[PATCH v4 6/8] crypto: sun4i-ss: fix kmap usage

Corentin Labbe
2020-12-14T20:05:51Z

With the recent kmap change, some tests which were conditional on
CONFIG_DEBUG_HIGHMEM now are enabled by default.
This permit to detect a problem in sun4i-ss usage of kmap.

sun4i-ss uses two kmap via sg_miter (one for input, one for output), but
using two kmap at the same time is hard:
"the ordering has to be correct and with sg_miter that's probably hard to get
right." (quoting Tlgx)

So the easiest solution is to never have two sg_miter/kmap open at the same time.
After each use of sg_miter, I store the current index, for being able to
resume sg_miter to the right place.

Fixes: 6298e948215f ("crypto: sunxi-ss - Add Allwinner Security System crypto accelerator")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
---
.../allwinner/sun4i-ss/sun4i-ss-cipher.c | 109 +++++++++++-------
1 file changed, 65 insertions(+), 44 deletions(-)

diff --git a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
index 5759fa79f293..ffa628c89e21 100644
--- a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
+++ b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
@@ -31,6 +31,8 @@ static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
unsigned int ileft = areq->cryptlen;
unsigned int oleft = areq->cryptlen;
unsigned int todo;
+ unsigned long pi = 0, po = 0; /* progress for in and out */
+ bool miter_err;
struct sg_mapping_iter mi, mo;
unsigned int oi, oo; /* offset for in and out */
unsigned long flags;
@@ -63,39 +65,51 @@ static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
}
writel(mode, ss->base + SS_CTL);

- sg_miter_start(&mi, areq->src, sg_nents(areq->src),
- SG_MITER_FROM_SG | SG_MITER_ATOMIC);
- sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
- SG_MITER_TO_SG | SG_MITER_ATOMIC);
- sg_miter_next(&mi);
- sg_miter_next(&mo);
- if (!mi.addr || !mo.addr) {
- dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
- err = -EINVAL;
- goto release_ss;
- }

ileft = areq->cryptlen / 4;
oleft = areq->cryptlen / 4;
oi = 0;
oo = 0;
do {
- todo = min(rx_cnt, ileft);
- todo = min_t(size_t, todo, (mi.length - oi) / 4);
- if (todo) {
- ileft -= todo;
- writesl(ss->base + SS_RXFIFO, mi.addr + oi, todo);
- oi += todo * 4;
- }
- if (oi == mi.length) {
- sg_miter_next(&mi);
- oi = 0;
+ if (ileft) {
+ sg_miter_start(&mi, areq->src, sg_nents(areq->src),
+ SG_MITER_FROM_SG | SG_MITER_ATOMIC);
+ if (pi)
+ sg_miter_skip(&mi, pi);
+ miter_err = sg_miter_next(&mi);
+ if (!miter_err || !mi.addr) {
+ dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
+ err = -EINVAL;
+ goto release_ss;
+ }
+ todo = min(rx_cnt, ileft);
+ todo = min_t(size_t, todo, (mi.length - oi) / 4);
+ if (todo) {
+ ileft -= todo;
+ writesl(ss->base + SS_RXFIFO, mi.addr + oi, todo);
+ oi += todo * 4;
+ }
+ if (oi == mi.length) {
+ pi += mi.length;
+ oi = 0;
+ }
+ sg_miter_stop(&mi);
}

spaces = readl(ss->base + SS_FCSR);
rx_cnt = SS_RXFIFO_SPACES(spaces);
tx_cnt = SS_TXFIFO_SPACES(spaces);

+ sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
+ SG_MITER_TO_SG | SG_MITER_ATOMIC);
+ if (po)
+ sg_miter_skip(&mo, po);
+ miter_err = sg_miter_next(&mo);
+ if (!miter_err || !mo.addr) {
+ dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
+ err = -EINVAL;
+ goto release_ss;
+ }
todo = min(tx_cnt, oleft);
todo = min_t(size_t, todo, (mo.length - oo) / 4);
if (todo) {
@@ -104,9 +118,10 @@ static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
oo += todo * 4;
}
if (oo == mo.length) {
- sg_miter_next(&mo);
oo = 0;
+ po += mo.length;
}
+ sg_miter_stop(&mo);
} while (oleft);

if (areq->iv) {
@@ -120,8 +135,6 @@ static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
}

release_ss:
- sg_miter_stop(&mi);
- sg_miter_stop(&mo);
writel(0, ss->base + SS_CTL);
spin_unlock_irqrestore(&ss->slock, flags);
return err;
@@ -174,6 +187,8 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
unsigned int todo;
void *backup_iv = NULL;
struct sg_mapping_iter mi, mo;
+ unsigned long pi = 0, po = 0; /* progress for in and out */
+ bool miter_err;
unsigned int oi, oo; /* offset for in and out */
unsigned int ob = 0; /* offset in buf */
unsigned int obo = 0; /* offset in bufo*/
@@ -234,17 +249,6 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
}
writel(mode, ss->base + SS_CTL);

- sg_miter_start(&mi, areq->src, sg_nents(areq->src),
- SG_MITER_FROM_SG | SG_MITER_ATOMIC);
- sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
- SG_MITER_TO_SG | SG_MITER_ATOMIC);
- sg_miter_next(&mi);
- sg_miter_next(&mo);
- if (!mi.addr || !mo.addr) {
- dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
- err = -EINVAL;
- goto release_ss;
- }
ileft = areq->cryptlen;
oleft = areq->cryptlen;
oi = 0;
@@ -252,6 +256,16 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)

while (oleft) {
if (ileft) {
+ sg_miter_start(&mi, areq->src, sg_nents(areq->src),
+ SG_MITER_FROM_SG | SG_MITER_ATOMIC);
+ if (pi)
+ sg_miter_skip(&mi, pi);
+ miter_err = sg_miter_next(&mi);
+ if (!miter_err || !mi.addr) {
+ dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
+ err = -EINVAL;
+ goto release_ss;
+ }
/*
* todo is the number of consecutive 4byte word that we
* can read from current SG
@@ -284,31 +298,38 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
}
}
if (oi == mi.length) {
- sg_miter_next(&mi);
+ pi += mi.length;
oi = 0;
}
+ sg_miter_stop(&mi);
}

spaces = readl(ss->base + SS_FCSR);
rx_cnt = SS_RXFIFO_SPACES(spaces);
tx_cnt = SS_TXFIFO_SPACES(spaces);
- dev_dbg(ss->dev,
- "%x %u/%zu %u/%u cnt=%u %u/%zu %u/%u cnt=%u %u\n",
- mode,
- oi, mi.length, ileft, areq->cryptlen, rx_cnt,
- oo, mo.length, oleft, areq->cryptlen, tx_cnt, ob);

if (!tx_cnt)
continue;
+ sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
+ SG_MITER_TO_SG | SG_MITER_ATOMIC);
+ if (po)
+ sg_miter_skip(&mo, po);
+ miter_err = sg_miter_next(&mo);
+ if (!miter_err || !mo.addr) {
+ dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
+ err = -EINVAL;
+ goto release_ss;
+ }
/* todo in 4bytes word */
todo = min(tx_cnt, oleft / 4);
todo = min_t(size_t, todo, (mo.length - oo) / 4);
+
if (todo) {
readsl(ss->base + SS_TXFIFO, mo.addr + oo, todo);
oleft -= todo * 4;
oo += todo * 4;
if (oo == mo.length) {
- sg_miter_next(&mo);
+ po += mo.length;
oo = 0;
}
} else {
@@ -333,12 +354,14 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
obo += todo;
oo += todo;
if (oo == mo.length) {
+ po += mo.length;
sg_miter_next(&mo);
oo = 0;
}
} while (obo < obl);
/* bufo must be fully used here */
}
+ sg_miter_stop(&mo);
}
if (areq->iv) {
if (mode & SS_DECRYPTION) {
@@ -351,8 +374,6 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
}

release_ss:
- sg_miter_stop(&mi);
- sg_miter_stop(&mo);
writel(0, ss->base + SS_CTL);
spin_unlock_irqrestore(&ss->slock, flags);

--
2.26.2