Hello
Any comments ?
I don’t see IoLibArm.c in master? I see IoLibNoIo.c.
The MMIO function look like ARM assembler with the correct barrier instructions. The IO operations in this lib are the x86 in/out instructions, so they just ASSERT on ARM.
On the X86 MemoryFence() is just a serializing intrinsic for the compiler to prevent optimizations from breaking the code, kind of like how you need to make MMIO as volatile in C.
Thanks,
Andrew Fish
-----Original Message-----
From: Wasim Khan
Sent: Friday, July 10, 2020 6:20 PM
To: michael.d.kinney@intel.com; liming.gao@intel.com; devel@edk2.groups.io
Subject: [edk2-discuss] Need memory barriers in IoLib for AARCH64
Hello,
MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsic.inf:
IoLib library uses IoLibArm.c for AARCH64/ARM architecture and IoLib.c for
other architectures.
While IoLib.c already has memory barriers in MmioWrite functions, there
barriers are missing in IoLibArm.c Is there any reason for **not** adding these
memory barriers in IoLibArm.c to guarantee that all MMIO operations are
serialized ?
I am facing some issues and I need to add memory barriers in IoLibArm.c for
AARCH64 also .
Regards,
Wasim