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libpayload arm64: Add support for read and write registers at current EL in assembly 

In order to ease the process of reading and writing any register at current EL,
provide read_current and write_current assembly macros. These are included in
arch/lib_helpers.h under the __ASSEMBLY__ macro condition. This is done to allow
the same header file to be included by .c and .S files.

BUG=chrome-os-partner:31634
BRANCH=None
TEST=Compiles successfully for ryu

Change-Id: I79241a944b68ebb24865e745a9835f54ab6d1a8f
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 2b55fbde466126c4de7f5f7bb2d1427196be842f
Original-Change-Id: I678ab89c4aa1b08898166e135b5ab2d6453bb5e8
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/214576
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/8801
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Furquan Shaikh 2014-08-27 15:57:47 -07:00 committed by Patrick Georgi
parent adabbe5e20
commit 4c2cb16d89
1 changed files with 57 additions and 0 deletions
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57
payloads/libpayload/include/arm64/arch/lib_helpers.h
View File

@ -33,6 +33,61 @@
#ifndef __ARCH_LIB_HELPERS_H__
#define __ARCH_LIB_HELPERS_H__
#ifdef __ASSEMBLY__
/* Macro to switch to label based on current el */
.macro switch_el xreg label1 label2 label3
mrs \xreg, CurrentEL
/* Currently at EL1 */
cmp \xreg, 0x4
b.eq \label1
/* Currently at EL2 */
cmp \xreg, 0x8
b.eq \label2
/* Currently at EL3 */
cmp \xreg, 0xc
b.eq \label3
.endm
/* Macro to read sysreg at current EL
xreg - reg in which read value needs to be stored
sysreg - system reg that is to be read
*/
.macro read_current xreg sysreg
switch_el \xreg, 101f, 102f, 103f
101:
mrs \xreg, \sysreg\()_el1
b 104f
102:
mrs \xreg, \sysreg\()_el2
b 104f
103:
mrs \xreg, \sysreg\()_el3
b 104f
104:
.endm
/* Macro to write sysreg at current EL
xreg - reg from which value needs to be written
sysreg - system reg that is to be written
temp - temp reg that can be used to read current EL
*/
.macro write_current sysreg xreg temp
switch_el \temp, 101f, 102f, 103f
101:
msr \sysreg\()_el1, \xreg
b 104f
102:
msr \sysreg\()_el2, \xreg
b 104f
103:
msr \sysreg\()_el3, \xreg
b 104f
104:
.endm
#else
#define EL0 0
#define EL1 1
#define EL2 2
@ -318,4 +373,6 @@ void tlbivaa_el1(uint64_t va);
/* Clock */
void set_cntfrq(uint32_t freq);
#endif // __ASSEMBLY__
#endif //__ARCH_LIB_HELPERS_H__