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| author | Kinsey Moore <kinsey.moore@oarcorp.com> | 2022-03-04 13:47:40 -0600 |
|---|---|---|
| committer | Joel Sherrill <joel@rtems.org> | 2022-03-25 10:17:15 -0500 |
| commit | df8261a46e9614f92023bb575fad7873b9d77302 (patch) | |
| tree | 7a40be11f6a36d1ff5248d28a393e30e1355285e /cpu-supplement/aarch64.rst | |
| parent | eng/tester.rst: Reference User Manual for rtems-test (diff) | |
| download | rtems-docs-df8261a46e9614f92023bb575fad7873b9d77302.tar.bz2 | |
cpu-supplement: Add note about device memory
Add information about restricted use of device memory for ARM and
AArch64.
Diffstat (limited to 'cpu-supplement/aarch64.rst')
| -rw-r--r-- | cpu-supplement/aarch64.rst | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/cpu-supplement/aarch64.rst b/cpu-supplement/aarch64.rst index 2b3d620..1e9b8d6 100644 --- a/cpu-supplement/aarch64.rst +++ b/cpu-supplement/aarch64.rst @@ -73,6 +73,11 @@ A flat 64-bit or 32-bit memory model is supported depending on the selected mult variant. All AArch64 CPU variants support a built-in MMU for which basic initialization for a flat memory model is handled. +Note that memcpy() and memset() must not be used on device memory as those +functions are hand-optimized and will take advantage of unaligned accesses. +*As per ARM*(https://developer.arm.com/documentation/ka004708/latest), unaligned +accesses are not permitted for device memory. + Interrupt Processing ==================== |