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From: AngeloGioacchino Del Regno <kholk11@gmail.com>
To: AngeloGioacchino Del Regno <kholk11@gmail.com>,
	Jens Axboe <axboe@kernel.dk>, Will Deacon <will.deacon@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>
Cc: AngeloGioacchino Del Regno <kholk11@gmail.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
Subject: [PATCH] arm64/io: Don't use WZR in writel
Date: Sat, 09 Feb 2019 19:34:53 +0100	[thread overview]
Message-ID: <68b71c15f32341468a868f6418e4fcb375bc49ba.camel@gmail.com> (raw)

From 33fb6d036de273bb71ac1c67d7a91b7a5148e659 Mon Sep 17 00:00:00 2001
From: "Angelo G. Del Regno" <kholk11@gmail.com>
Date: Sat, 9 Feb 2019 18:56:46 +0100
Subject: [PATCH] arm64/io: Don't use WZR in writel

This is a partial revert of commit ee5e41b5f21a
("arm64/io: Allow I/O writes to use {W,X}ZR")

When we try to use the zero register directly on some SoCs,
their security will make them freeze due to a firmware bug.
This behavior is seen with the arm-smmu driver freezing on
TLBI and TLBSYNC on MSM8996, MSM8998, SDM630, SDM660.

Allocating a temporary register to store the zero for the
write actually solves the issue on these SoCs.

Signed-off-by: Angelo G. Del Regno <kholk11@gmail.com>
---
 arch/arm64/include/asm/io.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index ee723835c1f4..a0a6d1aeb670 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -49,7 +49,7 @@ static inline void __raw_writew(u16 val, volatile void __iomem *addr)
 #define __raw_writel __raw_writel
 static inline void __raw_writel(u32 val, volatile void __iomem *addr)
 {
-	asm volatile("str %w0, [%1]" : : "rZ" (val), "r" (addr));
+	asm volatile("str %w0, [%1]" : : "r" (val), "r" (addr));
 }
 
 #define __raw_writeq __raw_writeq
-- 
2.19.1



             reply	other threads:[~2019-02-09 18:34 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-09 18:34 AngeloGioacchino Del Regno [this message]
2019-02-11 10:57 ` [PATCH] arm64/io: Don't use WZR in writel Will Deacon
2019-02-11 11:52   ` Marc Zyngier
2019-02-11 14:29     ` AngeloGioacchino Del Regno
2019-02-11 14:59       ` Marc Zyngier
2019-02-11 16:15         ` AngeloGioacchino Del Regno
2019-02-11 16:37         ` Robin Murphy
2019-02-23 18:12         ` Bjorn Andersson
2019-02-23 18:37           ` Marc Zyngier
2019-02-24  3:53             ` Bjorn Andersson
2019-03-12 12:36               ` Marc Gonzalez
2019-03-18 16:04                 ` Robin Murphy
2019-03-18 17:00                   ` Russell King - ARM Linux admin
2019-03-18 17:11                     ` Ard Biesheuvel
2019-03-18 17:19                     ` Robin Murphy
2019-03-18 17:24                       ` Robin Murphy
2019-03-19 11:45                         ` Robin Murphy
2019-03-18 17:30                       ` Marc Gonzalez
2019-03-18 17:59                         ` Robin Murphy
  -- strict thread matches above, loose matches on Subject: below --
2019-02-09 18:30 AngeloGioacchino Del Regno

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