1 files changed, 64 insertions, 0 deletions
diff --git a/arch/s390/include/asm/word-at-a-time.h b/arch/s390/include/asm/word-at-a-time.h
new file mode 100644
index 000000000000..2579f1694b82
--- /dev/null
+++ b/arch/s390/include/asm/word-at-a-time.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_WORD_AT_A_TIME_H
+#define _ASM_WORD_AT_A_TIME_H
+
+#include <linux/kernel.h>
+#include <asm/asm-extable.h>
+#include <asm/bitsperlong.h>
+
+struct word_at_a_time {
+	const unsigned long bits;
+};
+
+#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x7f) }
+
+static inline unsigned long prep_zero_mask(unsigned long val, unsigned long data, const struct word_at_a_time *c)
+{
+	return data;
+}
+
+static inline unsigned long create_zero_mask(unsigned long data)
+{
+	return __fls(data);
+}
+
+static inline unsigned long find_zero(unsigned long data)
+{
+	return (data ^ (BITS_PER_LONG - 1)) >> 3;
+}
+
+static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
+{
+	unsigned long mask = (val & c->bits) + c->bits;
+
+	*data = ~(mask | val | c->bits);
+	return *data;
+}
+
+static inline unsigned long zero_bytemask(unsigned long data)
+{
+	return ~1UL << data;
+}
+
+/*
+ * Load an unaligned word from kernel space.
+ *
+ * In the (very unlikely) case of the word being a page-crosser
+ * and the next page not being mapped, take the exception and
+ * return zeroes in the non-existing part.
+ */
+static inline unsigned long load_unaligned_zeropad(const void *addr)
+{
+	unsigned long data;
+
+	asm volatile(
+		"0:	lg	%[data],0(%[addr])\n"
+		"1:	nopr	%%r7\n"
+		EX_TABLE_ZEROPAD(0b, 1b, %[data], %[addr])
+		EX_TABLE_ZEROPAD(1b, 1b, %[data], %[addr])
+		: [data] "=d" (data)
+		: [addr] "a" (addr), "m" (*(unsigned long *)addr));
+	return data;
+}
+
+#endif /* _ASM_WORD_AT_A_TIME_H */