diff options
| -rw-r--r-- | BaseTools/Source/C/GenFv/GenFvInternalLib.c | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/BaseTools/Source/C/GenFv/GenFvInternalLib.c b/BaseTools/Source/C/GenFv/GenFvInternalLib.c index 6e296b8ad6..d650a527a5 100644 --- a/BaseTools/Source/C/GenFv/GenFvInternalLib.c +++ b/BaseTools/Source/C/GenFv/GenFvInternalLib.c @@ -34,9 +34,27 @@ SPDX-License-Identifier: BSD-2-Clause-Patent #include "FvLib.h"
#include "PeCoffLib.h"
-#define ARMT_UNCONDITIONAL_JUMP_INSTRUCTION 0xEB000000
#define ARM64_UNCONDITIONAL_JUMP_INSTRUCTION 0x14000000
+/*
+ * Arm instruction to jump to Fv entry instruction in Arm or Thumb mode.
+ * From ARM Arch Ref Manual versions b/c/d, section A8.8.25 BL, BLX (immediate)
+ * BLX (encoding A2) branches to offset in Thumb instruction set mode.
+ * BL (encoding A1) branches to offset in Arm instruction set mode.
+ */
+#define ARM_JUMP_OFFSET_MAX 0xffffff
+#define ARM_JUMP_TO_ARM(Offset) (0xeb000000 | ((Offset - 8) >> 2))
+
+#define _ARM_JUMP_TO_THUMB(Imm32) (0xfa000000 | \
+ (((Imm32) & (1 << 1)) << (24 - 1)) | \
+ (((Imm32) >> 2) & 0x7fffff))
+#define ARM_JUMP_TO_THUMB(Offset) _ARM_JUMP_TO_THUMB((Offset) - 8)
+
+/*
+ * Arm instruction to return from exception (MOVS PC, LR)
+ */
+#define ARM_RETURN_FROM_EXCEPTION 0xE1B0F07E
+
BOOLEAN mArm = FALSE;
BOOLEAN mRiscV = FALSE;
STATIC UINT32 MaxFfsAlignment = 0;
@@ -2203,23 +2221,25 @@ Returns: // if we found an SEC core entry point then generate a branch instruction
// to it and populate a debugger SWI entry as well
if (UpdateVectorSec) {
+ UINT32 EntryOffset;
VerboseMsg("UpdateArmResetVectorIfNeeded updating ARM SEC vector");
- // B SecEntryPoint - signed_immed_24 part +/-32MB offset
- // on ARM, the PC is always 8 ahead, so we're not really jumping from the base address, but from base address + 8
- ResetVector[0] = (INT32)(SecCoreEntryAddress - FvInfo->BaseAddress - 8) >> 2;
+ EntryOffset = (INT32)(SecCoreEntryAddress - FvInfo->BaseAddress);
- if (ResetVector[0] > 0x00FFFFFF) {
- Error(NULL, 0, 3000, "Invalid", "SEC Entry point must be within 32MB of the start of the FV");
+ if (EntryOffset > ARM_JUMP_OFFSET_MAX) {
+ Error(NULL, 0, 3000, "Invalid", "SEC Entry point offset above 1MB of the start of the FV");
return EFI_ABORTED;
}
- // Add opcode for an unconditional branch with no link. i.e.: " B SecEntryPoint"
- ResetVector[0] |= ARMT_UNCONDITIONAL_JUMP_INSTRUCTION;
+ if ((SecCoreEntryAddress & 1) != 0) {
+ ResetVector[0] = ARM_JUMP_TO_THUMB(EntryOffset);
+ } else {
+ ResetVector[0] = ARM_JUMP_TO_ARM(EntryOffset);
+ }
// SWI handler movs pc,lr. Just in case a debugger uses SWI
- ResetVector[2] = 0xE1B0F07E;
+ ResetVector[2] = ARM_RETURN_FROM_EXCEPTION;
// Place holder to support a common interrupt handler from ROM.
// Currently not supported. For this to be used the reset vector would not be in this FV
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