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//
// Copyright (c) 2011-2013, ARM Limited. All rights reserved.
// Copyright (c) 2014 - 2016, AMD Inc. All rights reserved.<BR>
//
// This program and the accompanying materials
// are licensed and made available under the terms and conditions of the BSD License
// which accompanies this distribution. The full text of the license may be found at
// http://opensource.org/licenses/bsd-license.php
//
// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
//
//**
// Derived from:
// ArmPkg/Library/BdsLib/AArch64/BdsLinuxLoaderHelper.S
//
//**
/* Secondary core pens for AArch64 Linux booting.
This code is placed in Linux kernel memory and marked reserved. UEFI ensures
that the secondary cores get to this pen and the kernel can then start the
cores from here.
NOTE: This code must be self-contained.
*/
#include <Library/ArmLib.h>
.text
.align 3
GCC_ASM_EXPORT(SecondariesPenStart)
ASM_GLOBAL SecondariesPenEnd
ASM_PFX(SecondariesPenStart):
// Registers x0-x3 are reserved for future use and should be set to zero.
mov x0, xzr
mov x1, xzr
mov x2, xzr
mov x3, xzr
mrs x4, mpidr_el1 // Get MPCore register
and x5, x4, #ARM_CORE_MASK // Get core number
and x4, x4, #ARM_CLUSTER_MASK // Get cluster number
add x4, x5, x4, LSR #7 // Add scaled cluster number to core number
mov x6, x4 // Save a copy to compute mp-parking offset
ldr x5, AsmMailboxBase // Get mailbox addr relative to PC
lsl x4, x4, 3 // Add 8-byte offset for this core
add x4, x4, x5 //
ldr x5, AsmParkingBase // Get mp-parking addr relative to PC
lsl x6, x6, 12 // Add 4K-byte offset for this core
add x6, x6, x5 //
mov x5, 1 // Get mp-parking id# at 2K offset
lsl x5, x5, 11 //
add x5, x5, x6 //
ldr x10, [x5] //
1: ldr x5, [x4] // Load jump-addr from spin-table mailbox
cmp xzr, x5 // Has the value been set?
b.ne 4f // If so, break out of loop
ldr x5, [x6] // Load mp-parking id#
cmp w10, w5 // Is it my id?
b.ne 2f // If not, continue polling
ldr x5, [x6, 8] // Load jump-addr from mp-parking
cmp xzr, x5 // Has the value been set?
b.ne 3f // If so, break out of loop
2: wfe // Wait a bit
b 1b // Wait over, check again
3: str xzr, [x6, 8] // Clear to acknowledge
mov x0, x6 // Return mp-parking address
4: br x5 // Jump to new addr
.align 3 // Make sure the variable below is 8 byte aligned.
.global AsmParkingBase
AsmParkingBase: .xword 0xdeaddeadbeefbeef
.global AsmMailboxBase
AsmMailboxBase: .xword 0xdeaddeadbeefbeef
SecondariesPenEnd:
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