1 files changed, 141 insertions, 0 deletions

diff --git a/arch/x86_64/lib/bitops.c b/arch/x86_64/lib/bitops.c
new file mode 100644
index 000000000000..a29fb75b33ac
--- /dev/null
+++ b/arch/x86_64/lib/bitops.c
@@ -0,0 +1,141 @@
+#include <linux/bitops.h>
+
+#undef find_first_zero_bit
+#undef find_next_zero_bit
+#undef find_first_bit
+#undef find_next_bit
+
+/**
+ * find_first_zero_bit - find the first zero bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit-number of the first zero bit, not the number of the byte
+ * containing a bit.
+ */
+inline long find_first_zero_bit(const unsigned long * addr, unsigned long size)
+{
+        long d0, d1, d2;
+        long res;
+
+        if (!size)
+                return 0;
+        asm volatile(
+                "  repe; scasq\n"
+                "  je 1f\n"
+                "  xorq -8(%%rdi),%%rax\n"
+                "  subq $8,%%rdi\n"
+                "  bsfq %%rax,%%rdx\n"
+                "1:  subq %[addr],%%rdi\n"
+                "  shlq $3,%%rdi\n"
+                "  addq %%rdi,%%rdx"
+                :"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2)
+                :"0" (0ULL), "1" ((size + 63) >> 6), "2" (addr), "3" (-1ULL),
+                 [addr] "r" (addr) : "memory");
+        return res;
+}
+
+/**
+ * find_next_zero_bit - find the first zero bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The maximum size to search
+ */
+long find_next_zero_bit (const unsigned long * addr, long size, long offset)
+{
+        unsigned long * p = ((unsigned long *) addr) + (offset >> 6);
+        unsigned long set = 0;
+        unsigned long res, bit = offset&63;
+
+        if (bit) {
+                /*
+                 * Look for zero in first word
+                 */
+                asm("bsfq %1,%0\n\t"
+                    "cmoveq %2,%0"
+                    : "=r" (set)
+                    : "r" (~(*p >> bit)), "r"(64L));
+                if (set < (64 - bit))
+                        return set + offset;
+                set = 64 - bit;
+                p++;
+        }
+        /*
+         * No zero yet, search remaining full words for a zero
+         */
+        res = find_first_zero_bit ((const unsigned long *)p,
+                                   size - 64 * (p - (unsigned long *) addr));
+        return (offset + set + res);
+}
+
+static inline long
+__find_first_bit(const unsigned long * addr, unsigned long size)
+{
+        long d0, d1;
+        long res;
+
+        asm volatile(
+                "   repe; scasq\n"
+                "   jz 1f\n"
+                "   subq $8,%%rdi\n"
+                "   bsfq (%%rdi),%%rax\n"
+                "1: subq %[addr],%%rdi\n"
+                "   shlq $3,%%rdi\n"
+                "   addq %%rdi,%%rax"
+                :"=a" (res), "=&c" (d0), "=&D" (d1)
+                :"0" (0ULL),
+                 "1" ((size + 63) >> 6), "2" (addr),
+                 [addr] "r" (addr) : "memory");
+        return res;
+}
+
+/**
+ * find_first_bit - find the first set bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit-number of the first set bit, not the number of the byte
+ * containing a bit.
+ */
+long find_first_bit(const unsigned long * addr, unsigned long size)
+{
+        return __find_first_bit(addr,size);
+}
+
+/**
+ * find_next_bit - find the first set bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The maximum size to search
+ */
+long find_next_bit(const unsigned long * addr, long size, long offset)
+{
+        const unsigned long * p = addr + (offset >> 6);
+        unsigned long set = 0, bit = offset & 63, res;
+
+        if (bit) {
+                /*
+                 * Look for nonzero in the first 64 bits:
+                 */
+                asm("bsfq %1,%0\n\t"
+                    "cmoveq %2,%0\n\t"
+                    : "=r" (set)
+                    : "r" (*p >> bit), "r" (64L));
+                if (set < (64 - bit))
+                        return set + offset;
+                set = 64 - bit;
+                p++;
+        }
+        /*
+         * No set bit yet, search remaining full words for a bit
+         */
+        res = __find_first_bit (p, size - 64 * (p - addr));
+        return (offset + set + res);
+}
+
+#include <linux/module.h>
+
+EXPORT_SYMBOL(find_next_bit);
+EXPORT_SYMBOL(find_first_bit);
+EXPORT_SYMBOL(find_first_zero_bit);
+EXPORT_SYMBOL(find_next_zero_bit);