[linux-yocto] [PATCH 1/8] tpm, tpm_crb: fix unaligned read of the command buffer address

jonathan.yong at intel.com jonathan.yong at intel.com
Mon Jun 13 21:14:03 PDT 2016

From: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>

The command buffer address must be read with exactly two 32-bit reads.
Otherwise, on some HW platforms, it seems that HW will abort the read
operation, which causes CPU to fill the read bytes with 1's. Therefore,
we cannot rely on memcpy_fromio() but must call ioread32() two times

Also, this matches the PC Client Platform TPM Profile specification,
which defines command buffer address with two 32-bit fields.

Cc: stable at kernel.org
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
Reviewed-by: Peter Huewe <peterhuewe at gmx.de>
Signed-off-by: Peter Huewe <peterhuewe at gmx.de>
(cherry picked from commit 149789ce9d472e6b4fd99336e779ab843754a96c)
Signed-off-by: Yong, Jonathan <jonathan.yong at intel.com>
 drivers/char/tpm/tpm_crb.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index b02d4b1..61e6429 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;
@@ -263,8 +264,8 @@ static int crb_acpi_add(struct acpi_device *device)
 		return -ENOMEM;
-	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,
 	if (!priv->cmd) {

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