUG_ON(_PAGE_HPTEFLAGS & _PAGE_SWP_SOFT_DIRTY) angry. >> >> While at it, make it clearer which bit we're actually using for >> _PAGE_SWP_SOFT_DIRTY by just using the proper define and introduce and >> use SWP_TYPE_MASK. >> >> Signed-off-by: David Hildenbrand <david@redhat.com> >> --- >> arch/powerpc/include/asm/book3s/64/pgtable.h | 12 +++++------- > > Why only BOOK3S ? Why not BOOK3E as well ? Hi Cristophe, I'm focusing on the most relevant enterprise architectures for now. I don't have the capacity to convert each and every architecture at this point (especially, I don't to waste my time in case this doesn't get merged, and book3e didn't look straight forward to me). Once this series hits upstream, I can look into other architectures -- and I'll be happy if other people jump in that have more familiarity with the architecture-specific swp pte layouts. Thanks
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 875730d5af40..8e98375d5c4a 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -13,7 +13,6 @@ /* * Common bits between hash and Radix page table */ -#define _PAGE_BIT_SWAP_TYPE 0 #define _PAGE_EXEC 0x00001 /* execute permission */ #define _PAGE_WRITE 0x00002 /* write access allowed */ @@ -751,17 +750,16 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) * Don't have overlapping bits with _PAGE_HPTEFLAGS \ * We filter HPTEFLAGS on set_pte. \ */ \ - BUILD_BUG_ON(_PAGE_HPTEFLAGS & (0x1f << _PAGE_BIT_SWAP_TYPE)); \ + BUILD_BUG_ON(_PAGE_HPTEFLAGS & SWP_TYPE_MASK); \ BUILD_BUG_ON(_PAGE_HPTEFLAGS & _PAGE_SWP_SOFT_DIRTY); \ } while (0) #define SWP_TYPE_BITS 5 -#define __swp_type(x) (((x).val >> _PAGE_BIT_SWAP_TYPE) \ - & ((1UL << SWP_TYPE_BITS) - 1)) +#define SWP_TYPE_MASK ((1UL << SWP_TYPE_BITS) - 1) +#define __swp_type(x) ((x).val & SWP_TYPE_MASK) #define __swp_offset(x) (((x).val & PTE_RPN_MASK) >> PAGE_SHIFT) #define __swp_entry(type, offset) ((swp_entry_t) { \ - ((type) << _PAGE_BIT_SWAP_TYPE) \ - | (((offset) << PAGE_SHIFT) & PTE_RPN_MASK)}) + (type) | (((offset) << PAGE_SHIFT) & PTE_RPN_MASK)}) /* * swp_entry_t must be independent of pte bits. We build a swp_entry_t from * swap type and offset we get from swap and convert that to pte to find a @@ -774,7 +772,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) #define __swp_entry_to_pmd(x) (pte_pmd(__swp_entry_to_pte(x))) #ifdef CONFIG_MEM_SOFT_DIRTY -#define _PAGE_SWP_SOFT_DIRTY (1UL << (SWP_TYPE_BITS + _PAGE_BIT_SWAP_TYPE)) +#define _PAGE_SWP_SOFT_DIRTY _PAGE_NON_IDEMPOTENT #else #define _PAGE_SWP_SOFT_DIRTY 0UL #endif /* CONFIG_MEM_SOFT_DIRTY */
The swap type is simply stored in bits 0x1f of the swap pte. Let's simplify by just getting rid of _PAGE_BIT_SWAP_TYPE. It's not like that we can simply change it: _PAGE_SWP_SOFT_DIRTY would suddenly fall into _RPAGE_RSV1, which isn't possible and would make the BUILD_BUG_ON(_PAGE_HPTEFLAGS & _PAGE_SWP_SOFT_DIRTY) angry. While at it, make it clearer which bit we're actually using for _PAGE_SWP_SOFT_DIRTY by just using the proper define and introduce and use SWP_TYPE_MASK. Signed-off-by: David Hildenbrand <david@redhat.com> --- arch/powerpc/include/asm/book3s/64/pgtable.h | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)