From faaa5b62d3f7907e217b179556038f9f8e157ee0 Mon Sep 17 00:00:00 2001
From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Date: Thu, 6 Jul 2017 15:38:50 -0700
Subject: [PATCH] mm/follow_page_mask: add support for hugetlb pgd entries
ppc64 supports pgd hugetlb entries. Add code to handle hugetlb pgd
entries to follow_page_mask so that ppc64 can switch to it to handle
hugetlbe entries.
Link: http://lkml.kernel.org/r/1494926612-23928-5-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/hugetlb.h | 4 ++++
mm/gup.c | 7 +++++++
mm/hugetlb.c | 9 +++++++++
3 files changed, 20 insertions(+)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index aa1df49b9a143..3656ce605dc9c 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -121,6 +121,9 @@ struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int flags);
struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,
pud_t *pud, int flags);
+struct page *follow_huge_pgd(struct mm_struct *mm, unsigned long address,
+ pgd_t *pgd, int flags);
+
int pmd_huge(pmd_t pmd);
int pud_huge(pud_t pud);
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
@@ -150,6 +153,7 @@ static inline void hugetlb_show_meminfo(void)
}
#define follow_huge_pmd(mm, addr, pmd, flags) NULL
#define follow_huge_pud(mm, addr, pud, flags) NULL
+#define follow_huge_pgd(mm, addr, pgd, flags) NULL
#define prepare_hugepage_range(file, addr, len) (-EINVAL)
#define pmd_huge(x) 0
#define pud_huge(x) 0
diff --git a/mm/gup.c b/mm/gup.c
index bf68e21d7a3a6..fe95a37a41725 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -357,6 +357,13 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
return no_page_table(vma, flags);
+ if (pgd_huge(*pgd)) {
+ page = follow_huge_pgd(mm, address, pgd, flags);
+ if (page)
+ return page;
+ return no_page_table(vma, flags);
+ }
+
return follow_p4d_mask(vma, address, pgd, flags, page_mask);
}
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 65c84414a6b76..a446869aa7f10 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4715,6 +4715,15 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,
return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
}
+struct page * __weak
+follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
+{
+ if (flags & FOLL_GET)
+ return NULL;
+
+ return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
+}
+
#ifdef CONFIG_MEMORY_FAILURE
/*
--
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