linux-kernel - [PATCH] tpm, tpm_crb: fix unaligned read of the command buffer address

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Message-Id: <1442250923-19804-1-git-send-email-jarkko.sakkinen@linux.intel.com>
Date:	Mon, 14 Sep 2015 20:15:23 +0300
From:	Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Cc:	Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
	Peter Huewe <peterhuewe@....de>,
	Marcel Selhorst <tpmdd@...horst.net>,
	Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Subject: [PATCH] tpm, tpm_crb: fix unaligned read of the command buffer address

The command buffer address is necessarily not naturally aligned.
The hardware drops the entire read on some platforms and fills the
address with 1's. This patch fixes the issue by splitting the read
into two 32 bit reads.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
---
 drivers/char/tpm/tpm_crb.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index b4564b6..12bb41c 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -68,7 +68,8 @@ struct crb_control_area {
 	u32 int_enable;
 	u32 int_sts;
 	u32 cmd_size;
-	u64 cmd_pa;
+	u32 cmd_pa_low;
+	u32 cmd_pa_high;
 	u32 rsp_size;
 	u64 rsp_pa;
 } __packed;
@@ -264,7 +265,9 @@ static int crb_acpi_add(struct acpi_device *device)
 	}
 
 	memcpy_fromio(&pa, &priv->cca->cmd_pa, 8);
-	pa = le64_to_cpu(pa);
+
+	pa = ((u64) le32_to_cpu(ioread32(&priv->cca->cmd_pa_high)) << 32) +
+		(u64) le32_to_cpu(ioread32(&priv->cca->cmd_pa_low));
 	priv->cmd = devm_ioremap_nocache(dev, pa,
 					 ioread32(&priv->cca->cmd_size));
 	if (!priv->cmd) {
-- 
2.5.0

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