diff options
author | Andrey Smirnov <andrew.smirnov@gmail.com> | 2020-03-19 09:12:28 -0700 |
---|---|---|
committer | Herbert Xu <herbert@gondor.apana.org.au> | 2020-03-30 11:50:49 +1100 |
commit | 2c5e88dc90f50022d1b4bf56c9b45d4162757094 (patch) | |
tree | a0388ee6ac85fa55785f4f72bc510cbf3f8cb17b /drivers/crypto/caam | |
parent | 1517f63cd84f00da3a3e21dff042410b2799c1c3 (diff) |
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>
Diffstat (limited to 'drivers/crypto/caam')
-rw-r--r-- | drivers/crypto/caam/caamrng.c | 322 |
1 files changed, 107 insertions, 215 deletions
diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c index 753625f2b2c0..e64f2d77fa03 100644 --- a/drivers/crypto/caam/caamrng.c +++ b/drivers/crypto/caam/caamrng.c @@ -7,35 +7,12 @@ * * Based on caamalg.c crypto API driver. * - * relationship between job descriptors to shared descriptors: - * - * --------------- -------------- - * | JobDesc #0 |-------------------->| ShareDesc | - * | *(buffer 0) | |------------->| (generate) | - * --------------- | | (move) | - * | | (store) | - * --------------- | -------------- - * | JobDesc #1 |------| - * | *(buffer 1) | - * --------------- - * - * A job desc looks like this: - * - * --------------------- - * | Header | - * | ShareDesc Pointer | - * | SEQ_OUT_PTR | - * | (output buffer) | - * --------------------- - * - * The SharedDesc never changes, and each job descriptor points to one of two - * buffers for each device, from which the data will be copied into the - * requested destination */ #include <linux/hw_random.h> #include <linux/completion.h> #include <linux/atomic.h> +#include <linux/kfifo.h> #include "compat.h" @@ -45,38 +22,26 @@ #include "jr.h" #include "error.h" +#define CAAM_RNG_MAX_FIFO_STORE_SIZE U16_MAX + +#define CAAM_RNG_FIFO_LEN SZ_32K /* Must be a multiple of 2 */ + /* - * Maximum buffer size: maximum number of random, cache-aligned bytes that - * will be generated and moved to seq out ptr (extlen not allowed) + * Length of used descriptors, see caam_init_desc() */ -#define RN_BUF_SIZE (0xffff / L1_CACHE_BYTES * \ - L1_CACHE_BYTES) - -/* length of descriptors */ -#define DESC_JOB_O_LEN (CAAM_CMD_SZ * 2 + CAAM_PTR_SZ_MAX * 2) -#define DESC_RNG_LEN (3 * CAAM_CMD_SZ) - -/* Buffer, its dma address and lock */ -struct buf_data { - u8 buf[RN_BUF_SIZE] ____cacheline_aligned; - dma_addr_t addr; - struct completion filled; - u32 hw_desc[DESC_JOB_O_LEN]; -#define BUF_NOT_EMPTY 0 -#define BUF_EMPTY 1 -#define BUF_PENDING 2 /* Empty, but with job pending --don't submit another */ - atomic_t empty; -}; +#define CAAM_RNG_DESC_LEN (CAAM_CMD_SZ + \ + CAAM_CMD_SZ + \ + CAAM_CMD_SZ + CAAM_PTR_SZ_MAX) /* rng per-device context */ struct caam_rng_ctx { struct hwrng rng; struct device *jrdev; - dma_addr_t sh_desc_dma; - u32 sh_desc[DESC_RNG_LEN]; - unsigned int cur_buf_idx; - int current_buf; - struct buf_data bufs[2]; + struct device *ctrldev; + void *desc_async; + void *desc_sync; + struct work_struct worker; + struct kfifo fifo; }; static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r) @@ -84,228 +49,153 @@ static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r) return (struct caam_rng_ctx *)r->priv; } -static inline void rng_unmap_buf(struct device *jrdev, struct buf_data *bd) +static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err, + void *context) { - if (bd->addr) - dma_unmap_single(jrdev, bd->addr, RN_BUF_SIZE, - DMA_FROM_DEVICE); -} - -static inline void rng_unmap_ctx(struct caam_rng_ctx *ctx) -{ - struct device *jrdev = ctx->jrdev; - - if (ctx->sh_desc_dma) - dma_unmap_single(jrdev, ctx->sh_desc_dma, - desc_bytes(ctx->sh_desc), DMA_TO_DEVICE); - rng_unmap_buf(jrdev, &ctx->bufs[0]); - rng_unmap_buf(jrdev, &ctx->bufs[1]); -} - -static void rng_done(struct device *jrdev, u32 *desc, u32 err, void *context) -{ - struct buf_data *bd; - - bd = container_of(desc, struct buf_data, hw_desc[0]); + struct completion *done = context; if (err) caam_jr_strstatus(jrdev, err); - atomic_set(&bd->empty, BUF_NOT_EMPTY); - complete(&bd->filled); - - /* Buffer refilled, invalidate cache */ - dma_sync_single_for_cpu(jrdev, bd->addr, RN_BUF_SIZE, DMA_FROM_DEVICE); - - print_hex_dump_debug("rng refreshed buf@: ", DUMP_PREFIX_ADDRESS, 16, 4, - bd->buf, RN_BUF_SIZE, 1); + complete(done); } -static inline int submit_job(struct caam_rng_ctx *ctx, int to_current) +static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma, int len) { - struct buf_data *bd = &ctx->bufs[!(to_current ^ ctx->current_buf)]; - struct device *jrdev = ctx->jrdev; - u32 *desc = bd->hw_desc; - int err; + init_job_desc(desc, 0); /* + 1 cmd_sz */ + /* Generate random bytes: + 1 cmd_sz */ + append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG); + /* Store bytes: + 1 cmd_sz + caam_ptr_sz */ + append_fifo_store(desc, dst_dma, len, FIFOST_TYPE_RNGSTORE); - dev_dbg(jrdev, "submitting job %d\n", !(to_current ^ ctx->current_buf)); - init_completion(&bd->filled); - err = caam_jr_enqueue(jrdev, desc, rng_done, ctx); - if (err != -EINPROGRESS) - complete(&bd->filled); /* don't wait on failed job*/ - else - atomic_inc(&bd->empty); /* note if pending */ + print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS, + 16, 4, desc, desc_bytes(desc), 1); - return err; + return desc; } -static int caam_read(struct hwrng *rng, void *data, size_t max, bool wait) +static int caam_rng_read_one(struct device *jrdev, + void *dst, int len, + void *desc, + struct completion *done) { - struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); - struct buf_data *bd = &ctx->bufs[ctx->current_buf]; - int next_buf_idx, copied_idx; + dma_addr_t dst_dma; int err; - if (atomic_read(&bd->empty)) { - /* try to submit job if there wasn't one */ - if (atomic_read(&bd->empty) == BUF_EMPTY) { - err = submit_job(ctx, 1); - /* if can't submit job, can't even wait */ - if (err != -EINPROGRESS) - return 0; - } - /* no immediate data, so exit if not waiting */ - if (!wait) - return 0; - - /* waiting for pending job */ - if (atomic_read(&bd->empty)) - wait_for_completion(&bd->filled); - } - - next_buf_idx = ctx->cur_buf_idx + max; - dev_dbg(ctx->jrdev, "%s: start reading at buffer %d, idx %d\n", - __func__, ctx->current_buf, ctx->cur_buf_idx); + len = min_t(int, len, CAAM_RNG_MAX_FIFO_STORE_SIZE); - /* if enough data in current buffer */ - if (next_buf_idx < RN_BUF_SIZE) { - memcpy(data, bd->buf + ctx->cur_buf_idx, max); - ctx->cur_buf_idx = next_buf_idx; - return max; + dst_dma = dma_map_single(jrdev, dst, len, DMA_FROM_DEVICE); + if (dma_mapping_error(jrdev, dst_dma)) { + dev_err(jrdev, "unable to map destination memory\n"); + return -ENOMEM; } - /* else, copy what's left... */ - copied_idx = RN_BUF_SIZE - ctx->cur_buf_idx; - memcpy(data, bd->buf + ctx->cur_buf_idx, copied_idx); - ctx->cur_buf_idx = 0; - atomic_set(&bd->empty, BUF_EMPTY); - - /* ...refill... */ - submit_job(ctx, 1); + init_completion(done); + err = caam_jr_enqueue(jrdev, + caam_init_desc(desc, dst_dma, len), + caam_rng_done, done); + if (err == -EINPROGRESS) { + wait_for_completion(done); + err = 0; + } - /* and use next buffer */ - ctx->current_buf = !ctx->current_buf; - dev_dbg(ctx->jrdev, "switched to buffer %d\n", ctx->current_buf); + dma_unmap_single(jrdev, dst_dma, len, DMA_FROM_DEVICE); - /* since there already is some data read, don't wait */ - return copied_idx + caam_read(rng, data + copied_idx, - max - copied_idx, false); + return err ?: len; } -static inline int rng_create_sh_desc(struct caam_rng_ctx *ctx) +static void caam_rng_fill_async(struct caam_rng_ctx *ctx) { - struct device *jrdev = ctx->jrdev; - u32 *desc = ctx->sh_desc; - - init_sh_desc(desc, HDR_SHARE_SERIAL); - - /* Generate random bytes */ - append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG); - - /* Store bytes */ - append_seq_fifo_store(desc, RN_BUF_SIZE, FIFOST_TYPE_RNGSTORE); - - ctx->sh_desc_dma = dma_map_single(jrdev, desc, desc_bytes(desc), - DMA_TO_DEVICE); - if (dma_mapping_error(jrdev, ctx->sh_desc_dma)) { - dev_err(jrdev, "unable to map shared descriptor\n"); - return -ENOMEM; - } - - print_hex_dump_debug("rng shdesc@: ", DUMP_PREFIX_ADDRESS, 16, 4, - desc, desc_bytes(desc), 1); + struct scatterlist sg[1]; + struct completion done; + int len, nents; + + sg_init_table(sg, ARRAY_SIZE(sg)); + nents = kfifo_dma_in_prepare(&ctx->fifo, sg, ARRAY_SIZE(sg), + CAAM_RNG_FIFO_LEN); + if (!nents) + return; + + len = caam_rng_read_one(ctx->jrdev, sg_virt(&sg[0]), + sg[0].length, + ctx->desc_async, + &done); + if (len < 0) + return; + + kfifo_dma_in_finish(&ctx->fifo, len); +} - return 0; +static void caam_rng_worker(struct work_struct *work) +{ + struct caam_rng_ctx *ctx = container_of(work, struct caam_rng_ctx, + worker); + caam_rng_fill_async(ctx); } -static inline int rng_create_job_desc(struct caam_rng_ctx *ctx, int buf_id) +static int caam_read(struct hwrng *rng, void *dst, size_t max, bool wait) { - struct device *jrdev = ctx->jrdev; - struct buf_data *bd = &ctx->bufs[buf_id]; - u32 *desc = bd->hw_desc; - int sh_len = desc_len(ctx->sh_desc); + struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); + int out; - init_job_desc_shared(desc, ctx->sh_desc_dma, sh_len, HDR_SHARE_DEFER | - HDR_REVERSE); + if (wait) { + struct completion done; - bd->addr = dma_map_single(jrdev, bd->buf, RN_BUF_SIZE, DMA_FROM_DEVICE); - if (dma_mapping_error(jrdev, bd->addr)) { - dev_err(jrdev, "unable to map dst\n"); - return -ENOMEM; + return caam_rng_read_one(ctx->jrdev, dst, max, + ctx->desc_sync, &done); } - append_seq_out_ptr_intlen(desc, bd->addr, RN_BUF_SIZE, 0); + out = kfifo_out(&ctx->fifo, dst, max); + if (kfifo_len(&ctx->fifo) <= CAAM_RNG_FIFO_LEN / 2) + schedule_work(&ctx->worker); - print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS, 16, 4, - desc, desc_bytes(desc), 1); - - return 0; + return out; } static void caam_cleanup(struct hwrng *rng) { struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); - int i; - struct buf_data *bd; - for (i = 0; i < 2; i++) { - bd = &ctx->bufs[i]; - if (atomic_read(&bd->empty) == BUF_PENDING) - wait_for_completion(&bd->filled); - } - - rng_unmap_ctx(ctx); + flush_work(&ctx->worker); caam_jr_free(ctx->jrdev); + kfifo_free(&ctx->fifo); } -static int caam_init_buf(struct caam_rng_ctx *ctx, int buf_id) +static int caam_init(struct hwrng *rng) { - struct buf_data *bd = &ctx->bufs[buf_id]; + struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); int err; - err = rng_create_job_desc(ctx, buf_id); - if (err) - return err; + ctx->desc_sync = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN, + GFP_DMA | GFP_KERNEL); + if (!ctx->desc_sync) + return -ENOMEM; - atomic_set(&bd->empty, BUF_EMPTY); - submit_job(ctx, buf_id == ctx->current_buf); - wait_for_completion(&bd->filled); + ctx->desc_async = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN, + GFP_DMA | GFP_KERNEL); + if (!ctx->desc_async) + return -ENOMEM; - return 0; -} + if (kfifo_alloc(&ctx->fifo, CAAM_RNG_FIFO_LEN, GFP_DMA | GFP_KERNEL)) + return -ENOMEM; -static int caam_init(struct hwrng *rng) -{ - struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); - int err; + INIT_WORK(&ctx->worker, caam_rng_worker); ctx->jrdev = caam_jr_alloc(); err = PTR_ERR_OR_ZERO(ctx->jrdev); if (err) { + kfifo_free(&ctx->fifo); pr_err("Job Ring Device allocation for transform failed\n"); return err; } - err = rng_create_sh_desc(ctx); - if (err) - goto free_jrdev; - - ctx->current_buf = 0; - ctx->cur_buf_idx = 0; - - err = caam_init_buf(ctx, 0); - if (err) - goto free_jrdev; - - err = caam_init_buf(ctx, 1); - if (err) - goto free_jrdev; + /* + * Fill async buffer to have early randomness data for + * hw_random + */ + caam_rng_fill_async(ctx); return 0; - -free_jrdev: - caam_jr_free(ctx->jrdev); - return err; } int caam_rng_init(struct device *ctrldev); @@ -335,10 +225,12 @@ int caam_rng_init(struct device *ctrldev) if (!devres_open_group(ctrldev, caam_rng_init, GFP_KERNEL)) return -ENOMEM; - 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; |