commit 4c7051c23e6b0402939f23ea474ec59099ab4751
author Giacomo Travaglini <giacomo.travaglini@arm.com> Mon Oct 29 11:10:33 2018 +0000
committer Giacomo Travaglini <giacomo.travaglini@arm.com> Wed Nov 07 15:22:43 2018 +0000
tree 06d36dc23dd692a05ed6667798e5ee172629a356
parent 6fa49382ef22e1b01fb24503e3bbe5ab3556750a

arch-arm: Deprecate usage of legacy bootloader patching

This patch is implicitly deprecating the usage of bootloader patching,
which is injecting instructions from gem5 into the bootloader
binary. This was probably meant to provide a dynamic bootloader
entry point.
This is not needed in ARMv8.0, since we can simply update the
ArmSystem::resetAddress with the bootloader entry point.

Change-Id: I0c469873b8d69f7b49a7383e0754468bc1f2bd72
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/14001
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

src/arch/arm/system.cc

diff --git a/src/arch/arm/system.cc b/src/arch/arm/system.cc
index 0630661..164c965 100644
--- a/src/arch/arm/system.cc
+++ b/src/arch/arm/system.cc
@@ -104,6 +104,12 @@
 
     if (bootldr) {
         bootldr->loadGlobalSymbols(debugSymbolTable);
+
+        warn_if(bootldr->entryPoint() != _resetAddr,
+                "Bootloader entry point %#x overriding reset address %#x",
+                bootldr->entryPoint(), _resetAddr);
+        const_cast<Addr&>(_resetAddr) = bootldr->entryPoint();
+
         if ((bootldr->getArch() == ObjectFile::Arm64) && !_highestELIs64) {
             warn("Highest ARM exception-level set to AArch32 but bootloader "
                   "is for AArch64. Assuming you wanted these to match.\n");
@@ -132,22 +138,6 @@
     if (bootldr) {
         bootldr->loadSections(physProxy);
 
-        uint8_t jump_to_bl_32[] =
-        {
-            0x07, 0xf0, 0xa0, 0xe1  // branch to r7 in aarch32
-        };
-
-        uint8_t jump_to_bl_64[] =
-        {
-            0xe0, 0x00, 0x1f, 0xd6  // instruction "br x7" in aarch64
-        };
-
-        // write the jump to branch table into address 0
-        if (!_highestELIs64)
-            physProxy.writeBlob(0x0, jump_to_bl_32, sizeof(jump_to_bl_32));
-        else
-            physProxy.writeBlob(0x0, jump_to_bl_64, sizeof(jump_to_bl_64));
-
         inform("Using bootloader at address %#x\n", bootldr->entryPoint());
 
         // Put the address of the boot loader into r7 so we know
@@ -160,9 +150,9 @@
             if (!_highestELIs64)
                 threadContexts[i]->setIntReg(3, (kernelEntry & loadAddrMask) +
                         loadAddrOffset);
+
             threadContexts[i]->setIntReg(4, params()->gic_cpu_addr);
             threadContexts[i]->setIntReg(5, params()->flags_addr);
-            threadContexts[i]->setIntReg(7, bootldr->entryPoint());
         }
         inform("Using kernel entry physical address at %#x\n",
                (kernelEntry & loadAddrMask) + loadAddrOffset);