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Subject[PATCH 1/2] tpm: tpm_crb: enhance command and response buffer size calculation code
Date
The purpose of crb_fixup_cmd_size() function is to work around broken
BIOSes and get the trustable size between the ACPI region and register.
When the TPM has a command buffer and response buffer independently,
the crb_map_io() function calls crb_fixup_cmd_size() twice to calculate
each buffer size. However, the current implementation of it considers
one of two buffers.

To support independent command and response buffers, I changed
crb_check_resource() function for storing ACPI TPB regions to a list.
I also changed crb_fixup_cmd_size() to use the list for calculating each
buffer size.

Signed-off-by: Seunghun Han <kkamagui@gmail.com>
---
drivers/char/tpm/tpm_crb.c | 44 +++++++++++++++++++++++++++++++-------
1 file changed, 36 insertions(+), 8 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index e59f1f91d7f3..14f486c23af2 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -442,6 +442,9 @@ static int crb_check_resource(struct acpi_resource *ares, void *data)
acpi_dev_resource_address_space(ares, &win)) {
*io_res = *res;
io_res->name = NULL;
+
+ /* Add this TPM CRB resource to the list */
+ return 0;
}

return 1;
@@ -471,7 +474,7 @@ static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
* region vs the registers. Trust the ACPI region. Such broken systems
* probably cannot send large TPM commands since the buffer will be truncated.
*/
-static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
+static u64 __crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
u64 start, u64 size)
{
if (io_res->start > start || io_res->end < start)
@@ -487,6 +490,26 @@ static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
return io_res->end - start + 1;
}

+static u64 crb_fixup_cmd_size(struct device *dev, struct list_head *resources,
+ u64 start, u64 size)
+{
+ struct resource_entry *pos;
+ struct resource *cur_res;
+ u64 ret = size;
+
+ /* Check all TPM CRB resources with the start and size values */
+ resource_list_for_each_entry(pos, resources) {
+ cur_res = pos->res;
+
+ ret = __crb_fixup_cmd_size(dev, cur_res, start, size);
+ /* Broken BIOS is detected. Trust the ACPI region. */
+ if (ret < size)
+ break;
+ }
+
+ return ret;
+}
+
static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
struct acpi_table_tpm2 *buf)
{
@@ -506,16 +529,18 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
&io_res);
if (ret < 0)
return ret;
- acpi_dev_free_resource_list(&resources);

if (resource_type(&io_res) != IORESOURCE_MEM) {
dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
- return -EINVAL;
+ ret = -EINVAL;
+ goto out_early;
}

priv->iobase = devm_ioremap_resource(dev, &io_res);
- if (IS_ERR(priv->iobase))
- return PTR_ERR(priv->iobase);
+ if (IS_ERR(priv->iobase)) {
+ ret = PTR_ERR(priv->iobase);
+ goto out_early;
+ }

/* The ACPI IO region starts at the head area and continues to include
* the control area, as one nice sane region except for some older
@@ -532,7 +557,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,

ret = __crb_request_locality(dev, priv, 0);
if (ret)
- return ret;
+ goto out_early;

priv->regs_t = crb_map_res(dev, priv, &io_res, buf->control_address,
sizeof(struct crb_regs_tail));
@@ -552,7 +577,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
pa_high = ioread32(&priv->regs_t->ctrl_cmd_pa_high);
pa_low = ioread32(&priv->regs_t->ctrl_cmd_pa_low);
cmd_pa = ((u64)pa_high << 32) | pa_low;
- cmd_size = crb_fixup_cmd_size(dev, &io_res, cmd_pa,
+ cmd_size = crb_fixup_cmd_size(dev, &resources, cmd_pa,
ioread32(&priv->regs_t->ctrl_cmd_size));

dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
@@ -566,7 +591,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,

memcpy_fromio(&__rsp_pa, &priv->regs_t->ctrl_rsp_pa, 8);
rsp_pa = le64_to_cpu(__rsp_pa);
- rsp_size = crb_fixup_cmd_size(dev, &io_res, rsp_pa,
+ rsp_size = crb_fixup_cmd_size(dev, &resources, rsp_pa,
ioread32(&priv->regs_t->ctrl_rsp_size));

if (cmd_pa != rsp_pa) {
@@ -596,6 +621,9 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,

__crb_relinquish_locality(dev, priv, 0);

+out_early:
+ acpi_dev_free_resource_list(&resources);
+
return ret;
}

--
2.21.0
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