| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20250917033703.1695933-2-zhangchunyan@iscas.ac.cn>
Date: Wed, 17 Sep 2025 11:36:58 +0800
From: Chunyan Zhang <zhangchunyan@...as.ac.cn>
To: linux-riscv@...ts.infradead.org,
linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Cc: Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Alexandre Ghiti <alex@...ti.fr>,
Conor Dooley <conor@...nel.org>,
Deepak Gupta <debug@...osinc.com>,
Ved Shanbhogue <ved@...osinc.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
Jan Kara <jack@...e.cz>,
Andrew Morton <akpm@...ux-foundation.org>,
Peter Xu <peterx@...hat.com>,
Arnd Bergmann <arnd@...db.de>,
David Hildenbrand <david@...hat.com>,
Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
"Liam R . Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Mike Rapoport <rppt@...nel.org>,
Suren Baghdasaryan <surenb@...gle.com>,
Michal Hocko <mhocko@...e.com>,
Axel Rasmussen <axelrasmussen@...gle.com>,
Yuanchu Xie <yuanchu@...gle.com>,
Chunyan Zhang <zhang.lyra@...il.com>
Subject: [PATCH V13 1/6] mm: softdirty: Add pgtable_supports_soft_dirty()
Some platforms can customize the PTE PMD entry soft-dirty bit making it
unavailable even if the architecture provides the resource.
Add an API which architectures can define their specific implementations
to detect if soft-dirty bit is available on which device the kernel is
running.
This patch is removing "ifdef CONFIG_MEM_SOFT_DIRTY" in favor of
pgtable_supports_soft_dirty() checks that defaults to
IS_ENABLED(CONFIG_MEM_SOFT_DIRTY), if not overridden by
the architecture, no change in behavior is expected.
We make sure to never set VM_SOFTDIRTY if !pgtable_supports_soft_dirty(),
so we will never run into VM_SOFTDIRTY checks.
Acked-by: David Hildenbrand <david@...hat.com>
Signed-off-by: Chunyan Zhang <zhangchunyan@...as.ac.cn>
---
fs/proc/task_mmu.c | 15 ++++++---------
include/linux/mm.h | 3 +++
include/linux/pgtable.h | 12 ++++++++++++
mm/debug_vm_pgtable.c | 10 +++++-----
mm/huge_memory.c | 13 +++++++------
mm/internal.h | 2 +-
mm/mmap.c | 6 ++++--
mm/mremap.c | 13 +++++++------
mm/userfaultfd.c | 10 ++++------
mm/vma.c | 6 ++++--
mm/vma_exec.c | 5 ++++-
11 files changed, 57 insertions(+), 38 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ced01cf3c5ab..18c55e21bd16 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1582,8 +1582,6 @@ struct clear_refs_private {
enum clear_refs_types type;
};
-#ifdef CONFIG_MEM_SOFT_DIRTY
-
static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
{
struct folio *folio;
@@ -1603,6 +1601,8 @@ static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr,
static inline void clear_soft_dirty(struct vm_area_struct *vma,
unsigned long addr, pte_t *pte)
{
+ if (!pgtable_supports_soft_dirty())
+ return;
/*
* The soft-dirty tracker uses #PF-s to catch writes
* to pages, so write-protect the pte as well. See the
@@ -1625,19 +1625,16 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
set_pte_at(vma->vm_mm, addr, pte, ptent);
}
}
-#else
-static inline void clear_soft_dirty(struct vm_area_struct *vma,
- unsigned long addr, pte_t *pte)
-{
-}
-#endif
-#if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE)
static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old, pmd = *pmdp;
+ if (!pgtable_supports_soft_dirty())
+ return;
+
if (pmd_present(pmd)) {
/* See comment in change_huge_pmd() */
old = pmdp_invalidate(vma, addr, pmdp);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d004fb7d805d..c5bc449a65d5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -798,6 +798,7 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
static inline void vm_flags_init(struct vm_area_struct *vma,
vm_flags_t flags)
{
+ VM_WARN_ON_ONCE(!pgtable_supports_soft_dirty() && (flags & VM_SOFTDIRTY));
ACCESS_PRIVATE(vma, __vm_flags) = flags;
}
@@ -816,6 +817,7 @@ static inline void vm_flags_reset(struct vm_area_struct *vma,
static inline void vm_flags_reset_once(struct vm_area_struct *vma,
vm_flags_t flags)
{
+ VM_WARN_ON_ONCE(!pgtable_supports_soft_dirty() && (flags & VM_SOFTDIRTY));
vma_assert_write_locked(vma);
WRITE_ONCE(ACCESS_PRIVATE(vma, __vm_flags), flags);
}
@@ -823,6 +825,7 @@ static inline void vm_flags_reset_once(struct vm_area_struct *vma,
static inline void vm_flags_set(struct vm_area_struct *vma,
vm_flags_t flags)
{
+ VM_WARN_ON_ONCE(!pgtable_supports_soft_dirty() && (flags & VM_SOFTDIRTY));
vma_start_write(vma);
ACCESS_PRIVATE(vma, __vm_flags) |= flags;
}
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 32e8457ad535..b13b6f42be3c 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1553,6 +1553,18 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
#define arch_start_context_switch(prev) do {} while (0)
#endif
+/*
+ * Some platforms can customize the PTE soft-dirty bit making it unavailable
+ * even if the architecture provides the resource.
+ * Adding this API allows architectures to add their own checks for the
+ * devices on which the kernel is running.
+ * Note: When overriding it, please make sure the CONFIG_MEM_SOFT_DIRTY
+ * is part of this macro.
+ */
+#ifndef pgtable_supports_soft_dirty
+#define pgtable_supports_soft_dirty() IS_ENABLED(CONFIG_MEM_SOFT_DIRTY)
+#endif
+
#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
#ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 830107b6dd08..6a5b226bda28 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -690,7 +690,7 @@ static void __init pte_soft_dirty_tests(struct pgtable_debug_args *args)
{
pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
- if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
+ if (!pgtable_supports_soft_dirty())
return;
pr_debug("Validating PTE soft dirty\n");
@@ -702,7 +702,7 @@ static void __init pte_swap_soft_dirty_tests(struct pgtable_debug_args *args)
{
pte_t pte;
- if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
+ if (!pgtable_supports_soft_dirty())
return;
pr_debug("Validating PTE swap soft dirty\n");
@@ -718,7 +718,7 @@ static void __init pmd_soft_dirty_tests(struct pgtable_debug_args *args)
{
pmd_t pmd;
- if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
+ if (!pgtable_supports_soft_dirty())
return;
if (!has_transparent_hugepage())
@@ -734,8 +734,8 @@ static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args)
{
pmd_t pmd;
- if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) ||
- !IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
+ if (!pgtable_supports_soft_dirty() ||
+ !IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
return;
if (!has_transparent_hugepage())
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5acca24bbabb..85dca384375e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2263,12 +2263,13 @@ static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
static pmd_t move_soft_dirty_pmd(pmd_t pmd)
{
-#ifdef CONFIG_MEM_SOFT_DIRTY
- if (unlikely(is_pmd_migration_entry(pmd)))
- pmd = pmd_swp_mksoft_dirty(pmd);
- else if (pmd_present(pmd))
- pmd = pmd_mksoft_dirty(pmd);
-#endif
+ if (pgtable_supports_soft_dirty()) {
+ if (unlikely(is_pmd_migration_entry(pmd)))
+ pmd = pmd_swp_mksoft_dirty(pmd);
+ else if (pmd_present(pmd))
+ pmd = pmd_mksoft_dirty(pmd);
+ }
+
return pmd;
}
diff --git a/mm/internal.h b/mm/internal.h
index 63e3ec8d63be..6a4219cdff58 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1530,7 +1530,7 @@ static inline bool vma_soft_dirty_enabled(struct vm_area_struct *vma)
* VM_SOFTDIRTY is defined as 0x0, then !(vm_flags & VM_SOFTDIRTY)
* will be constantly true.
*/
- if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
+ if (!pgtable_supports_soft_dirty())
return false;
/*
diff --git a/mm/mmap.c b/mm/mmap.c
index 266711d1c91c..4ce7d4667766 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1451,8 +1451,10 @@ static struct vm_area_struct *__install_special_mapping(
return ERR_PTR(-ENOMEM);
vma_set_range(vma, addr, addr + len, 0);
- vm_flags_init(vma, (vm_flags | mm->def_flags |
- VM_DONTEXPAND | VM_SOFTDIRTY) & ~VM_LOCKED_MASK);
+ vm_flags |= mm->def_flags | VM_DONTEXPAND;
+ if (pgtable_supports_soft_dirty())
+ vm_flags |= VM_SOFTDIRTY;
+ vm_flags_init(vma, vm_flags & ~VM_LOCKED_MASK);
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
vma->vm_ops = ops;
diff --git a/mm/mremap.c b/mm/mremap.c
index 35de0a7b910e..35a135cd149a 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -162,12 +162,13 @@ static pte_t move_soft_dirty_pte(pte_t pte)
* Set soft dirty bit so we can notice
* in userspace the ptes were moved.
*/
-#ifdef CONFIG_MEM_SOFT_DIRTY
- if (pte_present(pte))
- pte = pte_mksoft_dirty(pte);
- else if (is_swap_pte(pte))
- pte = pte_swp_mksoft_dirty(pte);
-#endif
+ if (pgtable_supports_soft_dirty()) {
+ if (pte_present(pte))
+ pte = pte_mksoft_dirty(pte);
+ else if (is_swap_pte(pte))
+ pte = pte_swp_mksoft_dirty(pte);
+ }
+
return pte;
}
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index af61b95c89e4..ea8ce18483fe 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -1116,9 +1116,8 @@ static long move_present_ptes(struct mm_struct *mm,
orig_dst_pte = folio_mk_pte(src_folio, dst_vma->vm_page_prot);
/* Set soft dirty bit so userspace can notice the pte was moved */
-#ifdef CONFIG_MEM_SOFT_DIRTY
- orig_dst_pte = pte_mksoft_dirty(orig_dst_pte);
-#endif
+ if (pgtable_supports_soft_dirty())
+ orig_dst_pte = pte_mksoft_dirty(orig_dst_pte);
if (pte_dirty(orig_src_pte))
orig_dst_pte = pte_mkdirty(orig_dst_pte);
orig_dst_pte = pte_mkwrite(orig_dst_pte, dst_vma);
@@ -1205,9 +1204,8 @@ static int move_swap_pte(struct mm_struct *mm, struct vm_area_struct *dst_vma,
}
orig_src_pte = ptep_get_and_clear(mm, src_addr, src_pte);
-#ifdef CONFIG_MEM_SOFT_DIRTY
- orig_src_pte = pte_swp_mksoft_dirty(orig_src_pte);
-#endif
+ if (pgtable_supports_soft_dirty())
+ orig_src_pte = pte_swp_mksoft_dirty(orig_src_pte);
set_pte_at(mm, dst_addr, dst_pte, orig_src_pte);
double_pt_unlock(dst_ptl, src_ptl);
diff --git a/mm/vma.c b/mm/vma.c
index 1be297f7bb00..674b7a7c6132 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -2568,7 +2568,8 @@ static void __mmap_complete(struct mmap_state *map, struct vm_area_struct *vma)
* then new mapped in-place (which must be aimed as
* a completely new data area).
*/
- vm_flags_set(vma, VM_SOFTDIRTY);
+ if (pgtable_supports_soft_dirty())
+ vm_flags_set(vma, VM_SOFTDIRTY);
vma_set_page_prot(vma);
}
@@ -2843,7 +2844,8 @@ int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
mm->data_vm += len >> PAGE_SHIFT;
if (vm_flags & VM_LOCKED)
mm->locked_vm += (len >> PAGE_SHIFT);
- vm_flags_set(vma, VM_SOFTDIRTY);
+ if (pgtable_supports_soft_dirty())
+ vm_flags_set(vma, VM_SOFTDIRTY);
return 0;
mas_store_fail:
diff --git a/mm/vma_exec.c b/mm/vma_exec.c
index 922ee51747a6..a822fb73f4e2 100644
--- a/mm/vma_exec.c
+++ b/mm/vma_exec.c
@@ -107,6 +107,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
int create_init_stack_vma(struct mm_struct *mm, struct vm_area_struct **vmap,
unsigned long *top_mem_p)
{
+ unsigned long flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
int err;
struct vm_area_struct *vma = vm_area_alloc(mm);
@@ -137,7 +138,9 @@ int create_init_stack_vma(struct mm_struct *mm, struct vm_area_struct **vmap,
BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
vma->vm_end = STACK_TOP_MAX;
vma->vm_start = vma->vm_end - PAGE_SIZE;
- vm_flags_init(vma, VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP);
+ if (pgtable_supports_soft_dirty())
+ flags |= VM_SOFTDIRTY;
+ vm_flags_init(vma, flags);
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
err = insert_vm_struct(mm, vma);
--
2.34.1
Powered by blists - more mailing lists