[edk2-platforms][PATCH V1 06/20] ArmPkg: Add support for FFA_MEM_PERM_GET/SET ABIs

["Nishant Sharma" <nishant.sharma@arm.com>]

From: Achin Gupta <achin.gupta@arm.com>

This patch uses the FFA_MEM_PERM_GET/SET ABIs to tweak the permissions of a
set of pages if FF-A v1.1 and above is supported by the SPMC. For FF-A v1.0
the previous method through FFA_MSG_SEND_DIRECT_REQ/RESP is used.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
---
 ArmPkg/Include/IndustryStandard/ArmFfaSvc.h               |   2 +
 ArmPkg/Library/StandaloneMmMmuLib/ArmMmuStandaloneMmLib.c | 132 +++++++++++++++++---
 2 files changed, 120 insertions(+), 14 deletions(-)

diff --git a/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h b/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h
index c80d783fad3f..7987678c996e 100644
--- a/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h
+++ b/ArmPkg/Include/IndustryStandard/ArmFfaSvc.h
@@ -23,6 +23,8 @@
 #define ARM_SVC_ID_FFA_MSG_SEND_DIRECT_RESP_AARCH64  0xC4000070
 #define ARM_SVC_ID_FFA_SUCCESS_AARCH32               0x84000061
 #define ARM_SVC_ID_FFA_SUCCESS_AARCH64               0xC4000061
+#define ARM_SVC_ID_FFA_MEM_PERM_SET_AARCH32          0x84000089
+#define ARM_SVC_ID_FFA_MEM_PERM_GET_AARCH32          0x84000088
 #define ARM_SVC_ID_FFA_ERROR_AARCH32                 0x84000060
 #define ARM_SVC_ID_FFA_ERROR_AARCH64                 0xC4000060
 #define ARM_SVC_ID_FFA_MSG_WAIT_AARCH32              0x8400006B
diff --git a/ArmPkg/Library/StandaloneMmMmuLib/ArmMmuStandaloneMmLib.c b/ArmPkg/Library/StandaloneMmMmuLib/ArmMmuStandaloneMmLib.c
index 1a41a289ef17..76ef214bcb85 100644
--- a/ArmPkg/Library/StandaloneMmMmuLib/ArmMmuStandaloneMmLib.c
+++ b/ArmPkg/Library/StandaloneMmMmuLib/ArmMmuStandaloneMmLib.c
@@ -25,6 +25,66 @@
 #include <Library/DebugLib.h>
 #include <Library/PcdLib.h>
 
+
+/**
+  Utility function to determine whether ABIs in FF-A v1.1 to set and get
+  memory permissions can be used. Ideally, this should be invoked once in the
+  library constructor and set a flag that can be used at runtime. However, the
+  StMM Core invokes this library before constructors are called and before the
+  StMM image itself is relocated.
+
+  @retval EFI_SUCCESS     The availability of ABIs was correctly determined.
+  @retval Other value     Software stack is misconfigured.
+
+**/
+STATIC
+BOOLEAN
+UseFfaMemPermAbis (
+  VOID
+  )
+{
+  ARM_SVC_ARGS    SvcArgs;
+  UINT32          SpmcFfaVersion;
+  STATIC UINT16   SpmcMajorVer = 0;
+  STATIC UINT16   SpmcMinorVer = 0;
+
+  // Use prefetched version info. if either is not 0, then the version is
+  // already fetched.
+  if ((SpmcMajorVer | SpmcMinorVer) != 0) {
+    return (SpmcMajorVer == SPM_MAJOR_VERSION_FFA) && (SpmcMinorVer >= SPM_MINOR_VERSION_FFA);
+  }
+
+  // Nothing to do if FF-A has not be enabled
+  if (FixedPcdGet32 (PcdFfaEnable) == 0) {
+    return FALSE;
+  }
+
+  // Prepare the message parameters.
+  ZeroMem (&SvcArgs, sizeof (ARM_SVC_ARGS));
+  SvcArgs.Arg0 = ARM_SVC_ID_FFA_VERSION_AARCH32;
+  SvcArgs.Arg1 = FFA_VERSION_COMPILED;
+
+  // Invoke the ABI
+  ArmCallSvc (&SvcArgs);
+
+  // Check if FF-A is supported and what version
+  SpmcFfaVersion = SvcArgs.Arg0;
+
+  // Damn! FF-A is not supported at all even though we specified v1.0 as our
+  // version. However, the feature flag has been turned on. This is a
+  // misconfigured software stack. So, return an error and assert in a debug build.
+  if (SpmcFfaVersion == ARM_FFA_SPM_RET_NOT_SUPPORTED) {
+    ASSERT (0);
+    return FALSE;
+  }
+
+  SpmcMajorVer = (SpmcFfaVersion >> FFA_VERSION_MAJOR_SHIFT) & FFA_VERSION_MAJOR_MASK;
+  SpmcMinorVer = (SpmcFfaVersion >> FFA_VERSION_MINOR_SHIFT) & FFA_VERSION_MINOR_MASK;
+
+  return (SpmcMajorVer == SPM_MAJOR_VERSION_FFA) && (SpmcMinorVer >= SPM_MINOR_VERSION_FFA);
+}
+
+
 /** Send memory permission request to target.
 
   @param [in, out]  SvcArgs     Pointer to SVC arguments to send. On
@@ -55,6 +115,36 @@ SendMemoryPermissionRequest (
 
   ArmCallSvc (SvcArgs);
   if (FixedPcdGet32 (PcdFfaEnable) != 0) {
+
+    // Check if FF-A memory permission ABIs were used.
+    if (UseFfaMemPermAbis()) {
+      switch (SvcArgs->Arg0) {
+
+        case ARM_SVC_ID_FFA_ERROR_AARCH32:
+        case ARM_SVC_ID_FFA_ERROR_AARCH64:
+          switch (SvcArgs->Arg2) {
+          case ARM_FFA_SPM_RET_INVALID_PARAMETERS:
+            return EFI_INVALID_PARAMETER;
+          case ARM_FFA_SPM_RET_NOT_SUPPORTED:
+            return EFI_UNSUPPORTED;
+          default:
+            // Undefined error code received.
+            ASSERT (0);
+            return EFI_INVALID_PARAMETER;
+          }
+
+        case ARM_SVC_ID_FFA_SUCCESS_AARCH32:
+        case ARM_SVC_ID_FFA_SUCCESS_AARCH64:
+          *RetVal = SvcArgs->Arg2;
+          return EFI_SUCCESS;
+
+        default:
+          // Undefined error code received.
+          ASSERT (0);
+          return EFI_INVALID_PARAMETER;
+      }
+    }
+
     // Get/Set memory attributes is an atomic call, with
     // StandaloneMm at S-EL0 being the caller and the SPM
     // core being the callee. Thus there won't be a
@@ -164,12 +254,18 @@ GetMemoryPermissions (
   // See [1], Section 13.5.5.1 MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64.
   ZeroMem (&SvcArgs, sizeof (ARM_SVC_ARGS));
   if (FixedPcdGet32 (PcdFfaEnable) != 0) {
-    // See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
-    SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
-    SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
-    SvcArgs.Arg2 = 0;
-    SvcArgs.Arg3 = ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES;
-    SvcArgs.Arg4 = BaseAddress;
+    // Check if FF-A memory permission ABIs can be used.
+    if (UseFfaMemPermAbis()) {
+      SvcArgs.Arg0 = ARM_SVC_ID_FFA_MEM_PERM_GET_AARCH32;
+      SvcArgs.Arg1 = BaseAddress;
+    } else {
+      // See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
+      SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
+      SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
+      SvcArgs.Arg2 = 0;
+      SvcArgs.Arg3 = ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES;
+      SvcArgs.Arg4 = BaseAddress;
+    }
   } else {
     SvcArgs.Arg0 = ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES;
     SvcArgs.Arg1 = BaseAddress;
@@ -219,14 +315,22 @@ RequestMemoryPermissionChange (
   // See [1], Section 13.5.5.2 MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64.
   ZeroMem (&SvcArgs, sizeof (ARM_SVC_ARGS));
   if (FixedPcdGet32 (PcdFfaEnable) != 0) {
-    // See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
-    SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
-    SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
-    SvcArgs.Arg2 = 0;
-    SvcArgs.Arg3 = ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES;
-    SvcArgs.Arg4 = BaseAddress;
-    SvcArgs.Arg5 = EFI_SIZE_TO_PAGES (Length);
-    SvcArgs.Arg6 = Permissions;
+    // Check if FF-A memory permission ABIs can be used.
+    if (UseFfaMemPermAbis()) {
+      SvcArgs.Arg0 = ARM_SVC_ID_FFA_MEM_PERM_SET_AARCH32;
+      SvcArgs.Arg1 = BaseAddress;
+      SvcArgs.Arg2 = EFI_SIZE_TO_PAGES (Length);
+      SvcArgs.Arg3 = Permissions;
+    } else {
+      // See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
+      SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
+      SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
+      SvcArgs.Arg2 = 0;
+      SvcArgs.Arg3 = ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES;
+      SvcArgs.Arg4 = BaseAddress;
+      SvcArgs.Arg5 = EFI_SIZE_TO_PAGES (Length);
+      SvcArgs.Arg6 = Permissions;
+    }
   } else {
     SvcArgs.Arg0 = ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES;
     SvcArgs.Arg1 = BaseAddress;
-- 
2.34.1