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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_VIRTIO_FEATURES_H
#define _LINUX_VIRTIO_FEATURES_H
#include <linux/bits.h>
#define VIRTIO_FEATURES_DWORDS 2
#define VIRTIO_FEATURES_MAX (VIRTIO_FEATURES_DWORDS * 64)
#define VIRTIO_FEATURES_WORDS (VIRTIO_FEATURES_DWORDS * 2)
#define VIRTIO_BIT(b) BIT_ULL((b) & 0x3f)
#define VIRTIO_DWORD(b) ((b) >> 6)
#define VIRTIO_DECLARE_FEATURES(name) \
union { \
u64 name; \
u64 name##_array[VIRTIO_FEATURES_DWORDS];\
}
static inline bool virtio_features_chk_bit(unsigned int bit)
{
if (__builtin_constant_p(bit)) {
/*
* Don't care returning the correct value: the build
* will fail before any bad features access
*/
BUILD_BUG_ON(bit >= VIRTIO_FEATURES_MAX);
} else {
if (WARN_ON_ONCE(bit >= VIRTIO_FEATURES_MAX))
return false;
}
return true;
}
static inline bool virtio_features_test_bit(const u64 *features,
unsigned int bit)
{
return virtio_features_chk_bit(bit) &&
!!(features[VIRTIO_DWORD(bit)] & VIRTIO_BIT(bit));
}
static inline void virtio_features_set_bit(u64 *features,
unsigned int bit)
{
if (virtio_features_chk_bit(bit))
features[VIRTIO_DWORD(bit)] |= VIRTIO_BIT(bit);
}
static inline void virtio_features_clear_bit(u64 *features,
unsigned int bit)
{
if (virtio_features_chk_bit(bit))
features[VIRTIO_DWORD(bit)] &= ~VIRTIO_BIT(bit);
}
static inline void virtio_features_zero(u64 *features)
{
memset(features, 0, sizeof(features[0]) * VIRTIO_FEATURES_DWORDS);
}
static inline void virtio_features_from_u64(u64 *features, u64 from)
{
virtio_features_zero(features);
features[0] = from;
}
static inline bool virtio_features_equal(const u64 *f1, const u64 *f2)
{
int i;
for (i = 0; i < VIRTIO_FEATURES_DWORDS; ++i)
if (f1[i] != f2[i])
return false;
return true;
}
static inline void virtio_features_copy(u64 *to, const u64 *from)
{
memcpy(to, from, sizeof(to[0]) * VIRTIO_FEATURES_DWORDS);
}
static inline void virtio_features_andnot(u64 *to, const u64 *f1, const u64 *f2)
{
int i;
for (i = 0; i < VIRTIO_FEATURES_DWORDS; i++)
to[i] = f1[i] & ~f2[i];
}
#endif
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