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-rw-r--r--arch/arm64/include/asm/assembler.h28
1 files changed, 10 insertions, 18 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 039fbd822ec6..e3a15c751b13 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -1,20 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Based on arch/arm/include/asm/assembler.h, arch/arm/mm/proc-macros.S
*
* Copyright (C) 1996-2000 Russell King
* Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASSEMBLY__
#error "Only include this from assembly code"
@@ -107,7 +96,11 @@
* RAS Error Synchronization barrier
*/
.macro esb
+#ifdef CONFIG_ARM64_RAS_EXTN
hint #16
+#else
+ nop
+#endif
.endm
/*
@@ -718,12 +711,11 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
* the output section, any use of such directives is undefined.
*
* The yield itself consists of the following:
- * - Check whether the preempt count is exactly 1, in which case disabling
- * preemption once will make the task preemptible. If this is not the case,
- * yielding is pointless.
- * - Check whether TIF_NEED_RESCHED is set, and if so, disable and re-enable
- * kernel mode NEON (which will trigger a reschedule), and branch to the
- * yield fixup code.
+ * - Check whether the preempt count is exactly 1 and a reschedule is also
+ * needed. If so, calling of preempt_enable() in kernel_neon_end() will
+ * trigger a reschedule. If it is not the case, yielding is pointless.
+ * - Disable and re-enable kernel mode NEON, and branch to the yield fixup
+ * code.
*
* This macro sequence may clobber all CPU state that is not guaranteed by the
* AAPCS to be preserved across an ordinary function call.