diff options
| author | Furquan Shaikh <furquan@google.com> | 2014-11-21 15:35:17 -0800 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2015-04-10 20:47:21 +0200 |
| commit | ff6d4facbb956175ef6ef9742545924b7fff4fad (patch) | |
| tree | 8c91b4a2d20881657d5c761212d14400457c4a03 | |
| parent | b718eab78d174be2d1a6dc6a21e64fdba341bced (diff) | |
arm64: Add conditional read/write from/to EL3 assembly macros.
Some registers are available only at EL3. Add conditional read/write functions
that perform operations only if currently we are in EL3.
BUG=chrome-os-partner:33962
BRANCH=None
TEST=Compiles and boots to kernel prompt.
Change-Id: Ic95838d10e18f58867b6b77aee937bdacae50597
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 62a0e324a00248dba92cb3e2ac2f4072d0e4e2a7
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Change-Id: Ia170d94adb9ecc141ff86e4a3041ddbf9045bc89
Original-Reviewed-on: https://chromium-review.googlesource.com/231549
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/9538
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
| -rw-r--r-- | src/arch/arm64/include/armv8/arch/lib_helpers.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/src/arch/arm64/include/armv8/arch/lib_helpers.h b/src/arch/arm64/include/armv8/arch/lib_helpers.h index a80474799d..422b81a56b 100644 --- a/src/arch/arm64/include/armv8/arch/lib_helpers.h +++ b/src/arch/arm64/include/armv8/arch/lib_helpers.h @@ -214,6 +214,31 @@ 104: .endm +/* Macro to read from a register at EL3 only if we are currently at that + level. This is required to ensure that we do not attempt to read registers + from a level lower than el3. e.g. SCR is available for read only at EL3. + IMPORTANT: if EL != EL3, macro silently doesn't perform the read. +*/ +.macro read_el3 xreg sysreg + switch_el \xreg, 402f, 402f, 401f +401: + mrs \xreg, \sysreg\()_el3 +402: +.endm + +/* Macro to write to a register at EL3 only if we are currently at that + level. This is required to ensure that we do not attempt to write to + registers from a level lower than el3. e.g. SCR is available to write only at + EL3. + IMPORTANT: if EL != EL3, macro silently doesn't perform the write. +*/ +.macro write_el3 sysreg xreg temp + switch_el \temp, 402f, 402f, 401f +401: + msr \sysreg\()_el3, \xreg +402: +.endm + #else #include <stdint.h> |