target/linux/x86/patches-5.15/120-hwrng-geode-fix-accessing-registers.patch

   1 From 859bd2e0c0052967536f3f902716f204d5a978b1 Mon Sep 17 00:00:00 2001
   2 From: Jonas Gorski <jonas.gorski@gmail.com>
   3 Date: Fri, 8 Sep 2023 22:48:33 +0200
   4 Subject: [PATCH] hwrng: geode: fix accessing registers
   5
   6 When the membase and pci_dev pointer were moved to a new struct in priv,
   7 the actual membase users were left untouched, and they started reading
   8 out arbitrary memory behind the struct instead of registers. This
   9 unfortunately turned the RNG into a constant number generator, depending
  10 on the content of what was at that offset.
  11
  12 To fix this, update geode_rng_data_{read,present}() to also get the
  13 membase via amd_geode_priv, and properly read from the right addresses
  14 again.
  15
  16 Fixes: 9f6ec8dc574e ("hwrng: geode - Fix PCI device refcount leak")
  17 Reported-by: Timur I. Davletshin <timur.davletshin@gmail.com>
  18 Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217882
  19 Tested-by: Timur I. Davletshin <timur.davletshin@gmail.com>
  20 Suggested-by: Jo-Philipp Wich <jo@mein.io>
  21 Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
  22 ---
  23  drivers/char/hw_random/geode-rng.c | 6 ++++--
  24  1 file changed, 4 insertions(+), 2 deletions(-)
  25
  26 --- a/drivers/char/hw_random/geode-rng.c
  27 +++ b/drivers/char/hw_random/geode-rng.c
  28 @@ -58,7 +58,8 @@ struct amd_geode_priv {
  29
  30  static int geode_rng_data_read(struct hwrng *rng, u32 *data)
  31  {
  32 -       void __iomem *mem = (void __iomem *)rng->priv;
  33 +       struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
  34 +       void __iomem *mem = priv->membase;
  35
  36         *data = readl(mem + GEODE_RNG_DATA_REG);
  37
  38 @@ -67,7 +68,8 @@ static int geode_rng_data_read(struct hw
  39
  40  static int geode_rng_data_present(struct hwrng *rng, int wait)
  41  {
  42 -       void __iomem *mem = (void __iomem *)rng->priv;
  43 +       struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
  44 +       void __iomem *mem = priv->membase;
  45         int data, i;
  46
  47         for (i = 0; i < 20; i++) {