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[PATCH V4 mm-hotfixes 1/3] mm: move page table sync declarations to linux/pgtable.h

Harry Yoo posted 3 patches 6 months ago
There is a newer version of this series
[PATCH V4 mm-hotfixes 1/3] mm: move page table sync declarations to linux/pgtable.h
Posted by Harry Yoo 6 months ago 
Move ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
linux/pgtable.h so that they can be used outside of vmalloc and ioremap.

Cc: <stable@vger.kernel.org>
Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
---
 include/linux/pgtable.h | 16 ++++++++++++++++
 include/linux/vmalloc.h | 16 ----------------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 4c035637eeb7..ba699df6ef69 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1467,6 +1467,22 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned
 }
 #endif
 
+/*
+ * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
+ * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
+ * needs to be called.
+ */
+#ifndef ARCH_PAGE_TABLE_SYNC_MASK
+#define ARCH_PAGE_TABLE_SYNC_MASK 0
+#endif
+
+/*
+ * There is no default implementation for arch_sync_kernel_mappings(). It is
+ * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
+ * is 0.
+ */
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
+
 #endif /* CONFIG_MMU */
 
 /*
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index fdc9aeb74a44..2759dac6be44 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -219,22 +219,6 @@ extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
 int vmap_pages_range(unsigned long addr, unsigned long end, pgprot_t prot,
 		     struct page **pages, unsigned int page_shift);
 
-/*
- * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
- * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
- * needs to be called.
- */
-#ifndef ARCH_PAGE_TABLE_SYNC_MASK
-#define ARCH_PAGE_TABLE_SYNC_MASK 0
-#endif
-
-/*
- * There is no default implementation for arch_sync_kernel_mappings(). It is
- * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
- * is 0.
- */
-void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
-
 /*
  *	Lowlevel-APIs (not for driver use!)
  */
-- 
2.43.0
Re: [PATCH V4 mm-hotfixes 1/3] mm: move page table sync declarations to linux/pgtable.h
Posted by Lorenzo Stoakes 6 months ago 
On Mon, Aug 11, 2025 at 02:34:18PM +0900, Harry Yoo wrote:
> Move ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
> linux/pgtable.h so that they can be used outside of vmalloc and ioremap.
>
> Cc: <stable@vger.kernel.org>
> Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> Signed-off-by: Harry Yoo <harry.yoo@oracle.com>

LGTM, obviously assuming you address Mike's comments about... comments :)

So:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
>  include/linux/pgtable.h | 16 ++++++++++++++++
>  include/linux/vmalloc.h | 16 ----------------
>  2 files changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 4c035637eeb7..ba699df6ef69 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1467,6 +1467,22 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned
>  }
>  #endif
>
> +/*
> + * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> + * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> + * needs to be called.
> + */
> +#ifndef ARCH_PAGE_TABLE_SYNC_MASK
> +#define ARCH_PAGE_TABLE_SYNC_MASK 0
> +#endif
> +
> +/*
> + * There is no default implementation for arch_sync_kernel_mappings(). It is
> + * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
> + * is 0.
> + */
> +void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
> +
>  #endif /* CONFIG_MMU */
>
>  /*
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index fdc9aeb74a44..2759dac6be44 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -219,22 +219,6 @@ extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
>  int vmap_pages_range(unsigned long addr, unsigned long end, pgprot_t prot,
>  		     struct page **pages, unsigned int page_shift);
>
> -/*
> - * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> - * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> - * needs to be called.
> - */
> -#ifndef ARCH_PAGE_TABLE_SYNC_MASK
> -#define ARCH_PAGE_TABLE_SYNC_MASK 0
> -#endif
> -
> -/*
> - * There is no default implementation for arch_sync_kernel_mappings(). It is
> - * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
> - * is 0.
> - */
> -void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
> -
>  /*
>   *	Lowlevel-APIs (not for driver use!)
>   */
> --
> 2.43.0
>
Re: [PATCH V4 mm-hotfixes 1/3] mm: move page table sync declarations to linux/pgtable.h
Posted by Mike Rapoport 6 months ago 
On Mon, Aug 11, 2025 at 02:34:18PM +0900, Harry Yoo wrote:
> Move ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
> linux/pgtable.h so that they can be used outside of vmalloc and ioremap.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
> ---
>  include/linux/pgtable.h | 16 ++++++++++++++++
>  include/linux/vmalloc.h | 16 ----------------
>  2 files changed, 16 insertions(+), 16 deletions(-)
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 4c035637eeb7..ba699df6ef69 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1467,6 +1467,22 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned
>  }
>  #endif
>  
> +/*
> + * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> + * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()

If ARCH_PAGE_TABLE_SYNC_MASK can be used outside vmalloc(), the comment
needs an update, maybe

... and let the generic code that modifies kernel page tables

Other than that

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> + * needs to be called.
> + */
> +#ifndef ARCH_PAGE_TABLE_SYNC_MASK
> +#define ARCH_PAGE_TABLE_SYNC_MASK 0
> +#endif
> +
> +/*
> + * There is no default implementation for arch_sync_kernel_mappings(). It is
> + * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
> + * is 0.
> + */
> +void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
> +
>  #endif /* CONFIG_MMU */
>  
>  /*
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index fdc9aeb74a44..2759dac6be44 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -219,22 +219,6 @@ extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
>  int vmap_pages_range(unsigned long addr, unsigned long end, pgprot_t prot,
>  		     struct page **pages, unsigned int page_shift);
>  
> -/*
> - * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> - * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> - * needs to be called.
> - */
> -#ifndef ARCH_PAGE_TABLE_SYNC_MASK
> -#define ARCH_PAGE_TABLE_SYNC_MASK 0
> -#endif
> -
> -/*
> - * There is no default implementation for arch_sync_kernel_mappings(). It is
> - * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
> - * is 0.
> - */
> -void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
> -
>  /*
>   *	Lowlevel-APIs (not for driver use!)
>   */
> -- 
> 2.43.0
> 

-- 
Sincerely yours,
Mike.
Re: [PATCH V4 mm-hotfixes 1/3] mm: move page table sync declarations to linux/pgtable.h
Posted by Uladzislau Rezki 6 months ago 
On Mon, Aug 11, 2025 at 11:05:51AM +0300, Mike Rapoport wrote:
> On Mon, Aug 11, 2025 at 02:34:18PM +0900, Harry Yoo wrote:
> > Move ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
> > linux/pgtable.h so that they can be used outside of vmalloc and ioremap.
> > 
> > Cc: <stable@vger.kernel.org>
> > Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> > Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
> > ---
> >  include/linux/pgtable.h | 16 ++++++++++++++++
> >  include/linux/vmalloc.h | 16 ----------------
> >  2 files changed, 16 insertions(+), 16 deletions(-)
> > 
> > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> > index 4c035637eeb7..ba699df6ef69 100644
> > --- a/include/linux/pgtable.h
> > +++ b/include/linux/pgtable.h
> > @@ -1467,6 +1467,22 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned
> >  }
> >  #endif
> >  
> > +/*
> > + * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> > + * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> 
> If ARCH_PAGE_TABLE_SYNC_MASK can be used outside vmalloc(), the comment
> needs an update, maybe
> 
> ... and let the generic code that modifies kernel page tables
> 
> Other than that
> 
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> 
> > + * needs to be called.
> > + */
> > +#ifndef ARCH_PAGE_TABLE_SYNC_MASK
> > +#define ARCH_PAGE_TABLE_SYNC_MASK 0
> > +#endif
> > +
> > +/*
> > + * There is no default implementation for arch_sync_kernel_mappings(). It is
> > + * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
> > + * is 0.
> > + */
> > +void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
> > +
> >  #endif /* CONFIG_MMU */
> >  
> >  /*
> > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> > index fdc9aeb74a44..2759dac6be44 100644
> > --- a/include/linux/vmalloc.h
> > +++ b/include/linux/vmalloc.h
> > @@ -219,22 +219,6 @@ extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
> >  int vmap_pages_range(unsigned long addr, unsigned long end, pgprot_t prot,
> >  		     struct page **pages, unsigned int page_shift);
> >  
> > -/*
> > - * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> > - * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> > - * needs to be called.
> > - */
> > -#ifndef ARCH_PAGE_TABLE_SYNC_MASK
> > -#define ARCH_PAGE_TABLE_SYNC_MASK 0
> > -#endif
> > -
> > -/*
> > - * There is no default implementation for arch_sync_kernel_mappings(). It is
> > - * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
> > - * is 0.
> > - */
> > -void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
> > -
> >  /*
> >   *	Lowlevel-APIs (not for driver use!)
> >   */
> > -- 
> > 2.43.0
> > 
> 
LGTM,

Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@gmail.com>

--
Uladzislau Rezki
Re: [PATCH V4 mm-hotfixes 1/3] mm: move page table sync declarations to linux/pgtable.h
Posted by Harry Yoo 6 months ago 
On Mon, Aug 11, 2025 at 11:05:51AM +0300, Mike Rapoport wrote:
> On Mon, Aug 11, 2025 at 02:34:18PM +0900, Harry Yoo wrote:
> > Move ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
> > linux/pgtable.h so that they can be used outside of vmalloc and ioremap.
> > 
> > Cc: <stable@vger.kernel.org>
> > Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> > Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
> > ---
> >  include/linux/pgtable.h | 16 ++++++++++++++++
> >  include/linux/vmalloc.h | 16 ----------------
> >  2 files changed, 16 insertions(+), 16 deletions(-)
> > 
> > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> > index 4c035637eeb7..ba699df6ef69 100644
> > --- a/include/linux/pgtable.h
> > +++ b/include/linux/pgtable.h
> > @@ -1467,6 +1467,22 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned
> >  }
> >  #endif
> >  
> > +/*
> > + * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> > + * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> 
> If ARCH_PAGE_TABLE_SYNC_MASK can be used outside vmalloc(), the comment
> needs an update, maybe
> 
> ... and let the generic code that modifies kernel page tables

Right, and patch 2 updates the comment as it uses it outside vmalloc():

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index ba699df6ef69..0cf5c6c3e483 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1469,8 +1469,8 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned

 /*
  * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
- * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
- * needs to be called.
+ * and let generic vmalloc, ioremap and page table update code know when
+ * arch_sync_kernel_mappings() needs to be called.
  */
 #ifndef ARCH_PAGE_TABLE_SYNC_MASK
 #define ARCH_PAGE_TABLE_SYNC_MASK 0

Or if you think "page table update code" is unclear, please let me know.

> Other than that
> 
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Thanks a lot for all the reviews, Mike!

-- 
Cheers,
Harry / Hyeonggon
Re: [PATCH V4 mm-hotfixes 1/3] mm: move page table sync declarations to linux/pgtable.h
Posted by Mike Rapoport 6 months ago 
On Mon, Aug 11, 2025 at 05:36:53PM +0900, Harry Yoo wrote:
> On Mon, Aug 11, 2025 at 11:05:51AM +0300, Mike Rapoport wrote:
> > On Mon, Aug 11, 2025 at 02:34:18PM +0900, Harry Yoo wrote:
> > > Move ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to
> > > linux/pgtable.h so that they can be used outside of vmalloc and ioremap.
> > > 
> > > Cc: <stable@vger.kernel.org>
> > > Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
> > > Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
> > > ---
> > >  include/linux/pgtable.h | 16 ++++++++++++++++
> > >  include/linux/vmalloc.h | 16 ----------------
> > >  2 files changed, 16 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> > > index 4c035637eeb7..ba699df6ef69 100644
> > > --- a/include/linux/pgtable.h
> > > +++ b/include/linux/pgtable.h
> > > @@ -1467,6 +1467,22 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned
> > >  }
> > >  #endif
> > >  
> > > +/*
> > > + * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> > > + * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> > 
> > If ARCH_PAGE_TABLE_SYNC_MASK can be used outside vmalloc(), the comment
> > needs an update, maybe
> > 
> > ... and let the generic code that modifies kernel page tables
> 
> Right, and patch 2 updates the comment as it uses it outside vmalloc():
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index ba699df6ef69..0cf5c6c3e483 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1469,8 +1469,8 @@ static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned
> 
>  /*
>   * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
> - * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
> - * needs to be called.
> + * and let generic vmalloc, ioremap and page table update code know when
> + * arch_sync_kernel_mappings() needs to be called.
>   */
>  #ifndef ARCH_PAGE_TABLE_SYNC_MASK
>  #define ARCH_PAGE_TABLE_SYNC_MASK 0
> 
> Or if you think "page table update code" is unclear, please let me know.

It's fine :)
 
> > Other than that
> > 
> > Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> 
> Thanks a lot for all the reviews, Mike!
> 
> -- 
> Cheers,
> Harry / Hyeonggon

-- 
Sincerely yours,
Mike.

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