The patch titled
Subject: mm: pagewalk: allow walking without vma
has been added to the -mm tree. Its filename is
mm-pagewalk-allow-walking-without-vma.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-pagewalk-allow-walking-without-vma.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-pagewalk-allow-walking-without-vma.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Steven Price <steven.price@xxxxxxx>
Subject: mm: pagewalk: allow walking without vma
Since 48684a65b4e3 ("mm: pagewalk: fix misbehavior of walk_page_range for
vma(VM_PFNMAP))", page_table_walk() will report any kernel area as a hole,
because it lacks a vma.
This means each arch has re-implemented page table walking when needed,
for example in the per-arch ptdump walker.
Remove the requirement to have a vma except when trying to split huge
pages.
Link: http://lkml.kernel.org/r/20190722154210.42799-13-steven.price@xxxxxxx
Signed-off-by: Steven Price <steven.price@xxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/pagewalk.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
--- a/mm/pagewalk.c~mm-pagewalk-allow-walking-without-vma
+++ a/mm/pagewalk.c
@@ -36,7 +36,7 @@ static int walk_pmd_range(pud_t *pud, un
do {
again:
next = pmd_addr_end(addr, end);
- if (pmd_none(*pmd) || !walk->vma) {
+ if (pmd_none(*pmd)) {
if (walk->pte_hole)
err = walk->pte_hole(addr, next, walk);
if (err)
@@ -59,9 +59,14 @@ again:
if (!walk->pte_entry)
continue;
- split_huge_pmd(walk->vma, pmd, addr);
- if (pmd_trans_unstable(pmd))
- goto again;
+ if (walk->vma) {
+ split_huge_pmd(walk->vma, pmd, addr);
+ if (pmd_trans_unstable(pmd))
+ goto again;
+ } else if (pmd_leaf(*pmd)) {
+ continue;
+ }
+
err = walk_pte_range(pmd, addr, next, walk);
if (err)
break;
@@ -81,7 +86,7 @@ static int walk_pud_range(p4d_t *p4d, un
do {
again:
next = pud_addr_end(addr, end);
- if (pud_none(*pud) || !walk->vma) {
+ if (pud_none(*pud)) {
if (walk->pte_hole)
err = walk->pte_hole(addr, next, walk);
if (err)
@@ -95,9 +100,13 @@ static int walk_pud_range(p4d_t *p4d, un
break;
}
- split_huge_pud(walk->vma, pud, addr);
- if (pud_none(*pud))
- goto again;
+ if (walk->vma) {
+ split_huge_pud(walk->vma, pud, addr);
+ if (pud_none(*pud))
+ goto again;
+ } else if (pud_leaf(*pud)) {
+ continue;
+ }
if (walk->pmd_entry || walk->pte_entry)
err = walk_pmd_range(pud, addr, next, walk);
_
Patches currently in -mm which might be from steven.price@xxxxxxx are
arc-mm-add-pd_leaf-definitions.patch
arm-mm-add-pd_leaf-definitions.patch
arm64-mm-add-pd_leaf-definitions.patch
mips-mm-add-pd_leaf-definitions.patch
powerpc-mm-add-pd_leaf-definitions.patch
riscv-mm-add-pd_leaf-definitions.patch
s390-mm-add-pd_leaf-definitions.patch
sparc-mm-add-pd_leaf-definitions.patch
x86-mm-add-pd_leaf-definitions.patch
mm-add-generic-pd_leaf-macros.patch
mm-pagewalk-add-p4d_entry-and-pgd_entry.patch
mm-pagewalk-allow-walking-without-vma.patch
mm-pagewalk-add-test_pd-callbacks.patch
x86-mm-dont-display-pages-which-arent-present-in-debugfs.patch
x86-mm-point-to-struct-seq_file-from-struct-pg_state.patch
x86-mmefi-convert-ptdump_walk_pgd_level-to-take-a-mm_struct.patch
x86-mm-convert-ptdump_walk_pgd_level_debugfs-to-take-an-mm_struct.patch
x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct.patch
mm-add-generic-ptdump.patch
x86-mm-convert-dump_pagetables-to-use-walk_page_range.patch
arm64-mm-convert-mm-dumpc-to-use-walk_page_range.patch
