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Subject[PATCH v5] tpm_crb: fix fTPM on AMD Zen+ CPUs
Date
From: Ivan Lazeev <ivan.lazeev@gmail.com>

Bug link: https://bugzilla.kernel.org/show_bug.cgi?id=195657

cmd/rsp buffers are expected to be in the same ACPI region.
For Zen+ CPUs BIOS's might report two different regions, some of
them also report region sizes inconsistent with values from TPM
registers.

Memory configuration on ASRock x470 ITX:

db0a0000-dc59efff : Reserved
dc57e000-dc57efff : MSFT0101:00
dc582000-dc582fff : MSFT0101:00

Work around the issue by storing ACPI regions declared for the
device in struct crb_resources. It contains fixed arrays of
copies of ACPI resourses (iores field) and pointers
to a possibly allocated with devm_ioremap_resource memory region
(iobase field), along with number of entries (num field).
This data was previously held for a single resource
in struct crb_priv (iobase field) and local variable io_res in
crb_map_io function. ACPI resources array is used to find index of
corresponding region for each buffer with crb_containing_res_idx,
make the buffer size consistent with region's length and map it at
most once, storing pointer to the allocated resource in iobase
array at the same index.

Signed-off-by: Ivan Lazeev <ivan.lazeev@gmail.com>
---

Changes in v5:
- prefix new symbols with tpm_crb_
- get rid of dynamic allocation in ACPI walker

drivers/char/tpm/tpm_crb.c | 129 +++++++++++++++++++++++++++----------
1 file changed, 96 insertions(+), 33 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index e59f1f91d7f3..3c2485c71260 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -22,6 +22,7 @@
#include "tpm.h"

#define ACPI_SIG_TPM2 "TPM2"
+#define TPM_CRB_MAX_RESOURCES 3

static const guid_t crb_acpi_start_guid =
GUID_INIT(0x6BBF6CAB, 0x5463, 0x4714,
@@ -91,7 +92,6 @@ 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 +108,12 @@ struct tpm2_crb_smc {
u32 smc_func_id;
};

+struct tpm_crb_resources {
+ struct resource iores[TPM_CRB_MAX_RESOURCES];
+ void __iomem *iobase[TPM_CRB_MAX_RESOURCES];
+ int num;
+};
+
static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
unsigned long timeout)
{
@@ -432,38 +438,75 @@ static const struct tpm_class_ops tpm_crb = {
.req_complete_val = CRB_DRV_STS_COMPLETE,
};

+static bool tpm_crb_resource_contains(struct resource *iores,
+ u64 address)
+{
+ return address >= iores->start && address <= iores->end;
+}
+
+static int tpm_crb_containing_res_idx(struct tpm_crb_resources *resources,
+ u64 address)
+{
+ int res_idx;
+
+ for (res_idx = 0; res_idx < resources->num; ++res_idx) {
+ if (tpm_crb_resource_contains(&resources->iores[res_idx],
+ address))
+ return res_idx;
+ }
+
+ return -1;
+}
+
static int crb_check_resource(struct acpi_resource *ares, void *data)
{
- struct resource *io_res = data;
+ struct tpm_crb_resources *resources = data;
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;
+ if (resources->num < TPM_CRB_MAX_RESOURCES) {
+ resources->iores[resources->num] = *res;
+ resources->iores[resources->num].name = NULL;
+ }
+ resources->num += 1;
}

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 tpm_crb_resources *resources,
+ int res_idx,
+ u64 start, u32 size)
{
struct resource new_res = {
.start = start,
.end = start + size - 1,
.flags = IORESOURCE_MEM,
};
+ struct resource *iores;
+ void __iomem *iobase;

/* Detect a 64 bit address on a 32 bit system */
if (start != new_res.start)
return (void __iomem *) ERR_PTR(-EINVAL);

- if (!resource_contains(io_res, &new_res))
+ if (res_idx < 0)
return devm_ioremap_resource(dev, &new_res);

- return priv->iobase + (new_res.start - io_res->start);
+ iores = &resources->iores[res_idx];
+ iobase = resources->iobase[res_idx];
+ if (!iobase) {
+ iobase = devm_ioremap_resource(dev, iores);
+ if (IS_ERR(iobase))
+ return iobase;
+
+ resources->iobase[res_idx] = iobase;
+ }
+
+ return iobase + (new_res.start - iores->start);
}

/*
@@ -490,9 +533,10 @@ 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;
struct device *dev = &device->dev;
+ struct tpm_crb_resources resources;
+ int res_idx;
u32 pa_high, pa_low;
u64 cmd_pa;
u32 cmd_size;
@@ -501,21 +545,36 @@ 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);
+ memset(&resources, 0, sizeof(resources));
+ ret = acpi_dev_get_resources(device, &acpi_resources,
+ crb_check_resource, &resources);
if (ret < 0)
return ret;
- acpi_dev_free_resource_list(&resources);
+ acpi_dev_free_resource_list(&acpi_resources);

- if (resource_type(&io_res) != IORESOURCE_MEM) {
+ if (resources.num == 0) {
dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
return -EINVAL;
+ } else if (resources.num > TPM_CRB_MAX_RESOURCES) {
+ dev_warn(dev, FW_BUG "TPM2 ACPI table defines too many memory resources\n");
+ resources.num = TPM_CRB_MAX_RESOURCES;
}

- priv->iobase = devm_ioremap_resource(dev, &io_res);
- if (IS_ERR(priv->iobase))
- return PTR_ERR(priv->iobase);
+ res_idx = tpm_crb_containing_res_idx(&resources, buf->control_address);
+
+ if (res_idx >= 0 &&
+ !tpm_crb_resource_contains(&resources.iores[res_idx],
+ buf->control_address +
+ sizeof(struct crb_regs_tail) - 1))
+ res_idx = -1;
+
+ priv->regs_t = crb_map_res(dev, &resources, res_idx,
+ buf->control_address,
+ sizeof(struct crb_regs_tail));
+
+ if (IS_ERR(priv->regs_t))
+ return PTR_ERR(priv->regs_t);

/* 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
@@ -523,9 +582,10 @@ 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 (res_idx >= 0 &&
+ buf->control_address == resources.iores[res_idx].start +
sizeof(*priv->regs_h))
- priv->regs_h = priv->iobase;
+ priv->regs_h = resources.iobase[res_idx];
else
dev_warn(dev, FW_BUG "Bad ACPI memory layout");
}
@@ -534,13 +594,6 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
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;
- }
-
/*
* PTT HW bug w/a: wake up the device to access
* possibly not retained registers.
@@ -552,13 +605,17 @@ 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);
+
+ res_idx = tpm_crb_containing_res_idx(&resources, cmd_pa);
+ if (res_idx >= 0)
+ cmd_size = crb_fixup_cmd_size(dev, &resources.iores[res_idx],
+ 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, &resources, res_idx, cmd_pa, cmd_size);
if (IS_ERR(priv->cmd)) {
ret = PTR_ERR(priv->cmd);
goto out;
@@ -566,11 +623,17 @@ 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);
+
+ res_idx = tpm_crb_containing_res_idx(&resources, rsp_pa);
+
+ if (res_idx >= 0)
+ rsp_size = crb_fixup_cmd_size(dev, &resources.iores[res_idx],
+ 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, &resources, res_idx,
+ rsp_pa, rsp_size);
ret = PTR_ERR_OR_ZERO(priv->rsp);
goto out;
}
--
2.20.1
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