Before the commit, the bootloader had a hardcoded entry point that it
would jump to.
However, the Linux kernel arm64 v5.8 forced us to change the kernel
entry point because the required memory alignment has changed at:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
commit/?h=v5.8&id=cfa7ede20f133cc81cef01dc3a516dda3a9721ee
Therefore the only way to have a single bootloader that boots both
pre-v5.8 and post-v5.8 kernels is to pass that information from gem5
to the bootloader, which we do in this patch via registers.
This approach was already used by the 32-bit bootloader, which passed
that value via r3, and we try to use the same register x3 in 64-bit.
Since we are now passing this information, the this patch also removes
the hardcoding of DTB and cpu-release-addr, and also passes those
values via registers.
We store the cpu-release-addr in x5 as that value appears to have a
function similar to flags_addr, which is used only in 32-bit arm and
gets stored in r5.
This commit renames atags_addr to dtb_addr, since both are mutually
exclusive, and serve a similar purpose, DTB being the newer recommended
approach.
Similarly, flags_addr is renamed to cpu_release_addr, and it is moved
from ArmSystem into ArmFsWorkload, since it is not an intrinsic system
property, and should be together with dtb_addr instead.
Before this commit, flags_addr was being set from FSConfig.py and
configs/example/arm/devices.py to self.realview.realview_io.pio_addr
+ 0x30. This commit moves that logic into RealView.py instead, and
sets the flags address 8 bytes before the start of the DTB address.
JIRA: https://gem5.atlassian.net/browse/GEM5-787
Change-Id: If70bea9690be04b84e6040e256a9b03e46710e10
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35076
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
CNTFRQ_EL0 should be initialised to a uniform value in all cores present
in the system. Previously, this was only done if EL3 was present,
however architecture states CNTFRQ_EL0 may be written from the highest
EL implemented.
This patch moves this initilization outside of the EL3-only one.
Change-Id: Ibaa197de53d531ba898e5137ba4f46a8c9554699
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/24683
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
First, remove a deprecated flag that gcc no longer recognizes.
Second, disable suffix based implicit makefile rules. These, in
combination with the %.o: boot.S rule, were tricking make into deleting
it's own makefile. How, you might ask?
make wants to update its makefile, since that's a thing it does
automatically. This is useful if you, for instance, have computed
header dependencies.
make decides it can make a file called "makefile" from a file called
"makefile.o" by doing a linking step.
make decides it can make makefile.o from boot.S from the %.o: boot.S
rule, which it does.
It then attempts to link makefile.o into makefile, but that fails
because it lacks a "main" function since it's using a built in rule
which doesn't know not to expect main. The makefile is clobbered in the
process.
make then deletes makefile.o because it was an implicit target,
eliminating all the evidence.
Change-Id: Ib0dfc333dc554caf5772dd8468dba6ba821f98ac
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/24329
Reviewed-by: Chun-Chen TK Hsu <chunchenhsu@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
