cpu: use MRS instruction to read arm64 system registers
Use the MRS instruction with the corresponding system register instead
of encoding the instructions using a WORD directive.
Change-Id: I2995dfa6ad731cb03867160127db84898adfdda5
Reviewed-on: https://go-review.googlesource.com/c/sys/+/583135
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
diff --git a/cpu/cpu_arm64.s b/cpu/cpu_arm64.s
index 9053a43..601a5f7 100644
--- a/cpu/cpu_arm64.s
+++ b/cpu/cpu_arm64.s
@@ -9,16 +9,14 @@
// func getisar0() uint64
TEXT ·getisar0(SB),NOSPLIT,$0-8
// get Instruction Set Attributes 0 into x0
- // mrs x0, ID_AA64ISAR0_EL1 = d5380600
- WORD $0xd5380600
+ MRS ID_AA64ISAR0_EL1, R0
MOVD R0, ret+0(FP)
RET
// func getisar1() uint64
TEXT ·getisar1(SB),NOSPLIT,$0-8
// get Instruction Set Attributes 1 into x0
- // mrs x0, ID_AA64ISAR1_EL1 = d5380620
- WORD $0xd5380620
+ MRS ID_AA64ISAR1_EL1, R0
MOVD R0, ret+0(FP)
RET
@@ -33,15 +31,13 @@
// func getpfr0() uint64
TEXT ·getpfr0(SB),NOSPLIT,$0-8
// get Processor Feature Register 0 into x0
- // mrs x0, ID_AA64PFR0_EL1 = d5380400
- WORD $0xd5380400
+ MRS ID_AA64PFR0_EL1, R0
MOVD R0, ret+0(FP)
RET
// func getzfr0() uint64
TEXT ·getzfr0(SB),NOSPLIT,$0-8
// get SVE Feature Register 0 into x0
- // mrs x0, ID_AA64ZFR0_EL1 = d5380480
- WORD $0xd5380480
+ MRS ID_AA64ZFR0_EL1, R0
MOVD R0, ret+0(FP)
RET
