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Subject[PATCH v2] Fix fTPM on AMD Zen+ CPUs
Date
From: Vanya Lazeev <ivan.lazeev@gmail.com>

The patch is an attempt to make fTPM on AMD Zen CPUs work.
Bug link: https://bugzilla.kernel.org/show_bug.cgi?id=195657

The problem seems to be that tpm_crb driver doesn't expect tpm command
and response memory regions to belong to different ACPI resources.

Tested on Asrock ITX motherboard with Ryzen 2600X CPU.
However, I don't have any other hardware to test the changes on and no
expertise to be sure that other TPMs won't break as a result.
Hopefully, the patch will be useful.

Changes from v1:
- use list_for_each_safe

Signed-off-by: Vanya Lazeev <ivan.lazeev@gmail.com>
---
drivers/char/tpm/tpm_crb.c | 146 ++++++++++++++++++++++++++++---------
1 file changed, 110 insertions(+), 36 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index e59f1f91d..b0e797464 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -91,7 +91,6 @@ enum crb_status {
struct crb_priv {
u32 sm;
const char *hid;
- void __iomem *iobase;
struct crb_regs_head __iomem *regs_h;
struct crb_regs_tail __iomem *regs_t;
u8 __iomem *cmd;
@@ -108,6 +107,13 @@ struct tpm2_crb_smc {
u32 smc_func_id;
};

+struct crb_resource {
+ struct resource io_res;
+ void __iomem *iobase;
+
+ struct list_head link;
+};
+
static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
unsigned long timeout)
{
@@ -432,23 +438,69 @@ static const struct tpm_class_ops tpm_crb = {
.req_complete_val = CRB_DRV_STS_COMPLETE,
};

+static void crb_free_resource_list(struct list_head *resources)
+{
+ struct list_head *position, *tmp;
+
+ list_for_each_safe(position, tmp, resources)
+ kfree(list_entry(position, struct crb_resource, link));
+}
+
+/**
+ * Checks if resource @io_res contains range with the specified @start and @size
+ * completely or, when @strict is false, at least it's beginning.
+ * Non-strict match is needed to work around broken BIOSes that return
+ * inconsistent values from ACPI regions vs registers.
+ */
+static inline bool crb_resource_contains(const struct resource *io_res,
+ u64 start, u32 size, bool strict)
+{
+ return start >= io_res->start &&
+ (start + size - 1 <= io_res->end ||
+ (!strict && start <= io_res->end));
+}
+
+static struct crb_resource *crb_containing_resource(
+ const struct list_head *resources,
+ u64 start, u32 size, bool strict)
+{
+ struct list_head *pos;
+
+ list_for_each(pos, resources) {
+ struct crb_resource *cres;
+
+ cres = list_entry(pos, struct crb_resource, link);
+ if (crb_resource_contains(&cres->io_res, start, size, strict))
+ return cres;
+ }
+
+ return NULL;
+}
+
static int crb_check_resource(struct acpi_resource *ares, void *data)
{
- struct resource *io_res = data;
+ struct list_head *list = data;
+ struct crb_resource *cres;
struct resource_win win;
struct resource *res = &(win.res);

if (acpi_dev_resource_memory(ares, res) ||
acpi_dev_resource_address_space(ares, &win)) {
- *io_res = *res;
- io_res->name = NULL;
+ cres = kzalloc(sizeof(*cres), GFP_KERNEL);
+ if (!cres)
+ return -ENOMEM;
+
+ cres->io_res = *res;
+ cres->io_res.name = NULL;
+
+ list_add_tail(&cres->link, list);
}

return 1;
}

-static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
- struct resource *io_res, u64 start, u32 size)
+static void __iomem *crb_map_res(struct device *dev, struct crb_resource *cres,
+ u64 start, u32 size)
{
struct resource new_res = {
.start = start,
@@ -460,10 +512,16 @@ static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
if (start != new_res.start)
return (void __iomem *) ERR_PTR(-EINVAL);

- if (!resource_contains(io_res, &new_res))
+ if (!cres)
return devm_ioremap_resource(dev, &new_res);

- return priv->iobase + (new_res.start - io_res->start);
+ if (!cres->iobase) {
+ cres->iobase = devm_ioremap_resource(dev, &cres->io_res);
+ if (IS_ERR(cres->iobase))
+ return cres->iobase;
+ }
+
+ return cres->iobase + (new_res.start - cres->io_res.start);
}

/*
@@ -490,9 +548,9 @@ static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
struct acpi_table_tpm2 *buf)
{
- struct list_head resources;
- struct resource io_res;
+ struct list_head acpi_resources, crb_resources;
struct device *dev = &device->dev;
+ struct crb_resource *cres;
u32 pa_high, pa_low;
u64 cmd_pa;
u32 cmd_size;
@@ -501,21 +559,30 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
u32 rsp_size;
int ret;

- INIT_LIST_HEAD(&resources);
- ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
- &io_res);
+ INIT_LIST_HEAD(&acpi_resources);
+ INIT_LIST_HEAD(&crb_resources);
+ ret = acpi_dev_get_resources(device, &acpi_resources,
+ crb_check_resource, &crb_resources);
if (ret < 0)
- return ret;
- acpi_dev_free_resource_list(&resources);
+ goto out_free_crb_resources;
+
+ acpi_dev_free_resource_list(&acpi_resources);

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

- priv->iobase = devm_ioremap_resource(dev, &io_res);
- if (IS_ERR(priv->iobase))
- return PTR_ERR(priv->iobase);
+ cres = crb_containing_resource(&crb_resources, buf->control_address,
+ sizeof(struct crb_regs_tail), true);
+
+ priv->regs_t = crb_map_res(dev, cres, buf->control_address,
+ sizeof(struct crb_regs_tail));
+ if (IS_ERR(priv->regs_t)) {
+ ret = PTR_ERR(priv->regs_t);
+ goto out_free_crb_resources;
+ }

/* 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
@@ -523,23 +590,17 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
*/
if ((priv->sm == ACPI_TPM2_COMMAND_BUFFER) ||
(priv->sm == ACPI_TPM2_MEMORY_MAPPED)) {
- if (buf->control_address == io_res.start +
+ if (cres &&
+ buf->control_address == cres->io_res.start +
sizeof(*priv->regs_h))
- priv->regs_h = priv->iobase;
+ priv->regs_h = cres->iobase;
else
dev_warn(dev, FW_BUG "Bad ACPI memory layout");
}

ret = __crb_request_locality(dev, priv, 0);
if (ret)
- return ret;
-
- priv->regs_t = crb_map_res(dev, priv, &io_res, buf->control_address,
- sizeof(struct crb_regs_tail));
- if (IS_ERR(priv->regs_t)) {
- ret = PTR_ERR(priv->regs_t);
- goto out_relinquish_locality;
- }
+ goto out_free_crb_resources;

/*
* PTT HW bug w/a: wake up the device to access
@@ -552,13 +613,17 @@ 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,
- ioread32(&priv->regs_t->ctrl_cmd_size));
+ cmd_size = ioread32(&priv->regs_t->ctrl_cmd_size);
+
+ cres = crb_containing_resource(&crb_resources, cmd_pa, cmd_size, false);
+ if (cres)
+ cmd_size = crb_fixup_cmd_size(dev, &cres->io_res,
+ cmd_pa, cmd_size);

dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
pa_high, pa_low, cmd_size);

- priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
+ priv->cmd = crb_map_res(dev, cres, cmd_pa, cmd_size);
if (IS_ERR(priv->cmd)) {
ret = PTR_ERR(priv->cmd);
goto out;
@@ -566,11 +631,16 @@ 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,
- ioread32(&priv->regs_t->ctrl_rsp_size));
+ rsp_size = ioread32(&priv->regs_t->ctrl_rsp_size);
+
+ cres = crb_containing_resource(&crb_resources, rsp_pa,
+ rsp_size, false);
+ if (cres)
+ rsp_size = crb_fixup_cmd_size(dev, &cres->io_res,
+ rsp_pa, rsp_size);

if (cmd_pa != rsp_pa) {
- priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
+ priv->rsp = crb_map_res(dev, cres, rsp_pa, rsp_size);
ret = PTR_ERR_OR_ZERO(priv->rsp);
goto out;
}
@@ -596,6 +666,10 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,

__crb_relinquish_locality(dev, priv, 0);

+out_free_crb_resources:
+
+ crb_free_resource_list(&crb_resources);
+
return ret;
}

--
2.20.1
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