--- /dev/null
+From 32b4d29280ed2a991dc196d5845b892acedc63b8 Mon Sep 17 00:00:00 2001
+From: Eric Biggers <ebiggers@kernel.org>
+Date: Sun, 31 May 2026 12:17:35 -0700
+Subject: crypto: xilinx-trng - Remove crypto_rng interface
+
+From: Eric Biggers <ebiggers@kernel.org>
+
+commit 32b4d29280ed2a991dc196d5845b892acedc63b8 upstream.
+
+Implementing the crypto_rng interface has no purpose, as it isn't used
+in practice. It's being removed from other drivers too. Just remove
+it. This leaves hwrng, which is actually used.
+
+Tagging with 'Cc stable' due to the bugs that this removes:
+
+ - xtrng_trng_generate() sometimes returned success even when it didn't
+ fill in all the bytes.
+
+ - It was possible for xtrng_trng_generate() and
+ xtrng_hwrng_trng_read() to run concurrently and interfere with each
+ other, as the locking code in xtrng_hwrng_trng_read() was broken.
+
+Fixes: 8979744aca80 ("crypto: xilinx - Add TRNG driver for Versal")
+Cc: stable@vger.kernel.org
+Signed-off-by: Eric Biggers <ebiggers@kernel.org>
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/crypto/Kconfig | 1
+ drivers/crypto/xilinx/xilinx-trng.c | 75 ------------------------------------
+ 2 files changed, 1 insertion(+), 75 deletions(-)
+
+--- a/drivers/crypto/Kconfig
++++ b/drivers/crypto/Kconfig
+@@ -728,7 +728,6 @@ config CRYPTO_DEV_TEGRA
+ config CRYPTO_DEV_XILINX_TRNG
+ tristate "Support for Xilinx True Random Generator"
+ depends on ZYNQMP_FIRMWARE || COMPILE_TEST
+- select CRYPTO_RNG
+ select HW_RANDOM
+ help
+ Xilinx Versal SoC driver provides kernel-side support for True Random Number
+--- a/drivers/crypto/xilinx/xilinx-trng.c
++++ b/drivers/crypto/xilinx/xilinx-trng.c
+@@ -6,7 +6,6 @@
+
+ #include <linux/bitfield.h>
+ #include <linux/clk.h>
+-#include <linux/crypto.h>
+ #include <linux/delay.h>
+ #include <linux/errno.h>
+ #include <linux/firmware/xlnx-zynqmp.h>
+@@ -15,12 +14,10 @@
+ #include <linux/iopoll.h>
+ #include <linux/kernel.h>
+ #include <linux/module.h>
+-#include <linux/mutex.h>
+ #include <linux/mod_devicetable.h>
+ #include <linux/platform_device.h>
+ #include <linux/string.h>
+ #include <crypto/internal/cipher.h>
+-#include <crypto/internal/rng.h>
+ #include <crypto/aes.h>
+
+ /* TRNG Registers Offsets */
+@@ -59,16 +56,9 @@
+ struct xilinx_rng {
+ void __iomem *rng_base;
+ struct device *dev;
+- struct mutex lock; /* Protect access to TRNG device */
+ struct hwrng trng;
+ };
+
+-struct xilinx_rng_ctx {
+- struct xilinx_rng *rng;
+-};
+-
+-static struct xilinx_rng *xilinx_rng_dev;
+-
+ static void xtrng_readwrite32(void __iomem *addr, u32 mask, u8 value)
+ {
+ u32 val;
+@@ -235,47 +225,6 @@ static int xtrng_random_bytes_generate(s
+ return nbytes;
+ }
+
+-static int xtrng_trng_generate(struct crypto_rng *tfm, const u8 *src, u32 slen,
+- u8 *dst, u32 dlen)
+-{
+- struct xilinx_rng_ctx *ctx = crypto_rng_ctx(tfm);
+- int ret;
+-
+- mutex_lock(&ctx->rng->lock);
+- ret = xtrng_random_bytes_generate(ctx->rng, dst, dlen, true);
+- mutex_unlock(&ctx->rng->lock);
+-
+- return ret < 0 ? ret : 0;
+-}
+-
+-static int xtrng_trng_seed(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
+-{
+- return 0;
+-}
+-
+-static int xtrng_trng_init(struct crypto_tfm *rtfm)
+-{
+- struct xilinx_rng_ctx *ctx = crypto_tfm_ctx(rtfm);
+-
+- ctx->rng = xilinx_rng_dev;
+-
+- return 0;
+-}
+-
+-static struct rng_alg xtrng_trng_alg = {
+- .generate = xtrng_trng_generate,
+- .seed = xtrng_trng_seed,
+- .seedsize = 0,
+- .base = {
+- .cra_name = "stdrng",
+- .cra_driver_name = "xilinx-trng",
+- .cra_priority = 300,
+- .cra_ctxsize = sizeof(struct xilinx_rng_ctx),
+- .cra_module = THIS_MODULE,
+- .cra_init = xtrng_trng_init,
+- },
+-};
+-
+ static int xtrng_hwrng_trng_read(struct hwrng *hwrng, void *data, size_t max, bool wait)
+ {
+ u8 buf[TRNG_SEC_STRENGTH_BYTES];
+@@ -283,12 +232,6 @@ static int xtrng_hwrng_trng_read(struct
+ int ret = -EINVAL, i = 0;
+
+ rng = container_of(hwrng, struct xilinx_rng, trng);
+- /* Return in case wait not set and lock not available. */
+- if (!mutex_trylock(&rng->lock) && !wait)
+- return 0;
+- else if (!mutex_is_locked(&rng->lock) && wait)
+- mutex_lock(&rng->lock);
+-
+ while (i < max) {
+ ret = xtrng_random_bytes_generate(rng, buf, TRNG_SEC_STRENGTH_BYTES, wait);
+ if (ret < 0)
+@@ -297,8 +240,6 @@ static int xtrng_hwrng_trng_read(struct
+ memcpy(data + i, buf, min_t(int, ret, (max - i)));
+ i += min_t(int, ret, (max - i));
+ }
+- mutex_unlock(&rng->lock);
+-
+ return ret;
+ }
+
+@@ -344,26 +285,14 @@ static int xtrng_probe(struct platform_d
+ return ret;
+ }
+
+- xilinx_rng_dev = rng;
+- mutex_init(&rng->lock);
+- ret = crypto_register_rng(&xtrng_trng_alg);
+- if (ret) {
+- dev_err(&pdev->dev, "Crypto Random device registration failed: %d\n", ret);
+- return ret;
+- }
+ ret = xtrng_hwrng_register(&rng->trng);
+ if (ret) {
+ dev_err(&pdev->dev, "HWRNG device registration failed: %d\n", ret);
+- goto crypto_rng_free;
++ return ret;
+ }
+ platform_set_drvdata(pdev, rng);
+
+ return 0;
+-
+-crypto_rng_free:
+- crypto_unregister_rng(&xtrng_trng_alg);
+-
+- return ret;
+ }
+
+ static void xtrng_remove(struct platform_device *pdev)
+@@ -373,13 +302,11 @@ static void xtrng_remove(struct platform
+
+ rng = platform_get_drvdata(pdev);
+ xtrng_hwrng_unregister(&rng->trng);
+- crypto_unregister_rng(&xtrng_trng_alg);
+ xtrng_write_multiple_registers(rng->rng_base + TRNG_EXT_SEED_OFFSET, zero,
+ TRNG_NUM_INIT_REGS);
+ xtrng_write_multiple_registers(rng->rng_base + TRNG_PER_STRNG_OFFSET, zero,
+ TRNG_NUM_INIT_REGS);
+ xtrng_hold_reset(rng->rng_base);
+- xilinx_rng_dev = NULL;
+ }
+
+ static const struct of_device_id xtrng_of_match[] = {
projects / thirdparty / kernel / stable-queue.git / commitdiff
