From df8261a46e9614f92023bb575fad7873b9d77302 Mon Sep 17 00:00:00 2001 From: Kinsey Moore Date: Fri, 4 Mar 2022 13:47:40 -0600 Subject: cpu-supplement: Add note about device memory Add information about restricted use of device memory for ARM and AArch64. --- cpu-supplement/aarch64.rst | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'cpu-supplement/aarch64.rst') 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 ==================== -- cgit v1.2.3