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SubjectCrypto/nx842: Ignore invalid XER[S0] return error
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NX842 coprocessor sets 3rd bit in CR register with XER[S0] which is
nothing to do with NX request. On powerpc, XER[S0] will be set if
overflow in FPU and stays until another floating point operation is
executed. Since this bit can be set with other valuable return status,
ignore this XER[S0] value.

One of other bits (INITIATED, BUSY or REJECTED) will be returned for
any given NX request.

Signed-off-by: Haren Myneni <haren@us.ibm.com>

diff --git a/arch/powerpc/include/asm/icswx.h b/arch/powerpc/include/asm/icswx.h
index 9f8402b..27e588f 100644
--- a/arch/powerpc/include/asm/icswx.h
+++ b/arch/powerpc/include/asm/icswx.h
@@ -164,6 +164,7 @@ struct coprocessor_request_block {
#define ICSWX_INITIATED (0x8)
#define ICSWX_BUSY (0x4)
#define ICSWX_REJECTED (0x2)
+#define ICSWX_XERS0 (0x1) /* undefined or set from XERSO. */

static inline int icswx(__be32 ccw, struct coprocessor_request_block *crb)
{
diff --git a/drivers/crypto/nx/nx-842-powernv.c b/drivers/crypto/nx/nx-842-powernv.c
index 9ef51fa..6bc33ae 100644
--- a/drivers/crypto/nx/nx-842-powernv.c
+++ b/drivers/crypto/nx/nx-842-powernv.c
@@ -442,6 +442,16 @@ static int nx842_powernv_function(const unsigned char *in, unsigned int inlen,
(unsigned int)ccw,
(unsigned int)be32_to_cpu(crb->ccw));

+ /*
+ * NX842 coprocessor sets 3rd bit in CR register with XER[S0].
+ * Setting XER[S0] happens if overflow in FPU and stays until
+ * other floating operation is executed. XER[S0] value is nothing
+ * to NX and no use to user. Since this bit can be set with other
+ * return values, ignore this error.
+ */
+ if (ret & ICSWX_XERS0)
+ ret &= ~ICSWX_XERS0;
+
switch (ret) {
case ICSWX_INITIATED:
ret = wait_for_csb(wmem, csb);
@@ -454,10 +464,6 @@ static int nx842_powernv_function(const unsigned char *in, unsigned int inlen,
pr_err_ratelimited("ICSWX rejected\n");
ret = -EPROTO;
break;
- default:
- pr_err_ratelimited("Invalid ICSWX return code %x\n", ret);
- ret = -EPROTO;
- break;
}

if (!ret)




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