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, 2 insertions, 2 deletions

diff --git a/src/arch/arm64/armv8/exception.c b/src/arch/arm64/armv8/exception.c
index 924c344e13..e32c79a85a 100644
--- a/src/arch/arm64/armv8/exception.c
+++ b/src/arch/arm64/armv8/exception.c
@@ -78,9 +78,9 @@ static void print_regs(struct exc_state *exc_state)
 	struct elx_state *elx = &exc_state->elx;
 	struct regs *regs = &exc_state->regs;
 
-	printk(BIOS_DEBUG, "ELR = 0x%016llx         ESR = 0x%08x\n",
+	printk(BIOS_DEBUG, "ELR = 0x%016llx         ESR = 0x%08llx\n",
 	       elx->elr, raw_read_esr_el3());
-	printk(BIOS_DEBUG, "FAR = 0x%016llx        SPSR = 0x%08x\n",
+	printk(BIOS_DEBUG, "FAR = 0x%016llx        SPSR = 0x%08llx\n",
 	       raw_read_far_el3(), raw_read_spsr_el3());
 	for (i = 0; i < 30; i += 2) {
 		printk(BIOS_DEBUG,