From: Steven Price <steven.price@arm.com>
To: 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>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: [PATCH v10 13/22] mm: pagewalk: Add test_p?d callbacks
Date: Wed, 31 Jul 2019 16:45:54 +0100 [thread overview]
Message-ID: <20190731154603.41797-14-steven.price@arm.com> (raw)
In-Reply-To: <20190731154603.41797-1-steven.price@arm.com>
It is useful to be able to skip parts of the page table tree even when
walking without VMAs. Add test_p?d callbacks similar to test_walk but
which are called just before a table at that level is walked. If the
callback returns non-zero then the entire table is skipped.
Signed-off-by: Steven Price <steven.price@arm.com>
---
include/linux/mm.h | 11 +++++++++++
mm/pagewalk.c | 24 ++++++++++++++++++++++++
2 files changed, 35 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0a1e83c4e267..e2581ec5324e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1447,6 +1447,11 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
* value means "do page table walk over the current vma,"
* and a negative one means "abort current page table walk
* right now." 1 means "skip the current vma."
+ * @test_pmd: similar to test_walk(), but called for every pmd.
+ * @test_pud: similar to test_walk(), but called for every pud.
+ * @test_p4d: similar to test_walk(), but called for every p4d.
+ * Returning 0 means walk this part of the page tables,
+ * returning 1 means to skip this range.
* @mm: mm_struct representing the target process of page table walk
* @vma: vma currently walked (NULL if walking outside vmas)
* @private: private data for callbacks' usage
@@ -1474,6 +1479,12 @@ struct mm_walk {
struct mm_walk *walk);
int (*test_walk)(unsigned long addr, unsigned long next,
struct mm_walk *walk);
+ int (*test_pmd)(unsigned long addr, unsigned long next,
+ pmd_t *pmd_start, struct mm_walk *walk);
+ int (*test_pud)(unsigned long addr, unsigned long next,
+ pud_t *pud_start, struct mm_walk *walk);
+ int (*test_p4d)(unsigned long addr, unsigned long next,
+ p4d_t *p4d_start, struct mm_walk *walk);
struct mm_struct *mm;
struct vm_area_struct *vma;
void *private;
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 1cbef99e9258..6bea79b95be3 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -32,6 +32,14 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
unsigned long next;
int err = 0;
+ if (walk->test_pmd) {
+ err = walk->test_pmd(addr, end, pmd_offset(pud, 0UL), walk);
+ if (err < 0)
+ return err;
+ if (err > 0)
+ return 0;
+ }
+
pmd = pmd_offset(pud, addr);
do {
again:
@@ -82,6 +90,14 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
unsigned long next;
int err = 0;
+ if (walk->test_pud) {
+ err = walk->test_pud(addr, end, pud_offset(p4d, 0UL), walk);
+ if (err < 0)
+ return err;
+ if (err > 0)
+ return 0;
+ }
+
pud = pud_offset(p4d, addr);
do {
again:
@@ -124,6 +140,14 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
unsigned long next;
int err = 0;
+ if (walk->test_p4d) {
+ err = walk->test_p4d(addr, end, p4d_offset(pgd, 0UL), walk);
+ if (err < 0)
+ return err;
+ if (err > 0)
+ return 0;
+ }
+
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
--
2.20.1
next prev parent reply other threads:[~2019-07-31 15:46 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 15:45 [PATCH v10 00/22] Generic page walk and ptdump Steven Price
2019-07-31 15:45 ` [PATCH v10 01/22] mm: Add generic p?d_leaf() macros Steven Price
2019-07-31 15:45 ` [PATCH v10 02/22] arc: mm: Add p?d_leaf() definitions Steven Price
2019-07-31 15:45 ` [PATCH v10 03/22] arm: " Steven Price
2019-07-31 15:45 ` [PATCH v10 04/22] arm64: " Steven Price
2019-07-31 15:45 ` [PATCH v10 05/22] mips: " Steven Price
2019-07-31 18:35 ` Paul Burton
2019-07-31 15:45 ` [PATCH v10 06/22] powerpc: " Steven Price
2019-07-31 15:45 ` [PATCH v10 07/22] riscv: " Steven Price
2019-07-31 15:45 ` [PATCH v10 08/22] s390: " Steven Price
2019-07-31 15:45 ` [PATCH v10 09/22] sparc: " Steven Price
2019-07-31 15:45 ` [PATCH v10 10/22] x86: " Steven Price
2019-07-31 15:45 ` [PATCH v10 11/22] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price
2019-07-31 15:45 ` [PATCH v10 12/22] mm: pagewalk: Allow walking without vma Steven Price
2019-07-31 15:45 ` Steven Price [this message]
2019-07-31 15:45 ` [PATCH v10 14/22] mm: pagewalk: Add 'depth' parameter to pte_hole Steven Price
2019-07-31 15:45 ` [PATCH v10 15/22] x86: mm: Point to struct seq_file from struct pg_state Steven Price
2019-07-31 15:45 ` [PATCH v10 16/22] x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price
2019-07-31 15:45 ` [PATCH v10 17/22] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price
2019-07-31 15:45 ` [PATCH v10 18/22] x86: mm: Convert ptdump_walk_pgd_level_core() " Steven Price
2019-07-31 15:46 ` [PATCH v10 19/22] mm: Add generic ptdump Steven Price
2019-07-31 15:46 ` [PATCH v10 20/22] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price
2019-08-06 23:58 ` Andrew Morton
2019-08-07 12:58 ` Steven Price
2019-08-07 20:16 ` Andrew Morton
2019-07-31 15:46 ` [PATCH v10 21/22] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price
2019-07-31 15:46 ` [PATCH v10 22/22] arm64: mm: Display non-present entries in ptdump Steven Price
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