u-boot/arch/arm/cpu/armv8/transition.S
Philipp Tomsich e6a0586277 armv8: move low-level assembly functions into function-sections
TPL builds today don't need to call into firmware or set up the MMU
(if this changes, it should be controlled through a config option
whether to include this or not), but include the needed support code
for this anyway.  By moving these unused low-level functions into
seperate function-sections, the linker can garbage-collect the unused
sections.

Note that (if DM support is enabled), there will be a call to the
cache-flushing code from alloc_priv(...) in drivers/core/device.c.
This then add 52 bytes of binary size (an increase from 20589 to 20641
bytes) compared to completely removing this code.

Even for a feature-rich TPL (including DM support as for the RK3368),
this equates to a size difference of significantly more than 10% in
TPL binary size.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:21 +02:00

52 lines
1.1 KiB
ArmAsm

/*
* (C) Copyright 2013
* David Feng <fenghua@phytium.com.cn>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <asm-offsets.h>
#include <config.h>
#include <linux/linkage.h>
#include <asm/macro.h>
.pushsection .text.armv8_switch_to_el2, "ax"
ENTRY(armv8_switch_to_el2)
switch_el x6, 1f, 0f, 0f
0:
cmp x5, #ES_TO_AARCH64
b.eq 2f
/*
* When loading 32-bit kernel, it will jump
* to secure firmware again, and never return.
*/
bl armv8_el2_to_aarch32
2:
/*
* x4 is kernel entry point or switch_to_el1
* if CONFIG_ARMV8_SWITCH_TO_EL1 is defined.
* When running in EL2 now, jump to the
* address saved in x4.
*/
br x4
1: armv8_switch_to_el2_m x4, x5, x6
ENDPROC(armv8_switch_to_el2)
.popsection
.pushsection .text.armv8_switch_to_el1, "ax"
ENTRY(armv8_switch_to_el1)
switch_el x6, 0f, 1f, 0f
0:
/* x4 is kernel entry point. When running in EL1
* now, jump to the address saved in x4.
*/
br x4
1: armv8_switch_to_el1_m x4, x5, x6
ENDPROC(armv8_switch_to_el1)
.popsection
.pushsection .text.armv8_el2_to_aarch32, "ax"
WEAK(armv8_el2_to_aarch32)
ret
ENDPROC(armv8_el2_to_aarch32)
.popsection