From 104a0c02e8b1936c049e18a6d4e4ab040fb61213 Mon Sep 17 00:00:00 2001
From: Andrew Pinski <apinski@cavium.com>
Date: Wed, 24 Feb 2016 17:44:57 -0800
Subject: arm64: Add workaround for Cavium erratum 27456

On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
instructions may cause the icache to become corrupted if it contains
data for a non-current ASID.

This patch implements the workaround (which invalidates the local
icache when switching the mm) by using code patching.

Signed-off-by: Andrew Pinski <apinski@cavium.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/mm/proc.S | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'arch/arm64/mm')

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 0c19534a901e..543f5198005a 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -25,6 +25,8 @@
 #include <asm/hwcap.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
+#include <asm/cpufeature.h>
+#include <asm/alternative.h>
 
 #include "proc-macros.S"
 
@@ -137,7 +139,17 @@ ENTRY(cpu_do_switch_mm)
 	bfi	x0, x1, #48, #16		// set the ASID
 	msr	ttbr0_el1, x0			// set TTBR0
 	isb
+alternative_if_not ARM64_WORKAROUND_CAVIUM_27456
 	ret
+	nop
+	nop
+	nop
+alternative_else
+	ic	iallu
+	dsb	nsh
+	isb
+	ret
+alternative_endif
 ENDPROC(cpu_do_switch_mm)
 
 	.pushsection ".idmap.text", "ax"
-- 
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