arm64: Turn architectural register accessors into inline functions

Accesses to architectural registers should be really fast -- they're
just registers, after all. In fact, the arm64 architecture uses them for
some timing-senstive uses like the architectural timer. A read should be:
one instruction, no data dependencies, done.

However, our current coreboot framework wraps each of these accesses
into a separate function. Suddenly you have to spill registers on a
stack, make a function call, move your stack pointer, etc. When running
without MMU this adds a significant enough delay to cause timing
problems when bitbanging a UART on SDM845.

This patch replaces all those existing functions with static inline
definitions in the header so they will get reduced to a single
instruction as they should be. Also use some macros to condense the code
a little since they're all so regular, which should make it easier to
add more in the future. This patch also expands all the data types to
uint64_t since that's what the actual assembly instruction accesses,
even if the register itself only has 32 bits (the others will be ignored
by the processor and set to 0 on read). Arm regularly expands registers
as they add new bit fields to them with newer iterations of the
architecture anyway, so this just prepares us for the inevitable.

Change-Id: I2c41cc3ce49ee26bf12cd34e3d0509d8e61ffc63
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/27881
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 0 insertions, 36 deletions

diff --git a/src/arch/arm64/armv8/lib/Makefile.inc b/src/arch/arm64/armv8/lib/Makefile.inc
deleted file mode 100644
index 8fc44de5b6..0000000000
--- a/src/arch/arm64/armv8/lib/Makefile.inc
+++ /dev/null
@@ -1,36 +0,0 @@
-################################################################################
-## This file is part of the coreboot project.
-##
-## Copyright (C) 2014 Google Inc
-##
-## This program is free software; you can redistribute it and/or
-## modify it under the terms of the GNU General Public License as
-## published by the Free Software Foundation; version 2 of
-## the License.
-##
-## This program is distributed in the hope that it will be useful,
-## but WITHOUT ANY WARRANTY; without even the implied warranty of
-## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-## GNU General Public License for more details.
-##
-################################################################################
-
-lib_access = pstate.c sysctrl.c cache.c tlb.c
-
-ifeq ($(CONFIG_ARCH_BOOTBLOCK_ARMV8_64),y)
-decompressor-y += $(lib_access)
-bootblock-y += $(lib_access)
-endif
-
-ifeq ($(CONFIG_ARCH_VERSTAGE_ARMV8_64),y)
-verstage-y += $(lib_access)
-endif
-
-ifeq ($(CONFIG_ARCH_ROMSTAGE_ARMV8_64),y)
-romstage-y += $(lib_access)
-endif
-
-ifeq ($(CONFIG_ARCH_RAMSTAGE_ARMV8_64),y)
-ramstage-y += $(lib_access)
-
-endif