From: Vanya Lazeev <ivan.laz...@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.

Signed-off-by: Vanya Lazeev <ivan.laz...@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..73e4b9105 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;
+
+       list_for_each(position, 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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