Linux/AM3352: Crypto driver crash

From 46bb67753612a4b8c33ba9ca6508f5474b57baf5 Mon Sep 17 00:00:00 2001
From: Tero Kristo <t-kristo@ti.com>
Date: Fri, 26 Oct 2018 18:08:02 +0300
Subject: [PATCH] crypto: omap-sham: split up data to multiple sg elements with
 huge data

When using huge data amount, allocating free pages fails as the kernel
isn't able to process get_free_page requests larger than MAX_ORDER.
Also, the DMA subsystem has an inherent limitation that data size
larger than some 2MB can't be handled properly. In these cases,
split up the data instead to smaller requests so that the kernel
can allocate the data, and also so that the DMA driver can handle
the separate SG elements.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Tested-by: Bin Liu <b-liu@ti.com>
---
 drivers/crypto/omap-sham.c | 81 ++++++++++++++++++++++++++++++--------
 1 file changed, 64 insertions(+), 17 deletions(-)

diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c
index 6c8bc4733f6d..ad26e7b91109 100644
--- a/drivers/crypto/omap-sham.c
+++ b/drivers/crypto/omap-sham.c
@@ -115,6 +115,8 @@
 #define FLAGS_BE32_SHA1		8
 #define FLAGS_SGS_COPIED	9
 #define FLAGS_SGS_ALLOCED	10
+#define FLAGS_HUGE		11
+
 /* context flags */
 #define FLAGS_FINUP		16
 
@@ -139,6 +141,8 @@
 #define BUFLEN			SHA512_BLOCK_SIZE
 #define OMAP_SHA_DMA_THRESHOLD	256
 
+#define OMAP_SHA_MAX_DMA_LEN	(1024 * 2048)
+
 struct omap_sham_dev;
 
 struct omap_sham_reqctx {
@@ -692,21 +696,20 @@ static int omap_sham_copy_sg_lists(struct omap_sham_reqctx *ctx,
 
 	set_bit(FLAGS_SGS_ALLOCED, &ctx->dd->flags);
 
+	ctx->offset += new_len - ctx->bufcnt;
 	ctx->bufcnt = 0;
 
 	return 0;
 }
 
 static int omap_sham_copy_sgs(struct omap_sham_reqctx *ctx,
-			      struct scatterlist *sg, int bs, int new_len)
+			      struct scatterlist *sg, int bs,
+			      unsigned int new_len)
 {
 	int pages;
 	void *buf;
-	int len;
-
-	len = new_len + ctx->bufcnt;
 
-	pages = get_order(ctx->total);
+	pages = get_order(new_len);
 
 	buf = (void *)__get_free_pages(GFP_ATOMIC, pages);
 	if (!buf) {
@@ -718,14 +721,14 @@ static int omap_sham_copy_sgs(struct omap_sham_reqctx *ctx,
 		memcpy(buf, ctx->dd->xmit_buf, ctx->bufcnt);
 
 	scatterwalk_map_and_copy(buf + ctx->bufcnt, sg, ctx->offset,
-				 ctx->total - ctx->bufcnt, 0);
+				 min(new_len, ctx->total) - ctx->bufcnt, 0);
 	sg_init_table(ctx->sgl, 1);
-	sg_set_buf(ctx->sgl, buf, len);
+	sg_set_buf(ctx->sgl, buf, new_len);
 	ctx->sg = ctx->sgl;
 	set_bit(FLAGS_SGS_COPIED, &ctx->dd->flags);
 	ctx->sg_len = 1;
+	ctx->offset += new_len - ctx->bufcnt;
 	ctx->bufcnt = 0;
-	ctx->offset = 0;
 
 	return 0;
 }
@@ -744,7 +747,7 @@ static int omap_sham_align_sgs(struct scatterlist *sg,
 	if (!sg || !sg->length || !nbytes)
 		return 0;
 
-	new_len = nbytes;
+	new_len = nbytes - offset;
 
 	if (offset)
 		list_ok = false;
@@ -754,6 +757,9 @@ static int omap_sham_align_sgs(struct scatterlist *sg,
 	else
 		new_len = (new_len - 1) / bs * bs;
 
+	if (!new_len)
+		return 0;
+
 	if (nbytes != new_len)
 		list_ok = false;
 
@@ -797,10 +803,17 @@ static int omap_sham_align_sgs(struct scatterlist *sg,
 		}
 	}
 
+	if (new_len > OMAP_SHA_MAX_DMA_LEN) {
+		new_len = OMAP_SHA_MAX_DMA_LEN;
+		aligned = false;
+	}
+
 	if (!aligned)
 		return omap_sham_copy_sgs(rctx, sg, bs, new_len);
 	else if (!list_ok)
 		return omap_sham_copy_sg_lists(rctx, sg, bs, new_len);
+	else
+		rctx->offset += new_len;
 
 	rctx->sg_len = n;
 	rctx->sg = sg;
@@ -827,7 +840,12 @@ static int omap_sham_prepare_request(struct ahash_request *req, bool update)
 	else
 		nbytes = 0;
 
-	rctx->total = nbytes + rctx->bufcnt;
+	rctx->total = nbytes + rctx->bufcnt - rctx->offset;
+
+	dev_dbg(rctx->dd->dev,
+		"%s: nbytes=%d, bs=%d, total=%d, offset=%d, bufcnt=%d\n",
+		__func__, nbytes, bs, rctx->total, rctx->offset,
+		rctx->bufcnt);
 
 	if (!rctx->total)
 		return 0;
@@ -853,12 +871,15 @@ static int omap_sham_prepare_request(struct ahash_request *req, bool update)
 
 	xmit_len = rctx->total;
 
+	if (xmit_len > OMAP_SHA_MAX_DMA_LEN)
+		xmit_len = OMAP_SHA_MAX_DMA_LEN;
+
 	if (!IS_ALIGNED(xmit_len, bs)) {
 		if (final)
 			xmit_len = DIV_ROUND_UP(xmit_len, bs) * bs;
 		else
 			xmit_len = xmit_len / bs * bs;
-	} else if (!final) {
+	} else if (!final && rctx->total == xmit_len) {
 		xmit_len -= bs;
 	}
 
@@ -886,7 +907,7 @@ static int omap_sham_prepare_request(struct ahash_request *req, bool update)
 		rctx->sg_len = 1;
 	}
 
-	if (hash_later) {
+	if (hash_later && hash_later <= rctx->buflen) {
 		int offset = 0;
 
 		if (hash_later > req->nbytes) {
@@ -907,6 +928,9 @@ static int omap_sham_prepare_request(struct ahash_request *req, bool update)
 		rctx->bufcnt = 0;
 	}
 
+	if (hash_later > rctx->buflen)
+		set_bit(FLAGS_HUGE, &rctx->dd->flags);
+
 	if (!final)
 		rctx->total = xmit_len;
 
@@ -1004,10 +1028,11 @@ static int omap_sham_update_req(struct omap_sham_dev *dd)
 	struct ahash_request *req = dd->req;
 	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
 	int err;
-	bool final = ctx->flags & BIT(FLAGS_FINUP);
+	bool final = (ctx->flags & BIT(FLAGS_FINUP)) &&
+			!(dd->flags & BIT(FLAGS_HUGE));
 
-	dev_dbg(dd->dev, "update_req: total: %u, digcnt: %d, finup: %d\n",
-		 ctx->total, ctx->digcnt, (ctx->flags & BIT(FLAGS_FINUP)) != 0);
+	dev_dbg(dd->dev, "update_req: total: %u, digcnt: %d, final: %d",
+		ctx->total, ctx->digcnt, final);
 
 	if (ctx->total < get_block_size(ctx) ||
 	    ctx->total < dd->fallback_sz)
@@ -1030,6 +1055,9 @@ static int omap_sham_final_req(struct omap_sham_dev *dd)
 	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
 	int err = 0, use_dma = 1;
 
+	if (dd->flags & BIT(FLAGS_HUGE))
+		return 0;
+
 	if ((ctx->total <= get_block_size(ctx)) || dd->polling_mode)
 		/*
 		 * faster to handle last block with cpu or
@@ -1090,7 +1118,7 @@ static void omap_sham_finish_req(struct ahash_request *req, int err)
 
 	if (test_bit(FLAGS_SGS_COPIED, &dd->flags))
 		free_pages((unsigned long)sg_virt(ctx->sg),
-			   get_order(ctx->sg->length + ctx->bufcnt));
+			   get_order(ctx->sg->length));
 
 	if (test_bit(FLAGS_SGS_ALLOCED, &dd->flags))
 		kfree(ctx->sg);
@@ -1099,6 +1127,21 @@ static void omap_sham_finish_req(struct ahash_request *req, int err)
 
 	dd->flags &= ~(BIT(FLAGS_SGS_ALLOCED) | BIT(FLAGS_SGS_COPIED));
 
+	if (dd->flags & BIT(FLAGS_HUGE)) {
+		dd->flags &= ~(BIT(FLAGS_CPU) | BIT(FLAGS_DMA_READY) |
+				BIT(FLAGS_OUTPUT_READY) | BIT(FLAGS_HUGE));
+		omap_sham_prepare_request(req, ctx->op == OP_UPDATE);
+		if (ctx->op == OP_UPDATE || (dd->flags & BIT(FLAGS_HUGE))) {
+			err = omap_sham_update_req(dd);
+			if (err != -EINPROGRESS &&
+			    (ctx->flags & BIT(FLAGS_FINUP)))
+				err = omap_sham_final_req(dd);
+		} else if (ctx->op == OP_FINAL) {
+			omap_sham_final_req(dd);
+		}
+		return;
+	}
+
 	if (!err) {
 		dd->pdata->copy_hash(req, 1);
 		if (test_bit(FLAGS_FINAL, &dd->flags))
@@ -1114,6 +1157,8 @@ static void omap_sham_finish_req(struct ahash_request *req, int err)
 	pm_runtime_mark_last_busy(dd->dev);
 	pm_runtime_put_autosuspend(dd->dev);
 
+	ctx->offset = 0;
+
 	if (req->base.complete)
 		req->base.complete(&req->base, err);
 }
@@ -1165,7 +1210,7 @@ static int omap_sham_handle_queue(struct omap_sham_dev *dd,
 		/* request has changed - restore hash */
 		dd->pdata->copy_hash(req, 0);
 
-	if (ctx->op == OP_UPDATE) {
+	if (ctx->op == OP_UPDATE || (dd->flags & BIT(FLAGS_HUGE))) {
 		err = omap_sham_update_req(dd);
 		if (err != -EINPROGRESS && (ctx->flags & BIT(FLAGS_FINUP)))
 			/* no final() after finup() */
@@ -1750,6 +1795,8 @@ static void omap_sham_done_task(unsigned long data)
 	struct omap_sham_dev *dd = (struct omap_sham_dev *)data;
 	int err = 0;
 
+	dev_dbg(dd->dev, "%s: flags=%lx\n", __func__, dd->flags);
+
 	if (!test_bit(FLAGS_BUSY, &dd->flags)) {
 		omap_sham_handle_queue(dd, NULL);
 		return;
-- 
2.17.1