Revert "runtime: Check LSE support on ARM64 at runtime init"

This reverts CL 610195.

Reason for revert: SIGILL on macOS. See issue #71411.

Updates #69124, #60905.
Fixes #71411.

Change-Id: Ie0624e516dfb32fb13563327bcd7f557e5cba940
Reviewed-on: https://go-review.googlesource.com/c/go/+/644695
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>

diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index 88bfd3ce5c3fa5fb8bf8893bd079fbe3f60e330f..64a1880589390d20b9c0fb77ec9b0628fb68f4cd 100644 (file)
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -8,11 +8,6 @@
 #include "funcdata.h"
 #include "textflag.h"
 
-#ifdef GOARM64_LSE
-DATA no_lse_msg<>+0x00(SB)/64, $"This program can only run on ARM64 processors with LSE support.\n"
-GLOBL no_lse_msg<>(SB), RODATA, $64
-#endif
-
 TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
        // SP = stack; R0 = argc; R1 = argv
 
@@ -82,21 +77,6 @@ nocgo:
        BL      runtime·wintls(SB)
 #endif
 
-       // Check that CPU we use for execution supports instructions targeted during compile-time.
-#ifdef GOARM64_LSE
-#ifndef GOOS_openbsd
-       // Read the ID_AA64ISAR0_EL1 register
-       MRS     ID_AA64ISAR0_EL1, R0
-
-       // Extract the LSE field (bits [23:20])
-       LSR     $20, R0, R0
-       AND     $0xf, R0, R0
-
-       // LSE support is indicated by a non-zero value
-       CBZ     R0, no_lse
-#endif
-#endif
-
        MOVW    8(RSP), R0      // copy argc
        MOVW    R0, -8(RSP)
        MOVD    16(RSP), R0             // copy argv
@@ -115,23 +95,6 @@ nocgo:
 
        // start this M
        BL      runtime·mstart(SB)
-        RET
-
-#ifdef GOARM64_LSE
-#ifndef GOOS_openbsd
-no_lse:
-       MOVD    $1, R0 // stderr
-       MOVD    R0, 8(RSP)
-       MOVD    $no_lse_msg<>(SB), R1 // message address
-       MOVD    R1, 16(RSP)
-       MOVD    $64, R2 // message length
-       MOVD    R2, 24(RSP)
-       CALL    runtime·write(SB)
-       CALL    runtime·exit(SB)
-       CALL    runtime·abort(SB)
-       RET
-#endif
-#endif
 
        // Prevent dead-code elimination of debugCallV2 and debugPinnerV1, which are
        // intended to be called by debuggers.