| Message ID | 1643029028-12710-32-git-send-email-anshuman.khandual@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/mmap: Drop protection_map[] and platform's __SXXX/__PXXX requirements | expand |
On 1/24/22 6:27 PM, Anshuman Khandual wrote: > These macros will be useful in cleaning up the all those switch statements > in vm_get_page_prot() across all platforms. > > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > include/linux/mm.h | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 6c0844b99b3e..b3691eeec500 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2828,6 +2828,45 @@ static inline bool range_in_vma(struct vm_area_struct *vma, > return (vma && vma->vm_start <= start && end <= vma->vm_end); > } > > +/* > + * Access permission related vm_flags combination is used to map into > + * platform defined page protection flags. This enumeration helps in > + * abstracting out possible indices after vm_flags is probed for all > + * access permission i.e (VM_SHARED | VM_EXEC | VM_READ | VM_WRITE). > + * > + * VM_EXEC ---------------------| > + * | > + * VM_WRITE ---------------| | > + * | | > + * VM_READ -----------| | | > + * | | | > + * VM_SHARED ----| | | | > + * | | | | > + * v v v v > + * VMFLAGS_IDX_(S|X)(R|X)(W|X)(E|X) > + * > + * X - Indicates that the access flag is absent > + */ > +enum vmflags_idx { > + VMFLAGS_IDX_XXXX, /* (VM_NONE) */ > + VMFLAGS_IDX_XRXX, /* (VM_READ) */ > + VMFLAGS_IDX_XXWX, /* (VM_WRITE) */ > + VMFLAGS_IDX_XRWX, /* (VM_READ | VM_WRITE) */ > + VMFLAGS_IDX_XXXE, /* (VM_EXEC) */ > + VMFLAGS_IDX_XRXE, /* (VM_EXEC | VM_READ) */ > + VMFLAGS_IDX_XXWE, /* (VM_EXEC | VM_WRITE) */ > + VMFLAGS_IDX_XRWE, /* (VM_EXEC | VM_READ | VM_WRITE) */ > + VMFLAGS_IDX_SXXX, /* (VM_SHARED | VM_NONE) */ > + VMFLAGS_IDX_SRXX, /* (VM_SHARED | VM_READ) */ > + VMFLAGS_IDX_SXWX, /* (VM_SHARED | VM_WRITE) */ > + VMFLAGS_IDX_SRWX, /* (VM_SHARED | VM_READ | VM_WRITE) */ > + VMFLAGS_IDX_SXXE, /* (VM_SHARED | VM_EXEC) */ > + VMFLAGS_IDX_SRXE, /* (VM_SHARED | VM_EXEC | VM_READ) */ > + VMFLAGS_IDX_SXWE, /* (VM_SHARED | VM_EXEC | VM_WRITE) */ > + VMFLAGS_IDX_SRWE, /* (VM_SHARED | VM_EXEC | VM_READ | VM_WRITE) */ > + VMFLAGS_IDX_MAX > +}; Defining platform specific vm_get_page_prot() involves a switch statement with various vm_flags access combinations as cases. Hence I am wondering, will it help to use these above macros, instead of existing combinations separated with '|' flags. I can move this patch earlier in the series and change all platform switch cases. Please do suggest. Thank you. - Anshuman
diff --git a/include/linux/mm.h b/include/linux/mm.h index 6c0844b99b3e..b3691eeec500 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2828,6 +2828,45 @@ static inline bool range_in_vma(struct vm_area_struct *vma, return (vma && vma->vm_start <= start && end <= vma->vm_end); } +/* + * Access permission related vm_flags combination is used to map into + * platform defined page protection flags. This enumeration helps in + * abstracting out possible indices after vm_flags is probed for all + * access permission i.e (VM_SHARED | VM_EXEC | VM_READ | VM_WRITE). + * + * VM_EXEC ---------------------| + * | + * VM_WRITE ---------------| | + * | | + * VM_READ -----------| | | + * | | | + * VM_SHARED ----| | | | + * | | | | + * v v v v + * VMFLAGS_IDX_(S|X)(R|X)(W|X)(E|X) + * + * X - Indicates that the access flag is absent + */ +enum vmflags_idx { + VMFLAGS_IDX_XXXX, /* (VM_NONE) */ + VMFLAGS_IDX_XRXX, /* (VM_READ) */ + VMFLAGS_IDX_XXWX, /* (VM_WRITE) */ + VMFLAGS_IDX_XRWX, /* (VM_READ | VM_WRITE) */ + VMFLAGS_IDX_XXXE, /* (VM_EXEC) */ + VMFLAGS_IDX_XRXE, /* (VM_EXEC | VM_READ) */ + VMFLAGS_IDX_XXWE, /* (VM_EXEC | VM_WRITE) */ + VMFLAGS_IDX_XRWE, /* (VM_EXEC | VM_READ | VM_WRITE) */ + VMFLAGS_IDX_SXXX, /* (VM_SHARED | VM_NONE) */ + VMFLAGS_IDX_SRXX, /* (VM_SHARED | VM_READ) */ + VMFLAGS_IDX_SXWX, /* (VM_SHARED | VM_WRITE) */ + VMFLAGS_IDX_SRWX, /* (VM_SHARED | VM_READ | VM_WRITE) */ + VMFLAGS_IDX_SXXE, /* (VM_SHARED | VM_EXEC) */ + VMFLAGS_IDX_SRXE, /* (VM_SHARED | VM_EXEC | VM_READ) */ + VMFLAGS_IDX_SXWE, /* (VM_SHARED | VM_EXEC | VM_WRITE) */ + VMFLAGS_IDX_SRWE, /* (VM_SHARED | VM_EXEC | VM_READ | VM_WRITE) */ + VMFLAGS_IDX_MAX +}; + #ifdef CONFIG_MMU pgprot_t vm_get_page_prot(unsigned long vm_flags); void vma_set_page_prot(struct vm_area_struct *vma);
These macros will be useful in cleaning up the all those switch statements in vm_get_page_prot() across all platforms. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- include/linux/mm.h | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)