[PATCH 09/14] powerpc/mm: Drop WIMG in favour of new constants
Michael Neuling
mikey at neuling.org
Tue Mar 22 15:59:57 AEDT 2016
On Mon, 2016-03-07 at 19:09 +0530, Aneesh Kumar K.V wrote:
> PowerISA 3.0 introduce three pte bits with the below meaning
> 000 -> Normal Memory
> 001 -> Strong Access Order
> 010 -> Non idempotent I/O ( Also cache inhibited and guarded)
> 100 -> Tolerant I/O (Cache inhibited)
Which PTE are you talking about here? Radix, new Hash (ISA 3.0) or
old Hash (ISA 2.07)?
A couple more comments below
> We drop the existing WIMG bits in linux page table in favour of above
> contants. We loose _PAGE_WRITETHRU with this conversion. We only use
> writethru via pgprot_cached_wthru() which is used by fbdev/controlfb.c
> which is Apple control display and also PPC32.
>
> With respect to _PAGE_COHERENCE, we have been marking hpte
> always coherent for some time now. htab_convert_pte_flags always added
> HPTE_R_M.
>
> NOTE: KVM changes need closer review.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
> ---
> arch/powerpc/include/asm/book3s/64/hash.h | 47 +++++++++----------------------
> arch/powerpc/include/asm/kvm_book3s_64.h | 29 ++++++++++---------
> arch/powerpc/kvm/book3s_64_mmu_hv.c | 11 ++++----
> arch/powerpc/kvm/book3s_hv_rm_mmu.c | 12 ++++----
> arch/powerpc/mm/hash64_64k.c | 2 +-
> arch/powerpc/mm/hash_utils_64.c | 14 ++++-----
> arch/powerpc/mm/pgtable.c | 2 +-
> arch/powerpc/mm/pgtable_64.c | 4 ---
> arch/powerpc/platforms/pseries/lpar.c | 4 ---
> 9 files changed, 48 insertions(+), 77 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
> index c2b567456796..edd3d47ef9a4 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash.h
> @@ -21,11 +21,9 @@
> #define _PAGE_RW (_PAGE_READ | _PAGE_WRITE)
> #define _PAGE_RWX (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)
> #define _PAGE_PRIVILEGED 0x00008 /* page can only be access by kernel */
> -#define _PAGE_GUARDED 0x00010 /* G: guarded (side-effect) page */
> -/* M (memory coherence) is always set in the HPTE, so we don't need it here */
> -#define _PAGE_COHERENT 0x0
> -#define _PAGE_NO_CACHE 0x00020 /* I: cache inhibit */
> -#define _PAGE_WRITETHRU 0x00040 /* W: cache write-through */
> +#define _PAGE_SAO 0x00010 /* Strong access order */
> +#define _PAGE_NON_IDEMPOTENT 0x00020 /* non idempotent memory */
> +#define _PAGE_TOLERANT 0x00040 /* tolerant memory, cache inhibited */
> #define _PAGE_DIRTY 0x00080 /* C: page changed */
> #define _PAGE_ACCESSED 0x00100 /* R: page referenced */
> #define _PAGE_SPECIAL 0x00400 /* software: special page */
> @@ -122,9 +120,6 @@
> #define _PAGE_KERNEL_RWX (_PAGE_PRIVILEGED | _PAGE_DIRTY | \
> _PAGE_RW | _PAGE_EXEC)
>
> -/* Strong Access Ordering */
> -#define _PAGE_SAO (_PAGE_WRITETHRU | _PAGE_NO_CACHE | _PAGE_COHERENT)
> -
> /* No page size encoding in the linux PTE */
> #define _PAGE_PSIZE 0
>
> @@ -150,10 +145,9 @@
> /*
> * Mask of bits returned by pte_pgprot()
> */
> -#define PAGE_PROT_BITS (_PAGE_GUARDED | _PAGE_COHERENT | _PAGE_NO_CACHE | \
> - _PAGE_WRITETHRU | _PAGE_4K_PFN | \
> - _PAGE_PRIVILEGED | _PAGE_ACCESSED | _PAGE_READ |\
> - _PAGE_WRITE | _PAGE_DIRTY | _PAGE_EXEC | \
> +#define PAGE_PROT_BITS (_PAGE_SAO | _PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT | \
> + _PAGE_4K_PFN | _PAGE_PRIVILEGED | _PAGE_ACCESSED | \
> + _PAGE_READ | _PAGE_WRITE | _PAGE_DIRTY | _PAGE_EXEC | \
> _PAGE_SOFT_DIRTY)
> /*is this
> * We define 2 sets of base prot bits, one for basic pages (ie,
> @@ -162,7 +156,7 @@
> * the processor might need it for DMA coherency.
> */
> #define _PAGE_BASE_NC (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)
> -#define _PAGE_BASE (_PAGE_BASE_NC | _PAGE_COHERENT)
> +#define _PAGE_BASE (_PAGE_BASE_NC)
>
> /* Permission masks used to generate the __P and __S table,
> *
> @@ -203,9 +197,9 @@
> /* Permission masks used for kernel mappings */
> #define PAGE_KERNEL __pgprot(_PAGE_BASE | _PAGE_KERNEL_RW)
> #define PAGE_KERNEL_NC __pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
> - _PAGE_NO_CACHE)
> + _PAGE_TOLERANT)
> #define PAGE_KERNEL_NCG __pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
> - _PAGE_NO_CACHE | _PAGE_GUARDED)
> + _PAGE_NON_IDEMPOTENT)
> #define PAGE_KERNEL_X __pgprot(_PAGE_BASE | _PAGE_KERNEL_RWX)
> #define PAGE_KERNEL_RO __pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)
> #define PAGE_KERNEL_ROX __pgprot(_PAGE_BASE | _PAGE_KERNEL_ROX)
> @@ -516,41 +510,26 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
> * Macro to mark a page protection value as "uncacheable".
> */
>
> -#define _PAGE_CACHE_CTL (_PAGE_COHERENT | _PAGE_GUARDED | _PAGE_NO_CACHE | \
> - _PAGE_WRITETHRU)
> +#define _PAGE_CACHE_CTL (_PAGE_SAO | _PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
The comment here says 'Macro to mark a page protection value as
"uncacheable"' but why do we put _PAGE_SAO in that?
>
> #define pgprot_noncached pgprot_noncached
> static inline pgprot_t pgprot_noncached(pgprot_t prot)
> {
> return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
> - _PAGE_NO_CACHE | _PAGE_GUARDED);
> + _PAGE_NON_IDEMPOTENT);
> }
>
> #define pgprot_noncached_wc pgprot_noncached_wc
> static inline pgprot_t pgprot_noncached_wc(pgprot_t prot)
> {
> return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
> - _PAGE_NO_CACHE);
> + _PAGE_TOLERANT);
> }
>
> #define pgprot_cached pgprot_cached
> static inline pgprot_t pgprot_cached(pgprot_t prot)
> {
> - return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
> - _PAGE_COHERENT);
> -}
> -
> -#define pgprot_cached_wthru pgprot_cached_wthru
> -static inline pgprot_t pgprot_cached_wthru(pgprot_t prot)
> -{
> - return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
> - _PAGE_COHERENT | _PAGE_WRITETHRU);
> -}
> -
> -#define pgprot_cached_noncoherent pgprot_cached_noncoherent
> -static inline pgprot_t pgprot_cached_noncoherent(pgprot_t prot)
> -{
> - return __pgprot(pgprot_val(prot) & ~_PAGE_CACHE_CTL);
> + return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL));
> }
>
> #define pgprot_writecombine pgprot_writecombine
> diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
> index f9a7a89a3e4f..f23b1698ad3c 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_64.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_64.h
> @@ -278,19 +278,24 @@ static inline unsigned long hpte_make_readonly(unsigned long ptel)
> return ptel;
> }
>
> -static inline int hpte_cache_flags_ok(unsigned long ptel, unsigned long io_type)
> +static inline bool hpte_cache_flags_ok(unsigned long hptel, bool is_ci)
> {
> - unsigned int wimg = ptel & HPTE_R_WIMG;
> + unsigned int wimg = hptel & HPTE_R_WIMG;
>
> /* Handle SAO */
> if (wimg == (HPTE_R_W | HPTE_R_I | HPTE_R_M) &&
> cpu_has_feature(CPU_FTR_ARCH_206))
> wimg = HPTE_R_M;
>
> - if (!io_type)
> + if (!is_ci)
> return wimg == HPTE_R_M;
> -
> - return (wimg & (HPTE_R_W | HPTE_R_I)) == io_type;
> + /*
> + * if host is mapped cache inhibited, make sure hptel also have
> + * cache inhibited.
> + */
> + if (wimg & HPTE_R_W) /* FIXME!! is this ok for all guest. ? */
> + return false;
> + return !!(wimg & HPTE_R_I);
> }
>
> /*
> @@ -333,16 +338,12 @@ static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing)
> return new_pte;
> }
>
> -
> -/* Return HPTE cache control bits corresponding to Linux pte bits */
> -static inline unsigned long hpte_cache_bits(unsigned long pte_val)
> +/*
> + * check whether the mapping is cache inhibited
> + */
> +static inline bool hpte_is_cache_inhibited(unsigned long pte_val)
> {
> -#if _PAGE_NO_CACHE == HPTE_R_I && _PAGE_WRITETHRU == HPTE_R_W
> - return pte_val & (HPTE_R_W | HPTE_R_I);
> -#else
> - return ((pte_val & _PAGE_NO_CACHE) ? HPTE_R_I : 0) +
> - ((pte_val & _PAGE_WRITETHRU) ? HPTE_R_W : 0);
> -#endif
> + return !!(pte_val & (_PAGE_TOLERANT | _PAGE_NON_IDEMPOTENT));
Can we use _PAGE_CACHE_CTL here?
> }
>
> static inline bool hpte_read_permission(unsigned long pp, unsigned long key)
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> index c7b78d8336b2..40ad06c41ca1 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -447,7 +447,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
> struct revmap_entry *rev;
> struct page *page, *pages[1];
> long index, ret, npages;
> - unsigned long is_io;
> + bool is_ci;
> unsigned int writing, write_ok;
> struct vm_area_struct *vma;
> unsigned long rcbits;
> @@ -503,7 +503,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
> smp_rmb();
>
> ret = -EFAULT;
> - is_io = 0;
> + is_ci = false;
> pfn = 0;
> page = NULL;
> pte_size = PAGE_SIZE;
> @@ -521,7 +521,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
> pfn = vma->vm_pgoff +
> ((hva - vma->vm_start) >> PAGE_SHIFT);
> pte_size = psize;
> - is_io = hpte_cache_bits(pgprot_val(vma->vm_page_prot));
> + is_ci = hpte_is_cache_inhibited(pgprot_val(vma->vm_page_prot));
> write_ok = vma->vm_flags & VM_WRITE;
> }
> up_read(¤t->mm->mmap_sem);
> @@ -558,10 +558,9 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
> goto out_put;
>
> /* Check WIMG vs. the actual page we're accessing */
> - if (!hpte_cache_flags_ok(r, is_io)) {
> - if (is_io)
> + if (!hpte_cache_flags_ok(r, is_ci)) {
> + if (is_ci)
> goto out_put;
> -
> /*
> * Allow guest to map emulated device memory as
> * uncacheable, but actually make it cacheable.
> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> index 4cb8db05f3e5..3ebd620589a9 100644
> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> @@ -175,7 +175,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
> unsigned long g_ptel;
> struct kvm_memory_slot *memslot;
> unsigned hpage_shift;
> - unsigned long is_io;
> + bool is_ci;
> unsigned long *rmap;
> pte_t *ptep;
> unsigned int writing;
> @@ -199,7 +199,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
> gfn = gpa >> PAGE_SHIFT;
> memslot = __gfn_to_memslot(kvm_memslots_raw(kvm), gfn);
> pa = 0;
> - is_io = ~0ul;
> + is_ci = false;
> rmap = NULL;
> if (!(memslot && !(memslot->flags & KVM_MEMSLOT_INVALID))) {
> /* Emulated MMIO - mark this with key=31 */
> @@ -250,7 +250,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
> if (writing && !pte_write(pte))
> /* make the actual HPTE be read-only */
> ptel = hpte_make_readonly(ptel);
> - is_io = hpte_cache_bits(pte_val(pte));
> + is_ci = hpte_is_cache_inhibited(pte_val(pte));
> pa = pte_pfn(pte) << PAGE_SHIFT;
> pa |= hva & (host_pte_size - 1);
> pa |= gpa & ~PAGE_MASK;
> @@ -267,9 +267,9 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
> else
> pteh |= HPTE_V_ABSENT;
>
> - /* Check WIMG */
> - if (is_io != ~0ul && !hpte_cache_flags_ok(ptel, is_io)) {
> - if (is_io)
> + /*If we had host pte mapping then Check WIMG */
> + if (ptep && !hpte_cache_flags_ok(ptel, is_ci)) {
> + if (is_ci)
> return H_PARAMETER;
> /*
> * Allow guest to map emulated device memory as
> diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c
> index f33b410d6c8a..243c822913e4 100644
> --- a/arch/powerpc/mm/hash64_64k.c
> +++ b/arch/powerpc/mm/hash64_64k.c
> @@ -248,7 +248,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
> * If so, bail out and refault as a 4k page
> */
> if (!mmu_has_feature(MMU_FTR_CI_LARGE_PAGE) &&
> - unlikely(old_pte & _PAGE_NO_CACHE))
> + unlikely(old_pte & _PAGE_TOLERANT))
> return 0;
> /*
> * Try to lock the PTE, add ACCESSED and DIRTY if it was
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index c81c08aaff0e..728acd17f2a6 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -192,12 +192,12 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
> /*
> * Add in WIG bits
> */
> - if (pteflags & _PAGE_WRITETHRU)
> - rflags |= HPTE_R_W;
> - if (pteflags & _PAGE_NO_CACHE)
> + if (pteflags & _PAGE_TOLERANT)
> rflags |= HPTE_R_I;
> - if (pteflags & _PAGE_GUARDED)
> - rflags |= HPTE_R_G;
> + if (pteflags & _PAGE_NON_IDEMPOTENT)
> + rflags |= (HPTE_R_I | HPTE_R_G);
> + if (pteflags & _PAGE_SAO)
> + rflags |= (HPTE_R_I | HPTE_R_W);
>
> return rflags;
> }
> @@ -1139,7 +1139,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
> * using non cacheable large pages, then we switch to 4k
> */
> if (mmu_ci_restrictions && psize == MMU_PAGE_64K &&
> - (pte_val(*ptep) & _PAGE_NO_CACHE)) {
> + (pte_val(*ptep) & _PAGE_TOLERANT)) {
> if (user_region) {
> demote_segment_4k(mm, ea);
> psize = MMU_PAGE_4K;
> @@ -1298,7 +1298,7 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
> * That way we don't have to duplicate all of the logic for segment
> * page size demotion here
> */
> - if (pte_val(*ptep) & (_PAGE_4K_PFN | _PAGE_NO_CACHE))
> + if (pte_val(*ptep) & (_PAGE_4K_PFN | _PAGE_TOLERANT))
> goto out_exit;
> #endif /* CONFIG_PPC_64K_PAGES */
>
> diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
> index 7b492283d502..ad8b6432f7e3 100644
> --- a/arch/powerpc/mm/pgtable.c
> +++ b/arch/powerpc/mm/pgtable.c
> @@ -46,7 +46,7 @@ static inline int pte_looks_normal(pte_t pte)
>
> #if defined(CONFIG_PPC_BOOK3S_64)
> if ((pte_val(pte) &
> - (_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_NO_CACHE)) ==
> + (_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_TOLERANT)) ==
> _PAGE_PRESENT) {
> if (!(pte_val(pte) & _PAGE_PRIVILEGED))
> return 1;
> diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
> index 6f1b7064f822..db924c54f370 100644
> --- a/arch/powerpc/mm/pgtable_64.c
> +++ b/arch/powerpc/mm/pgtable_64.c
> @@ -167,10 +167,6 @@ void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
> if ((flags & _PAGE_PRESENT) == 0)
> flags |= pgprot_val(PAGE_KERNEL);
>
> - /* Non-cacheable page cannot be coherent */
> - if (flags & _PAGE_NO_CACHE)
> - flags &= ~_PAGE_COHERENT;
> -
> /* We don't support the 4K PFN hack with ioremap */
> if (flags & _PAGE_4K_PFN)
> return NULL;
> diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
> index 2415a0d31f8f..0d4608990702 100644
> --- a/arch/powerpc/platforms/pseries/lpar.c
> +++ b/arch/powerpc/platforms/pseries/lpar.c
> @@ -152,10 +152,6 @@ static long pSeries_lpar_hpte_insert(unsigned long hpte_group,
> /* Exact = 0 */
> flags = 0;
>
> - /* Make pHyp happy */
> - if ((rflags & _PAGE_NO_CACHE) && !(rflags & _PAGE_WRITETHRU))
> - hpte_r &= ~HPTE_R_M;
> -
> if (firmware_has_feature(FW_FEATURE_XCMO) && !(hpte_r & HPTE_R_N))
> flags |= H_COALESCE_CAND;
>
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