On Thu, Apr 04, 2013 at 11:27:55AM +0530, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>
> We now have pmd entries covering to 16MB range. To implement THP on powerpc,
> we double the size of PMD. The second half is used to deposit the pgtable (PTE page).
> We also use the depoisted PTE page for tracking the HPTE information. The information
> include [ secondary group | 3 bit hidx | valid ]. We use one byte per each HPTE entry.
> With 16MB hugepage and 64K HPTE we need 256 entries and with 4K HPTE we need
> 4096 entries. Both will fit in a 4K PTE page.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/include/asm/page.h | 2 +-
> arch/powerpc/include/asm/pgtable-ppc64-64k.h | 3 +-
> arch/powerpc/include/asm/pgtable-ppc64.h | 2 +-
> arch/powerpc/include/asm/pgtable.h | 240 ++++++++++++++++++++
> arch/powerpc/mm/pgtable.c | 314 ++++++++++++++++++++++++++
> arch/powerpc/mm/pgtable_64.c | 13 ++
> arch/powerpc/platforms/Kconfig.cputype | 1 +
> 7 files changed, 572 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
> index 38e7ff6..b927447 100644
> --- a/arch/powerpc/include/asm/page.h
> +++ b/arch/powerpc/include/asm/page.h
> @@ -40,7 +40,7 @@
> #ifdef CONFIG_HUGETLB_PAGE
> extern unsigned int HPAGE_SHIFT;
> #else
> -#define HPAGE_SHIFT PAGE_SHIFT
> +#define HPAGE_SHIFT PMD_SHIFT
That looks like it could break everything except the 64k page size
64-bit base.
> #endif
> #define HPAGE_SIZE ((1UL) << HPAGE_SHIFT)
> #define HPAGE_MASK (~(HPAGE_SIZE - 1))
> diff --git a/arch/powerpc/include/asm/pgtable-ppc64-64k.h b/arch/powerpc/include/asm/pgtable-ppc64-64k.h
> index 3c529b4..5c5541a 100644
> --- a/arch/powerpc/include/asm/pgtable-ppc64-64k.h
> +++ b/arch/powerpc/include/asm/pgtable-ppc64-64k.h
> @@ -33,7 +33,8 @@
> #define PGDIR_MASK (~(PGDIR_SIZE-1))
>
> /* Bits to mask out from a PMD to get to the PTE page */
> -#define PMD_MASKED_BITS 0x1ff
> +/* PMDs point to PTE table fragments which are 4K aligned. */
> +#define PMD_MASKED_BITS 0xfff
> /* Bits to mask out from a PGD/PUD to get to the PMD page */
> #define PUD_MASKED_BITS 0x1ff
>
> diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
> index 0182c20..c0747c7 100644
> --- a/arch/powerpc/include/asm/pgtable-ppc64.h
> +++ b/arch/powerpc/include/asm/pgtable-ppc64.h
> @@ -150,7 +150,7 @@
> #define pmd_present(pmd) (pmd_val(pmd) != 0)
> #define pmd_clear(pmdp) (pmd_val(*(pmdp)) = 0)
> #define pmd_page_vaddr(pmd) (pmd_val(pmd) & ~PMD_MASKED_BITS)
> -#define pmd_page(pmd) virt_to_page(pmd_page_vaddr(pmd))
> +extern struct page *pmd_page(pmd_t pmd);
Does unconditionally changing pmd_page() from a macro to an external
function have a noticeable performance impact?
> #define pud_set(pudp, pudval) (pud_val(*(pudp)) = (pudval))
> #define pud_none(pud) (!pud_val(pud))
> diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
> index 4b52726..9fbe2a7 100644
> --- a/arch/powerpc/include/asm/pgtable.h
> +++ b/arch/powerpc/include/asm/pgtable.h
> @@ -23,7 +23,247 @@ struct mm_struct;
> */
> #define PTE_PAGE_HIDX_OFFSET (PTRS_PER_PTE * 8)
>
> +/* A large part matches with pte bits */
> +#define PMD_HUGE_PRESENT 0x001 /* software: pte contains a translation */
> +#define PMD_HUGE_USER 0x002 /* matches one of the PP bits */
> +#define PMD_HUGE_FILE 0x002 /* (!present only) software: pte holds file offset */
Can we actually get hugepage PMDs that are in this state?
> +#define PMD_HUGE_EXEC 0x004 /* No execute on POWER4 and newer (we invert) */
> +#define PMD_HUGE_SPLITTING 0x008
> +#define PMD_HUGE_SAO 0x010 /* strong Access order */
> +#define PMD_HUGE_HASHPTE 0x020
> +#define PMD_ISHUGE 0x040
> +#define PMD_HUGE_DIRTY 0x080 /* C: page changed */
> +#define PMD_HUGE_ACCESSED 0x100 /* R: page referenced */
> +#define PMD_HUGE_RW 0x200 /* software: user write access allowed */
> +#define PMD_HUGE_BUSY 0x800 /* software: PTE & hash are busy */
> +#define PMD_HUGE_HPTEFLAGS (PMD_HUGE_BUSY | PMD_HUGE_HASHPTE)
> +/*
> + * We keep both the pmd and pte rpn shift same, eventhough we use only
> + * lower 12 bits for hugepage flags at pmd level
Why?
> + */
> +#define PMD_HUGE_RPN_SHIFT PTE_RPN_SHIFT
> +#define HUGE_PAGE_SIZE (ASM_CONST(1) << 24)
> +#define HUGE_PAGE_MASK (~(HUGE_PAGE_SIZE - 1))
> +
> #ifndef __ASSEMBLY__
> +extern void hpte_need_hugepage_flush(struct mm_struct *mm, unsigned long addr,
> + pmd_t *pmdp);
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
> +extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
> +extern pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot);
> +extern void set_pmd_at(struct mm_struct *mm, unsigned long addr,
> + pmd_t *pmdp, pmd_t pmd);
> +extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
> + pmd_t *pmd);
> +static inline int pmd_large(pmd_t pmd)
> +{
> + return (pmd_val(pmd) & (PMD_ISHUGE | PMD_HUGE_PRESENT)) ==
> + (PMD_ISHUGE | PMD_HUGE_PRESENT);
> +}
> +
> +static inline int pmd_trans_splitting(pmd_t pmd)
> +{
> + return (pmd_val(pmd) & (PMD_ISHUGE|PMD_HUGE_SPLITTING)) ==
> + (PMD_ISHUGE|PMD_HUGE_SPLITTING);
> +}
> +
> +static inline int pmd_trans_huge(pmd_t pmd)
> +{
> + return pmd_val(pmd) & PMD_ISHUGE;
> +}
> +/* We will enable it in the last patch */
> +#define has_transparent_hugepage() 0
> +#else
> +#define pmd_large(pmd) 0
> +#define has_transparent_hugepage() 0
> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> +
> +static inline unsigned long pmd_pfn(pmd_t pmd)
> +{
> + /*
> + * Only called for hugepage pmd
> + */
> + return pmd_val(pmd) >> PMD_HUGE_RPN_SHIFT;
> +}
> +
> +static inline int pmd_young(pmd_t pmd)
> +{
> + return pmd_val(pmd) & PMD_HUGE_ACCESSED;
> +}
> +
> +static inline pmd_t pmd_mkhuge(pmd_t pmd)
> +{
> + /* Do nothing, mk_pmd() does this part. */
> + return pmd;
> +}
> +
> +#define __HAVE_ARCH_PMD_WRITE
> +static inline int pmd_write(pmd_t pmd)
> +{
> + return pmd_val(pmd) & PMD_HUGE_RW;
> +}
> +
> +static inline pmd_t pmd_mkold(pmd_t pmd)
> +{
> + pmd_val(pmd) &= ~PMD_HUGE_ACCESSED;
> + return pmd;
> +}
> +
> +static inline pmd_t pmd_wrprotect(pmd_t pmd)
> +{
> + pmd_val(pmd) &= ~PMD_HUGE_RW;
> + return pmd;
> +}
> +
> +static inline pmd_t pmd_mkdirty(pmd_t pmd)
> +{
> + pmd_val(pmd) |= PMD_HUGE_DIRTY;
> + return pmd;
> +}
> +
> +static inline pmd_t pmd_mkyoung(pmd_t pmd)
> +{
> + pmd_val(pmd) |= PMD_HUGE_ACCESSED;
> + return pmd;
> +}
> +
> +static inline pmd_t pmd_mkwrite(pmd_t pmd)
> +{
> + pmd_val(pmd) |= PMD_HUGE_RW;
> + return pmd;
> +}
> +
> +static inline pmd_t pmd_mknotpresent(pmd_t pmd)
> +{
> + pmd_val(pmd) &= ~PMD_HUGE_PRESENT;
> + return pmd;
> +}
> +
> +static inline pmd_t pmd_mksplitting(pmd_t pmd)
> +{
> + pmd_val(pmd) |= PMD_HUGE_SPLITTING;
> + return pmd;
> +}
> +
> +/*
> + * Set the dirty and/or accessed bits atomically in a linux hugepage PMD, this
> + * function doesn't need to flush the hash entry
> + */
> +static inline void __pmdp_set_access_flags(pmd_t *pmdp, pmd_t entry)
> +{
> + unsigned long bits = pmd_val(entry) & (PMD_HUGE_DIRTY |
> + PMD_HUGE_ACCESSED |
> + PMD_HUGE_RW | PMD_HUGE_EXEC);
> +#ifdef PTE_ATOMIC_UPDATES
> + unsigned long old, tmp;
> +
> + __asm__ __volatile__(
> + "1: ldarx %0,0,%4\n\
> + andi. %1,%0,%6\n\
> + bne- 1b \n\
> + or %0,%3,%0\n\
> + stdcx. %0,0,%4\n\
> + bne- 1b"
> + :"=&r" (old), "=&r" (tmp), "=m" (*pmdp)
> + :"r" (bits), "r" (pmdp), "m" (*pmdp), "i" (PMD_HUGE_BUSY)
> + :"cc");
> +#else
> + unsigned long old = pmd_val(*pmdp);
> + *pmdp = __pmd(old | bits);
> +#endif
> +}
> +
> +#define __HAVE_ARCH_PMD_SAME
> +static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
> +{
> + return (((pmd_val(pmd_a) ^ pmd_val(pmd_b)) & ~PMD_HUGE_HPTEFLAGS) == 0);
> +}
> +
> +#define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
> +extern int pmdp_set_access_flags(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp,
> + pmd_t entry, int dirty);
> +
> +static inline unsigned long pmd_hugepage_update(struct mm_struct *mm,
> + unsigned long addr,
> + pmd_t *pmdp, unsigned long clr)
> +{
> +#ifdef PTE_ATOMIC_UPDATES
> + unsigned long old, tmp;
> +
> + __asm__ __volatile__(
> + "1: ldarx %0,0,%3\n\
> + andi. %1,%0,%6\n\
> + bne- 1b \n\
> + andc %1,%0,%4 \n\
> + stdcx. %1,0,%3 \n\
> + bne- 1b"
> + : "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
> + : "r" (pmdp), "r" (clr), "m" (*pmdp), "i" (PMD_HUGE_BUSY)
> + : "cc" );
> +#else
> + unsigned long old = pmd_val(*pmdp);
> + *pmdp = __pmd(old & ~clr);
> +#endif
> +
> +#ifdef CONFIG_PPC_STD_MMU_64
> + if (old & PMD_HUGE_HASHPTE)
> + hpte_need_hugepage_flush(mm, addr, pmdp);
> +#endif
> + return old;
> +}
> +
> +static inline int __pmdp_test_and_clear_young(struct mm_struct *mm,
> + unsigned long addr, pmd_t *pmdp)
> +{
> + unsigned long old;
> +
> + if ((pmd_val(*pmdp) & (PMD_HUGE_ACCESSED | PMD_HUGE_HASHPTE)) == 0)
> + return 0;
> + old = pmd_hugepage_update(mm, addr, pmdp, PMD_HUGE_ACCESSED);
> + return ((old & PMD_HUGE_ACCESSED) != 0);
> +}
> +
> +#define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
> +extern int pmdp_test_and_clear_young(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp);
> +#define __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
> +extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp);
> +
> +#define __HAVE_ARCH_PMDP_GET_AND_CLEAR
> +static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
> + unsigned long addr, pmd_t *pmdp)
> +{
> + unsigned long old = pmd_hugepage_update(mm, addr, pmdp, ~0UL);
> + return __pmd(old);
> +}
> +
> +#define __HAVE_ARCH_PMDP_SET_WRPROTECT
> +static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr,
> + pmd_t *pmdp)
> +{
> +
> + if ((pmd_val(*pmdp) & PMD_HUGE_RW) == 0)
> + return;
> +
> + pmd_hugepage_update(mm, addr, pmdp, PMD_HUGE_RW);
> +}
> +
> +#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
> +extern void pmdp_splitting_flush(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp);
> +
> +#define __HAVE_ARCH_PGTABLE_DEPOSIT
> +extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
> + pgtable_t pgtable);
> +#define __HAVE_ARCH_PGTABLE_WITHDRAW
> +extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
> +
> +#define __HAVE_ARCH_PMDP_INVALIDATE
> +extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
> + pmd_t *pmdp);
>
> #include <asm/tlbflush.h>
>
> diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
> index 214130a..9f33780 100644
> --- a/arch/powerpc/mm/pgtable.c
> +++ b/arch/powerpc/mm/pgtable.c
> @@ -31,6 +31,7 @@
> #include <asm/pgalloc.h>
> #include <asm/tlbflush.h>
> #include <asm/tlb.h>
> +#include <asm/machdep.h>
>
> #include "mmu_decl.h"
>
> @@ -240,3 +241,316 @@ void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
> }
> #endif /* CONFIG_DEBUG_VM */
>
> +
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +static pmd_t set_hugepage_access_flags_filter(pmd_t pmd,
> + struct vm_area_struct *vma,
> + int dirty)
> +{
> + return pmd;
> +}
I don't really see why you're splitting out these trivial ...filter()
functions, rather than just doing it inline in the (single) caller.
> +
> +/*
> + * This is called when relaxing access to a hugepage. It's also called in the page
> + * fault path when we don't hit any of the major fault cases, ie, a minor
> + * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have
> + * handled those two for us, we additionally deal with missing execute
> + * permission here on some processors
> + */
> +int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
> + pmd_t *pmdp, pmd_t entry, int dirty)
> +{
> + int changed;
> + entry = set_hugepage_access_flags_filter(entry, vma, dirty);
> + changed = !pmd_same(*(pmdp), entry);
> + if (changed) {
> + __pmdp_set_access_flags(pmdp, entry);
> + /*
> + * Since we are not supporting SW TLB systems, we don't
> + * have any thing similar to flush_tlb_page_nohash()
> + */
> + }
> + return changed;
> +}
> +
> +int pmdp_test_and_clear_young(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp)
> +{
> + return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp);
> +}
> +
> +/*
> + * We currently remove entries from the hashtable regardless of whether
> + * the entry was young or dirty. The generic routines only flush if the
> + * entry was young or dirty which is not good enough.
> + *
> + * We should be more intelligent about this but for the moment we override
> + * these functions and force a tlb flush unconditionally
> + */
> +int pmdp_clear_flush_young(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp)
> +{
> + return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp);
> +}
> +
> +/*
> + * We mark the pmd splitting and invalidate all the hpte
> + * entries for this hugepage.
> + */
> +void pmdp_splitting_flush(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp)
> +{
> + unsigned long old, tmp;
> +
> + VM_BUG_ON(address & ~HPAGE_PMD_MASK);
> +#ifdef PTE_ATOMIC_UPDATES
> +
> + __asm__ __volatile__(
> + "1: ldarx %0,0,%3\n\
> + andi. %1,%0,%6\n\
> + bne- 1b \n\
> + ori %1,%0,%4 \n\
> + stdcx. %1,0,%3 \n\
> + bne- 1b"
> + : "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
> + : "r" (pmdp), "i" (PMD_HUGE_SPLITTING), "m" (*pmdp), "i" (PMD_HUGE_BUSY)
> + : "cc" );
> +#else
> + old = pmd_val(*pmdp);
> + *pmdp = __pmd(old | PMD_HUGE_SPLITTING);
> +#endif
> + /*
> + * If we didn't had the splitting flag set, go and flush the
> + * HPTE entries and serialize against gup fast.
> + */
> + if (!(old & PMD_HUGE_SPLITTING)) {
> +#ifdef CONFIG_PPC_STD_MMU_64
> + /* We need to flush the hpte */
> + if (old & PMD_HUGE_HASHPTE)
> + hpte_need_hugepage_flush(vma->vm_mm, address, pmdp);
> +#endif
> + /* need tlb flush only to serialize against gup-fast */
> + flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
> + }
> +}
> +
> +/*
> + * We want to put the pgtable in pmd and use pgtable for tracking
> + * the base page size hptes
> + */
> +void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
> + pgtable_t pgtable)
> +{
> + unsigned long *pgtable_slot;
> + assert_spin_locked(&mm->page_table_lock);
> + /*
> + * we store the pgtable in the second half of PMD
> + */
> + pgtable_slot = pmdp + PTRS_PER_PMD;
> + *pgtable_slot = (unsigned long)pgtable;
> +}
> +
> +#define PTE_FRAG_SIZE (2 * PTRS_PER_PTE * sizeof(pte_t))
Another example of why this define should be moved to a header.
> +pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
> +{
> + pgtable_t pgtable;
> + unsigned long *pgtable_slot;
> +
> + assert_spin_locked(&mm->page_table_lock);
> + pgtable_slot = pmdp + PTRS_PER_PMD;
> + pgtable = (pgtable_t) *pgtable_slot;
> + /*
> + * We store HPTE information in the deposited PTE fragment.
> + * zero out the content on withdraw.
> + */
> + memset(pgtable, 0, PTE_FRAG_SIZE);
> + return pgtable;
> +}
> +
> +/*
> + * Since we are looking at latest ppc64, we don't need to worry about
> + * i/d cache coherency on exec fault
> + */
> +static pmd_t set_pmd_filter(pmd_t pmd, unsigned long addr)
> +{
> + pmd = __pmd(pmd_val(pmd) & ~PMD_HUGE_HPTEFLAGS);
> + return pmd;
> +}
> +
> +/*
> + * We can make it less convoluted than __set_pte_at, because
> + * we can ignore lot of hardware here, because this is only for
> + * MPSS
> + */
> +static inline void __set_pmd_at(struct mm_struct *mm, unsigned long addr,
> + pmd_t *pmdp, pmd_t pmd, int percpu)
> +{
> + /*
> + * There is nothing in hash page table now, so nothing to
> + * invalidate, set_pte_at is used for adding new entry.
> + * For updating we should use update_hugepage_pmd()
> + */
> + *pmdp = pmd;
> +}
> +
> +/*
> + * set a new huge pmd. We should not be called for updating
> + * an existing pmd entry. That should go via pmd_hugepage_update.
> + */
> +void set_pmd_at(struct mm_struct *mm, unsigned long addr,
> + pmd_t *pmdp, pmd_t pmd)
> +{
> + /*
> + * Note: mm->context.id might not yet have been assigned as
> + * this context might not have been activated yet when this
> + * is called.
> + */
> + pmd = set_pmd_filter(pmd, addr);
> +
> + __set_pmd_at(mm, addr, pmdp, pmd, 0);
> +
> +}
> +
> +void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
> + pmd_t *pmdp)
> +{
> + pmd_hugepage_update(vma->vm_mm, address, pmdp, PMD_HUGE_PRESENT);
> + flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
> +}
> +
> +/*
> + * A linux hugepage PMD was changed and the corresponding hash table entry
> + * neesd to be flushed.
> + *
> + * The linux hugepage PMD now include the pmd entries followed by the address
> + * to the stashed pgtable_t. The stashed pgtable_t contains the hpte bits.
> + * [ secondary group | 3 bit hidx | valid ]. We use one byte per each HPTE entry.
> + * With 16MB hugepage and 64K HPTE we need 256 entries and with 4K HPTE we need
> + * 4096 entries. Both will fit in a 4K pgtable_t.
> + */
> +void hpte_need_hugepage_flush(struct mm_struct *mm, unsigned long addr,
> + pmd_t *pmdp)
> +{
> + int ssize, i;
> + unsigned long s_addr;
> + unsigned int psize, valid;
> + unsigned char *hpte_slot_array;
> + unsigned long hidx, vpn, vsid, hash, shift, slot;
> +
> + /*
> + * Flush all the hptes mapping this hugepage
> + */
> + s_addr = addr & HUGE_PAGE_MASK;
> + /*
> + * The hpte hindex are stored in the pgtable whose address is in the
> + * second half of the PMD
> + */
> + hpte_slot_array = *(char **)(pmdp + PTRS_PER_PMD);
> +
> + /* get the base page size */
> + psize = get_slice_psize(mm, s_addr);
> + shift = mmu_psize_defs[psize].shift;
> +
> + for (i = 0; i < HUGE_PAGE_SIZE/(1ul << shift); i++) {
HUGE_PAGE_SIZE >> shift would be a simpler way to do this calculation.
> + /*
> + * 8 bits per each hpte entries
> + * 000| [ secondary group (one bit) | hidx (3 bits) | valid bit]
> + */
> + valid = hpte_slot_array[i] & 0x1;
> + if (!valid)
> + continue;
> + hidx = hpte_slot_array[i] >> 1;
> +
> + /* get the vpn */
> + addr = s_addr + (i * (1ul << shift));
> + if (!is_kernel_addr(addr)) {
> + ssize = user_segment_size(addr);
> + vsid = get_vsid(mm->context.id, addr, ssize);
> + WARN_ON(vsid == 0);
> + } else {
> + vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
> + ssize = mmu_kernel_ssize;
> + }
> +
> + vpn = hpt_vpn(addr, vsid, ssize);
> + hash = hpt_hash(vpn, shift, ssize);
> + if (hidx & _PTEIDX_SECONDARY)
> + hash = ~hash;
> +
> + slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
> + slot += hidx & _PTEIDX_GROUP_IX;
> + ppc_md.hpte_invalidate(slot, vpn, psize, ssize, 0);
> + }
> +}
> +
> +static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)
> +{
> + unsigned long pmd_prot = 0;
> + unsigned long prot = pgprot_val(pgprot);
> +
> + if (prot & _PAGE_PRESENT)
> + pmd_prot |= PMD_HUGE_PRESENT;
> + if (prot & _PAGE_USER)
> + pmd_prot |= PMD_HUGE_USER;
> + if (prot & _PAGE_FILE)
> + pmd_prot |= PMD_HUGE_FILE;
> + if (prot & _PAGE_EXEC)
> + pmd_prot |= PMD_HUGE_EXEC;
> + /*
> + * _PAGE_COHERENT should always be set
> + */
> + VM_BUG_ON(!(prot & _PAGE_COHERENT));
> +
> + if (prot & _PAGE_SAO)
> + pmd_prot |= PMD_HUGE_SAO;
This looks dubious because _PAGE_SAO is not a single bit. What
happens if WRITETHRU or NO_CACHE is set without the other?
> + if (prot & _PAGE_DIRTY)
> + pmd_prot |= PMD_HUGE_DIRTY;
> + if (prot & _PAGE_ACCESSED)
> + pmd_prot |= PMD_HUGE_ACCESSED;
> + if (prot & _PAGE_RW)
> + pmd_prot |= PMD_HUGE_RW;
> +
> + pmd_val(pmd) |= pmd_prot;
> + return pmd;
> +}
> +
> +pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
> +{
> + pmd_t pmd;
> +
> + pmd_val(pmd) = pfn << PMD_HUGE_RPN_SHIFT;
> + pmd_val(pmd) |= PMD_ISHUGE;
> + pmd = pmd_set_protbits(pmd, pgprot);
> + return pmd;
> +}
> +
> +pmd_t mk_pmd(struct page *page, pgprot_t pgprot)
> +{
> + return pfn_pmd(page_to_pfn(page), pgprot);
> +}
> +
> +pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
> +{
> + /* FIXME!! why are this bits cleared ? */
You really need to answer this question...
> + pmd_val(pmd) &= ~(PMD_HUGE_PRESENT |
> + PMD_HUGE_RW |
> + PMD_HUGE_EXEC);
> + pmd = pmd_set_protbits(pmd, newprot);
> + return pmd;
> +}
> +
> +/*
> + * This is called at the end of handling a user page fault, when the
> + * fault has been handled by updating a HUGE PMD entry in the linux page tables.
> + * We use it to preload an HPTE into the hash table corresponding to
> + * the updated linux HUGE PMD entry.
> + */
> +void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
> + pmd_t *pmd)
> +{
> + /* FIXME!!
> + * Will be done in a later patch
> + */
If you need another patch to make the code in this patch work, they
should probably be folded together.
> +}
> +
> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
> index e79840b..6fc3488 100644
> --- a/arch/powerpc/mm/pgtable_64.c
> +++ b/arch/powerpc/mm/pgtable_64.c
> @@ -338,6 +338,19 @@ EXPORT_SYMBOL(iounmap);
> EXPORT_SYMBOL(__iounmap);
> EXPORT_SYMBOL(__iounmap_at);
>
> +/*
> + * For hugepage we have pfn in the pmd, we use PMD_HUGE_RPN_SHIFT bits for flags
> + * For PTE page, we have a PTE_FRAG_SIZE (4K) aligned virtual address.
> + */
> +struct page *pmd_page(pmd_t pmd)
> +{
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> + if (pmd_val(pmd) & PMD_ISHUGE)
> + return pfn_to_page(pmd_pfn(pmd));
> +#endif
> + return virt_to_page(pmd_page_vaddr(pmd));
> +}
> +
> #ifdef CONFIG_PPC_64K_PAGES
> /*
> * we support 16 fragments per PTE page. This is limited by how many
> diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
> index 72afd28..90ee19b 100644
> --- a/arch/powerpc/platforms/Kconfig.cputype
> +++ b/arch/powerpc/platforms/Kconfig.cputype
> @@ -71,6 +71,7 @@ config PPC_BOOK3S_64
> select PPC_FPU
> select PPC_HAVE_PMU_SUPPORT
> select SYS_SUPPORTS_HUGETLBFS
> + select HAVE_ARCH_TRANSPARENT_HUGEPAGE if PPC_64K_PAGES
>
> config PPC_BOOK3E_64
> bool "Embedded processors"
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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