[PATCH 08/13] arm64: mm: Convert mm/dump.c to use walk_page_range()

Steven Price
2019-02-15T17:03:36Z

Now walk_page_range() can walk kernel page tables, we can switch the
arm64 ptdump code over to using it, simplifying the code.

Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/arm64/mm/dump.c | 108 +++++++++++++++++++++----------------------
1 file changed, 53 insertions(+), 55 deletions(-)

diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index 99bb8facb5cb..ee0bc1441dd0 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -286,73 +286,71 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,

}

-static void walk_pte(struct pg_state *st, pmd_t *pmdp, unsigned long start,
- unsigned long end)
+static int pud_entry(pud_t *pud, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
{
- unsigned long addr = start;
- pte_t *ptep = pte_offset_kernel(pmdp, start);
+ struct pg_state *st = walk->private;
+ pud_t val = READ_ONCE(*pud);

- do {
- note_page(st, addr, 4, READ_ONCE(pte_val(*ptep)));
- } while (ptep++, addr += PAGE_SIZE, addr != end);
+ if (pud_table(val))
+ return 0;
+
+ note_page(st, addr, 2, pud_val(val));
+
+ return 0;
}

-static void walk_pmd(struct pg_state *st, pud_t *pudp, unsigned long start,
- unsigned long end)
+static int pmd_entry(pmd_t *pmd, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
{
- unsigned long next, addr = start;
- pmd_t *pmdp = pmd_offset(pudp, start);
-
- do {
- pmd_t pmd = READ_ONCE(*pmdp);
- next = pmd_addr_end(addr, end);
-
- if (pmd_none(pmd) || pmd_sect(pmd)) {
- note_page(st, addr, 3, pmd_val(pmd));
- } else {
- BUG_ON(pmd_bad(pmd));
- walk_pte(st, pmdp, addr, next);
- }
- } while (pmdp++, addr = next, addr != end);
+ struct pg_state *st = walk->private;
+ pmd_t val = READ_ONCE(*pmd);
+
+ if (pmd_table(val))
+ return 0;
+
+ note_page(st, addr, 3, pmd_val(val));
+
+ return 0;
}

-static void walk_pud(struct pg_state *st, pgd_t *pgdp, unsigned long start,
- unsigned long end)
+static int pte_entry(pte_t *pte, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
{
- unsigned long next, addr = start;
- pud_t *pudp = pud_offset(pgdp, start);
-
- do {
- pud_t pud = READ_ONCE(*pudp);
- next = pud_addr_end(addr, end);
-
- if (pud_none(pud) || pud_sect(pud)) {
- note_page(st, addr, 2, pud_val(pud));
- } else {
- BUG_ON(pud_bad(pud));
- walk_pmd(st, pudp, addr, next);
- }
- } while (pudp++, addr = next, addr != end);
+ struct pg_state *st = walk->private;
+ pte_t val = READ_ONCE(*pte);
+
+ note_page(st, addr, 4, pte_val(val));
+
+ return 0;
+}
+
+static int pte_hole(unsigned long addr, unsigned long next, int depth,
+ struct mm_walk *walk)
+{
+ struct pg_state *st = walk->private;
+
+ note_page(st, addr, depth+1, 0);
+
+ return 0;
}

static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
- unsigned long start)
+ unsigned long start)
{
- unsigned long end = (start < TASK_SIZE_64) ? TASK_SIZE_64 : 0;
- unsigned long next, addr = start;
- pgd_t *pgdp = pgd_offset(mm, start);
-
- do {
- pgd_t pgd = READ_ONCE(*pgdp);
- next = pgd_addr_end(addr, end);
-
- if (pgd_none(pgd)) {
- note_page(st, addr, 1, pgd_val(pgd));
- } else {
- BUG_ON(pgd_bad(pgd));
- walk_pud(st, pgdp, addr, next);
- }
- } while (pgdp++, addr = next, addr != end);
+ struct mm_walk walk = {
+ .mm = mm,
+ .private = st,
+ .pud_entry = pud_entry,
+ .pmd_entry = pmd_entry,
+ .pte_entry = pte_entry,
+ .pte_hole = pte_hole
+ };
+ down_read(&mm->mmap_sem);
+ walk_page_range(start, start | (((unsigned long)PTRS_PER_PGD <<
+ PGDIR_SHIFT) - 1),
+ &walk);
+ up_read(&mm->mmap_sem);
}

void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info)
--
2.20.1