From ebfc726eae3f31bdb5fae1bbd74ef235d71046ca Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Wed, 8 May 2024 09:13:57 +0100
Subject: [PATCH] arm64: barrier: Restore spec_bar() macro
Upcoming errata workarounds will need to use SB from C code. Restore the
spec_bar() macro so that we can use SB.
This is effectively a revert of commit:
4f30ba1cce36d413 ("arm64: barrier: Remove spec_bar() macro")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240508081400.235362-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/include/asm/barrier.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index cf2987464c186..1ca947d5c9396 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -40,6 +40,10 @@
*/
#define dgh() asm volatile("hint #6" : : : "memory")
+#define spec_bar() asm volatile(ALTERNATIVE("dsb nsh\nisb\n", \
+ SB_BARRIER_INSN"nop\n", \
+ ARM64_HAS_SB))
+
#ifdef CONFIG_ARM64_PSEUDO_NMI
#define pmr_sync() \
do { \
--
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