Re: [PATCH V5 02/26] mm/mmap: Define DECLARE_VM_GET_PAGE_PROT
Le 27/06/2022 à 06:58, Anshuman Khandual a écrit :
> This just converts the generic vm_get_page_prot() implementation into a new
> macro i.e DECLARE_VM_GET_PAGE_PROT which later can be used across platforms
> when enabling them with ARCH_HAS_VM_GET_PAGE_PROT. This does not create any
> functional change.
>
> Cc: Andrew Morton
> Cc: linux...@kvack.org
> Cc: linux-ker...@vger.kernel.org
> Suggested-by: Christoph Hellwig
> Signed-off-by: Anshuman Khandual
Reviewed-by: Christophe Leroy
> ---
> include/linux/pgtable.h | 28
> mm/mmap.c | 26 +-
> 2 files changed, 29 insertions(+), 25 deletions(-)
>
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 3cdc16cfd867..014ee8f0fbaa 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1689,4 +1689,32 @@ typedef unsigned int pgtbl_mod_mask;
> #define MAX_PTRS_PER_P4D PTRS_PER_P4D
> #endif
>
> +/* description of effects of mapping type and prot in current implementation.
> + * this is due to the limited x86 page protection hardware. The expected
> + * behavior is in parens:
> + *
> + * map_type prot
> + * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
> + * MAP_SHAREDr: (no) no r: (yes) yesr: (no) yes r: (no)
> yes
> + * w: (no) no w: (no) no w: (yes) yesw: (no) no
> + * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
> + *
> + * MAP_PRIVATE r: (no) no r: (yes) yesr: (no) yes r: (no)
> yes
> + * w: (no) no w: (no) no w: (copy) copy w: (no) no
> + * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
> + *
> + * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
> + * MAP_PRIVATE (with Enhanced PAN supported):
> + * r: (no) no
> + * w: (no) no
> + * x: (yes) yes
> + */
> +#define DECLARE_VM_GET_PAGE_PROT \
> +pgprot_t vm_get_page_prot(unsigned long vm_flags)\
> +{\
> + return protection_map[vm_flags &\
> + (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)];\
> +}\
> +EXPORT_SYMBOL(vm_get_page_prot);
> +
> #endif /* _LINUX_PGTABLE_H */
> diff --git a/mm/mmap.c b/mm/mmap.c
> index b01f0280bda2..b46d5e931bb3 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -81,26 +81,6 @@ static void unmap_region(struct mm_struct *mm,
> struct vm_area_struct *vma, struct vm_area_struct *prev,
> unsigned long start, unsigned long end);
>
> -/* description of effects of mapping type and prot in current implementation.
> - * this is due to the limited x86 page protection hardware. The expected
> - * behavior is in parens:
> - *
> - * map_type prot
> - * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
> - * MAP_SHAREDr: (no) no r: (yes) yesr: (no) yes r: (no)
> yes
> - * w: (no) no w: (no) no w: (yes) yesw: (no) no
> - * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
> - *
> - * MAP_PRIVATE r: (no) no r: (yes) yesr: (no) yes r: (no)
> yes
> - * w: (no) no w: (no) no w: (copy) copy w: (no) no
> - * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
> - *
> - * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
> - * MAP_PRIVATE (with Enhanced PAN supported):
> - * r: (no) no
> - * w: (no) no
> - * x: (yes) yes
> - */
> #ifdef __P000
> pgprot_t protection_map[16] __ro_after_init = {
> [VM_NONE] = __P000,
> @@ -123,11 +103,7 @@ pgprot_t protection_map[16] __ro_after_init = {
> #endif
>
> #ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
> -pgprot_t vm_get_page_prot(unsigned long vm_flags)
> -{
> - return protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
> -}
> -EXPORT_SYMBOL(vm_get_page_prot);
> +DECLARE_VM_GET_PAGE_PROT
> #endif /* CONFIG_ARCH_HAS_VM_GET_PAGE_PROT */
>
> static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
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[PATCH V5 02/26] mm/mmap: Define DECLARE_VM_GET_PAGE_PROT
This just converts the generic vm_get_page_prot() implementation into a new
macro i.e DECLARE_VM_GET_PAGE_PROT which later can be used across platforms
when enabling them with ARCH_HAS_VM_GET_PAGE_PROT. This does not create any
functional change.
Cc: Andrew Morton
Cc: linux...@kvack.org
Cc: linux-ker...@vger.kernel.org
Suggested-by: Christoph Hellwig
Signed-off-by: Anshuman Khandual
---
include/linux/pgtable.h | 28
mm/mmap.c | 26 +-
2 files changed, 29 insertions(+), 25 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 3cdc16cfd867..014ee8f0fbaa 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1689,4 +1689,32 @@ typedef unsigned int pgtbl_mod_mask;
#define MAX_PTRS_PER_P4D PTRS_PER_P4D
#endif
+/* description of effects of mapping type and prot in current implementation.
+ * this is due to the limited x86 page protection hardware. The expected
+ * behavior is in parens:
+ *
+ * map_typeprot
+ * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
+ * MAP_SHARED r: (no) no r: (yes) yesr: (no) yes r: (no) yes
+ * w: (no) no w: (no) no w: (yes) yesw: (no) no
+ * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
+ *
+ * MAP_PRIVATE r: (no) no r: (yes) yesr: (no) yes r: (no) yes
+ * w: (no) no w: (no) no w: (copy) copy w: (no) no
+ * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
+ *
+ * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
+ * MAP_PRIVATE (with Enhanced PAN supported):
+ * r: (no) no
+ * w: (no) no
+ * x: (yes) yes
+ */
+#define DECLARE_VM_GET_PAGE_PROT \
+pgprot_t vm_get_page_prot(unsigned long vm_flags) \
+{ \
+ return protection_map[vm_flags &\
+ (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)];\
+} \
+EXPORT_SYMBOL(vm_get_page_prot);
+
#endif /* _LINUX_PGTABLE_H */
diff --git a/mm/mmap.c b/mm/mmap.c
index b01f0280bda2..b46d5e931bb3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -81,26 +81,6 @@ static void unmap_region(struct mm_struct *mm,
struct vm_area_struct *vma, struct vm_area_struct *prev,
unsigned long start, unsigned long end);
-/* description of effects of mapping type and prot in current implementation.
- * this is due to the limited x86 page protection hardware. The expected
- * behavior is in parens:
- *
- * map_typeprot
- * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
- * MAP_SHARED r: (no) no r: (yes) yesr: (no) yes r: (no) yes
- * w: (no) no w: (no) no w: (yes) yesw: (no) no
- * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
- *
- * MAP_PRIVATE r: (no) no r: (yes) yesr: (no) yes r: (no) yes
- * w: (no) no w: (no) no w: (copy) copy w: (no) no
- * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
- *
- * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
- * MAP_PRIVATE (with Enhanced PAN supported):
- * r: (no) no
- * w: (no) no
- * x: (yes) yes
- */
#ifdef __P000
pgprot_t protection_map[16] __ro_after_init = {
[VM_NONE] = __P000,
@@ -123,11 +103,7 @@ pgprot_t protection_map[16] __ro_after_init = {
#endif
#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
-pgprot_t vm_get_page_prot(unsigned long vm_flags)
-{
- return protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
-}
-EXPORT_SYMBOL(vm_get_page_prot);
+DECLARE_VM_GET_PAGE_PROT
#endif /* CONFIG_ARCH_HAS_VM_GET_PAGE_PROT */
static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
--
2.25.1
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