The IdMap.S asm source file has not executable content, but its lack of
a BTI annotation prevents the linker from marking any executables it
emits as BTI compatible if this object is part of the build. So add the
BTI note by hand.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The initial ID map used by ArmVirtQemu only covers 2 MiB of NOR flash,
while the NOOPT build can be up to 3 MiB in size, resulting in a crash
if the unmapped 1 MiB is accessed before the real page tables are up.
So increate the initial flash mapping to 4 MiB.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
The early ID map used by ArmVirtQemu uses ASID scoped non-global
mappings, as this allows us to switch to the permanent ID map seamlessly
without the need for explicit TLB maintenance.
However, this triggers a known erratum on ThunderX, which does not
tolerate non-global mappings that are executable at EL1, as this appears
to result in I-cache corruption. (Linux disables the KPTI based Meltdown
mitigation on ThunderX for the same reason)
So work around this, by detecting the CPU implementor and part number,
and proceeding without the early ID map if a ThunderX CPU is detected.
Note that this requires the C code to be built with strict alignment
again, as we may end up executing it with the MMU and caches off.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: dann frazier <dann.frazier@canonical.com>
Now that we build the early code without strict alignment and without
suppressing the use of SIMD registers, ensure that the VFP unit is on
before entering C code.
While at it, simplyify the mov_i macro, which is only used for 32-bit
quantities.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: dann frazier <dann.frazier@canonical.com>
To substantially reduce the amount of processing that takes place with
the MMU and caches off, implement a version of ArmPlatformLib specific
for QEMU/mach-virt in AArch64 mode that carries a statically allocated
and populated ID map that covers the NOR flash and device region, and
128 MiB of DRAM at the base of memory (0x4000_0000).
Note that 128 MiB has always been the minimum amount of DRAM we support
for this configuration, and the existing code already ASSERT()s in DEBUG
mode when booting with less.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Ard Biesheuvel