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 <[email protected]>
Reviewed-by: Keith Randall <[email protected]>
Reviewed-by: Keith Randall <[email protected]>
Reviewed-by: Mauri de Souza Meneguzzo <[email protected]>

Author: cherrymui

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.