arch/tile: finish enabling support for TILE-Gx 64-bit chip

This support was partially present in the existing code (look for
"__tilegx__" ifdefs) but with this change you can build a working
kernel using the TILE-Gx toolchain and ARCH=tilegx.

Most of these files are new, generally adding a foo_64.c file
where previously there was just a foo_32.c file.

The ARCH=tilegx directive redirects to arch/tile, not arch/tilegx,
using the existing SRCARCH mechanism in the top-level Makefile.

Changes to existing files:

- <asm/bitops.h> and <asm/bitops_32.h> changed to factor the
  include of <asm-generic/bitops/non-atomic.h> in the common header.

- <asm/compat.h> and arch/tile/kernel/compat.c changed to remove
  the "const" markers I had put on compat_sys_execve() when trying
  to match some recent similar changes to the non-compat execve.
  It turns out the compat version wasn't "upgraded" to use const.

- <asm/opcode-tile_64.h> and <asm/opcode_constants_64.h> were
  previously included accidentally, with the 32-bit contents.  Now
  they have the proper 64-bit contents.

Finally, I had to hack the existing hacky drivers/input/input-compat.h
to add yet another "#ifdef" for INPUT_COMPAT_TEST (same as x86_64).

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> [drivers/input]

1 files changed, 67 insertions, 0 deletions

diff --git a/arch/tile/lib/strchr_64.c b/arch/tile/lib/strchr_64.c
new file mode 100644
index 000000000000..617a9273aaa8
--- /dev/null
+++ b/arch/tile/lib/strchr_64.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/module.h>
+
+#undef strchr
+
+char *strchr(const char *s, int c)
+{
+	int z, g;
+
+	/* Get an aligned pointer. */
+	const uintptr_t s_int = (uintptr_t) s;
+	const uint64_t *p = (const uint64_t *)(s_int & -8);
+
+	/* Create eight copies of the byte for which we are looking. */
+	const uint64_t goal = 0x0101010101010101ULL * (uint8_t) c;
+
+	/* Read the first aligned word, but force bytes before the string to
+	 * match neither zero nor goal (we make sure the high bit of each
+	 * byte is 1, and the low 7 bits are all the opposite of the goal
+	 * byte).
+	 *
+	 * Note that this shift count expression works because we know shift
+	 * counts are taken mod 64.
+	 */
+	const uint64_t before_mask = (1ULL << (s_int << 3)) - 1;
+	uint64_t v = (*p | before_mask) ^
+		(goal & __insn_v1shrsi(before_mask, 1));
+
+	uint64_t zero_matches, goal_matches;
+	while (1) {
+		/* Look for a terminating '\0'. */
+		zero_matches = __insn_v1cmpeqi(v, 0);
+
+		/* Look for the goal byte. */
+		goal_matches = __insn_v1cmpeq(v, goal);
+
+		if (__builtin_expect((zero_matches | goal_matches) != 0, 0))
+			break;
+
+		v = *++p;
+	}
+
+	z = __insn_ctz(zero_matches);
+	g = __insn_ctz(goal_matches);
+
+	/* If we found c before '\0' we got a match. Note that if c == '\0'
+	 * then g == z, and we correctly return the address of the '\0'
+	 * rather than NULL.
+	 */
+	return (g <= z) ? ((char *)p) + (g >> 3) : NULL;
+}
+EXPORT_SYMBOL(strchr);