Protect STM32 CRC device from concurrent accesses.
As we create a spinlocked section that increase with buffer size,
we provide a module parameter to release the pressure by splitting
critical section in chunks.
Size of each chunk is defined in burst_size module parameter.
By default burst_size=0, i.e. don't split incoming buffer.
Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff@xxxxxx>
---
drivers/crypto/stm32/stm32-crc32.c | 47 ++++++++++++++++++++++++++++--
1 file changed, 45 insertions(+), 2 deletions(-)
diff --git a/drivers/crypto/stm32/stm32-crc32.c b/drivers/crypto/stm32/stm32-crc32.c
index 413415c216ef..3ba41148c2a4 100644
--- a/drivers/crypto/stm32/stm32-crc32.c
+++ b/drivers/crypto/stm32/stm32-crc32.c
@@ -35,11 +35,16 @@
#define CRC_AUTOSUSPEND_DELAY 50
+static unsigned int burst_size;
+module_param(burst_size, uint, 0644);
+MODULE_PARM_DESC(burst_size, "Select burst byte size (0 unlimited)");
+
struct stm32_crc {
struct list_head list;
struct device *dev;
void __iomem *regs;
struct clk *clk;
+ spinlock_t lock;
};
struct stm32_crc_list {
@@ -109,6 +114,7 @@ static int stm32_crc_init(struct shash_desc *desc)
struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
struct stm32_crc *crc;
+ unsigned long flags;
crc = stm32_crc_get_next_crc();
if (!crc)
@@ -116,6 +122,8 @@ static int stm32_crc_init(struct shash_desc *desc)
pm_runtime_get_sync(crc->dev);
+ spin_lock_irqsave(&crc->lock, flags);
+
/* Reset, set key, poly and configure in bit reverse mode */
writel_relaxed(bitrev32(mctx->key), crc->regs + CRC_INIT);
writel_relaxed(bitrev32(mctx->poly), crc->regs + CRC_POL);
@@ -125,18 +133,21 @@ static int stm32_crc_init(struct shash_desc *desc)
/* Store partial result */
ctx->partial = readl_relaxed(crc->regs + CRC_DR);
+ spin_unlock_irqrestore(&crc->lock, flags);
+
pm_runtime_mark_last_busy(crc->dev);
pm_runtime_put_autosuspend(crc->dev);
return 0;
}
-static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
- unsigned int length)
+static int burst_update(struct shash_desc *desc, const u8 *d8,
+ size_t length)
{
struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
struct stm32_crc *crc;
+ unsigned long flags;
crc = stm32_crc_get_next_crc();
if (!crc)
@@ -144,6 +155,8 @@ static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
pm_runtime_get_sync(crc->dev);
+ spin_lock_irqsave(&crc->lock, flags);
+
/*
* Restore previously calculated CRC for this context as init value
* Restore polynomial configuration
@@ -182,12 +195,40 @@ static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
/* Store partial result */
ctx->partial = readl_relaxed(crc->regs + CRC_DR);
+ spin_unlock_irqrestore(&crc->lock, flags);
+
pm_runtime_mark_last_busy(crc->dev);
pm_runtime_put_autosuspend(crc->dev);
return 0;
}
+static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
+ unsigned int length)
+{
+ const unsigned int burst_sz = burst_size;
+ unsigned int rem_sz;
+ const u8 *cur;
+ size_t size;
+ int ret;
+
+ if (!burst_sz)
+ return burst_update(desc, d8, length);
+
+ /* Digest first bytes not 32bit aligned at first pass in the loop */
+ size = min(length,
+ burst_sz + (unsigned int)d8 - ALIGN_DOWN((unsigned int)d8,
+ sizeof(u32)));
+ for (rem_sz = length, cur = d8; rem_sz;
+ rem_sz -= size, cur += size, size = min(rem_sz, burst_sz)) {
+ ret = burst_update(desc, cur, size);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
static int stm32_crc_final(struct shash_desc *desc, u8 *out)
{
struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
@@ -300,6 +341,8 @@ static int stm32_crc_probe(struct platform_device *pdev)
pm_runtime_irq_safe(dev);
pm_runtime_enable(dev);
+ spin_lock_init(&crc->lock);
+
platform_set_drvdata(pdev, crc);
spin_lock(&crc_list.lock);
--
2.17.1
