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| author | Sandrine Bailleux <sandrine.bailleux@arm.com> | 2016-06-14 16:31:09 +0100 |
|---|---|---|
| committer | Sandrine Bailleux <sandrine.bailleux@arm.com> | 2016-07-08 14:37:11 +0100 |
| commit | b9161469fa95d290ba448d65e1d886ec1ff091e5 (patch) | |
| tree | f3a47715bba95e7884992303900689680388359a /include/lib | |
| parent | bcbe19afaa7a19083164dd1be80c741d23ee9caf (diff) | |
xlat lib: Introduce MT_EXECUTE/MT_EXECUTE_NEVER attributes
This patch introduces the MT_EXECUTE/MT_EXECUTE_NEVER memory mapping
attributes in the translation table library to specify the
access permissions for instruction execution of a memory region.
These new attributes should be used only for normal, read-only
memory regions. For other types of memory, the translation table
library still enforces the following rules, regardless of the
MT_EXECUTE/MT_EXECUTE_NEVER attribute:
- Device memory is always marked as execute-never.
- Read-write normal memory is always marked as execute-never.
Change-Id: I8bd27800a8c1d8ac1559910caf4a4840cf25b8b0
Diffstat (limited to 'include/lib')
| -rw-r--r-- | include/lib/xlat_tables.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/lib/xlat_tables.h b/include/lib/xlat_tables.h index 7d57521b..b51a1de5 100644 --- a/include/lib/xlat_tables.h +++ b/include/lib/xlat_tables.h @@ -134,6 +134,8 @@ #define MT_PERM_SHIFT 3 /* Security state (SECURE/NS) */ #define MT_SEC_SHIFT 4 +/* Access permissions for instruction execution (EXECUTE/EXECUTE_NEVER) */ +#define MT_EXECUTE_SHIFT 5 /* * Memory mapping attributes @@ -155,8 +157,21 @@ typedef enum { MT_SECURE = 0 << MT_SEC_SHIFT, MT_NS = 1 << MT_SEC_SHIFT, + + /* + * Access permissions for instruction execution are only relevant for + * normal read-only memory, i.e. MT_MEMORY | MT_RO. They are ignored + * (and potentially overridden) otherwise: + * - Device memory is always marked as execute-never. + * - Read-write normal memory is always marked as execute-never. + */ + MT_EXECUTE = 0 << MT_EXECUTE_SHIFT, + MT_EXECUTE_NEVER = 1 << MT_EXECUTE_SHIFT, } mmap_attr_t; +#define MT_CODE (MT_MEMORY | MT_RO | MT_EXECUTE) +#define MT_RO_DATA (MT_MEMORY | MT_RO | MT_EXECUTE_NEVER) + /* * Structure for specifying a single region of memory. */ |