| Message ID | 20171009132341.1678-9-julien.grall@arm.com |
|---|---|
| State | Accepted |
| Commit | 28f2ad440a08908010abec43b7ccc3283051e943 |
| Headers | show |
| Series | xen/arm: Memory subsystem clean-up | expand |
On Mon, 9 Oct 2017, Julien Grall wrote: > Currently, it is not possible to specify the permission of a new > mapping. It would be necessary to use the function modify_xen_mappings > with a different set of flags. > > Introduce a couple of new flags for the permissions (Non-eXecutable, > Read-Only) and also provides definition that combine the memory attribute > and permission for common combinations. > > PAGE_HYPERVISOR is now an alias to PAGE_HYPERVISOR_RW (read-write, > non-executable mappings). This does not affect the current mapping using > PAGE_HYPERVISOR because Xen is currently forcing all the mapping to be > non-executable by default (see mfn_to_xen_entry). > > A follow-up patch will change modify_xen_mappings to use the new flags. > > Signed-off-by: Julien Grall <julien.grall@arm.com> > > --- > > Changes in v3: > - Add a comment about _PAGE_DEVICE and _PAGE_NORMAL > > Changes in v2: > - Update the commit message > --- > xen/include/asm-arm/page.h | 25 ++++++++++++++++++++++--- > 1 file changed, 22 insertions(+), 3 deletions(-) > > diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h > index aa3e83f5b4..e2b3e402d0 100644 > --- a/xen/include/asm-arm/page.h > +++ b/xen/include/asm-arm/page.h > @@ -69,12 +69,31 @@ > * Layout of the flags used for updating the hypervisor page tables > * > * [0:2] Memory Attribute Index > + * [3:4] Permission flags > */ > #define PAGE_AI_MASK(x) ((x) & 0x7U) > > -#define PAGE_HYPERVISOR (MT_NORMAL) > -#define PAGE_HYPERVISOR_NOCACHE (MT_DEVICE_nGnRE) > -#define PAGE_HYPERVISOR_WC (MT_NORMAL_NC) > +#define _PAGE_XN_BIT 3 > +#define _PAGE_RO_BIT 4 > +#define _PAGE_XN (1U << _PAGE_XN_BIT) > +#define _PAGE_RO (1U << _PAGE_RO_BIT) > +#define PAGE_XN_MASK(x) (((x) >> _PAGE_XN_BIT) & 0x1U) > +#define PAGE_RO_MASK(x) (((x) >> _PAGE_RO_BIT) & 0x1U) > + > +/* > + * _PAGE_DEVICE and _PAGE_NORMAL are conveniences defines. They are not > + * meant to be used outside of the headers. just grammar NITs: _PAGE_DEVICE and _PAGE_NORMAL are convenience defines. They are not meant to be used outside of this header. I'll fix on commit Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > + */ > +#define _PAGE_DEVICE _PAGE_XN > +#define _PAGE_NORMAL MT_NORMAL > + > +#define PAGE_HYPERVISOR_RO (_PAGE_NORMAL|_PAGE_RO|_PAGE_XN) > +#define PAGE_HYPERVISOR_RX (_PAGE_NORMAL|_PAGE_RO) > +#define PAGE_HYPERVISOR_RW (_PAGE_NORMAL|_PAGE_XN) > + > +#define PAGE_HYPERVISOR PAGE_HYPERVISOR_RW > +#define PAGE_HYPERVISOR_NOCACHE (_PAGE_DEVICE|MT_DEVICE_nGnRE) > +#define PAGE_HYPERVISOR_WC (_PAGE_DEVICE|MT_NORMAL_NC) > > /* > * Defines for changing the hypervisor PTE .ro and .nx bits. This is only to be > -- > 2.11.0 >
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h index aa3e83f5b4..e2b3e402d0 100644 --- a/xen/include/asm-arm/page.h +++ b/xen/include/asm-arm/page.h @@ -69,12 +69,31 @@ * Layout of the flags used for updating the hypervisor page tables * * [0:2] Memory Attribute Index + * [3:4] Permission flags */ #define PAGE_AI_MASK(x) ((x) & 0x7U) -#define PAGE_HYPERVISOR (MT_NORMAL) -#define PAGE_HYPERVISOR_NOCACHE (MT_DEVICE_nGnRE) -#define PAGE_HYPERVISOR_WC (MT_NORMAL_NC) +#define _PAGE_XN_BIT 3 +#define _PAGE_RO_BIT 4 +#define _PAGE_XN (1U << _PAGE_XN_BIT) +#define _PAGE_RO (1U << _PAGE_RO_BIT) +#define PAGE_XN_MASK(x) (((x) >> _PAGE_XN_BIT) & 0x1U) +#define PAGE_RO_MASK(x) (((x) >> _PAGE_RO_BIT) & 0x1U) + +/* + * _PAGE_DEVICE and _PAGE_NORMAL are conveniences defines. They are not + * meant to be used outside of the headers. + */ +#define _PAGE_DEVICE _PAGE_XN +#define _PAGE_NORMAL MT_NORMAL + +#define PAGE_HYPERVISOR_RO (_PAGE_NORMAL|_PAGE_RO|_PAGE_XN) +#define PAGE_HYPERVISOR_RX (_PAGE_NORMAL|_PAGE_RO) +#define PAGE_HYPERVISOR_RW (_PAGE_NORMAL|_PAGE_XN) + +#define PAGE_HYPERVISOR PAGE_HYPERVISOR_RW +#define PAGE_HYPERVISOR_NOCACHE (_PAGE_DEVICE|MT_DEVICE_nGnRE) +#define PAGE_HYPERVISOR_WC (_PAGE_DEVICE|MT_NORMAL_NC) /* * Defines for changing the hypervisor PTE .ro and .nx bits. This is only to be
Currently, it is not possible to specify the permission of a new mapping. It would be necessary to use the function modify_xen_mappings with a different set of flags. Introduce a couple of new flags for the permissions (Non-eXecutable, Read-Only) and also provides definition that combine the memory attribute and permission for common combinations. PAGE_HYPERVISOR is now an alias to PAGE_HYPERVISOR_RW (read-write, non-executable mappings). This does not affect the current mapping using PAGE_HYPERVISOR because Xen is currently forcing all the mapping to be non-executable by default (see mfn_to_xen_entry). A follow-up patch will change modify_xen_mappings to use the new flags. Signed-off-by: Julien Grall <julien.grall@arm.com> --- Changes in v3: - Add a comment about _PAGE_DEVICE and _PAGE_NORMAL Changes in v2: - Update the commit message --- xen/include/asm-arm/page.h | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-)