[PATCH 4/6] arm64: Move PTE_RDONLY bit handling out of set_pte_at()

[Catalin Marinas]

On Thu, Aug 17, 2017 at 02:27:42PM +0100, Will Deacon wrote:
> On Tue, Jul 25, 2017 at 02:53:06PM +0100, Catalin Marinas wrote:
> > Currently PTE_RDONLY is treated as a hardware only bit and not handled
> > by the pte_mkwrite(), pte_wrprotect() or the user PAGE_* definitions.
> > The set_pte_at() function is responsible for setting this bit based on
> > the write permission or dirty state. This patch moves the PTE_RDONLY
> > handling out of set_pte_at into the pte_mkwrite()/pte_wrprotect()
> > functions. The PAGE_* definitions to need to be updated to explicitly
> > include PTE_RDONLY when !PTE_WRITE.
> > 
> > Cc: Will Deacon <will.deacon at arm.com>
> > Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> > ---
> >  arch/arm64/include/asm/pgtable-prot.h | 12 ++++++------
> >  arch/arm64/include/asm/pgtable.h      | 34 ++++++++++------------------------
> >  arch/arm64/kernel/hibernate.c         |  4 ++--
> >  arch/arm64/mm/fault.c                 |  6 +-----
> >  4 files changed, 19 insertions(+), 37 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
> > index 2142c7726e76..9b7af598b375 100644
> > --- a/arch/arm64/include/asm/pgtable-prot.h
> > +++ b/arch/arm64/include/asm/pgtable-prot.h
> > @@ -63,14 +63,14 @@
> >  #define PAGE_S2			__pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
> >  #define PAGE_S2_DEVICE		__pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
> >  
> > -#define PAGE_NONE		__pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_PXN | PTE_UXN)
> > +#define PAGE_NONE		__pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_PXN | PTE_UXN)
> >  #define PAGE_SHARED		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
> >  #define PAGE_SHARED_EXEC	__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_WRITE)
> > -#define PAGE_COPY		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
> > -#define PAGE_COPY_EXEC		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
> > -#define PAGE_READONLY		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
> > -#define PAGE_READONLY_EXEC	__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
> > -#define PAGE_EXECONLY		__pgprot(_PAGE_DEFAULT | PTE_NG | PTE_PXN)
> > +#define PAGE_COPY		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
> > +#define PAGE_COPY_EXEC		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN)
> > +#define PAGE_READONLY		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
> > +#define PAGE_READONLY_EXEC	__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN)
> > +#define PAGE_EXECONLY		__pgprot(_PAGE_DEFAULT | PTE_RDONLY | PTE_NG | PTE_PXN)
> 
> What's the point in keeping both the COPY and the READONLY variants of these
> macros now that they're identical?

Good point, I'll delete the COPY ones.

-- 
Catalin