diff options
Diffstat (limited to 'ArmPlatformPkg/PrePi/ModuleEntryPoint.asm')
| -rw-r--r-- | ArmPlatformPkg/PrePi/ModuleEntryPoint.asm | 59 |
1 files changed, 39 insertions, 20 deletions
diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm index 52690f8ecd..00abcb304a 100644 --- a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm +++ b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm @@ -31,28 +31,51 @@ _ModuleEntryPoint mrc p15, 0, r0, c0, c0, 5
and r0, #0xf
-_UefiMemoryBase
-#if FixedPcdGet32(PcdStandalone)
+_SetSVCMode
+ // Enter SVC mode
+ mov r1, #0x13|0x80|0x40
+ msr CPSR_c, r1
+
+// Check if we can install the size at the top of the System Memory or if we need
+// to install the stacks at the bottom of the Firmware Device (case the FD is located
+// at the top of the DRAM)
+_SetupStackPosition
// Compute Top of System Memory
LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryBase), r1)
LoadConstantToReg (FixedPcdGet32(PcdSystemMemorySize), r2)
add r1, r1, r2 // r1 = SystemMemoryTop = PcdSystemMemoryBase + PcdSystemMemorySize
-#else
- // If it is not a Standalone, we must compute the top of the UEFI memory with the base of the FD
- LoadConstantToReg (FixedPcdGet32(PcdNormalFdBaseAddress), r1)
-#endif
- // Compute Base of UEFI Memory
- LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryUefiRegionSize), r2)
- sub r1, r1, r2 // r1 = SystemMemoryTop - PcdSystemMemoryUefiRegionSize = UefiMemoryBase
+ // Calculate Top of the Firmware Device
+ LoadConstantToReg (FixedPcdGet32(PcdNormalFdBaseAddress), r2)
+ LoadConstantToReg (FixedPcdGet32(PcdNormalFdSize), r3)
+ add r3, r3, r2 // r4 = FdTop = PcdNormalFdBaseAddress + PcdNormalFdSize
+
+ // UEFI Memory Size (stacks are allocated in this region)
+ LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryUefiRegionSize), r4)
+
+ //
+ // Reserve the memory for the UEFI region (contain stacks on its top)
+ //
+
+ // Calculate how much space there is between the top of the Firmware and the Top of the System Memory
+ subs r5, r1, r3 // r5 = SystemMemoryTop - FdTop
+ bmi _SetupStack // Jump if negative (FdTop > SystemMemoryTop)
+ cmp r5, r4
+ bge _SetupStack
+
+ // Case the top of stacks is the FdBaseAddress
+ mov r1, r2
_SetupStack
// Compute Base of Normal stacks for CPU Cores
- LoadConstantToReg (FixedPcdGet32(PcdCPUCoresNonSecStackSize), r2)
- mul r3, r0, r2 // r3 = core_id * stack_size = offset from the stack base
- sub sp, r1, r3 // r3 = UefiMemoryBase - StackOffset = TopOfStack
+ LoadConstantToReg (FixedPcdGet32(PcdCPUCoresNonSecStackSize), r5)
+ mul r3, r0, r5 // r3 = core_id * stack_size = offset from the stack base
+ sub sp, r1, r3 // r3 = (SystemMemoryTop|FdBaseAddress) - StackOffset = TopOfStack
+
+ // Calculate the Base of the UEFI Memory
+ sub r1, r1, r4
- // Only allocate memory in top of the primary core stack
+ // Only allocate memory for global variables at top of the primary core stack
cmp r0, #0
bne _PrepareArguments
@@ -66,17 +89,13 @@ _AllocateGlobalPrePiVariables sub sp, sp, r4
_PrepareArguments
- // Pass the StackBase to the C Entrypoint (UefiMemoryBase - StackSize - StackOffset)
- sub r2, r1, r2
- sub r2, r3
// Move sec startup address into a data register
// Ensure we're jumping to FV version of the code (not boot remapped alias)
- ldr r3, StartupAddr
+ ldr r2, StartupAddr
- // jump to PrePiCore C code
+ // Jump to PrePiCore C code
// r0 = core_id
// r1 = UefiMemoryBase
- // r2 = StackBase
- blx r3
+ blx r2
END
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