1 files changed, 94 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h
new file mode 100644
index 000000000000..aab5bf09e9d9
--- /dev/null
+++ b/arch/arm64/include/asm/word-at-a-time.h
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ASM_WORD_AT_A_TIME_H
+#define __ASM_WORD_AT_A_TIME_H
+
+#ifndef __AARCH64EB__
+
+#include <linux/kernel.h>
+
+struct word_at_a_time {
+        const unsigned long one_bits, high_bits;
+};
+
+#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
+
+static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
+                                     const struct word_at_a_time *c)
+{
+        unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
+        *bits = mask;
+        return mask;
+}
+
+#define prep_zero_mask(a, bits, c) (bits)
+
+static inline unsigned long create_zero_mask(unsigned long bits)
+{
+        bits = (bits - 1) & ~bits;
+        return bits >> 7;
+}
+
+static inline unsigned long find_zero(unsigned long mask)
+{
+        return fls64(mask) >> 3;
+}
+
+#define zero_bytemask(mask) (mask)
+
+#else   /* __AARCH64EB__ */
+#include <asm-generic/word-at-a-time.h>
+#endif
+
+/*
+ * 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 ret, offset;
+
+        /* Load word from unaligned pointer addr */
+        asm(
+        "1:     ldr     %0, %3\n"
+        "2:\n"
+        "       .pushsection .fixup,\"ax\"\n"
+        "       .align 2\n"
+        "3:     and     %1, %2, #0x7\n"
+        "       bic     %2, %2, #0x7\n"
+        "       ldr     %0, [%2]\n"
+        "       lsl     %1, %1, #0x3\n"
+#ifndef __AARCH64EB__
+        "       lsr     %0, %0, %1\n"
+#else
+        "       lsl     %0, %0, %1\n"
+#endif
+        "       b       2b\n"
+        "       .popsection\n"
+        "       .pushsection __ex_table,\"a\"\n"
+        "       .align  3\n"
+        "       .quad   1b, 3b\n"
+        "       .popsection"
+        : "=&r" (ret), "=&r" (offset)
+        : "r" (addr), "Q" (*(unsigned long *)addr));
+
+        return ret;
+}
+
+#endif /* __ASM_WORD_AT_A_TIME_H */