Using get_current_el_maybe_constant() produces more optimized code because in most cases, we know the exception level at build-time. For example, BL31 runs at EL3, so unneeded code will be trimmed. [before] 0000000000000000 <is_dcache_enabled>: 0: d5384240 mrs x0, currentel 4: 53020c00 ubfx w0, w0, #2, #2 8: 7100041f cmp w0, #0x1 c: 54000081 b.ne 1c <is_dcache_enabled+0x1c> // b.any 10: d5381000 mrs x0, sctlr_el1 14: 53020800 ubfx w0, w0, #2, #1 18: d65f03c0 ret 1c: 7100081f cmp w0, #0x2 20: 54000061 b.ne 2c <is_dcache_enabled+0x2c> // b.any 24: d53c1000 mrs x0, sctlr_el2 28: 17fffffb b 14 <is_dcache_enabled+0x14> 2c: d53e1000 mrs x0, sctlr_el3 30: 17fffff9 b 14 <is_dcache_enabled+0x14> [after] 0000000000000000 <is_dcache_enabled>: 0: d53e1000 mrs x0, sctlr_el3 4: 53020800 ubfx w0, w0, #2, #1 8: d65f03c0 ret Change-Id: I3698fae9b517022ff9fbfd4cad3a320c6e137e10 Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> |
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bl1 | ||
bl2 | ||
bl2u | ||
bl31 | ||
bl32 | ||
common | ||
docs | ||
drivers | ||
fdts | ||
include | ||
lib | ||
make_helpers | ||
plat | ||
services | ||
tools | ||
.checkpatch.conf | ||
.editorconfig | ||
.gitignore | ||
.gitreview | ||
Makefile | ||
dco.txt | ||
license.rst | ||
readme.rst |
readme.rst
Trusted Firmware-A
Trusted Firmware-A (TF-A) is a reference implementation of secure world software for Arm A-Profile architectures (Armv8-A and Armv7-A), including an Exception Level 3 (EL3) Secure Monitor. It provides a suitable starting point for productization of secure world boot and runtime firmware, in either the AArch32 or AArch64 execution states.
TF-A implements Arm interface standards, including:
- Power State Coordination Interface (PSCI)
- Trusted Board Boot Requirements CLIENT (TBBR-CLIENT)
- SMC Calling Convention
- System Control and Management Interface (SCMI)
- Software Delegated Exception Interface (SDEI)
The code is designed to be portable and reusable across hardware platforms and software models that are based on the Armv8-A and Armv7-A architectures.
In collaboration with interested parties, we will continue to enhance TF-A with reference implementations of Arm standards to benefit developers working with Armv7-A and Armv8-A TrustZone technology.
Users are encouraged to do their own security validation, including penetration testing, on any secure world code derived from TF-A.
More Info and Documentation
To find out more about Trusted Firmware-A, please view the full documentation that is available through trustedfirmware.org.
Copyright (c) 2013-2019, Arm Limited and Contributors. All rights reserved.