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authorDave Gerlach <d-gerlach@ti.com>2017-01-12 23:52:20 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-25 13:48:03 +0300
commit37afff0d87c9939843c664970af6c6d952f95712 (patch)
tree8ea28a8a049eec9ff3b3d4eee4becfab678d9a45 /Documentation/devicetree/bindings/sram
parent728bbe75c82fdc6bdf157652a4351856ed08afc4 (diff)
downloadlinux-37afff0d87c9939843c664970af6c6d952f95712.tar.xz
misc: sram: Integrate protect-exec reserved sram area type
Introduce a new "protect-exec" reserved sram area type which is makes use of the the existing functionality provided for the "pool" sram region type for use with the genalloc framework and with the added requirement that it be maintained as read-only and executable while allowing for an arbitrary number of drivers to share the space. This introduces a common way to maintain a region of sram as read-only and executable and also introduces a helper function, sram_exec_copy, which allows for copying data to this protected region while maintaining locking to avoid conflicts between multiple users of the same space. A region of memory that is marked with the "protect-exec" flag in the device tree also has the requirement of providing a page aligned block of memory so that the page attribute manipulation does not affect surrounding regions. Also, selectively enable this only for builds that support set_memory_* calls, for now just ARM, through the use of Kconfig. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/devicetree/bindings/sram')
-rw-r--r--Documentation/devicetree/bindings/sram/sram.txt6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt
index 068c2c03c38f..267da4410aef 100644
--- a/Documentation/devicetree/bindings/sram/sram.txt
+++ b/Documentation/devicetree/bindings/sram/sram.txt
@@ -42,6 +42,12 @@ Optional properties in the area nodes:
and in use by another device or devices
- export : indicates that the reserved SRAM area may be accessed outside
of the kernel, e.g. by bootloader or userspace
+- protect-exec : Same as 'pool' above but with the additional
+ constraint that code wil be run from the region and
+ that the memory is maintained as read-only, executable
+ during code execution. NOTE: This region must be page
+ aligned on start and end in order to properly allow
+ manipulation of the page attributes.
- label : the name for the reserved partition, if omitted, the label
is taken from the node name excluding the unit address.