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crypto: xilinx-trng - Remove crypto_rng interface

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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: 8979744aca ("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>
This commit is contained in:
Eric Biggers 2026-05-31 12:17:35 -07:00 committed by Herbert Xu
parent c9fedb3b23
commit 32b4d29280
2 changed files with 4 additions and 82 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/crypto/Kconfig
View File

@ -703,7 +703,6 @@ config CRYPTO_DEV_XILINX_TRNG
tristate "Support for Xilinx True Random Generator"
depends on ZYNQMP_FIRMWARE || COMPILE_TEST
select CRYPTO_DF80090A
select CRYPTO_RNG
select HW_RANDOM
help
Xilinx Versal SoC driver provides kernel-side support for True Random Number

85
drivers/crypto/xilinx/xilinx-trng.c
View File

@ -6,7 +6,6 @@
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/crypto.h>
#include <linux/delay.h>
#include <linux/firmware/xlnx-zynqmp.h>
#include <linux/hw_random.h>
@ -14,13 +13,11 @@
#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 <crypto/aes.h>
#include <crypto/df_sp80090a.h>
#include <crypto/internal/cipher.h>
#include <crypto/internal/rng.h>
/* TRNG Registers Offsets */
#define TRNG_STATUS_OFFSET 0x4U
@ -60,16 +57,9 @@ struct xilinx_rng {
struct device *dev;
unsigned char *scratchpadbuf;
struct aes_enckey *aeskey;
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;
@ -245,47 +235,6 @@ static int xtrng_random_bytes_generate(struct xilinx_rng *rng, u8 *rand_buf_ptr,
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];
@ -293,12 +242,6 @@ static int xtrng_hwrng_trng_read(struct hwrng *hwrng, void *data, size_t max, bo
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)
@ -307,8 +250,6 @@ static int xtrng_hwrng_trng_read(struct hwrng *hwrng, void *data, size_t max, bo
memcpy(data + i, buf, min_t(int, ret, (max - i)));
i += min_t(int, ret, (max - i));
}
mutex_unlock(&rng->lock);
return ret;
}
@ -354,40 +295,24 @@ static int xtrng_probe(struct platform_device *pdev)
sb_size = crypto_drbg_ctr_df_datalen(TRNG_SEED_LEN_BYTES, AES_BLOCK_SIZE);
rng->scratchpadbuf = devm_kzalloc(&pdev->dev, sb_size, GFP_KERNEL);
if (!rng->scratchpadbuf) {
ret = -ENOMEM;
goto end;
}
if (!rng->scratchpadbuf)
return -ENOMEM;
xtrng_trng_reset(rng->rng_base);
ret = xtrng_reseed_internal(rng);
if (ret) {
dev_err(&pdev->dev, "TRNG Seed fail\n");
goto end;
}
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);
goto end;
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);
end:
return ret;
}
static void xtrng_remove(struct platform_device *pdev)
@ -397,13 +322,11 @@ static void xtrng_remove(struct platform_device *pdev)
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[] = {