[edk2-devel] [PATCH v7 3/5] MdePkg: Implement RISC-V Cache Management Operations

[Dhaval Sharma]

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. Not able to verify actual instruction in HW as Qemu ignores
   any actual cache operations.

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

Signed-off-by: Dhaval Sharma <dhaval at rivosinc.com>
Reviewed-by: Laszlo Ersek <lersek at redhat.com>
---

Notes:
    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 d4b56a9601da..c42cc165dc82 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -226,6 +226,39 @@ RiscVInvalidateDataCacheAsmFence (
   VOID
   );
 
+/**
+  RISC-V flush cache block. Atomically perform a clean operation
+  followed by an invalidate operation
+
+**/
+VOID
+EFIAPI
+RiscVCpuCacheFlushAsmCmo (
+  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
+RiscVCpuCacheCleanAsmCmo (
+  IN UINTN
+  );
+
+/**
+Deallocate the copy of the cache block
+
+**/
+VOID
+EFIAPI
+RiscVCpuCacheInvalAsmCmo (
+  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 e0eea0b5fb25..3c7be3229e3b 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(RiscVInvalidateInstCacheAsmFence)
@@ -19,3 +21,18 @@ ASM_PFX(RiscVInvalidateInstCacheAsmFence):
 ASM_PFX(RiscVInvalidateDataCacheAsmFence):
     fence
     ret
+
+ASM_GLOBAL ASM_PFX (RiscVCpuCacheFlushAsmCmo)
+ASM_PFX (RiscVCpuCacheFlushAsmCmo):
+    RISCVCMOFLUSH
+    ret
+
+ASM_GLOBAL ASM_PFX (RiscVCpuCacheCleanAsmCmo)
+ASM_PFX (RiscVCpuCacheCleanAsmCmo):
+    RISCVCMOCLEAN
+    ret
+
+ASM_GLOBAL ASM_PFX (RiscVCpuCacheInvalAsmCmo)
+ASM_PFX (RiscVCpuCacheInvalAsmCmo):
+    RISCVCMOINVALIDATE
+    ret
-- 
2.39.2



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