commit 93354d866ac44d0f9d65b2e4adb5cc9a1c1912c9 (patch)
parent a64dcfb451e254 Linux 6.14-rc2
tree 20e41d60c45658bfad117fd1e110cda1bf85e696
author Markus Theil <theil.markus@gmail.com> 2025-02-10 14:35:56 +0100
committer Jason A. Donenfeld <Jason@zx2c4.com> 2025-02-10 14:46:17 +0100
prandom: remove next_pseudo_random32
next_pseudo_random32 implements a LCG with known bad statistical
properties and is only used in two pieces of testing code. Remove and
convert the remaining two users to the single PRNG interface in
prandom.h
This removes another option of using an insecure PRNG.
Signed-off-by: Markus Theil <theil.markus@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
drivers/gpu/drm/i915/selftests/i915_gem.c | 7 ++++---
drivers/media/test-drivers/vivid/vivid-vid-cap.c | 4 +++-
include/linux/prandom.h | 6 ------
3 files changed, 7 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem.c b/drivers/gpu/drm/i915/selftests/i915_gem.c
index 0727492576be28..14efa6edd9e63c 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem.c
@@ -45,13 +45,15 @@ static void trash_stolen(struct drm_i915_private *i915)
struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
const u64 slot = ggtt->error_capture.start;
const resource_size_t size = resource_size(&i915->dsm.stolen);
+ struct rnd_state prng;
unsigned long page;
- u32 prng = 0x12345678;
/* XXX: fsck. needs some more thought... */
if (!i915_ggtt_has_aperture(ggtt))
return;
+ prandom_seed_state(&prng, 0x12345678);
+
for (page = 0; page < size; page += PAGE_SIZE) {
const dma_addr_t dma = i915->dsm.stolen.start + page;
u32 __iomem *s;
@@ -64,8 +66,7 @@ static void trash_stolen(struct drm_i915_private *i915)
s = io_mapping_map_atomic_wc(&ggtt->iomap, slot);
for (x = 0; x < PAGE_SIZE / sizeof(u32); x++) {
- prng = next_pseudo_random32(prng);
- iowrite32(prng, &s[x]);
+ iowrite32(prandom_u32_state(&prng), &s[x]);
}
io_mapping_unmap_atomic(s);
}
diff --git a/drivers/media/test-drivers/vivid/vivid-vid-cap.c b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
index b166d90177c641..166372d5f927ae 100644
--- a/drivers/media/test-drivers/vivid/vivid-vid-cap.c
+++ b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
@@ -300,8 +300,10 @@ void vivid_update_quality(struct vivid_dev *dev)
*/
freq_modulus = (dev->tv_freq - 676 /* (43.25-1) * 16 */) % (6 * 16);
if (freq_modulus > 2 * 16) {
+ struct rnd_state prng;
+ prandom_seed_state(&prng, dev->tv_freq ^ 0x55);
tpg_s_quality(&dev->tpg, TPG_QUAL_NOISE,
- next_pseudo_random32(dev->tv_freq ^ 0x55) & 0x3f);
+ prandom_u32_state(&prng) & 0x3f);
return;
}
if (freq_modulus < 12 /*0.75 * 16*/ || freq_modulus > 20 /*1.25 * 16*/)
diff --git a/include/linux/prandom.h b/include/linux/prandom.h
index f2ed5b72b3d6f2..ff7dcc3fa1057a 100644
--- a/include/linux/prandom.h
+++ b/include/linux/prandom.h
@@ -47,10 +47,4 @@ static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
state->s4 = __seed(i, 128U);
}
-/* Pseudo random number generator from numerical recipes. */
-static inline u32 next_pseudo_random32(u32 seed)
-{
- return seed * 1664525 + 1013904223;
-}
-
#endif
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git clone https://yhbt.net/lore/pub/scm/linux/kernel/git/crng/random.git