crypto: caam - remove duplicated sg copy functions

commit 307fd543 upstream.

Replace equivalent (and partially incorrect) scatter-gather functions
with ones from crypto-API.

The replacement is motivated by page-faults in sg_copy_part triggered
by successive calls to crypto_hash_update. The following fault appears
after calling crypto_ahash_update twice, first with 13 and then
with 285 bytes:

Unable to handle kernel paging request for data at address 0x00000008
Faulting instruction address: 0xf9bf9a8c
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=8 CoreNet Generic
Modules linked in: tcrypt(+) caamhash caam_jr caam tls
CPU: 6 PID: 1497 Comm: cryptomgr_test Not tainted
3.12.19-rt30-QorIQ-SDK-V1.6+g9fda9f2 #75
task: e9308530 ti: e700e000 task.ti: e700e000
NIP: f9bf9a8c LR: f9bfcf28 CTR: c0019ea0
REGS: e700fb80 TRAP: 0300   Not tainted
(3.12.19-rt30-QorIQ-SDK-V1.6+g9fda9f2)
MSR: 00029002 <CE,EE,ME>  CR: 44f92024  XER: 20000000
DEAR: 00000008, ESR: 00000000

GPR00: f9bfcf28 e700fc30 e9308530 e70b1e55 00000000 ffffffdd e70b1e54 0bebf888
GPR08: 902c7ef5 c0e771e2 00000002 00000888 c0019ea0 00000000 00000000 c07a4154
GPR16: c08d0000 e91a8f9c 00000001 e98fb400 00000100 e9c83028 e70b1e08 e70b1d48
GPR24: e992ce10 e70b1dc8 f9bfe4f4 e70b1e55 ffffffdd e70b1ce0 00000000 00000000
NIP [f9bf9a8c] sg_copy+0x1c/0x100 [caamhash]
LR [f9bfcf28] ahash_update_no_ctx+0x628/0x660 [caamhash]
Call Trace:
[e700fc30] [f9bf9c50] sg_copy_part+0xe0/0x160 [caamhash] (unreliable)
[e700fc50] [f9bfcf28] ahash_update_no_ctx+0x628/0x660 [caamhash]
[e700fcb0] [f954e19c] crypto_tls_genicv+0x13c/0x300 [tls]
[e700fd10] [f954e65c] crypto_tls_encrypt+0x5c/0x260 [tls]
[e700fd40] [c02250ec] __test_aead.constprop.9+0x2bc/0xb70
[e700fe40] [c02259f0] alg_test_aead+0x50/0xc0
[e700fe60] [c02241e4] alg_test+0x114/0x2e0
[e700fee0] [c022276c] cryptomgr_test+0x4c/0x60
[e700fef0] [c004f658] kthread+0x98/0xa0
[e700ff40] [c000fd04] ret_from_kernel_thread+0x5c/0x64
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/crypto/caam/caamhash.c

@@ -825,8 +825,9 @@ static int ahash_update_ctx(struct ahash_request *req)
 					   edesc->sec4_sg + sec4_sg_src_index,
 					   chained);
 			if (*next_buflen) {
-				sg_copy_part(next_buf, req->src, to_hash -
-					     *buflen, req->nbytes);
+				scatterwalk_map_and_copy(next_buf, req->src,
+							 to_hash - *buflen,
+							 *next_buflen, 0);
 				state->current_buf = !state->current_buf;
 			}
 		} else {
@@ -859,7 +860,8 @@ static int ahash_update_ctx(struct ahash_request *req)
 			kfree(edesc);
 		}
 	} else if (*next_buflen) {
-		sg_copy(buf + *buflen, req->src, req->nbytes);
+		scatterwalk_map_and_copy(buf + *buflen, req->src, 0,
+					 req->nbytes, 0);
 		*buflen = *next_buflen;
 		*next_buflen = last_buflen;
 	}
@@ -1206,8 +1208,9 @@ static int ahash_update_no_ctx(struct ahash_request *req)
 		src_map_to_sec4_sg(jrdev, req->src, src_nents,
 				   edesc->sec4_sg + 1, chained);
 		if (*next_buflen) {
-			sg_copy_part(next_buf, req->src, to_hash - *buflen,
-				    req->nbytes);
+			scatterwalk_map_and_copy(next_buf, req->src,
+						 to_hash - *buflen,
+						 *next_buflen, 0);
 			state->current_buf = !state->current_buf;
 		}
 
@@ -1238,7 +1241,8 @@ static int ahash_update_no_ctx(struct ahash_request *req)
 			kfree(edesc);
 		}
 	} else if (*next_buflen) {
-		sg_copy(buf + *buflen, req->src, req->nbytes);
+		scatterwalk_map_and_copy(buf + *buflen, req->src, 0,
+					 req->nbytes, 0);
 		*buflen = *next_buflen;
 		*next_buflen = 0;
 	}
@@ -1395,7 +1399,8 @@ static int ahash_update_first(struct ahash_request *req)
 		}
 
 		if (*next_buflen)
-			sg_copy_part(next_buf, req->src, to_hash, req->nbytes);
+			scatterwalk_map_and_copy(next_buf, req->src, to_hash,
+						 *next_buflen, 0);
 
 		sh_len = desc_len(sh_desc);
 		desc = edesc->hw_desc;
@@ -1428,7 +1433,8 @@ static int ahash_update_first(struct ahash_request *req)
 		state->update = ahash_update_no_ctx;
 		state->finup = ahash_finup_no_ctx;
 		state->final = ahash_final_no_ctx;
-		sg_copy(next_buf, req->src, req->nbytes);
+		scatterwalk_map_and_copy(next_buf, req->src, 0,
+					 req->nbytes, 0);
 	}
 #ifdef DEBUG
 	print_hex_dump(KERN_ERR, "next buf@"__stringify(__LINE__)": ",

drivers/crypto/caam/sg_sw_sec4.h

@@ -116,57 +116,3 @@ static int dma_unmap_sg_chained(struct device *dev, struct scatterlist *sg,
 	}
 	return nents;
 }
-
-/* Map SG page in kernel virtual address space and copy */
-static inline void sg_map_copy(u8 *dest, struct scatterlist *sg,
-			       int len, int offset)
-{
-	u8 *mapped_addr;
-
-	/*
-	 * Page here can be user-space pinned using get_user_pages
-	 * Same must be kmapped before use and kunmapped subsequently
-	 */
-	mapped_addr = kmap_atomic(sg_page(sg));
-	memcpy(dest, mapped_addr + offset, len);
-	kunmap_atomic(mapped_addr);
-}
-
-/* Copy from len bytes of sg to dest, starting from beginning */
-static inline void sg_copy(u8 *dest, struct scatterlist *sg, unsigned int len)
-{
-	struct scatterlist *current_sg = sg;
-	int cpy_index = 0, next_cpy_index = current_sg->length;
-
-	while (next_cpy_index < len) {
-		sg_map_copy(dest + cpy_index, current_sg, current_sg->length,
-			    current_sg->offset);
-		current_sg = scatterwalk_sg_next(current_sg);
-		cpy_index = next_cpy_index;
-		next_cpy_index += current_sg->length;
-	}
-	if (cpy_index < len)
-		sg_map_copy(dest + cpy_index, current_sg, len-cpy_index,
-			    current_sg->offset);
-}
-
-/* Copy sg data, from to_skip to end, to dest */
-static inline void sg_copy_part(u8 *dest, struct scatterlist *sg,
-				      int to_skip, unsigned int end)
-{
-	struct scatterlist *current_sg = sg;
-	int sg_index, cpy_index, offset;
-
-	sg_index = current_sg->length;
-	while (sg_index <= to_skip) {
-		current_sg = scatterwalk_sg_next(current_sg);
-		sg_index += current_sg->length;
-	}
-	cpy_index = sg_index - to_skip;
-	offset = current_sg->offset + current_sg->length - cpy_index;
-	sg_map_copy(dest, current_sg, cpy_index, offset);
-	if (end - sg_index) {
-		current_sg = scatterwalk_sg_next(current_sg);
-		sg_copy(dest + cpy_index, current_sg, end - sg_index);
-	}
-}