From: Steven Price <steven.price@arm.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Cc: "Steven Price" <steven.price@arm.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
"Arnd Bergmann" <arnd@arndb.de>, "Borislav Petkov" <bp@alien8.de>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Ingo Molnar" <mingo@redhat.com>,
"James Morse" <james.morse@arm.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Will Deacon" <will@kernel.org>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Mark Rutland" <Mark.Rutland@arm.com>,
"Liang, Kan" <kan.liang@linux.intel.com>
Subject: [PATCH v15 12/23] mm: pagewalk: Allow walking without vma
Date: Fri, 1 Nov 2019 14:09:31 +0000 [thread overview]
Message-ID: <20191101140942.51554-13-steven.price@arm.com> (raw)
In-Reply-To: <20191101140942.51554-1-steven.price@arm.com>
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 in the generic code and add a new
function walk_page_range_novma() which ignores the VMAs and simply walks
the page tables.
Signed-off-by: Steven Price <steven.price@arm.com>
---
include/linux/pagewalk.h | 5 +++++
mm/pagewalk.c | 44 ++++++++++++++++++++++++++++++++--------
2 files changed, 41 insertions(+), 8 deletions(-)
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h
index 12004b097eae..ed2bb399fac2 100644
--- a/include/linux/pagewalk.h
+++ b/include/linux/pagewalk.h
@@ -53,6 +53,7 @@ struct mm_walk_ops {
* @ops: operation to call during the walk
* @mm: mm_struct representing the target process of page table walk
* @vma: vma currently walked (NULL if walking outside vmas)
+ * @no_vma: walk ignoring vmas (vma will always be NULL)
* @private: private data for callbacks' usage
*
* (see the comment on walk_page_range() for more details)
@@ -61,12 +62,16 @@ struct mm_walk {
const struct mm_walk_ops *ops;
struct mm_struct *mm;
struct vm_area_struct *vma;
+ bool no_vma;
void *private;
};
int walk_page_range(struct mm_struct *mm, unsigned long start,
unsigned long end, const struct mm_walk_ops *ops,
void *private);
+int walk_page_range_novma(struct mm_struct *mm, unsigned long start,
+ unsigned long end, const struct mm_walk_ops *ops,
+ void *private);
int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
void *private);
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index fc4d98a3a5a0..626e7fdb0508 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -38,7 +38,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
do {
again:
next = pmd_addr_end(addr, end);
- if (pmd_none(*pmd) || !walk->vma) {
+ if (pmd_none(*pmd) || (!walk->vma && !walk->no_vma)) {
if (ops->pte_hole)
err = ops->pte_hole(addr, next, walk);
if (err)
@@ -61,9 +61,14 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
if (!ops->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;
@@ -84,7 +89,7 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
do {
again:
next = pud_addr_end(addr, end);
- if (pud_none(*pud) || !walk->vma) {
+ if (pud_none(*pud) || (!walk->vma && !walk->no_vma)) {
if (ops->pte_hole)
err = ops->pte_hole(addr, next, walk);
if (err)
@@ -98,9 +103,13 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
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 (ops->pmd_entry || ops->pte_entry)
err = walk_pmd_range(pud, addr, next, walk);
@@ -358,6 +367,25 @@ int walk_page_range(struct mm_struct *mm, unsigned long start,
return err;
}
+int walk_page_range_novma(struct mm_struct *mm, unsigned long start,
+ unsigned long end, const struct mm_walk_ops *ops,
+ void *private)
+{
+ struct mm_walk walk = {
+ .ops = ops,
+ .mm = mm,
+ .private = private,
+ .no_vma = true
+ };
+
+ if (start >= end || !walk.mm)
+ return -EINVAL;
+
+ lockdep_assert_held(&walk.mm->mmap_sem);
+
+ return __walk_page_range(start, end, &walk);
+}
+
int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
void *private)
{
--
2.20.1
next prev parent reply other threads:[~2019-11-01 14:10 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-01 14:09 [PATCH v15 00/23] Generic page walk and ptdump Steven Price
2019-11-01 14:09 ` [PATCH v15 01/23] mm: Add generic p?d_leaf() macros Steven Price
2019-11-01 14:09 ` [PATCH v15 02/23] arc: mm: Add p?d_leaf() definitions Steven Price
2019-11-01 14:09 ` [PATCH v15 03/23] arm: " Steven Price
2019-11-01 14:09 ` [PATCH v15 04/23] arm64: " Steven Price
2019-11-01 14:09 ` [PATCH v15 05/23] mips: " Steven Price
2019-11-01 14:09 ` [PATCH v15 06/23] powerpc: " Steven Price
2019-11-01 14:09 ` [PATCH v15 07/23] riscv: " Steven Price
2019-11-01 14:09 ` [PATCH v15 08/23] s390: " Steven Price
2019-11-01 14:09 ` [PATCH v15 09/23] sparc: " Steven Price
2019-11-01 14:09 ` [PATCH v15 10/23] x86: " Steven Price
2019-11-01 14:09 ` [PATCH v15 11/23] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price
2019-11-01 14:09 ` Steven Price [this message]
2019-11-01 14:09 ` [PATCH v15 13/23] mm: pagewalk: Add test_p?d callbacks Steven Price
2019-11-01 14:09 ` [PATCH v15 14/23] mm: pagewalk: Add 'depth' parameter to pte_hole Steven Price
2019-11-01 14:09 ` [PATCH v15 15/23] x86: mm: Point to struct seq_file from struct pg_state Steven Price
2019-11-01 14:09 ` [PATCH v15 16/23] x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price
2019-11-01 14:09 ` [PATCH v15 17/23] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price
2019-11-01 14:09 ` [PATCH v15 18/23] x86: mm: Convert ptdump_walk_pgd_level_core() " Steven Price
2019-11-01 14:09 ` [PATCH v15 19/23] mm: Add generic ptdump Steven Price
2019-11-01 14:09 ` [PATCH v15 20/23] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price
2019-11-01 14:09 ` [PATCH v15 21/23] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price
2019-11-01 14:09 ` [PATCH v15 22/23] arm64: mm: Display non-present entries in ptdump Steven Price
2019-11-01 14:09 ` [PATCH v15 23/23] mm: ptdump: Reduce level numbers by 1 in note_page() Steven Price
2019-11-04 19:35 ` [PATCH v15 00/23] Generic page walk and ptdump Qian Cai
2019-11-06 13:31 ` Qian Cai
2019-11-06 15:05 ` Steven Price
2019-12-03 11:02 ` David Hildenbrand
2019-12-04 14:54 ` Qian Cai
2019-12-04 14:56 ` David Hildenbrand
2019-12-04 16:32 ` Steven Price
2019-12-04 17:51 ` Thomas Hellstrom
2019-12-05 13:15 ` Qian Cai
2019-12-05 14:32 ` Thomas Hellstrom
2019-12-05 14:38 ` Qian Cai
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