[PATCH v2 21/39] xen/riscv: introduce bit operations

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in V2:
 - Nothing changed. Only rebase.
---
 xen/arch/riscv/Makefile            |   1 +
 xen/arch/riscv/lib/Makefile        |   1 +
 xen/arch/riscv/lib/find_next_bit.c | 278 +++++++++++++++++++++++++++++
 3 files changed, 280 insertions(+)
 create mode 100644 xen/arch/riscv/lib/Makefile
 create mode 100644 xen/arch/riscv/lib/find_next_bit.c

diff --git a/xen/arch/riscv/Makefile b/xen/arch/riscv/Makefile
index 2fefe14e7c..b08048948f 100644
--- a/xen/arch/riscv/Makefile
+++ b/xen/arch/riscv/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-y += entry.o
+obj-y += lib/
 obj-y += mm.o
 obj-$(CONFIG_RISCV_64) += riscv64/
 obj-y += sbi.o
diff --git a/xen/arch/riscv/lib/Makefile b/xen/arch/riscv/lib/Makefile
new file mode 100644
index 0000000000..6fae6a1f10
--- /dev/null
+++ b/xen/arch/riscv/lib/Makefile
@@ -0,0 +1 @@
+obj-y += find_next_bit.o
diff --git a/xen/arch/riscv/lib/find_next_bit.c 
b/xen/arch/riscv/lib/find_next_bit.c
new file mode 100644
index 0000000000..ac5a4687e3
--- /dev/null
+++ b/xen/arch/riscv/lib/find_next_bit.c
@@ -0,0 +1,278 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * find_next_bit.c: fallback find next bit implementation
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@xxxxxxxxxx)
+ */
+#include <xen/bitops.h>
+#include <asm/types.h>
+#include <asm/byteorder.h>
+
+#ifndef find_next_bit
+/*
+ * Find the next set bit in a memory region.
+ */
+unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
+                           unsigned long offset)
+{
+       const unsigned long *p = addr + BIT_WORD(offset);
+       unsigned long result = offset & ~(BITS_PER_LONG-1);
+       unsigned long tmp;
+
+       if (offset >= size)
+               return size;
+       size -= result;
+       offset %= BITS_PER_LONG;
+       if (offset) {
+               tmp = *(p++);
+               tmp &= (~0UL << offset);
+               if (size < BITS_PER_LONG)
+                       goto found_first;
+               if (tmp)
+                       goto found_middle;
+               size -= BITS_PER_LONG;
+               result += BITS_PER_LONG;
+       }
+       while (size & ~(BITS_PER_LONG-1)) {
+               if ((tmp = *(p++)))
+                       goto found_middle;
+               result += BITS_PER_LONG;
+               size -= BITS_PER_LONG;
+       }
+       if (!size)
+               return result;
+       tmp = *p;
+
+found_first:
+       tmp &= (~0UL >> (BITS_PER_LONG - size));
+       if (tmp == 0UL)         /* Are any bits set? */
+               return result + size;   /* Nope. */
+found_middle:
+       return result + __ffs(tmp);
+}
+EXPORT_SYMBOL(find_next_bit);
+#endif
+
+#ifndef find_next_zero_bit
+/*
+ * This implementation of find_{first,next}_zero_bit was stolen from
+ * Linus' asm-alpha/bitops.h.
+ */
+unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
+                                unsigned long offset)
+{
+       const unsigned long *p = addr + BIT_WORD(offset);
+       unsigned long result = offset & ~(BITS_PER_LONG-1);
+       unsigned long tmp;
+
+       if (offset >= size)
+               return size;
+       size -= result;
+       offset %= BITS_PER_LONG;
+       if (offset) {
+               tmp = *(p++);
+               tmp |= ~0UL >> (BITS_PER_LONG - offset);
+               if (size < BITS_PER_LONG)
+                       goto found_first;
+               if (~tmp)
+                       goto found_middle;
+               size -= BITS_PER_LONG;
+               result += BITS_PER_LONG;
+       }
+       while (size & ~(BITS_PER_LONG-1)) {
+               if (~(tmp = *(p++)))
+                       goto found_middle;
+               result += BITS_PER_LONG;
+               size -= BITS_PER_LONG;
+       }
+       if (!size)
+               return result;
+       tmp = *p;
+
+found_first:
+       tmp |= ~0UL << size;
+       if (tmp == ~0UL)        /* Are any bits zero? */
+               return result + size;   /* Nope. */
+found_middle:
+       return result + ffz(tmp);
+}
+EXPORT_SYMBOL(find_next_zero_bit);
+#endif
+
+#ifndef find_first_bit
+/*
+ * Find the first set bit in a memory region.
+ */
+unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
+{
+       const unsigned long *p = addr;
+       unsigned long result = 0;
+       unsigned long tmp;
+
+       while (size & ~(BITS_PER_LONG-1)) {
+               if ((tmp = *(p++)))
+                       goto found;
+               result += BITS_PER_LONG;
+               size -= BITS_PER_LONG;
+       }
+       if (!size)
+               return result;
+
+       tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
+       if (tmp == 0UL)         /* Are any bits set? */
+               return result + size;   /* Nope. */
+found:
+       return result + __ffs(tmp);
+}
+EXPORT_SYMBOL(find_first_bit);
+#endif
+
+#ifndef find_first_zero_bit
+/*
+ * Find the first cleared bit in a memory region.
+ */
+unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long 
size)
+{
+       const unsigned long *p = addr;
+       unsigned long result = 0;
+       unsigned long tmp;
+
+       while (size & ~(BITS_PER_LONG-1)) {
+               if (~(tmp = *(p++)))
+                       goto found;
+               result += BITS_PER_LONG;
+               size -= BITS_PER_LONG;
+       }
+       if (!size)
+               return result;
+
+       tmp = (*p) | (~0UL << size);
+       if (tmp == ~0UL)        /* Are any bits zero? */
+               return result + size;   /* Nope. */
+found:
+       return result + ffz(tmp);
+}
+EXPORT_SYMBOL(find_first_zero_bit);
+#endif
+
+#ifdef __BIG_ENDIAN
+
+/* include/linux/byteorder does not support "unsigned long" type */
+static inline unsigned long ext2_swabp(const unsigned long * x)
+{
+#if BITS_PER_LONG == 64
+       return (unsigned long) __swab64p((u64 *) x);
+#elif BITS_PER_LONG == 32
+       return (unsigned long) __swab32p((u32 *) x);
+#else
+#error BITS_PER_LONG not defined
+#endif
+}
+
+/* include/linux/byteorder doesn't support "unsigned long" type */
+static inline unsigned long ext2_swab(const unsigned long y)
+{
+#if BITS_PER_LONG == 64
+       return (unsigned long) __swab64((u64) y);
+#elif BITS_PER_LONG == 32
+       return (unsigned long) __swab32((u32) y);
+#else
+#error BITS_PER_LONG not defined
+#endif
+}
+
+#ifndef find_next_zero_bit_le
+unsigned long find_next_zero_bit_le(const void *addr, unsigned
+               long size, unsigned long offset)
+{
+       const unsigned long *p = addr;
+       unsigned long result = offset & ~(BITS_PER_LONG - 1);
+       unsigned long tmp;
+
+       if (offset >= size)
+               return size;
+       p += BIT_WORD(offset);
+       size -= result;
+       offset &= (BITS_PER_LONG - 1UL);
+       if (offset) {
+               tmp = ext2_swabp(p++);
+               tmp |= (~0UL >> (BITS_PER_LONG - offset));
+               if (size < BITS_PER_LONG)
+                       goto found_first;
+               if (~tmp)
+                       goto found_middle;
+               size -= BITS_PER_LONG;
+               result += BITS_PER_LONG;
+       }
+
+       while (size & ~(BITS_PER_LONG - 1)) {
+               if (~(tmp = *(p++)))
+                       goto found_middle_swap;
+               result += BITS_PER_LONG;
+               size -= BITS_PER_LONG;
+       }
+       if (!size)
+               return result;
+       tmp = ext2_swabp(p);
+found_first:
+       tmp |= ~0UL << size;
+       if (tmp == ~0UL)        /* Are any bits zero? */
+               return result + size; /* Nope. Skip ffz */
+found_middle:
+       return result + ffz(tmp);
+
+found_middle_swap:
+       return result + ffz(ext2_swab(tmp));
+}
+EXPORT_SYMBOL(find_next_zero_bit_le);
+#endif
+
+#ifndef find_next_bit_le
+unsigned long find_next_bit_le(const void *addr, unsigned
+               long size, unsigned long offset)
+{
+       const unsigned long *p = addr;
+       unsigned long result = offset & ~(BITS_PER_LONG - 1);
+       unsigned long tmp;
+
+       if (offset >= size)
+               return size;
+       p += BIT_WORD(offset);
+       size -= result;
+       offset &= (BITS_PER_LONG - 1UL);
+       if (offset) {
+               tmp = ext2_swabp(p++);
+               tmp &= (~0UL << offset);
+               if (size < BITS_PER_LONG)
+                       goto found_first;
+               if (tmp)
+                       goto found_middle;
+               size -= BITS_PER_LONG;
+               result += BITS_PER_LONG;
+       }
+
+       while (size & ~(BITS_PER_LONG - 1)) {
+               tmp = *(p++);
+               if (tmp)
+                       goto found_middle_swap;
+               result += BITS_PER_LONG;
+               size -= BITS_PER_LONG;
+       }
+       if (!size)
+               return result;
+       tmp = ext2_swabp(p);
+found_first:
+       tmp &= (~0UL >> (BITS_PER_LONG - size));
+       if (tmp == 0UL)         /* Are any bits set? */
+               return result + size; /* Nope. */
+found_middle:
+       return result + __ffs(tmp);
+
+found_middle_swap:
+       return result + __ffs(ext2_swab(tmp));
+}
+EXPORT_SYMBOL(find_next_bit_le);
+#endif
+
+#endif /* __BIG_ENDIAN */
-- 
2.42.0