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-rw-r--r--payloads/libpayload/include/arm64/arch/lib_helpers.h57
1 files changed, 57 insertions, 0 deletions
diff --git a/payloads/libpayload/include/arm64/arch/lib_helpers.h b/payloads/libpayload/include/arm64/arch/lib_helpers.h
index 3adba81c88..d98d6f7d6b 100644
--- a/payloads/libpayload/include/arm64/arch/lib_helpers.h
+++ b/payloads/libpayload/include/arm64/arch/lib_helpers.h
@@ -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__