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

["Jingyu Li via groups.io" <jingyu.li01=sophgo.com@groups.io>]

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On Tue, Oct 31, 2023 at 05:55 PM, Dhaval Sharma wrote:

> 
> I am posting an update on behalf of Jingyu as he had trouble with posting.
> CC'ing him here:
> In summary what we have verified so far:
> * I have verified that instructions/op codes are okay. I have also
> verified on Qemu that functionally it seems to be calling correct
> instructions. Ensured with negative test cases that any other op codes do
> cause exceptions as expected.
> * Jingyu was able to verify the CpuFlushCpuDataCache function with this
> framework (he had to use custom op code based on his soc implementation)
> on SG2042. There is one issue that he is debugging now which is related to
> other cache instructions and he will get back with more data. P.S. SG2042
> does not implement the exact same CMO opcodes but equivalent ones. So this
> experiment is just an additional data point that helps verify the
> framework and not CMO itself.
> * In general it sounds like framework flows are alright and as long as
> instructions do their job as claimed in the spec, it is lower risk.
> Guess this is what we have so far. If it makes sense to everyone, we could
> go ahead with merging with this *feature disabled by default* after Jingyu
> provides clarity reg failures on SG2042 platform. Otherwise we can wait
> until newer Si is available where these exact instructions can be tested
> and then upstreamed.
> 
> [From Jingyu]
> I verified this CMO framework on an actual HW platform.
> 
> SW:
> edk2: https://github.com/rivosinc/edk2/tree/dev-rv-cmo-v7 branch:
> dev-rv-cmo-v7
> edk2-platforms: https://github.com/sophgo/edk2-platforms branch: sg2042-dev
> 
> 
> HW:
> Milk-V Pioneer Box, a developer motherboard based on SG2042 with 64-Core
> T-HEAD C920.
> 
> Attention:
> The T-HEAD C920 implemented its own CMO Extension and is different from
> the standard CMO Extension.
> 
> Test steps:
> 1. Modified the opcodes in RiscVasm.inc to accommodate the C920 CMO
> feature.

Update the test status.
The InvalidateInstructionCacheRange and the InvalidateDataCacheRange execute the same instruction "cbo.inval", but the T-HEAD C920 executes different instructions for the two functions. Please see the form below for details.
I replaced ".long 0x02a5000b" with "fence.i", which solved unexpected exceptions that occurred yesterday.

RISC-V standard CMO Extension

C920 CMO Extension

WriteBackInvalidateDataCache

WriteBackInvalidateDataCacheRange

cbo. flush

".long 0x02b5000b"

WriteBackDataCache

WriteBackDataCacheRange

cbo. clean

".long 0x02b5000b"

InvalidateDataCache

fence

fence

InvalidateDataCacheRange

cbo. inval

".long 0x02a5000b"

InvalidateInstructionCache

fence. i

fence. i

InvalidateInstructionCacheRange

cbo. inval

fence. i

Now, I enable CMO in the entire edk2 phase, not just during PCIe inbound. No exceptions found so far. Hope to give you some reference.

Update the patches:
diff --git a/MdePkg/Include/RiscV64/RiscVasm.inc b/MdePkg/Include/RiscV64/RiscVasm.inc
index 29de735885..c2e573eb3d 100644
--- a/MdePkg/Include/RiscV64/RiscVasm.inc
+++ b/MdePkg/Include/RiscV64/RiscVasm.inc
@@ -7,13 +7,13 @@
*/

.macro RISCVCMOFLUSH
-    .word 0x25200f
+    .long 0x02b5000b^M
.endm

.macro RISCVCMOINVALIDATE
-    .word 0x05200f
+    .long 0x02a5000b^M
.endm

.macro RISCVCMOCLEAN
-    .word 0x15200f
+    .long 0x02b5000b^M
.endm

diff --git a/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c b/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c
index 5b3104afb6..ee85d0548c 100644
--- a/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c
+++ b/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c
@@ -89,7 +89,7 @@ CacheOpCacheRange (
Start &= ~((UINTN)CacheLineSize - 1);

DEBUG (
-    (DEBUG_INFO,
+    (DEBUG_VERBOSE,^M
"CacheOpCacheRange:\
Performing Cache Management Operation %d \n", Op)
);
@@ -163,7 +163,8 @@ InvalidateInstructionCacheRange (
)
{
if (RiscVIsCMOEnabled ()) {
-    CacheOpCacheRange (Address, Length, Invld);
+    // CacheOpCacheRange (Address, Length, Invld);^M
+    InvalidateInstructionCache ();^M
} else {
DEBUG (
(DEBUG_VERBOSE,

diff --git a/UefiCpuPkg/CpuDxeRiscV64/CpuDxe.c b/UefiCpuPkg/CpuDxeRiscV64/CpuDxe.c
index 2af3b62234..824667bc87 100644
--- a/UefiCpuPkg/CpuDxeRiscV64/CpuDxe.c
+++ b/UefiCpuPkg/CpuDxeRiscV64/CpuDxe.c
@@ -9,6 +9,7 @@
**/

#include "CpuDxe.h"
+#include <Library/CacheMaintenanceLib.h>^M

//
// Global Variables
@@ -59,7 +60,7 @@ EFI_CPU_ARCH_PROTOCOL  gCpu = {
CpuGetTimerValue,
CpuSetMemoryAttributes,
1,                          // NumberOfTimers
-  4                           // DmaBufferAlignment
+  64                          // DmaBufferAlignment^M
};

//
@@ -90,6 +91,20 @@ CpuFlushCpuDataCache (
IN EFI_CPU_FLUSH_TYPE     FlushType
)
{
+  switch (FlushType) {^M
+    case EfiCpuFlushTypeWriteBack:^M
+      WriteBackDataCacheRange ((VOID *)(UINTN)Start, (UINTN)Length);^M
+      break;^M
+    case EfiCpuFlushTypeInvalidate:^M
+      InvalidateDataCacheRange ((VOID *)(UINTN)Start, (UINTN)Length);^M
+      break;^M
+    case EfiCpuFlushTypeWriteBackInvalidate:^M
+      WriteBackInvalidateDataCacheRange ((VOID *)(UINTN)Start, (UINTN)Length);^M
+      break;^M
+    default:^M
+      return EFI_INVALID_PARAMETER;^M
+  }^M
+^M
return EFI_SUCCESS;
}

diff --git a/Platform/Sophgo/SG2042_EVB_Board/SG2042.fdf b/Platform/Sophgo/SG2042_EVB_Board/SG2042.fdf
index 844fc3eac0..9cbb1d3f65 100644
--- a/Platform/Sophgo/SG2042_EVB_Board/SG2042.fdf
+++ b/Platform/Sophgo/SG2042_EVB_Board/SG2042.fdf
@@ -77,7 +77,7 @@ INF  Silicon/Sophgo/SG2042Pkg/Drivers/SdHostDxe/SdHostDxe.inf

# RISC-V Core Drivers
INF  UefiCpuPkg/CpuTimerDxeRiscV64/CpuTimerDxeRiscV64.inf
-INF  Silicon/Sophgo/SG2042Pkg/Override/UefiCpuPkg/CpuDxeRiscV64/CpuDxeRiscV64.inf
+INF  UefiCpuPkg/CpuDxeRiscV64/CpuDxeRiscV64.inf

INF  MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteDxe.inf
INF  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf

diff --git a/Platform/Sophgo/SG2042_EVB_Board/SG2042.dsc b/Platform/Sophgo/SG2042_EVB_Board/SG2042.dsc
index 51ff89678c..bc3f96e21b 100644
--- a/Platform/Sophgo/SG2042_EVB_Board/SG2042.dsc
+++ b/Platform/Sophgo/SG2042_EVB_Board/SG2042.dsc
@@ -389,6 +389,7 @@

[PcdsPatchableInModule]
gSophgoSG2042PlatformPkgTokenSpaceGuid.PcdSG2042PhyAddrToVirAddr|0
+  gEfiMdePkgTokenSpaceGuid.PcdRiscVFeatureOverride|0x1

################################################################################
#
@@ -500,7 +501,7 @@
# RISC-V Core module
#
UefiCpuPkg/CpuTimerDxeRiscV64/CpuTimerDxeRiscV64.inf
-  Silicon/Sophgo/SG2042Pkg/Override/UefiCpuPkg/CpuDxeRiscV64/CpuDxeRiscV64.inf
+  UefiCpuPkg/CpuDxeRiscV64/CpuDxeRiscV64.inf
MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystemRuntimeDxe.inf

MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteDxe.inf

Thanks,
Jingyu


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