1 files changed, 91 insertions, 0 deletions
diff --git a/arch/s390/lib/csum-partial.c b/arch/s390/lib/csum-partial.c
new file mode 100644
index 000000000000..458abd9bac70
--- /dev/null
+++ b/arch/s390/lib/csum-partial.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <asm/checksum.h>
+#include <asm/fpu.h>
+
+/*
+ * Computes the checksum of a memory block at src, length len,
+ * and adds in "sum" (32-bit). If copy is true copies to dst.
+ *
+ * Returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic.
+ *
+ * This function must be called with even lengths, except
+ * for the last fragment, which may be odd.
+ *
+ * It's best to have src and dst aligned on a 64-bit boundary.
+ */
+static __always_inline __wsum csum_copy(void *dst, const void *src, int len, __wsum sum, bool copy)
+{
+	DECLARE_KERNEL_FPU_ONSTACK8(vxstate);
+
+	if (!cpu_has_vx()) {
+		if (copy)
+			memcpy(dst, src, len);
+		return cksm(dst, len, sum);
+	}
+	kernel_fpu_begin(&vxstate, KERNEL_VXR_V16V23);
+	fpu_vlvgf(16, (__force u32)sum, 1);
+	fpu_vzero(17);
+	fpu_vzero(18);
+	fpu_vzero(19);
+	while (len >= 64) {
+		fpu_vlm(20, 23, src);
+		if (copy) {
+			fpu_vstm(20, 23, dst);
+			dst += 64;
+		}
+		fpu_vcksm(16, 20, 16);
+		fpu_vcksm(17, 21, 17);
+		fpu_vcksm(18, 22, 18);
+		fpu_vcksm(19, 23, 19);
+		src += 64;
+		len -= 64;
+	}
+	while (len >= 32) {
+		fpu_vlm(20, 21, src);
+		if (copy) {
+			fpu_vstm(20, 21, dst);
+			dst += 32;
+		}
+		fpu_vcksm(16, 20, 16);
+		fpu_vcksm(17, 21, 17);
+		src += 32;
+		len -= 32;
+	}
+	while (len >= 16) {
+		fpu_vl(20, src);
+		if (copy) {
+			fpu_vst(20, dst);
+			dst += 16;
+		}
+		fpu_vcksm(16, 20, 16);
+		src += 16;
+		len -= 16;
+	}
+	if (len) {
+		fpu_vll(20, len - 1, src);
+		if (copy)
+			fpu_vstl(20, len - 1, dst);
+		fpu_vcksm(16, 20, 16);
+	}
+	fpu_vcksm(18, 19, 18);
+	fpu_vcksm(16, 17, 16);
+	fpu_vcksm(16, 18, 16);
+	sum = (__force __wsum)fpu_vlgvf(16, 1);
+	kernel_fpu_end(&vxstate, KERNEL_VXR_V16V23);
+	return sum;
+}
+
+__wsum csum_partial(const void *buff, int len, __wsum sum)
+{
+	return csum_copy(NULL, buff, len, sum, false);
+}
+EXPORT_SYMBOL(csum_partial);
+
+__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
+{
+	return csum_copy(dst, src, len, 0, true);
+}
+EXPORT_SYMBOL(csum_partial_copy_nocheck);