The global variable mSystemMemoryEnd is initialized by PrePi only if it has not been initialized by ArmPlatformPeiBootAction(). This allows platforms executing under, e.g., ARM Trusted Firmware to dynamically reserve a window at the top of memory that will be used by the secure firmware. However, PrePi is a SEC module, and writing to a global variable violates the SEC constraints, since SEC and PEI may execute from NOR flash. So instead, initialize mSystemMemoryEnd statically. This will ensure it holds the correct value for all implementations where the value is not overridden, but still allows it to be overridden during the call to ArmPlatformPeiBootAction(). Note that this patch also fixes a latent bug on 32-bit platforms where a value of mSystemMemoryEnd exceeding 4 GB would be truncated to 32-bits rather than limited to (4 GB - 1) Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Laszlo Ersek <lersek@redhat.com> Tested-by: Ryan Harkin <ryan.harkin@linaro.org> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
		
			
				
	
	
		
			120 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			120 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
//
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//  Copyright (c) 2011-2015, ARM Limited. All rights reserved.
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//
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//  This program and the accompanying materials
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//  are licensed and made available under the terms and conditions of the BSD License
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//  which accompanies this distribution.  The full text of the license may be found at
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//  http://opensource.org/licenses/bsd-license.php
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//
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//  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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//  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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//
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//
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#include <AsmMacroIoLibV8.h>
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ASM_FUNC(_ModuleEntryPoint)
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  // Do early platform specific actions
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  bl    ASM_PFX(ArmPlatformPeiBootAction)
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  // Get ID of this CPU in Multicore system
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  bl    ASM_PFX(ArmReadMpidr)
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  // Keep a copy of the MpId register value
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  mov   x10, x0
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_SetSVCMode:
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// Check if we can install the stack at the top of the System Memory or if we need
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// to install the stacks at the bottom of the Firmware Device (case the FD is located
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// at the top of the DRAM)
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_SystemMemoryEndInit:
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  ldr   x1, mSystemMemoryEnd
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_SetupStackPosition:
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  // r1 = SystemMemoryTop
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  // Calculate Top of the Firmware Device
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  MOV64 (x2, FixedPcdGet64(PcdFdBaseAddress))
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  MOV32 (x3, FixedPcdGet32(PcdFdSize) - 1)
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  sub   x3, x3, #1
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  add   x3, x3, x2      // x3 = FdTop = PcdFdBaseAddress + PcdFdSize
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  // UEFI Memory Size (stacks are allocated in this region)
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  MOV32 (x4, FixedPcdGet32(PcdSystemMemoryUefiRegionSize))
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  //
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  // Reserve the memory for the UEFI region (contain stacks on its top)
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  //
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  // Calculate how much space there is between the top of the Firmware and the Top of the System Memory
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  subs  x0, x1, x3   // x0 = SystemMemoryTop - FdTop
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  b.mi  _SetupStack  // Jump if negative (FdTop > SystemMemoryTop). Case when the PrePi is in XIP memory outside of the DRAM
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  cmp   x0, x4
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  b.ge  _SetupStack
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  // Case the top of stacks is the FdBaseAddress
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  mov   x1, x2
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_SetupStack:
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  // x1 contains the top of the stack (and the UEFI Memory)
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  // Because the 'push' instruction is equivalent to 'stmdb' (decrement before), we need to increment
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  // one to the top of the stack. We check if incrementing one does not overflow (case of DRAM at the
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  // top of the memory space)
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  adds  x11, x1, #1
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  b.cs  _SetupOverflowStack
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_SetupAlignedStack:
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  mov   x1, x11
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  b     _GetBaseUefiMemory
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_SetupOverflowStack:
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  // Case memory at the top of the address space. Ensure the top of the stack is EFI_PAGE_SIZE
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  // aligned (4KB)
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  and   x1, x1, ~EFI_PAGE_MASK
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_GetBaseUefiMemory:
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  // Calculate the Base of the UEFI Memory
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  sub   x11, x1, x4
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_GetStackBase:
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  // r1 = The top of the Mpcore Stacks
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  // Stack for the primary core = PrimaryCoreStack
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  MOV32 (x2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
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  sub   x12, x1, x2
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  // Stack for the secondary core = Number of Cores - 1
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  MOV32 (x1, (FixedPcdGet32(PcdCoreCount) - 1) * FixedPcdGet32(PcdCPUCoreSecondaryStackSize))
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  sub   x12, x12, x1
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  // x12 = The base of the MpCore Stacks (primary stack & secondary stacks)
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  mov   x0, x12
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  mov   x1, x10
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  //ArmPlatformStackSet(StackBase, MpId, PrimaryStackSize, SecondaryStackSize)
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  MOV32 (x2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
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  MOV32 (x3, FixedPcdGet32(PcdCPUCoreSecondaryStackSize))
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  bl    ASM_PFX(ArmPlatformStackSet)
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  // Is it the Primary Core ?
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  mov   x0, x10
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  bl    ASM_PFX(ArmPlatformIsPrimaryCore)
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  cmp   x0, #1
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  bne   _PrepareArguments
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_PrepareArguments:
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  mov   x0, x10
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  mov   x1, x11
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  mov   x2, x12
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  // Move sec startup address into a data register
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  // Ensure we're jumping to FV version of the code (not boot remapped alias)
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  ldr   x4, =ASM_PFX(CEntryPoint)
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  // Jump to PrePiCore C code
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  //    x0 = MpId
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  //    x1 = UefiMemoryBase
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  //    x2 = StacksBase
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  blr   x4
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_NeverReturn:
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  b _NeverReturn
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