[edk2-devel] [PATCH v9 3/5] MdePkg: Implement RISC-V Cache Management Operations

["Dhaval Sharma" <dhaval@rivosinc.com>]

Implement Cache Management Operations (CMO) defined by
RISC-V spec https://github.com/riscv/riscv-CMOs.

Notes:
1. CMO only supports block based Operations. Meaning cache
   flush/invd/clean Operations are not available for the entire
   range. In that case we fallback on fence.i instructions.
2. Operations are implemented using Opcodes to make them compiler
   independent. binutils 2.39+ compilers support CMO instructions.

Test:
1. Ensured correct instructions are refelecting in asm
2. Qemu implements basic support for CMO operations in that it allwos
   instructions without exceptions. Verified it works properly in
   that sense.
3. SG2042Pkg implements CMO-like instructions. It was verified that
   CpuFlushCpuDataCache works fine. This more of less
   confirms that framework is alright.
4. TODO: Once Silicon is available with exact instructions, we will
   further verify this.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Sunil V L <sunilvl@ventanamicro.com>
Cc: Daniel Schaefer <git@danielschaefer.me>
Cc: Laszlo Ersek <lersek@redhat.com>

Signed-off-by: Dhaval Sharma <dhaval@rivosinc.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Sunil V L <sunilvl@...>
Reviewed-by: Jingyu Li <jingyu.li01@...>
---

Notes:
    v8:
    - Add *asm* postfix to cmo functions
    - Add reviewed by tags
    V7:
    - Modify instruction names as per feedback from V6
    - Added RB
    V6:
    - Implement Cache management instructions in Baselib

 MdePkg/Library/BaseLib/BaseLib.inf                                |  2 +-
 MdePkg/Include/Library/BaseLib.h                                  | 33 ++++++++++++++++++++
 MdePkg/Include/RiscV64/RiscVasm.inc                               | 19 +++++++++++
 MdePkg/Library/BaseLib/RiscV64/{FlushCache.S => RiscVCacheMgmt.S} | 17 ++++++++++
 4 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf
index 03c7b02e828b..53389389448c 100644
--- a/MdePkg/Library/BaseLib/BaseLib.inf
+++ b/MdePkg/Library/BaseLib/BaseLib.inf
@@ -400,7 +400,7 @@ [Sources.RISCV64]
   RiscV64/RiscVCpuBreakpoint.S      | GCC
   RiscV64/RiscVCpuPause.S           | GCC
   RiscV64/RiscVInterrupt.S          | GCC
-  RiscV64/FlushCache.S              | GCC
+  RiscV64/RiscVCacheMgmt.S          | GCC
   RiscV64/CpuScratch.S              | GCC
   RiscV64/ReadTimer.S               | GCC
   RiscV64/RiscVMmu.S                | GCC
diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
index d80e27285424..47424709cd72 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -226,6 +226,39 @@ RiscVInvalidateDataCacheFenceAsm (
   VOID
   );
 
+/**
+  RISC-V flush cache block. Atomically perform a clean operation
+  followed by an invalidate operation
+
+**/
+VOID
+EFIAPI
+RiscVCpuCacheFlushCmoAsm (
+  IN UINTN
+  );
+
+/**
+Perform a write transfer to another cache or to memory if the
+data in the copy of the cache block have been modified by a store
+operation
+
+**/
+VOID
+EFIAPI
+RiscVCpuCacheCleanCmoAsm (
+  IN UINTN
+  );
+
+/**
+Deallocate the copy of the cache block
+
+**/
+VOID
+EFIAPI
+RiscVCpuCacheInvalCmoAsm (
+  IN UINTN
+  );
+
 #endif // defined (MDE_CPU_RISCV64)
 
 #if defined (MDE_CPU_LOONGARCH64)
diff --git a/MdePkg/Include/RiscV64/RiscVasm.inc b/MdePkg/Include/RiscV64/RiscVasm.inc
new file mode 100644
index 000000000000..29de7358855c
--- /dev/null
+++ b/MdePkg/Include/RiscV64/RiscVasm.inc
@@ -0,0 +1,19 @@
+/*
+ *
+ * RISC-V cache operation encoding.
+ * Copyright (c) 2023, Rivos Inc. All rights reserved.<BR>
+ * SPDX-License-Identifier: BSD-2-Clause-Patent
+ *
+ */
+
+.macro RISCVCMOFLUSH
+    .word 0x25200f
+.endm
+
+.macro RISCVCMOINVALIDATE
+    .word 0x05200f
+.endm
+
+.macro RISCVCMOCLEAN
+    .word 0x15200f
+.endm
diff --git a/MdePkg/Library/BaseLib/RiscV64/FlushCache.S b/MdePkg/Library/BaseLib/RiscV64/RiscVCacheMgmt.S
similarity index 56%
rename from MdePkg/Library/BaseLib/RiscV64/FlushCache.S
rename to MdePkg/Library/BaseLib/RiscV64/RiscVCacheMgmt.S
index 8cfb85097996..4752aa72d95e 100644
--- a/MdePkg/Library/BaseLib/RiscV64/FlushCache.S
+++ b/MdePkg/Library/BaseLib/RiscV64/RiscVCacheMgmt.S
@@ -3,10 +3,12 @@
 // RISC-V cache operation.
 //
 // Copyright (c) 2020, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
+// Copyright (c) 2023, Rivos Inc. All rights reserved.<BR>
 //
 // SPDX-License-Identifier: BSD-2-Clause-Patent
 //
 //------------------------------------------------------------------------------
+.include "RiscVasm.inc"
 
 .align 3
 ASM_GLOBAL ASM_PFX(RiscVInvalidateInstCacheFenceAsm)
@@ -19,3 +21,18 @@ ASM_PFX(RiscVInvalidateInstCacheFenceAsm):
 ASM_PFX(RiscVInvalidateDataCacheFenceAsm):
     fence
     ret
+
+ASM_GLOBAL ASM_PFX (RiscVCpuCacheFlushCmoAsm)
+ASM_PFX (RiscVCpuCacheFlushCmoAsm):
+    RISCVCMOFLUSH
+    ret
+
+ASM_GLOBAL ASM_PFX (RiscVCpuCacheCleanCmoAsm)
+ASM_PFX (RiscVCpuCacheCleanCmoAsm):
+    RISCVCMOCLEAN
+    ret
+
+ASM_GLOBAL ASM_PFX (RiscVCpuCacheInvalCmoAsm)
+ASM_PFX (RiscVCpuCacheInvalCmoAsm):
+    RISCVCMOINVALIDATE
+    ret
-- 
2.39.2



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