[PATCH v9 2/3] riscv: mm: support Svnapot in hugetlb page

panqinglin2020
2022-12-04T14:12:20Z

From: Qinglin Pan <panqinglin2020@iscas.ac.cn>

Svnapot can be used to support 64KB hugetlb page, so it can become a new
option when using hugetlbfs. Add a basic implementation of hugetlb page,
and support 64KB as a size in it by using Svnapot.

For test, boot kernel with command line contains "default_hugepagesz=64K
hugepagesz=64K hugepages=20" and run a simple test like this:

tools/testing/selftests/vm/map_hugetlb 1 16

And it should be passed.

Signed-off-by: Qinglin Pan <panqinglin2020@iscas.ac.cn>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 1d8477c0af7c..be5c1edea70f 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -43,7 +43,7 @@ config RISCV
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
select ARCH_WANT_FRAME_POINTERS
- select ARCH_WANT_GENERAL_HUGETLB
+ select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
diff --git a/arch/riscv/include/asm/hugetlb.h b/arch/riscv/include/asm/hugetlb.h
index ec19d6afc896..fe6f23006641 100644
--- a/arch/riscv/include/asm/hugetlb.h
+++ b/arch/riscv/include/asm/hugetlb.h
@@ -2,7 +2,6 @@
#ifndef _ASM_RISCV_HUGETLB_H
#define _ASM_RISCV_HUGETLB_H

-#include <asm-generic/hugetlb.h>
#include <asm/page.h>

static inline void arch_clear_hugepage_flags(struct page *page)
@@ -11,4 +10,37 @@ static inline void arch_clear_hugepage_flags(struct page *page)
}
#define arch_clear_hugepage_flags arch_clear_hugepage_flags

+#ifdef CONFIG_RISCV_ISA_SVNAPOT
+#define __HAVE_ARCH_HUGE_PTE_CLEAR
+void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, unsigned long sz);
+
+#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);
+
+#define __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep);
+
+#define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
+pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep);
+
+#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
+void huge_ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep);
+
+#define __HAVE_ARCH_HUGE_PTEP_SET_ACCESS_FLAGS
+int huge_ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep,
+ pte_t pte, int dirty);
+
+pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
+#define arch_make_huge_pte arch_make_huge_pte
+
+#endif /*CONFIG_RISCV_ISA_SVNAPOT*/
+
+#include <asm-generic/hugetlb.h>
+
#endif /* _ASM_RISCV_HUGETLB_H */
diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index 932dadfdca54..49f92f8cd431 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -2,6 +2,301 @@
#include <linux/hugetlb.h>
#include <linux/err.h>

+#ifdef CONFIG_RISCV_ISA_SVNAPOT
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ unsigned long sz)
+{
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte = NULL;
+ unsigned long order;
+
+ pgd = pgd_offset(mm, addr);
+ p4d = p4d_alloc(mm, pgd, addr);
+ if (!p4d)
+ return NULL;
+
+ pud = pud_alloc(mm, p4d, addr);
+ if (!pud)
+ return NULL;
+
+ if (sz == PUD_SIZE) {
+ pte = (pte_t *)pud;
+ goto out;
+ }
+
+ if (sz == PMD_SIZE) {
+ if (want_pmd_share(vma, addr) && pud_none(*pud))
+ pte = huge_pmd_share(mm, vma, addr, pud);
+ else
+ pte = (pte_t *)pmd_alloc(mm, pud, addr);
+ goto out;
+ }
+
+ pmd = pmd_alloc(mm, pud, addr);
+ if (!pmd)
+ return NULL;
+
+ for_each_napot_order(order) {
+ if (napot_cont_size(order) == sz) {
+ pte = pte_alloc_map(mm, pmd, (addr & napot_cont_mask(order)));
+ break;
+ }
+ }
+
+out:
+ WARN_ON_ONCE(pte && pte_present(*pte) && !pte_huge(*pte));
+ return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm,
+ unsigned long addr,
+ unsigned long sz)
+{
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte = NULL;
+ unsigned long order;
+
+ pgd = pgd_offset(mm, addr);
+ if (!pgd_present(*pgd))
+ return NULL;
+ p4d = p4d_offset(pgd, addr);
+ if (!p4d_present(*p4d))
+ return NULL;
+
+ pud = pud_offset(p4d, addr);
+ if (sz == PUD_SIZE)
+ /* must be pud huge, non-present or none */
+ return (pte_t *)pud;
+ if (!pud_present(*pud))
+ return NULL;
+
+ pmd = pmd_offset(pud, addr);
+ if (sz == PMD_SIZE)
+ /* must be pmd huge, non-present or none */
+ return (pte_t *)pmd;
+ if (!pmd_present(*pmd))
+ return NULL;
+
+ for_each_napot_order(order) {
+ if (napot_cont_size(order) == sz) {
+ pte = pte_offset_kernel(pmd, (addr & napot_cont_mask(order)));
+ break;
+ }
+ }
+ return pte;
+}
+
+static pte_t get_clear_contig(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep,
+ unsigned long pte_num)
+{
+ pte_t orig_pte = ptep_get(ptep);
+ unsigned long i;
+
+ for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++) {
+ pte_t pte = ptep_get_and_clear(mm, addr, ptep);
+
+ if (pte_dirty(pte))
+ orig_pte = pte_mkdirty(orig_pte);
+
+ if (pte_young(pte))
+ orig_pte = pte_mkyoung(orig_pte);
+ }
+ return orig_pte;
+}
+
+static pte_t get_clear_contig_flush(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep,
+ unsigned long pte_num)
+{
+ pte_t orig_pte = get_clear_contig(mm, addr, ptep, pte_num);
+ bool valid = !pte_none(orig_pte);
+ struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
+
+ if (valid)
+ flush_tlb_range(&vma, addr, addr + (PAGE_SIZE * pte_num));
+
+ return orig_pte;
+}
+
+pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
+{
+ unsigned long order;
+
+ for_each_napot_order(order) {
+ if (shift == napot_cont_shift(order)) {
+ entry = pte_mknapot(entry, order);
+ break;
+ }
+ }
+ if (order == NAPOT_ORDER_MAX)
+ entry = pte_mkhuge(entry);
+
+ return entry;
+}
+
+void set_huge_pte_at(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep,
+ pte_t pte)
+{
+ int i;
+ int pte_num;
+
+ if (!pte_napot(pte)) {
+ set_pte_at(mm, addr, ptep, pte);
+ return;
+ }
+
+ pte_num = napot_pte_num(napot_cont_order(pte));
+ for (i = 0; i < pte_num; i++, ptep++, addr += PAGE_SIZE)
+ set_pte_at(mm, addr, ptep, pte);
+}
+
+int huge_ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t *ptep,
+ pte_t pte,
+ int dirty)
+{
+ pte_t orig_pte;
+ int i;
+ int pte_num;
+ struct mm_struct *mm = vma->vm_mm;
+
+ if (!pte_napot(pte))
+ return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
+
+ pte_num = napot_pte_num(napot_cont_order(pte));
+ ptep = huge_pte_offset(mm, addr,
+ napot_cont_size(napot_cont_order(pte)));
+ orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
+
+ if (pte_dirty(orig_pte))
+ pte = pte_mkdirty(pte);
+
+ if (pte_young(orig_pte))
+ pte = pte_mkyoung(pte);
+
+ for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
+ set_pte_at(mm, addr, ptep, pte);
+
+ return true;
+}
+
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep)
+{
+ int pte_num;
+ pte_t orig_pte = ptep_get(ptep);
+
+ if (!pte_napot(orig_pte))
+ return ptep_get_and_clear(mm, addr, ptep);
+
+ pte_num = napot_pte_num(napot_cont_order(orig_pte));
+
+ return get_clear_contig(mm, addr, ptep, pte_num);
+}
+
+void huge_ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep)
+{
+ int i;
+ int pte_num;
+ pte_t pte = ptep_get(ptep);
+
+ if (!pte_napot(pte)) {
+ ptep_set_wrprotect(mm, addr, ptep);
+ return;
+ }
+
+ pte_num = napot_pte_num(napot_cont_order(pte));
+ ptep = huge_pte_offset(mm, addr, napot_cont_size(napot_cont_order(pte)));
+
+ for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
+ ptep_set_wrprotect(mm, addr, ptep);
+}
+
+pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long addr,
+ pte_t *ptep)
+{
+ int pte_num;
+ pte_t pte = ptep_get(ptep);
+
+ if (!pte_napot(pte))
+ return ptep_clear_flush(vma, addr, ptep);
+
+ pte_num = napot_pte_num(napot_cont_order(pte));
+
+ return get_clear_contig_flush(vma->vm_mm, addr, ptep, pte_num);
+}
+
+void huge_pte_clear(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep,
+ unsigned long sz)
+{
+ int i, pte_num;
+ pte_t pte = READ_ONCE(*ptep);
+
+ if (!pte_napot(pte)) {
+ pte_clear(mm, addr, ptep);
+ return;
+ }
+
+ pte_num = napot_pte_num(napot_cont_order(pte));
+ for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
+ pte_clear(mm, addr, ptep);
+}
+
+bool __init is_napot_size(unsigned long size)
+{
+ unsigned long order;
+
+ if (!has_svnapot())
+ return false;
+
+ for_each_napot_order(order) {
+ if (size == napot_cont_size(order))
+ return true;
+ }
+ return false;
+}
+
+static __init int napot_hugetlbpages_init(void)
+{
+ if (has_svnapot()) {
+ unsigned long order;
+
+ for_each_napot_order(order)
+ hugetlb_add_hstate(order);
+ }
+ return 0;
+}
+arch_initcall(napot_hugetlbpages_init);
+
+#else
+
+bool __init is_napot_size(unsigned long size)
+{
+ return false;
+}
+
+#endif /*CONFIG_RISCV_ISA_SVNAPOT*/
+
int pud_huge(pud_t pud)
{
return pud_leaf(pud);
@@ -18,6 +313,8 @@ bool __init arch_hugetlb_valid_size(unsigned long size)
return true;
else if (IS_ENABLED(CONFIG_64BIT) && size == PUD_SIZE)
return true;
+ else if (is_napot_size(size))
+ return true;
else
return false;
}
--
2.37.4