[PATCH AUTOSEL 5.4 004/109] crypto: mxs-dcp - Use sg_mapping_iter to copy data

Sasha Levin
2021-09-09T12:55:06Z

From: Sean Anderson <sean.anderson@seco.com>

[ Upstream commit 2e6d793e1bf07fe5e20cfbbdcec9e1af7e5097eb ]

This uses the sg_pcopy_from_buffer to copy data, instead of doing it
ourselves.

In addition to reducing code size, this fixes the following oops
resulting from failing to kmap the page:

[ 68.896381] Unable to handle kernel NULL pointer dereference at virtual address 00000ab8
[ 68.904539] pgd = 3561adb3
[ 68.907475] [00000ab8] *pgd=00000000
[ 68.911153] Internal error: Oops: 805 [#1] ARM
[ 68.915618] Modules linked in: cfg80211 rfkill des_generic libdes arc4 libarc4 cbc ecb algif_skcipher sha256_generic libsha256 sha1_generic hmac aes_generic libaes cmac sha512_generic md5 md4 algif_hash af_alg i2c_imx i2c_core ci_hdrc_imx ci_hdrc mxs_dcp ulpi roles udc_core imx_sdma usbmisc_imx usb_common firmware_class virt_dma phy_mxs_usb nf_tables nfnetlink ip_tables x_tables ipv6 autofs4
[ 68.950741] CPU: 0 PID: 139 Comm: mxs_dcp_chan/ae Not tainted 5.10.34 #296
[ 68.958501] Hardware name: Freescale i.MX6 Ultralite (Device Tree)
[ 68.964710] PC is at memcpy+0xa8/0x330
[ 68.968479] LR is at 0xd7b2bc9d
[ 68.971638] pc : [<c053e7c8>] lr : [<d7b2bc9d>] psr: 000f0013
[ 68.977920] sp : c2cbbee4 ip : 00000010 fp : 00000010
[ 68.983159] r10: 00000000 r9 : c3283a40 r8 : 1a5a6f08
[ 68.988402] r7 : 4bfe0ecc r6 : 76d8a220 r5 : c32f9050 r4 : 00000001
[ 68.994945] r3 : 00000ab8 r2 : fffffff0 r1 : c32f9050 r0 : 00000ab8
[ 69.001492] Flags: nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 69.008646] Control: 10c53c7d Table: 83664059 DAC: 00000051
[ 69.014414] Process mxs_dcp_chan/ae (pid: 139, stack limit = 0x667b57ab)
[ 69.021133] Stack: (0xc2cbbee4 to 0xc2cbc000)
[ 69.025519] bee0: c32f9050 c3235408 00000010 00000010 00000ab8 00000001 bf10406c
[ 69.033720] bf00: 00000000 00000000 00000010 00000000 c32355d0 832fb080 00000000 c13de2fc
[ 69.041921] bf20: c3628010 00000010 c33d5780 00000ab8 bf1067e8 00000002 c21e5010 c2cba000
[ 69.050125] bf40: c32f8040 00000000 bf106a40 c32f9040 c3283a80 00000001 bf105240 c3234040
[ 69.058327] bf60: ffffe000 c3204100 c2c69800 c2cba000 00000000 bf103b84 00000000 c2eddc54
[ 69.066530] bf80: c3204144 c0140d1c c2cba000 c2c69800 c0140be8 00000000 00000000 00000000
[ 69.074730] bfa0: 00000000 00000000 00000000 c0100114 00000000 00000000 00000000 00000000
[ 69.082932] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 69.091131] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[ 69.099364] [<c053e7c8>] (memcpy) from [<bf10406c>] (dcp_chan_thread_aes+0x4e8/0x840 [mxs_dcp])
[ 69.108117] [<bf10406c>] (dcp_chan_thread_aes [mxs_dcp]) from [<c0140d1c>] (kthread+0x134/0x160)
[ 69.116941] [<c0140d1c>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
[ 69.124178] Exception stack(0xc2cbbfb0 to 0xc2cbbff8)
[ 69.129250] bfa0: 00000000 00000000 00000000 00000000
[ 69.137450] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 69.145648] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[ 69.152289] Code: e320f000 e4803004 e4804004 e4805004 (e4806004)

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/crypto/mxs-dcp.c | 36 +++++++++---------------------------
1 file changed, 9 insertions(+), 27 deletions(-)

diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
index f8a48a84df2a..658a78974a22 100644
--- a/drivers/crypto/mxs-dcp.c
+++ b/drivers/crypto/mxs-dcp.c
@@ -281,21 +281,20 @@ static int mxs_dcp_aes_block_crypt(struct crypto_async_request *arq)

struct scatterlist *dst = req->dst;
struct scatterlist *src = req->src;
- const int nents = sg_nents(req->src);
+ int dst_nents = sg_nents(dst);

const int out_off = DCP_BUF_SZ;
uint8_t *in_buf = sdcp->coh->aes_in_buf;
uint8_t *out_buf = sdcp->coh->aes_out_buf;

- uint8_t *out_tmp, *src_buf, *dst_buf = NULL;
uint32_t dst_off = 0;
+ uint8_t *src_buf = NULL;
uint32_t last_out_len = 0;

uint8_t *key = sdcp->coh->aes_key;

int ret = 0;
- int split = 0;
- unsigned int i, len, clen, rem = 0, tlen = 0;
+ unsigned int i, len, clen, tlen = 0;
int init = 0;
bool limit_hit = false;

@@ -313,7 +312,7 @@ static int mxs_dcp_aes_block_crypt(struct crypto_async_request *arq)
memset(key + AES_KEYSIZE_128, 0, AES_KEYSIZE_128);
}

- for_each_sg(req->src, src, nents, i) {
+ for_each_sg(req->src, src, sg_nents(src), i) {
src_buf = sg_virt(src);
len = sg_dma_len(src);
tlen += len;
@@ -338,34 +337,17 @@ static int mxs_dcp_aes_block_crypt(struct crypto_async_request *arq)
* submit the buffer.
*/
if (actx->fill == out_off || sg_is_last(src) ||
- limit_hit) {
+ limit_hit) {
ret = mxs_dcp_run_aes(actx, req, init);
if (ret)
return ret;
init = 0;

- out_tmp = out_buf;
+ sg_pcopy_from_buffer(dst, dst_nents, out_buf,
+ actx->fill, dst_off);
+ dst_off += actx->fill;
last_out_len = actx->fill;
- while (dst && actx->fill) {
- if (!split) {
- dst_buf = sg_virt(dst);
- dst_off = 0;
- }
- rem = min(sg_dma_len(dst) - dst_off,
- actx->fill);
-
- memcpy(dst_buf + dst_off, out_tmp, rem);
- out_tmp += rem;
- dst_off += rem;
- actx->fill -= rem;
-
- if (dst_off == sg_dma_len(dst)) {
- dst = sg_next(dst);
- split = 0;
- } else {
- split = 1;
- }
- }
+ actx->fill = 0;
}
} while (len);

--
2.30.2