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From 859bd2e0c0052967536f3f902716f204d5a978b1 Mon Sep 17 00:00:00 2001
From: Jonas Gorski <jonas.gorski@gmail.com>
Date: Fri, 8 Sep 2023 22:48:33 +0200
Subject: [PATCH] hwrng: geode: fix accessing registers
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>
---
drivers/char/hw_random/geode-rng.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- 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 hw
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++) {
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