Ring3: Defined SysCallBootService() for ARM.

ArmPkg/Include/Library/DefaultExceptionHandlerLib.h

@@ -9,6 +9,14 @@
 #ifndef DEFAULT_EXCEPTION_HANDLER_LIB_H_
 #define DEFAULT_EXCEPTION_HANDLER_LIB_H_
 
+typedef
+EFI_STATUS
+(EFIAPI *EFI_SYS_CALL_BOOT_SERVICE)(
+  IN  UINT8  Type,
+  IN  VOID   *CoreRbp,
+  IN  VOID   *UserRsp
+  );
+
 /**
   This is the default action to take on an unexpected exception
 
@@ -26,7 +34,7 @@ DefaultExceptionHandler (
 VOID
 EFIAPI
 InitializeSysCallHandler (
-  IN VOID  *Handler
+  IN EFI_SYS_CALL_BOOT_SERVICE  Handler
   );
 
 #endif // DEFAULT_EXCEPTION_HANDLER_LIB_H_

ArmPkg/Library/ArmExceptionLib/Arm/ExceptionSupport.S

@@ -220,8 +220,12 @@ ASM_PFX(AsmCommonExceptionEntry):
   cmp       R3, #0x1f               @ if ((CPSR == 0x10) || (CPSR == 0x1f))
   cmpne     R3, #0x10               @
   stmdaeq   R2, {lr}^               @   save unbanked lr
+  addeq     R2, SP, #0x34           @   Make R2 point to EFI_SYSTEM_CONTEXT_ARM.SP
+  stmdaeq   R2, {sp}^               @   save unbanked sp
                                     @ else
   stmdane   R2, {lr}                @   save SVC lr
+  addne     R1, SP, #0x60           @   We pushed 0x60 bytes on the stack
+  strne     R1, [SP, #0x34]         @   Store it in EFI_SYSTEM_CONTEXT_ARM.SP
 
 
   ldr       R5, [SP, #0x58]         @ PC is the LR pushed by srsfd
@@ -230,6 +234,7 @@ ASM_PFX(AsmCommonExceptionEntry):
   cmp       r4, #1                  @   // UND & SVC have different LR adjust for Thumb
   bhi       NoAdjustNeeded
 
+  ldr       R1, [SP, #0x5c]         @ srsdb saved pre-exception CPSR on the stack
   tst       r1, #0x20               @   if ((CPSR & T)) == T) {  // Thumb Mode on entry
   addne     R5, R5, #2              @     PC += 2;
   strne     R5,[SP,#0x58]           @ Update LR value pushed by srsfd
@@ -238,9 +243,6 @@ NoAdjustNeeded:
 
   str       R5, [SP, #0x3c]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.PC
 
-  add       R1, SP, #0x60           @ We pushed 0x60 bytes on the stack
-  str       R1, [SP, #0x34]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.SP
-
                                     @ R0 is ExceptionType
   mov       R1,SP                   @ R1 is SystemContext
 
@@ -253,7 +255,7 @@ NoAdjustNeeded:
   subne     SP, SP, #4              @ Adjust SP if not 8-byte aligned
 
 /*
-VOID
+EFI_STATUS
 EFIAPI
 CommonCExceptionHandler (
   IN     EFI_EXCEPTION_TYPE           ExceptionType,   R0
@@ -261,6 +263,8 @@ CommonCExceptionHandler (
   )
 
 */
+  mov       R5, R0                  @ R5 is ExceptionType
+
   blx       ASM_PFX(CommonCExceptionHandler)  @ Call exception handler
 
   mov       SP, R4                  @ Restore SP
@@ -275,25 +279,14 @@ CommonCExceptionHandler (
   ldr       R1, [SP, #0x44]         @ Restore EFI_SYSTEM_CONTEXT_ARM.DFSR
   mcr       p15, 0, R1, c5, c0, 0   @ Write DFSR
 
-  ldr       R1,[SP,#0x3c]           @ EFI_SYSTEM_CONTEXT_ARM.PC
+  cmp       R5, #2                  @ if (ExceptionType == SoftwareInterrupt)
-  str       R1,[SP,#0x58]           @ Store it back to srsfd stack slot so it can be restored
+  addeq     SP, SP, #0x4            @   Preserve EFI_STATUS return result in R0.
-
+  ldmfdeq   SP!, {R1-R12}           @
-  ldr       R1,[SP,#0x40]           @ EFI_SYSTEM_CONTEXT_ARM.CPSR
-  str       R1,[SP,#0x5c]           @ Store it back to srsfd stack slot so it can be restored
-
-  add       R3, SP, #0x54           @ Make R3 point to SVC LR saved on entry
-  add       R2, SP, #0x38           @ Make R2 point to EFI_SYSTEM_CONTEXT_ARM.LR
-  and       R1, R1, #0x1f           @ Check to see if User or System Mode
-  cmp       R1, #0x1f               @ if ((CPSR == 0x10) || (CPSR == 0x1f))
-  cmpne     R1, #0x10               @
-  ldmibeq   R2, {lr}^               @   restore unbanked lr
                                     @ else
-  ldmibne   R3, {lr}                @   restore SVC lr, via ldmfd SP!, {LR}
+  ldmfdne   SP!, {R0-R12}           @   Restore general purpose registers
 
-  ldmfd     SP!,{R0-R12}            @ Restore general purpose registers
                                     @ Exception handler can not change SP
 
   add       SP,SP,#0x20             @ Clear out the remaining stack space
   ldmfd     SP!,{LR}                @ restore the link register for this context
   rfefd     SP!                     @ return from exception via srsfd stack slot
-

ArmPkg/Library/DefaultExceptionHandlerLib/AArch64/DefaultExceptionHandler.c

@@ -22,6 +22,7 @@
 #include <Guid/DebugImageInfoTable.h>
 #include <Protocol/DebugSupport.h>
 #include <Protocol/LoadedImage.h>
+#include <Library/DefaultExceptionHandlerLib.h>
 
 //
 // Maximum number of characters to print to serial (UINT8s) and to console if
@@ -29,14 +30,6 @@
 //
 #define MAX_PRINT_CHARS  100
 
-typedef
-EFI_STATUS
-(EFIAPI *EFI_SYS_CALL_BOOT_SERVICE)(
-  IN  UINT8             Type,
-  IN  VOID              *CoreRbp,
-  IN  VOID              *UserRsp
-  );
-
 STATIC CHAR8  *gExceptionTypeString[] = {
   "Synchronous",
   "IRQ",
@@ -195,10 +188,10 @@ BaseName (
 VOID
 EFIAPI
 InitializeSysCallHandler (
-  IN VOID  *Handler
+  IN EFI_SYS_CALL_BOOT_SERVICE  Handler
   )
 {
-  mSysCallHandler = (EFI_SYS_CALL_BOOT_SERVICE)Handler;
+  mSysCallHandler = Handler;
 }
 
 /**

ArmPkg/Library/DefaultExceptionHandlerLib/Arm/DefaultExceptionHandler.c

@@ -39,6 +39,8 @@ typedef struct {
   CHAR8     Char;
 } CPSR_CHAR;
 
+STATIC EFI_SYS_CALL_BOOT_SERVICE  mSysCallHandler;
+
 STATIC CONST CPSR_CHAR  mCpsrChar[] = {
   { 31, 'n' },
   { 30, 'z' },
@@ -187,6 +189,15 @@ STATIC CHAR8  *gExceptionTypeString[] = {
   "FIQ"
 };
 
+VOID
+EFIAPI
+InitializeSysCallHandler (
+  IN EFI_SYS_CALL_BOOT_SERVICE  Handler
+  )
+{
+  mSysCallHandler = Handler;
+}
+
 /**
   This is the default action to take on an unexpected exception
 
@@ -212,6 +223,14 @@ DefaultExceptionHandler (
   BOOLEAN  DfsrWrite;
   UINT32   PcAdjust;
 
+  if (ExceptionType == EXCEPT_ARM_SOFTWARE_INTERRUPT) {
+    return mSysCallHandler (
+             SystemContext.SystemContextArm->R0,
+             &(SystemContext.SystemContextArm->R1),
+             &(SystemContext.SystemContextArm->SP)
+             );
+  }
+
   PcAdjust = 0;
 
   CharCount = AsciiSPrint (

MdeModulePkg/Core/Dxe/SysCall/ARM/CoreBootServices.S

@@ -22,26 +22,6 @@
 ASM_FUNC(CallInstallMultipleProtocolInterfaces)
     bx    LR
 
-//------------------------------------------------------------------------------
-// EFI_STATUS
-// EFIAPI
-// CoreBootServices (
-//   IN  UINT8  Type,
-//   ...
-//   );
-//
-//   (rcx) RIP of the next instruction saved by SYSCALL in SysCall().
-//   (rdx) Argument 1 of the called function.
-//   (r8)  Argument 2 of the called function.
-//   (r9)  Argument 3 of the called function.
-//   (r10) Type.
-//   (r11) RFLAGS saved by SYSCALL in SysCall().
-//
-//   (On User Stack) Argument 4, 5, ...
-//------------------------------------------------------------------------------
-ASM_FUNC(CoreBootServices)
-    bx    LR
-
 //------------------------------------------------------------------------------
 // EFI_STATUS
 // EFIAPI

MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c

@@ -6,6 +6,7 @@
 **/
 
 #include <Library/ArmLib.h>
+#include <Library/DefaultExceptionHandlerLib.h>
 
 #include "DxeMain.h"
 
@@ -33,6 +34,50 @@ ArmClearPan (
   VOID
   );
 
+STATIC
+EFI_STATUS
+EFIAPI
+SysCallBootService (
+  IN  UINT8  Type,
+  IN  VOID   *CoreRbp,
+  IN  VOID   *UserRsp
+  )
+{
+  EFI_STATUS              Status;
+  EFI_PHYSICAL_ADDRESS    Physical;
+
+  Status = CoreAllocatePages (
+             AllocateAnyPages,
+             EfiRing3MemoryType,
+             EFI_SIZE_TO_PAGES (9 * sizeof (UINTN)),
+             &Physical
+             );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  DisableSMAP ();
+  //
+  // First 3 arguments are passed through R1-R3 and copied to SysCall Stack.
+  //
+  CopyMem ((VOID *)((UINTN)Physical + sizeof (UINTN)), (VOID *)CoreRbp, 3 * sizeof (UINTN));
+  //
+  // All remaining arguments are on User Stack.
+  //
+  CopyMem ((VOID *)((UINTN)Physical + 4 * sizeof (UINTN)), (VOID *)UserRsp, 5 * sizeof (UINTN));
+  EnableSMAP ();
+
+  Status = CallBootService (
+             Type,
+             (CORE_STACK *)CoreRbp,
+             (RING3_STACK *)(UINTN)Physical
+             );
+
+  CoreFreePages (Physical, EFI_SIZE_TO_PAGES (9 * sizeof (UINTN)));
+
+  return Status;
+}
+
 VOID
 EFIAPI
 InitializeMsr (
@@ -49,6 +94,8 @@ InitializeMsr (
     DEBUG ((DEBUG_ERROR, "Core: Failed to initialize MSRs for Ring3.\n"));
     // ASSERT (FALSE);
   }
+
+  InitializeSysCallHandler (SysCallBootService);
 }
 
 VOID