sim: Implement load_addr_mask auto-calculation Recent Linux kernels for AArch64 have changed their start addresses but we still want to relocate the kernel to 0x80080000 which required hacking the load_addr_mask in Realview.py to be 0x7ffffff from 0xfffffff to mask off the proper number of MSBs to load the kernel in the desired location. To avoid having to make this change in the future again, we auto-calculate the load_addr_mask if it is specified as 0x0 in the System sim-object to find the most restrictive address mask instead of having the configuration specify it. If the configuration does specify the address mask, we use it instead of auto-calculating. Change-Id: I18aabb5d09945c6e3e3819c9c8036ea24b6c35cf Signed-off-by: Geoffrey Blake <Geoffrey.Blake@arm.com> Reviewed-by: Curtis Dunham <curtis.dunham@arm.com> Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/2323 Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
diff --git a/src/arch/arm/ArmSystem.py b/src/arch/arm/ArmSystem.py index ac04a56..9dd6386 100644 --- a/src/arch/arm/ArmSystem.py +++ b/src/arch/arm/ArmSystem.py
@@ -1,4 +1,4 @@ -# Copyright (c) 2009, 2012-2013, 2015 ARM Limited +# Copyright (c) 2009, 2012-2013, 2015-2017 ARM Limited # All rights reserved. # # The license below extends only to copyright in the software and shall @@ -51,7 +51,6 @@ class ArmSystem(System): type = 'ArmSystem' cxx_header = "arch/arm/system.hh" - load_addr_mask = 0xffffffff multi_proc = Param.Bool(True, "Multiprocessor system?") boot_loader = VectorParam.String([], "File that contains the boot loader code. Zero or more files may be " @@ -78,7 +77,6 @@ class GenericArmSystem(ArmSystem): type = 'GenericArmSystem' cxx_header = "arch/arm/system.hh" - load_addr_mask = 0x0fffffff machine_type = Param.ArmMachineType('VExpress_EMM', "Machine id from http://www.arm.linux.org.uk/developer/machines/") atags_addr = Param.Addr("Address where default atags structure should " \ @@ -106,6 +104,10 @@ def export_methods(cls, code): code('''void dumpDmesg();''') + # Have Linux systems for ARM auto-calc their load_addr_mask for proper + # kernel relocation. + load_addr_mask = 0x0 + class FreebsdArmSystem(GenericArmSystem): type = 'FreebsdArmSystem' cxx_header = "arch/arm/freebsd/system.hh"
diff --git a/src/dev/arm/RealView.py b/src/dev/arm/RealView.py index 8b9b4c2..66940d6 100644 --- a/src/dev/arm/RealView.py +++ b/src/dev/arm/RealView.py
@@ -346,7 +346,6 @@ self.nvmem.port = mem_bus.master cur_sys.boot_loader = loc('boot.arm') cur_sys.atags_addr = 0x100 - cur_sys.load_addr_mask = 0xfffffff cur_sys.load_offset = 0 @@ -659,7 +658,6 @@ self.nvmem.port = mem_bus.master cur_sys.boot_loader = loc('boot_emm.arm') cur_sys.atags_addr = 0x8000000 - cur_sys.load_addr_mask = 0xfffffff cur_sys.load_offset = 0x80000000 # Attach I/O devices that are on chip and also set the appropriate @@ -770,7 +768,6 @@ self.nvmem.port = mem_bus.master cur_sys.boot_loader = loc('boot_emm.arm64') cur_sys.atags_addr = 0x8000000 - cur_sys.load_addr_mask = 0xfffffff cur_sys.load_offset = 0x80000000 @@ -939,5 +936,4 @@ self.nvmem.port = mem_bus.master cur_sys.boot_loader = [ loc('boot_emm.arm64'), loc('boot_emm.arm') ] cur_sys.atags_addr = 0x8000000 - cur_sys.load_addr_mask = 0xfffffff cur_sys.load_offset = 0x80000000
diff --git a/src/sim/System.py b/src/sim/System.py index 0d02516..7fc8520 100644 --- a/src/sim/System.py +++ b/src/sim/System.py
@@ -1,3 +1,15 @@ +# Copyright (c) 2017 ARM Limited +# All rights reserved. +# +# The license below extends only to copyright in the software and shall +# not be construed as granting a license to any other intellectual +# property including but not limited to intellectual property relating +# to a hardware implementation of the functionality of the software +# licensed hereunder. You may use the software subject to the license +# terms below provided that you ensure that this notice is replicated +# unmodified and in its entirety in all distributions of the software, +# modified or unmodified, in source code or in binary form. +# # Copyright (c) 2005-2007 The Regents of The University of Michigan # Copyright (c) 2011 Regents of the University of California # All rights reserved. @@ -101,8 +113,10 @@ "whether to address check on kernel (disable for baremetal)") readfile = Param.String("", "file to read startup script from") symbolfile = Param.String("", "file to get the symbols from") - load_addr_mask = Param.UInt64(0xffffffffff, - "Address to mask loading binaries with") + load_addr_mask = Param.UInt64(0xffffffffffffffff, + "Address to mask loading binaries with, if 0, system " + "auto-calculates the mask to be the most restrictive, " + "otherwise it obeys a custom mask.") load_offset = Param.UInt64(0, "Address to offset loading binaries with") multi_thread = Param.Bool(False,
diff --git a/src/sim/system.cc b/src/sim/system.cc index 9f240c9..99eb947 100644 --- a/src/sim/system.cc +++ b/src/sim/system.cc
@@ -1,5 +1,5 @@ /* - * Copyright (c) 2011-2014 ARM Limited + * Copyright (c) 2011-2014,2017 ARM Limited * All rights reserved * * The license below extends only to copyright in the software and shall @@ -140,6 +140,14 @@ kernelEnd = kernel->bssBase() + kernel->bssSize(); kernelEntry = kernel->entryPoint(); + // If load_addr_mask is set to 0x0, then auto-calculate + // the smallest mask to cover all kernel addresses so gem5 + // can relocate the kernel to a new offset. + if (loadAddrMask == 0) { + Addr shift_amt = findMsbSet(kernelEnd - kernelStart) + 1; + loadAddrMask = ((Addr)1 << shift_amt) - 1; + } + // load symbols if (!kernel->loadGlobalSymbols(kernelSymtab)) fatal("could not load kernel symbols\n");