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From:   Mikko Perttunen <cyndis@kapsi.fi>
To:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>
Cc:     Timo Alho <talho@nvidia.com>,
        Mikko Perttunen <mperttunen@nvidia.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mian Yousaf Kaukab <ykaukab@suse.de>,
        linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] firmware: tegra: bpmp: do only aligned access to IPC memory area
Date:   Wed, 22 Jun 2022 16:22:59 +0300
Message-Id: <20220622132300.1746201-1-cyndis@kapsi.fi>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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From: Timo Alho <talho@nvidia.com>

Use memcpy_toio and memcpy_fromio variants of memcpy to guarantee
no unaligned access to IPC memory area. This is to allow the IPC
memory to be mapped as Device memory to further suppress speculative
reads from happening within the 64kB memory area above the IPC memory
when 64kB memory pages are used.

Signed-off-by: Timo Alho <talho@nvidia.com>
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---
 drivers/firmware/tegra/bpmp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/tegra/bpmp.c b/drivers/firmware/tegra/bpmp.c
index 5654c5e9862b..037db21de510 100644
--- a/drivers/firmware/tegra/bpmp.c
+++ b/drivers/firmware/tegra/bpmp.c
@@ -201,7 +201,7 @@ static ssize_t __tegra_bpmp_channel_read(struct tegra_bpmp_channel *channel,
 	int err;
 
 	if (data && size > 0)
-		memcpy(data, channel->ib->data, size);
+		memcpy_fromio(data, channel->ib->data, size);
 
 	err = tegra_bpmp_ack_response(channel);
 	if (err < 0)
@@ -245,7 +245,7 @@ static ssize_t __tegra_bpmp_channel_write(struct tegra_bpmp_channel *channel,
 	channel->ob->flags = flags;
 
 	if (data && size > 0)
-		memcpy(channel->ob->data, data, size);
+		memcpy_toio(channel->ob->data, data, size);
 
 	return tegra_bpmp_post_request(channel);
 }
@@ -420,7 +420,7 @@ void tegra_bpmp_mrq_return(struct tegra_bpmp_channel *channel, int code,
 	channel->ob->code = code;
 
 	if (data && size > 0)
-		memcpy(channel->ob->data, data, size);
+		memcpy_toio(channel->ob->data, data, size);
 
 	err = tegra_bpmp_post_response(channel);
 	if (WARN_ON(err < 0))
-- 
2.36.1