hwrng: geode - fix accessing registers

[ Upstream commit 464bd8ec2f06707f3773676a1bd2c64832a3c805 ]

When the membase and pci_dev pointer were moved to a new struct in priv,
the actual membase users were left untouched, and they started reading
out arbitrary memory behind the struct instead of registers. This
unfortunately turned the RNG into a constant number generator, depending
on the content of what was at that offset.

To fix this, update geode_rng_data_{read,present}() to also get the
membase via amd_geode_priv, and properly read from the right addresses
again.

Fixes: 9f6ec8dc574e ("hwrng: geode - Fix PCI device refcount leak")
Reported-by: Timur I. Davletshin <timur.davletshin@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217882
Tested-by: Timur I. Davletshin <timur.davletshin@gmail.com>
Suggested-by: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/char/hw_random/geode-rng.c b/drivers/char/hw_random/geode-rng.c
index 12fbe80..159baf0 100644 (file)
--- a/drivers/char/hw_random/geode-rng.c
+++ b/drivers/char/hw_random/geode-rng.c
@@ -58,7 +58,8 @@ struct amd_geode_priv {
 
 static int geode_rng_data_read(struct hwrng *rng, u32 *data)
 {
-       void __iomem *mem = (void __iomem *)rng->priv;
+       struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
+       void __iomem *mem = priv->membase;
 
        *data = readl(mem + GEODE_RNG_DATA_REG);
 
@@ -67,7 +68,8 @@ static int geode_rng_data_read(struct hwrng *rng, u32 *data)
 
 static int geode_rng_data_present(struct hwrng *rng, int wait)
 {
-       void __iomem *mem = (void __iomem *)rng->priv;
+       struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
+       void __iomem *mem = priv->membase;
        int data, i;
 
        for (i = 0; i < 20; i++) {