[PATCH] SAUCE: crypto: thunderx_zip: Fix fallout from CONFIG_VMAP_STACK

Paolo Pisati paolo.pisati at canonical.com
Tue Mar 27 10:31:53 UTC 2018


From: Jan Glauber <jglauber at cavium.com>

BugLink: http://bugs.launchpad.net/bugs/1755073

Enabling virtual mapped kernel stacks breaks the thunderx_zip
driver. On compression or decompression the executing CPU hangs
in an endless loop. The reason for this is the usage of __pa()
by the driver that does not work for an address that is
not part of the 1:1 mapping.

The zip driver allocates a result struct on the stack and needs
to tell the hardware the pysical address within this struct
that is used to signal the completion of the request.
With CONFIG_VMAP_STACK __pa() is no longer usable for a stack address.

As the hardware gets the wrong address it writes the result byte
to an arbitrary address. The zip driver then waits forever for the
completion byte to contain a non-zero value.

Allocating the result struct from 1:1 mapped memory resolves this
bug.

Note that there are more outstanding issues with the used completion
mechanism:
- volatile is used for a bitfield
- no barriers at all re used
- the completion loop should have a retry counter and not run forever
- polling for the result should use a delay
- interrupts for completion and error notification should be used

Signed-off-by: Jan Glauber <jglauber at cavium.com>
Signed-off-by: Paolo Pisati <paolo.pisati at canonical.com>
---
 drivers/crypto/cavium/zip/zip_crypto.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/crypto/cavium/zip/zip_crypto.c b/drivers/crypto/cavium/zip/zip_crypto.c
index 8df4d26..2fc9b03 100644
--- a/drivers/crypto/cavium/zip/zip_crypto.c
+++ b/drivers/crypto/cavium/zip/zip_crypto.c
@@ -124,7 +124,7 @@ int zip_compress(const u8 *src, unsigned int slen,
 		 struct zip_kernel_ctx *zip_ctx)
 {
 	struct zip_operation  *zip_ops   = NULL;
-	struct zip_state      zip_state;
+	struct zip_state      *zip_state;
 	struct zip_device     *zip = NULL;
 	int ret;
 
@@ -135,20 +135,23 @@ int zip_compress(const u8 *src, unsigned int slen,
 	if (!zip)
 		return -ENODEV;
 
-	memset(&zip_state, 0, sizeof(struct zip_state));
+	zip_state = kzalloc(sizeof(*zip_state), GFP_KERNEL);
+	if (!zip_state)
+		return -ENOMEM;
+
 	zip_ops = &zip_ctx->zip_comp;
 
 	zip_ops->input_len  = slen;
 	zip_ops->output_len = *dlen;
 	memcpy(zip_ops->input, src, slen);
 
-	ret = zip_deflate(zip_ops, &zip_state, zip);
+	ret = zip_deflate(zip_ops, zip_state, zip);
 
 	if (!ret) {
 		*dlen = zip_ops->output_len;
 		memcpy(dst, zip_ops->output, *dlen);
 	}
-
+	kfree(zip_state);
 	return ret;
 }
 
@@ -157,7 +160,7 @@ int zip_decompress(const u8 *src, unsigned int slen,
 		   struct zip_kernel_ctx *zip_ctx)
 {
 	struct zip_operation  *zip_ops   = NULL;
-	struct zip_state      zip_state;
+	struct zip_state      *zip_state;
 	struct zip_device     *zip = NULL;
 	int ret;
 
@@ -168,7 +171,10 @@ int zip_decompress(const u8 *src, unsigned int slen,
 	if (!zip)
 		return -ENODEV;
 
-	memset(&zip_state, 0, sizeof(struct zip_state));
+	zip_state = kzalloc(sizeof(*zip_state), GFP_KERNEL);
+	if (!zip_state)
+		return -ENOMEM;
+
 	zip_ops = &zip_ctx->zip_decomp;
 	memcpy(zip_ops->input, src, slen);
 
@@ -179,13 +185,13 @@ int zip_decompress(const u8 *src, unsigned int slen,
 	zip_ops->input_len  = slen;
 	zip_ops->output_len = *dlen;
 
-	ret = zip_inflate(zip_ops, &zip_state, zip);
+	ret = zip_inflate(zip_ops, zip_state, zip);
 
 	if (!ret) {
 		*dlen = zip_ops->output_len;
 		memcpy(dst, zip_ops->output, *dlen);
 	}
-
+	kfree(zip_state);
 	return ret;
 }
 
-- 
2.7.4





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