| Message ID | 20190227170608.27963-6-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Convert x86 & arm64 to use generic page walk | expand |
On Wed, Feb 27, 2019 at 05:05:39PM +0000, Steven Price wrote: > walk_page_range() is going to be allowed to walk page tables other than > those of user space. For this it needs to know when it has reached a > 'leaf' entry in the page tables. This information is provided by the > p?d_large() functions/macros. > > For c6x there's no MMU so there's never a large page, so just add stubs. Other option would be to provide the stubs via generic headers form !MMU.
On 01/03/2019 21:48, Kirill A. Shutemov wrote: > On Wed, Feb 27, 2019 at 05:05:39PM +0000, Steven Price wrote: >> walk_page_range() is going to be allowed to walk page tables other than >> those of user space. For this it needs to know when it has reached a >> 'leaf' entry in the page tables. This information is provided by the >> p?d_large() functions/macros. >> >> For c6x there's no MMU so there's never a large page, so just add stubs. > > Other option would be to provide the stubs via generic headers form !MMU. > I agree that could be done, but equally the definitions of p?d_present/p?d_none/p?d_bad etc could be provided by a generic header for !MMU but currently are not. It makes sense to keep the p?d_large definitions next to the others. I'd prefer to stick with a (relatively) small change here - it's already quite a long series! But this is certainly something that could be tidied up for !MMU archs. Steve
On Mon, Mar 04, 2019 at 12:01:37PM +0000, Steven Price wrote: > On 01/03/2019 21:48, Kirill A. Shutemov wrote: > > On Wed, Feb 27, 2019 at 05:05:39PM +0000, Steven Price wrote: > >> walk_page_range() is going to be allowed to walk page tables other than > >> those of user space. For this it needs to know when it has reached a > >> 'leaf' entry in the page tables. This information is provided by the > >> p?d_large() functions/macros. > >> > >> For c6x there's no MMU so there's never a large page, so just add stubs. > > > > Other option would be to provide the stubs via generic headers form !MMU. > > > > I agree that could be done, but equally the definitions of > p?d_present/p?d_none/p?d_bad etc could be provided by a generic header > for !MMU but currently are not. It makes sense to keep the p?d_large > definitions next to the others. > > I'd prefer to stick with a (relatively) small change here - it's already > quite a long series! But this is certainly something that could be > tidied up for !MMU archs. Agreed.
diff --git a/arch/c6x/include/asm/pgtable.h b/arch/c6x/include/asm/pgtable.h index ec4db6df5e0d..d532b7df9001 100644 --- a/arch/c6x/include/asm/pgtable.h +++ b/arch/c6x/include/asm/pgtable.h @@ -26,6 +26,7 @@ #define pgd_present(pgd) (1) #define pgd_none(pgd) (0) #define pgd_bad(pgd) (0) +#define pgd_large(pgd) (0) #define pgd_clear(pgdp) #define kern_addr_valid(addr) (1) @@ -34,6 +35,7 @@ #define pmd_present(x) (pmd_val(x)) #define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0) #define pmd_bad(x) (pmd_val(x) & ~PAGE_MASK) +#define pmd_large(pgd) (0) #define PAGE_NONE __pgprot(0) /* these mean nothing to NO_MM */ #define PAGE_SHARED __pgprot(0) /* these mean nothing to NO_MM */
walk_page_range() is going to be allowed to walk page tables other than those of user space. For this it needs to know when it has reached a 'leaf' entry in the page tables. This information is provided by the p?d_large() functions/macros. For c6x there's no MMU so there's never a large page, so just add stubs. CC: Mark Salter <msalter@redhat.com> CC: Aurelien Jacquiot <jacquiot.aurelien@gmail.com> CC: linux-c6x-dev@linux-c6x.org Signed-off-by: Steven Price <steven.price@arm.com> --- arch/c6x/include/asm/pgtable.h | 2 ++ 1 file changed, 2 insertions(+)