forked from Minki/linux
crypto: caam - simplify RNG implementation
Rework CAAM RNG implementation as follows: - Make use of the fact that HWRNG supports partial reads and will handle such cases gracefully by removing recursion in caam_read() - Convert blocking caam_read() codepath to do a single blocking job read directly into requested buffer, bypassing any intermediary buffers - Convert async caam_read() codepath into a simple single reader/single writer FIFO use-case, thus simplifying concurrency handling and delegating buffer read/write position management to KFIFO subsystem. - Leverage the same low level RNG data extraction code for both async and blocking caam_read() scenarios, get rid of the shared job descriptor and make non-shared one as a simple as possible (just HEADER + ALGORITHM OPERATION + FIFO STORE) - Split private context from DMA related memory, so that the former could be allocated without GFP_DMA. NOTE: On its face value this commit decreased throughput numbers reported by dd if=/dev/hwrng of=/dev/null bs=1 count=100K [iflag=nonblock] by about 15%, however commits that enable prediction resistance and limit JR total size impact the performance so much and move the bottleneck such as to make this regression irrelevant. NOTE: On the bright side, this commit reduces RNG in kernel DMA buffer memory usage from 2 x RN_BUF_SIZE (~256K) to 32K. Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> Reviewed-by: Horia Geantă <horia.geanta@nxp.com> Cc: Chris Healy <cphealy@gmail.com> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Horia Geantă <horia.geanta@nxp.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Iuliana Prodan <iuliana.prodan@nxp.com> Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-imx@nxp.com Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Andrey Smirnov
Herbert Xu
parent
1517f63cd8
commit
2c5e88dc90
@ -7,35 +7,12 @@
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*
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* Based on caamalg.c crypto API driver.
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*
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* relationship between job descriptors to shared descriptors:
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*
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* --------------- --------------
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* | JobDesc #0 |-------------------->| ShareDesc |
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* | *(buffer 0) | |------------->| (generate) |
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* --------------- | | (move) |
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* | | (store) |
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* --------------- | --------------
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* | JobDesc #1 |------|
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* | *(buffer 1) |
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* ---------------
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*
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* A job desc looks like this:
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*
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* ---------------------
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* | Header |
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* | ShareDesc Pointer |
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* | SEQ_OUT_PTR |
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* | (output buffer) |
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* ---------------------
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*
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* The SharedDesc never changes, and each job descriptor points to one of two
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* buffers for each device, from which the data will be copied into the
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* requested destination
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*/
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#include <linux/hw_random.h>
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#include <linux/completion.h>
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#include <linux/atomic.h>
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#include <linux/kfifo.h>
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#include "compat.h"
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@ -45,38 +22,26 @@
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#include "jr.h"
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#include "error.h"
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#define CAAM_RNG_MAX_FIFO_STORE_SIZE U16_MAX
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#define CAAM_RNG_FIFO_LEN SZ_32K /* Must be a multiple of 2 */
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/*
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* Maximum buffer size: maximum number of random, cache-aligned bytes that
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* will be generated and moved to seq out ptr (extlen not allowed)
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* Length of used descriptors, see caam_init_desc()
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*/
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#define RN_BUF_SIZE (0xffff / L1_CACHE_BYTES * \
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L1_CACHE_BYTES)
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/* length of descriptors */
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#define DESC_JOB_O_LEN (CAAM_CMD_SZ * 2 + CAAM_PTR_SZ_MAX * 2)
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#define DESC_RNG_LEN (3 * CAAM_CMD_SZ)
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/* Buffer, its dma address and lock */
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struct buf_data {
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u8 buf[RN_BUF_SIZE] ____cacheline_aligned;
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dma_addr_t addr;
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struct completion filled;
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u32 hw_desc[DESC_JOB_O_LEN];
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#define BUF_NOT_EMPTY 0
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#define BUF_EMPTY 1
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#define BUF_PENDING 2 /* Empty, but with job pending --don't submit another */
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atomic_t empty;
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};
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#define CAAM_RNG_DESC_LEN (CAAM_CMD_SZ + \
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CAAM_CMD_SZ + \
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CAAM_CMD_SZ + CAAM_PTR_SZ_MAX)
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/* rng per-device context */
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struct caam_rng_ctx {
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struct hwrng rng;
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struct device *jrdev;
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dma_addr_t sh_desc_dma;
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u32 sh_desc[DESC_RNG_LEN];
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unsigned int cur_buf_idx;
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int current_buf;
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struct buf_data bufs[2];
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struct device *ctrldev;
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void *desc_async;
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void *desc_sync;
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struct work_struct worker;
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struct kfifo fifo;
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};
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static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)
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@ -84,194 +49,116 @@ static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)
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return (struct caam_rng_ctx *)r->priv;
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}
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static inline void rng_unmap_buf(struct device *jrdev, struct buf_data *bd)
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static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err,
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void *context)
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{
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if (bd->addr)
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dma_unmap_single(jrdev, bd->addr, RN_BUF_SIZE,
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DMA_FROM_DEVICE);
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}
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static inline void rng_unmap_ctx(struct caam_rng_ctx *ctx)
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{
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struct device *jrdev = ctx->jrdev;
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if (ctx->sh_desc_dma)
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dma_unmap_single(jrdev, ctx->sh_desc_dma,
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desc_bytes(ctx->sh_desc), DMA_TO_DEVICE);
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rng_unmap_buf(jrdev, &ctx->bufs[0]);
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rng_unmap_buf(jrdev, &ctx->bufs[1]);
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}
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static void rng_done(struct device *jrdev, u32 *desc, u32 err, void *context)
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{
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struct buf_data *bd;
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bd = container_of(desc, struct buf_data, hw_desc[0]);
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struct completion *done = context;
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if (err)
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caam_jr_strstatus(jrdev, err);
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atomic_set(&bd->empty, BUF_NOT_EMPTY);
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complete(&bd->filled);
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/* Buffer refilled, invalidate cache */
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dma_sync_single_for_cpu(jrdev, bd->addr, RN_BUF_SIZE, DMA_FROM_DEVICE);
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print_hex_dump_debug("rng refreshed buf@: ", DUMP_PREFIX_ADDRESS, 16, 4,
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bd->buf, RN_BUF_SIZE, 1);
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complete(done);
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}
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static inline int submit_job(struct caam_rng_ctx *ctx, int to_current)
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static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma, int len)
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{
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struct buf_data *bd = &ctx->bufs[!(to_current ^ ctx->current_buf)];
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struct device *jrdev = ctx->jrdev;
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u32 *desc = bd->hw_desc;
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init_job_desc(desc, 0); /* + 1 cmd_sz */
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/* Generate random bytes: + 1 cmd_sz */
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append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG);
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/* Store bytes: + 1 cmd_sz + caam_ptr_sz */
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append_fifo_store(desc, dst_dma, len, FIFOST_TYPE_RNGSTORE);
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print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS,
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16, 4, desc, desc_bytes(desc), 1);
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return desc;
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}
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static int caam_rng_read_one(struct device *jrdev,
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void *dst, int len,
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void *desc,
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struct completion *done)
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{
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dma_addr_t dst_dma;
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int err;
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dev_dbg(jrdev, "submitting job %d\n", !(to_current ^ ctx->current_buf));
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init_completion(&bd->filled);
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err = caam_jr_enqueue(jrdev, desc, rng_done, ctx);
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if (err != -EINPROGRESS)
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complete(&bd->filled); /* don't wait on failed job*/
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else
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atomic_inc(&bd->empty); /* note if pending */
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len = min_t(int, len, CAAM_RNG_MAX_FIFO_STORE_SIZE);
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return err;
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dst_dma = dma_map_single(jrdev, dst, len, DMA_FROM_DEVICE);
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if (dma_mapping_error(jrdev, dst_dma)) {
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dev_err(jrdev, "unable to map destination memory\n");
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return -ENOMEM;
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}
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init_completion(done);
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err = caam_jr_enqueue(jrdev,
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caam_init_desc(desc, dst_dma, len),
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caam_rng_done, done);
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if (err == -EINPROGRESS) {
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wait_for_completion(done);
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err = 0;
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}
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dma_unmap_single(jrdev, dst_dma, len, DMA_FROM_DEVICE);
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return err ?: len;
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}
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static int caam_read(struct hwrng *rng, void *data, size_t max, bool wait)
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static void caam_rng_fill_async(struct caam_rng_ctx *ctx)
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{
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struct scatterlist sg[1];
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struct completion done;
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int len, nents;
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sg_init_table(sg, ARRAY_SIZE(sg));
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nents = kfifo_dma_in_prepare(&ctx->fifo, sg, ARRAY_SIZE(sg),
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CAAM_RNG_FIFO_LEN);
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if (!nents)
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return;
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len = caam_rng_read_one(ctx->jrdev, sg_virt(&sg[0]),
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sg[0].length,
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ctx->desc_async,
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&done);
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if (len < 0)
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return;
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kfifo_dma_in_finish(&ctx->fifo, len);
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}
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static void caam_rng_worker(struct work_struct *work)
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{
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struct caam_rng_ctx *ctx = container_of(work, struct caam_rng_ctx,
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worker);
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caam_rng_fill_async(ctx);
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}
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static int caam_read(struct hwrng *rng, void *dst, size_t max, bool wait)
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{
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struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
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struct buf_data *bd = &ctx->bufs[ctx->current_buf];
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int next_buf_idx, copied_idx;
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int err;
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int out;
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if (atomic_read(&bd->empty)) {
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/* try to submit job if there wasn't one */
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if (atomic_read(&bd->empty) == BUF_EMPTY) {
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err = submit_job(ctx, 1);
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/* if can't submit job, can't even wait */
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if (err != -EINPROGRESS)
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return 0;
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}
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/* no immediate data, so exit if not waiting */
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if (!wait)
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return 0;
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if (wait) {
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struct completion done;
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/* waiting for pending job */
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if (atomic_read(&bd->empty))
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wait_for_completion(&bd->filled);
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return caam_rng_read_one(ctx->jrdev, dst, max,
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ctx->desc_sync, &done);
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}
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next_buf_idx = ctx->cur_buf_idx + max;
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dev_dbg(ctx->jrdev, "%s: start reading at buffer %d, idx %d\n",
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__func__, ctx->current_buf, ctx->cur_buf_idx);
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out = kfifo_out(&ctx->fifo, dst, max);
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if (kfifo_len(&ctx->fifo) <= CAAM_RNG_FIFO_LEN / 2)
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schedule_work(&ctx->worker);
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/* if enough data in current buffer */
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if (next_buf_idx < RN_BUF_SIZE) {
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memcpy(data, bd->buf + ctx->cur_buf_idx, max);
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ctx->cur_buf_idx = next_buf_idx;
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return max;
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}
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/* else, copy what's left... */
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copied_idx = RN_BUF_SIZE - ctx->cur_buf_idx;
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memcpy(data, bd->buf + ctx->cur_buf_idx, copied_idx);
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ctx->cur_buf_idx = 0;
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atomic_set(&bd->empty, BUF_EMPTY);
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/* ...refill... */
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submit_job(ctx, 1);
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/* and use next buffer */
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ctx->current_buf = !ctx->current_buf;
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dev_dbg(ctx->jrdev, "switched to buffer %d\n", ctx->current_buf);
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/* since there already is some data read, don't wait */
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return copied_idx + caam_read(rng, data + copied_idx,
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max - copied_idx, false);
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}
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static inline int rng_create_sh_desc(struct caam_rng_ctx *ctx)
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{
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struct device *jrdev = ctx->jrdev;
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u32 *desc = ctx->sh_desc;
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init_sh_desc(desc, HDR_SHARE_SERIAL);
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/* Generate random bytes */
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append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG);
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/* Store bytes */
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append_seq_fifo_store(desc, RN_BUF_SIZE, FIFOST_TYPE_RNGSTORE);
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ctx->sh_desc_dma = dma_map_single(jrdev, desc, desc_bytes(desc),
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DMA_TO_DEVICE);
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if (dma_mapping_error(jrdev, ctx->sh_desc_dma)) {
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dev_err(jrdev, "unable to map shared descriptor\n");
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return -ENOMEM;
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}
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print_hex_dump_debug("rng shdesc@: ", DUMP_PREFIX_ADDRESS, 16, 4,
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desc, desc_bytes(desc), 1);
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return 0;
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}
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static inline int rng_create_job_desc(struct caam_rng_ctx *ctx, int buf_id)
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{
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struct device *jrdev = ctx->jrdev;
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struct buf_data *bd = &ctx->bufs[buf_id];
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u32 *desc = bd->hw_desc;
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int sh_len = desc_len(ctx->sh_desc);
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init_job_desc_shared(desc, ctx->sh_desc_dma, sh_len, HDR_SHARE_DEFER |
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HDR_REVERSE);
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bd->addr = dma_map_single(jrdev, bd->buf, RN_BUF_SIZE, DMA_FROM_DEVICE);
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if (dma_mapping_error(jrdev, bd->addr)) {
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dev_err(jrdev, "unable to map dst\n");
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return -ENOMEM;
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}
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append_seq_out_ptr_intlen(desc, bd->addr, RN_BUF_SIZE, 0);
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print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS, 16, 4,
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desc, desc_bytes(desc), 1);
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return 0;
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return out;
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}
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static void caam_cleanup(struct hwrng *rng)
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{
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struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
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int i;
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struct buf_data *bd;
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for (i = 0; i < 2; i++) {
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bd = &ctx->bufs[i];
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if (atomic_read(&bd->empty) == BUF_PENDING)
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wait_for_completion(&bd->filled);
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}
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rng_unmap_ctx(ctx);
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flush_work(&ctx->worker);
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caam_jr_free(ctx->jrdev);
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}
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static int caam_init_buf(struct caam_rng_ctx *ctx, int buf_id)
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{
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struct buf_data *bd = &ctx->bufs[buf_id];
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int err;
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err = rng_create_job_desc(ctx, buf_id);
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if (err)
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return err;
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atomic_set(&bd->empty, BUF_EMPTY);
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submit_job(ctx, buf_id == ctx->current_buf);
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wait_for_completion(&bd->filled);
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return 0;
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kfifo_free(&ctx->fifo);
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}
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static int caam_init(struct hwrng *rng)
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@ -279,33 +166,36 @@ static int caam_init(struct hwrng *rng)
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struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
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int err;
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ctx->desc_sync = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,
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GFP_DMA | GFP_KERNEL);
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if (!ctx->desc_sync)
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return -ENOMEM;
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ctx->desc_async = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,
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GFP_DMA | GFP_KERNEL);
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if (!ctx->desc_async)
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return -ENOMEM;
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if (kfifo_alloc(&ctx->fifo, CAAM_RNG_FIFO_LEN, GFP_DMA | GFP_KERNEL))
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return -ENOMEM;
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INIT_WORK(&ctx->worker, caam_rng_worker);
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ctx->jrdev = caam_jr_alloc();
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err = PTR_ERR_OR_ZERO(ctx->jrdev);
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if (err) {
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kfifo_free(&ctx->fifo);
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pr_err("Job Ring Device allocation for transform failed\n");
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return err;
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}
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err = rng_create_sh_desc(ctx);
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if (err)
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goto free_jrdev;
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ctx->current_buf = 0;
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ctx->cur_buf_idx = 0;
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err = caam_init_buf(ctx, 0);
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if (err)
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goto free_jrdev;
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err = caam_init_buf(ctx, 1);
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if (err)
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goto free_jrdev;
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/*
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* Fill async buffer to have early randomness data for
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* hw_random
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*/
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caam_rng_fill_async(ctx);
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return 0;
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free_jrdev:
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caam_jr_free(ctx->jrdev);
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return err;
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}
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int caam_rng_init(struct device *ctrldev);
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@ -335,10 +225,12 @@ int caam_rng_init(struct device *ctrldev)
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if (!devres_open_group(ctrldev, caam_rng_init, GFP_KERNEL))
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return -ENOMEM;
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ctx = devm_kzalloc(ctrldev, sizeof(*ctx), GFP_DMA | GFP_KERNEL);
|
||||
ctx = devm_kzalloc(ctrldev, sizeof(*ctx), GFP_KERNEL);
|
||||
if (!ctx)
|
||||
return -ENOMEM;
|
||||
|
||||
ctx->ctrldev = ctrldev;
|
||||
|
||||
ctx->rng.name = "rng-caam";
|
||||
ctx->rng.init = caam_init;
|
||||
ctx->rng.cleanup = caam_cleanup;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user