[PATCH v5 17/18] powerpc/mm: Remove hugepd leftovers

From: Christophe Leroy
Date: Mon Jun 10 2024 - 01:59:49 EST

All targets have now opted out of CONFIG_ARCH_HAS_HUGEPD so
remove left over code.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Acked-by: Oscar Salvador <osalvador@xxxxxxx>
---
v5: Fix a forgotten #endif which ended up in following patch
---
arch/powerpc/include/asm/hugetlb.h | 7 -
arch/powerpc/include/asm/page.h | 6 -
arch/powerpc/include/asm/pgtable-be-types.h | 10 -
arch/powerpc/include/asm/pgtable-types.h | 9 -
arch/powerpc/mm/hugetlbpage.c | 413 --------------------
arch/powerpc/mm/init-common.c | 8 +-
arch/powerpc/mm/pgtable.c | 27 +-
7 files changed, 3 insertions(+), 477 deletions(-)

diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index e959c26c0b52..18a3028ac3b6 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -30,13 +30,6 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
}
#define is_hugepage_only_range is_hugepage_only_range

-#ifdef CONFIG_ARCH_HAS_HUGEPD
-#define __HAVE_ARCH_HUGETLB_FREE_PGD_RANGE
-void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
- unsigned long end, unsigned long floor,
- unsigned long ceiling);
-#endif
-
#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
pte_t pte, unsigned long sz);
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index c0af246a64ff..83d0a4fc5f75 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -269,12 +269,6 @@ static inline const void *pfn_to_kaddr(unsigned long pfn)
#define is_kernel_addr(x) ((x) >= TASK_SIZE)
#endif

-/*
- * Some number of bits at the level of the page table that points to
- * a hugepte are used to encode the size. This masks those bits.
- */
-#define HUGEPD_SHIFT_MASK 0x3f
-
#ifndef __ASSEMBLY__

#ifdef CONFIG_PPC_BOOK3S_64
diff --git a/arch/powerpc/include/asm/pgtable-be-types.h b/arch/powerpc/include/asm/pgtable-be-types.h
index 82633200b500..6bd8f89b25dc 100644
--- a/arch/powerpc/include/asm/pgtable-be-types.h
+++ b/arch/powerpc/include/asm/pgtable-be-types.h
@@ -101,14 +101,4 @@ static inline bool pmd_xchg(pmd_t *pmdp, pmd_t old, pmd_t new)
return pmd_raw(old) == prev;
}

-#ifdef CONFIG_ARCH_HAS_HUGEPD
-typedef struct { __be64 pdbe; } hugepd_t;
-#define __hugepd(x) ((hugepd_t) { cpu_to_be64(x) })
-
-static inline unsigned long hpd_val(hugepd_t x)
-{
- return be64_to_cpu(x.pdbe);
-}
-#endif
-
#endif /* _ASM_POWERPC_PGTABLE_BE_TYPES_H */
diff --git a/arch/powerpc/include/asm/pgtable-types.h b/arch/powerpc/include/asm/pgtable-types.h
index db965d98e0ae..7b3d4c592a10 100644
--- a/arch/powerpc/include/asm/pgtable-types.h
+++ b/arch/powerpc/include/asm/pgtable-types.h
@@ -87,13 +87,4 @@ static inline bool pte_xchg(pte_t *ptep, pte_t old, pte_t new)
}
#endif

-#ifdef CONFIG_ARCH_HAS_HUGEPD
-typedef struct { unsigned long pd; } hugepd_t;
-#define __hugepd(x) ((hugepd_t) { (x) })
-static inline unsigned long hpd_val(hugepd_t x)
-{
- return x.pd;
-}
-#endif
-
#endif /* _ASM_POWERPC_PGTABLE_TYPES_H */
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 1fe2843f5b12..6b043180220a 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -28,8 +28,6 @@

bool hugetlb_disabled = false;

-#define hugepd_none(hpd) (hpd_val(hpd) == 0)
-
#define PTE_T_ORDER (__builtin_ffs(sizeof(pte_basic_t)) - \
__builtin_ffs(sizeof(void *)))

@@ -42,156 +40,6 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long s
return __find_linux_pte(mm->pgd, addr, NULL, NULL);
}

-#ifdef CONFIG_ARCH_HAS_HUGEPD
-static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
- unsigned long address, unsigned int pdshift,
- unsigned int pshift, spinlock_t *ptl)
-{
- struct kmem_cache *cachep;
- pte_t *new;
- int i;
- int num_hugepd;
-
- if (pshift >= pdshift) {
- cachep = PGT_CACHE(PTE_T_ORDER);
- num_hugepd = 1 << (pshift - pdshift);
- } else {
- cachep = PGT_CACHE(pdshift - pshift);
- num_hugepd = 1;
- }
-
- if (!cachep) {
- WARN_ONCE(1, "No page table cache created for hugetlb tables");
- return -ENOMEM;
- }
-
- new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));
-
- BUG_ON(pshift > HUGEPD_SHIFT_MASK);
- BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
-
- if (!new)
- return -ENOMEM;
-
- /*
- * Make sure other cpus find the hugepd set only after a
- * properly initialized page table is visible to them.
- * For more details look for comment in __pte_alloc().
- */
- smp_wmb();
-
- spin_lock(ptl);
- /*
- * We have multiple higher-level entries that point to the same
- * actual pte location. Fill in each as we go and backtrack on error.
- * We need all of these so the DTLB pgtable walk code can find the
- * right higher-level entry without knowing if it's a hugepage or not.
- */
- for (i = 0; i < num_hugepd; i++, hpdp++) {
- if (unlikely(!hugepd_none(*hpdp)))
- break;
- hugepd_populate(hpdp, new, pshift);
- }
- /* If we bailed from the for loop early, an error occurred, clean up */
- if (i < num_hugepd) {
- for (i = i - 1 ; i >= 0; i--, hpdp--)
- *hpdp = __hugepd(0);
- kmem_cache_free(cachep, new);
- } else {
- kmemleak_ignore(new);
- }
- spin_unlock(ptl);
- return 0;
-}
-
-/*
- * At this point we do the placement change only for BOOK3S 64. This would
- * possibly work on other subarchs.
- */
-pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, unsigned long sz)
-{
- pgd_t *pg;
- p4d_t *p4;
- pud_t *pu;
- pmd_t *pm;
- hugepd_t *hpdp = NULL;
- unsigned pshift = __ffs(sz);
- unsigned pdshift = PGDIR_SHIFT;
- spinlock_t *ptl;
-
- addr &= ~(sz-1);
- pg = pgd_offset(mm, addr);
- p4 = p4d_offset(pg, addr);
-
-#ifdef CONFIG_PPC_BOOK3S_64
- if (pshift == PGDIR_SHIFT)
- /* 16GB huge page */
- return (pte_t *) p4;
- else if (pshift > PUD_SHIFT) {
- /*
- * We need to use hugepd table
- */
- ptl = &mm->page_table_lock;
- hpdp = (hugepd_t *)p4;
- } else {
- pdshift = PUD_SHIFT;
- pu = pud_alloc(mm, p4, addr);
- if (!pu)
- return NULL;
- if (pshift == PUD_SHIFT)
- return (pte_t *)pu;
- else if (pshift > PMD_SHIFT) {
- ptl = pud_lockptr(mm, pu);
- hpdp = (hugepd_t *)pu;
- } else {
- pdshift = PMD_SHIFT;
- pm = pmd_alloc(mm, pu, addr);
- if (!pm)
- return NULL;
- if (pshift == PMD_SHIFT)
- /* 16MB hugepage */
- return (pte_t *)pm;
- else {
- ptl = pmd_lockptr(mm, pm);
- hpdp = (hugepd_t *)pm;
- }
- }
- }
-#else
- if (pshift >= PGDIR_SHIFT) {
- ptl = &mm->page_table_lock;
- hpdp = (hugepd_t *)p4;
- } else {
- pdshift = PUD_SHIFT;
- pu = pud_alloc(mm, p4, addr);
- if (!pu)
- return NULL;
- if (pshift >= PUD_SHIFT) {
- ptl = pud_lockptr(mm, pu);
- hpdp = (hugepd_t *)pu;
- } else {
- pdshift = PMD_SHIFT;
- pm = pmd_alloc(mm, pu, addr);
- if (!pm)
- return NULL;
- ptl = pmd_lockptr(mm, pm);
- hpdp = (hugepd_t *)pm;
- }
- }
-#endif
- if (!hpdp)
- return NULL;
-
- BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
-
- if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
- pdshift, pshift, ptl))
- return NULL;
-
- return hugepte_offset(*hpdp, addr, pdshift);
-}
-#else
pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, unsigned long sz)
{
@@ -230,7 +78,6 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,

return pte_alloc_huge(mm, pmd, addr);
}
-#endif

#ifdef CONFIG_PPC_BOOK3S_64
/*
@@ -286,266 +133,6 @@ int __init alloc_bootmem_huge_page(struct hstate *h, int nid)
return __alloc_bootmem_huge_page(h, nid);
}

-#ifdef CONFIG_ARCH_HAS_HUGEPD
-#ifndef CONFIG_PPC_BOOK3S_64
-#define HUGEPD_FREELIST_SIZE \
- ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
-
-struct hugepd_freelist {
- struct rcu_head rcu;
- unsigned int index;
- void *ptes[];
-};
-
-static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
-
-static void hugepd_free_rcu_callback(struct rcu_head *head)
-{
- struct hugepd_freelist *batch =
- container_of(head, struct hugepd_freelist, rcu);
- unsigned int i;
-
- for (i = 0; i < batch->index; i++)
- kmem_cache_free(PGT_CACHE(PTE_T_ORDER), batch->ptes[i]);
-
- free_page((unsigned long)batch);
-}
-
-static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
-{
- struct hugepd_freelist **batchp;
-
- batchp = &get_cpu_var(hugepd_freelist_cur);
-
- if (atomic_read(&tlb->mm->mm_users) < 2 ||
- mm_is_thread_local(tlb->mm)) {
- kmem_cache_free(PGT_CACHE(PTE_T_ORDER), hugepte);
- put_cpu_var(hugepd_freelist_cur);
- return;
- }
-
- if (*batchp == NULL) {
- *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
- (*batchp)->index = 0;
- }
-
- (*batchp)->ptes[(*batchp)->index++] = hugepte;
- if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
- call_rcu(&(*batchp)->rcu, hugepd_free_rcu_callback);
- *batchp = NULL;
- }
- put_cpu_var(hugepd_freelist_cur);
-}
-#else
-static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
-#endif
-
-/* Return true when the entry to be freed maps more than the area being freed */
-static bool range_is_outside_limits(unsigned long start, unsigned long end,
- unsigned long floor, unsigned long ceiling,
- unsigned long mask)
-{
- if ((start & mask) < floor)
- return true;
- if (ceiling) {
- ceiling &= mask;
- if (!ceiling)
- return true;
- }
- return end - 1 > ceiling - 1;
-}
-
-static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
- unsigned long start, unsigned long end,
- unsigned long floor, unsigned long ceiling)
-{
- pte_t *hugepte = hugepd_page(*hpdp);
- int i;
-
- unsigned long pdmask = ~((1UL << pdshift) - 1);
- unsigned int num_hugepd = 1;
- unsigned int shift = hugepd_shift(*hpdp);
-
- /* Note: On fsl the hpdp may be the first of several */
- if (shift > pdshift)
- num_hugepd = 1 << (shift - pdshift);
-
- if (range_is_outside_limits(start, end, floor, ceiling, pdmask))
- return;
-
- for (i = 0; i < num_hugepd; i++, hpdp++)
- *hpdp = __hugepd(0);
-
- if (shift >= pdshift)
- hugepd_free(tlb, hugepte);
- else
- pgtable_free_tlb(tlb, hugepte,
- get_hugepd_cache_index(pdshift - shift));
-}
-
-static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
-{
- pgtable_t token = pmd_pgtable(*pmd);
-
- if (range_is_outside_limits(addr, end, floor, ceiling, PMD_MASK))
- return;
-
- pmd_clear(pmd);
- pte_free_tlb(tlb, token, addr);
- mm_dec_nr_ptes(tlb->mm);
-}
-
-static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
-{
- pmd_t *pmd;
- unsigned long next;
- unsigned long start;
-
- start = addr;
- do {
- unsigned long more;
-
- pmd = pmd_offset(pud, addr);
- next = pmd_addr_end(addr, end);
- if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
- if (pmd_none_or_clear_bad(pmd))
- continue;
-
- /*
- * if it is not hugepd pointer, we should already find
- * it cleared.
- */
- WARN_ON(!IS_ENABLED(CONFIG_PPC_8xx));
-
- hugetlb_free_pte_range(tlb, pmd, addr, end, floor, ceiling);
-
- continue;
- }
- /*
- * Increment next by the size of the huge mapping since
- * there may be more than one entry at this level for a
- * single hugepage, but all of them point to
- * the same kmem cache that holds the hugepte.
- */
- more = addr + (1UL << hugepd_shift(*(hugepd_t *)pmd));
- if (more > next)
- next = more;
-
- free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
- addr, next, floor, ceiling);
- } while (addr = next, addr != end);
-
- if (range_is_outside_limits(start, end, floor, ceiling, PUD_MASK))
- return;
-
- pmd = pmd_offset(pud, start & PUD_MASK);
- pud_clear(pud);
- pmd_free_tlb(tlb, pmd, start & PUD_MASK);
- mm_dec_nr_pmds(tlb->mm);
-}
-
-static void hugetlb_free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
-{
- pud_t *pud;
- unsigned long next;
- unsigned long start;
-
- start = addr;
- do {
- pud = pud_offset(p4d, addr);
- next = pud_addr_end(addr, end);
- if (!is_hugepd(__hugepd(pud_val(*pud)))) {
- if (pud_none_or_clear_bad(pud))
- continue;
- hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
- ceiling);
- } else {
- unsigned long more;
- /*
- * Increment next by the size of the huge mapping since
- * there may be more than one entry at this level for a
- * single hugepage, but all of them point to
- * the same kmem cache that holds the hugepte.
- */
- more = addr + (1UL << hugepd_shift(*(hugepd_t *)pud));
- if (more > next)
- next = more;
-
- free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
- addr, next, floor, ceiling);
- }
- } while (addr = next, addr != end);
-
- if (range_is_outside_limits(start, end, floor, ceiling, PGDIR_MASK))
- return;
-
- pud = pud_offset(p4d, start & PGDIR_MASK);
- p4d_clear(p4d);
- pud_free_tlb(tlb, pud, start & PGDIR_MASK);
- mm_dec_nr_puds(tlb->mm);
-}
-
-/*
- * This function frees user-level page tables of a process.
- */
-void hugetlb_free_pgd_range(struct mmu_gather *tlb,
- unsigned long addr, unsigned long end,
- unsigned long floor, unsigned long ceiling)
-{
- pgd_t *pgd;
- p4d_t *p4d;
- unsigned long next;
-
- /*
- * Because there are a number of different possible pagetable
- * layouts for hugepage ranges, we limit knowledge of how
- * things should be laid out to the allocation path
- * (huge_pte_alloc(), above). Everything else works out the
- * structure as it goes from information in the hugepd
- * pointers. That means that we can't here use the
- * optimization used in the normal page free_pgd_range(), of
- * checking whether we're actually covering a large enough
- * range to have to do anything at the top level of the walk
- * instead of at the bottom.
- *
- * To make sense of this, you should probably go read the big
- * block comment at the top of the normal free_pgd_range(),
- * too.
- */
-
- do {
- next = pgd_addr_end(addr, end);
- pgd = pgd_offset(tlb->mm, addr);
- p4d = p4d_offset(pgd, addr);
- if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
- if (p4d_none_or_clear_bad(p4d))
- continue;
- hugetlb_free_pud_range(tlb, p4d, addr, next, floor, ceiling);
- } else {
- unsigned long more;
- /*
- * Increment next by the size of the huge mapping since
- * there may be more than one entry at the pgd level
- * for a single hugepage, but all of them point to the
- * same kmem cache that holds the hugepte.
- */
- more = addr + (1UL << hugepd_shift(*(hugepd_t *)pgd));
- if (more > next)
- next = more;
-
- free_hugepd_range(tlb, (hugepd_t *)p4d, PGDIR_SHIFT,
- addr, next, floor, ceiling);
- }
- } while (addr = next, addr != end);
-}
-#endif
-
bool __init arch_hugetlb_valid_size(unsigned long size)
{
int shift = __ffs(size);
diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index d3a7726ecf51..024e95c62a2d 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -120,12 +120,8 @@ void pgtable_cache_add(unsigned int shift)
/* When batching pgtable pointers for RCU freeing, we store
* the index size in the low bits. Table alignment must be
* big enough to fit it.
- *
- * Likewise, hugeapge pagetable pointers contain a (different)
- * shift value in the low bits. All tables must be aligned so
- * as to leave enough 0 bits in the address to contain it. */
- unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
- HUGEPD_SHIFT_MASK + 1);
+ */
+ unsigned long minalign = MAX_PGTABLE_INDEX_SIZE + 1;
struct kmem_cache *new = NULL;

/* It would be nice if this was a BUILD_BUG_ON(), but at the
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 218792cb2c47..ab0656115424 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -409,11 +409,10 @@ unsigned long vmalloc_to_phys(void *va)
EXPORT_SYMBOL_GPL(vmalloc_to_phys);

/*
- * We have 4 cases for pgds and pmds:
+ * We have 3 cases for pgds and pmds:
* (1) invalid (all zeroes)
* (2) pointer to next table, as normal; bottom 6 bits == 0
* (3) leaf pte for huge page _PAGE_PTE set
- * (4) hugepd pointer, _PAGE_PTE = 0 and bits [2..6] indicate size of table
*
* So long as we atomically load page table pointers we are safe against teardown,
* we can follow the address down to the page and take a ref on it.
@@ -430,7 +429,6 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
#endif
pmd_t pmd, *pmdp;
pte_t *ret_pte;
- hugepd_t *hpdp = NULL;
unsigned pdshift;

if (hpage_shift)
@@ -463,11 +461,6 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
goto out;
}

- if (is_hugepd(__hugepd(p4d_val(p4d)))) {
- hpdp = (hugepd_t *)&p4d;
- goto out_huge;
- }
-
/*
* Even if we end up with an unmap, the pgtable will not
* be freed, because we do an rcu free and here we are
@@ -485,11 +478,6 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
goto out;
}

- if (is_hugepd(__hugepd(pud_val(pud)))) {
- hpdp = (hugepd_t *)&pud;
- goto out_huge;
- }
-
pmdp = pmd_offset(&pud, ea);
#else
pmdp = pmd_offset(pud_offset(p4d_offset(pgdp, ea), ea), ea);
@@ -527,21 +515,8 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
goto out;
}

- if (is_hugepd(__hugepd(pmd_val(pmd)))) {
- hpdp = (hugepd_t *)&pmd;
- goto out_huge;
- }
-
return pte_offset_kernel(&pmd, ea);

-out_huge:
- if (!hpdp)
- return NULL;
-
-#ifdef CONFIG_ARCH_HAS_HUGEPD
- ret_pte = hugepte_offset(*hpdp, ea, pdshift);
- pdshift = hugepd_shift(*hpdp);
-#endif
out:
if (hpage_shift)
*hpage_shift = pdshift;
--
2.44.0