arm-trusted-firmware/bl1/aarch64/bl1_entrypoint.S
Sandrine Bailleux a9bec67dfd Introduce COLD_BOOT_SINGLE_CPU build option
This patch introduces a new build option named COLD_BOOT_SINGLE_CPU,
which allows platforms that only release a single CPU out of reset to
slightly optimise their cold boot code, both in terms of code size
and performance.

COLD_BOOT_SINGLE_CPU defaults to 0, which assumes that the platform
may release several CPUs out of reset. In this case, the cold reset
code needs to coordinate all CPUs via the usual primary/secondary
CPU distinction.

If a platform guarantees that only a single CPU will ever be released
out of reset, there is no need to arbitrate execution ; the notion of
primary and secondary CPUs itself no longer exists. Such platforms
may set COLD_BOOT_SINGLE_CPU to 1 in order to compile out the
primary/secondary CPU identification in the cold reset code.

All ARM standard platforms can release several CPUs out of reset
so they use COLD_BOOT_SINGLE_CPU=0. However, on CSS platforms like
Juno, bringing up more than one CPU at reset should only be attempted
when booting an EL3 payload, as it is not fully supported in the
normal boot flow.

For platforms using COLD_BOOT_SINGLE_CPU=1, the following 2 platform
APIs become optional:
  - plat_secondary_cold_boot_setup();
  - plat_is_my_cpu_primary().
The Porting Guide has been updated to reflect that.

User Guide updated as well.

Change-Id: Ic5b474e61b7aec1377d1e0b6925d17dfc376c46b
2015-11-26 21:32:38 +00:00

78 lines
3 KiB
ArmAsm

/*
* Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of ARM nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <arch.h>
#include <el3_common_macros.S>
.globl bl1_entrypoint
/* -----------------------------------------------------
* bl1_entrypoint() is the entry point into the trusted
* firmware code when a cpu is released from warm or
* cold reset.
* -----------------------------------------------------
*/
func bl1_entrypoint
/* ---------------------------------------------------------------------
* If the reset address is programmable then bl1_entrypoint() is
* executed only on the cold boot path. Therefore, we can skip the warm
* boot mailbox mechanism.
* ---------------------------------------------------------------------
*/
el3_entrypoint_common \
_set_endian=1 \
_warm_boot_mailbox=!PROGRAMMABLE_RESET_ADDRESS \
_secondary_cold_boot=!COLD_BOOT_SINGLE_CPU \
_init_memory=1 \
_init_c_runtime=1 \
_exception_vectors=bl1_exceptions
/* ---------------------------------------------
* Architectural init. can be generic e.g.
* enabling stack alignment and platform spec-
* ific e.g. MMU & page table setup as per the
* platform memory map. Perform the latter here
* and the former in bl1_main.
* ---------------------------------------------
*/
bl bl1_early_platform_setup
bl bl1_plat_arch_setup
/* --------------------------------------------------
* Initialize platform and jump to our c-entry point
* for this type of reset. Panic if it returns
* --------------------------------------------------
*/
bl bl1_main
panic:
b panic
endfunc bl1_entrypoint