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Subject[PATCH 4.10 075/111] hwrng: amd - Revert managed API changes
Date
4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Prarit Bhargava <prarit@redhat.com>

commit 69db7009318758769d625b023402161c750f7876 upstream.

After commit 31b2a73c9c5f ("hwrng: amd - Migrate to managed API"), the
amd-rng driver uses devres with pci_dev->dev to keep track of resources,
but does not actually register a PCI driver. This results in the
following issues:

1. The message

WARNING: CPU: 2 PID: 621 at drivers/base/dd.c:349 driver_probe_device+0x38c

is output when the i2c_amd756 driver loads and attempts to register a PCI
driver. The PCI & device subsystems assume that no resources have been
registered for the device, and the WARN_ON() triggers since amd-rng has
already do so.

2. The driver leaks memory because the driver does not attach to a
device. The driver only uses the PCI device as a reference. devm_*()
functions will release resources on driver detach, which the amd-rng
driver will never do. As a result,

3. The driver cannot be reloaded because there is always a use of the
ioport and region after the first load of the driver.

Revert the changes made by 31b2a73c9c5f ("hwrng: amd - Migrate to managed
API").

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Fixes: 31b2a73c9c5f ("hwrng: amd - Migrate to managed API").
Cc: Matt Mackall <mpm@selenic.com>
Cc: Corentin LABBE <clabbe.montjoie@gmail.com>
Cc: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-geode@lists.infradead.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/char/hw_random/amd-rng.c | 42 +++++++++++++++++++++++++++++++--------
1 file changed, 34 insertions(+), 8 deletions(-)

--- a/drivers/char/hw_random/amd-rng.c
+++ b/drivers/char/hw_random/amd-rng.c
@@ -55,6 +55,7 @@ MODULE_DEVICE_TABLE(pci, pci_tbl);
struct amd768_priv {
void __iomem *iobase;
struct pci_dev *pcidev;
+ u32 pmbase;
};

static int amd_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -148,33 +149,58 @@ found:
if (pmbase == 0)
return -EIO;

- priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;

- if (!devm_request_region(&pdev->dev, pmbase + PMBASE_OFFSET,
- PMBASE_SIZE, DRV_NAME)) {
+ if (!request_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE, DRV_NAME)) {
dev_err(&pdev->dev, DRV_NAME " region 0x%x already in use!\n",
pmbase + 0xF0);
- return -EBUSY;
+ err = -EBUSY;
+ goto out;
}

- priv->iobase = devm_ioport_map(&pdev->dev, pmbase + PMBASE_OFFSET,
- PMBASE_SIZE);
+ priv->iobase = ioport_map(pmbase + PMBASE_OFFSET, PMBASE_SIZE);
if (!priv->iobase) {
pr_err(DRV_NAME "Cannot map ioport\n");
- return -ENOMEM;
+ err = -EINVAL;
+ goto err_iomap;
}

amd_rng.priv = (unsigned long)priv;
+ priv->pmbase = pmbase;
priv->pcidev = pdev;

pr_info(DRV_NAME " detected\n");
- return devm_hwrng_register(&pdev->dev, &amd_rng);
+ err = hwrng_register(&amd_rng);
+ if (err) {
+ pr_err(DRV_NAME " registering failed (%d)\n", err);
+ goto err_hwrng;
+ }
+ return 0;
+
+err_hwrng:
+ ioport_unmap(priv->iobase);
+err_iomap:
+ release_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+out:
+ kfree(priv);
+ return err;
}

static void __exit mod_exit(void)
{
+ struct amd768_priv *priv;
+
+ priv = (struct amd768_priv *)amd_rng.priv;
+
+ hwrng_unregister(&amd_rng);
+
+ ioport_unmap(priv->iobase);
+
+ release_region(priv->pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+
+ kfree(priv);
}

module_init(mod_init);

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