[Minios-devel] [UNIKRAFT PATCH v5 08/15] include/uk: bitopts.h - remove already existing functions

[Yuri Volchkov <yuri.volchkov@xxxxxxxxx>]

Some of the functions provided by bitopts.h are already implemented in
unikraft. This patch turns these functions into wrappers around
existing ones.

The original FreeBSD code is using the same (atomic) function for both
__set_bit and set_bit. That is not correct. The underscored version
should be non-atomic.

This patch also drops the test_bit for now, because there is a problem
with it's implementation.

Signed-off-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
---
 include/uk/bitops.h | 76 ++++++++++-----------------------------------
 1 file changed, 17 insertions(+), 59 deletions(-)

diff --git a/include/uk/bitops.h b/include/uk/bitops.h
index e003a43..bb77e04 100644
--- a/include/uk/bitops.h
+++ b/include/uk/bitops.h
@@ -58,11 +58,11 @@
        (((~0ULL) >> (BITS_PER_LONG_LONG - (h) - 1)) & ((~0ULL) << (l)))
 #define BITS_PER_BYTE  8
 
-#define        hweight8(x)     bitcount((uint8_t)(x))
-#define        hweight16(x)    bitcount16(x)
-#define        hweight32(x)    bitcount32(x)
-#define        hweight64(x)    bitcount64(x)
-#define        hweight_long(x) bitcountl(x)
+#define        hweight8(x)     uk_bitcount((uint8_t)(x))
+#define        hweight16(x)    uk_bitcount16(x)
+#define        hweight32(x)    uk_bitcount32(x)
+#define        hweight64(x)    uk_bitcount64(x)
+#define        hweight_long(x) uk_bitcountl(x)
 
 static inline int
 fls64(uint64_t mask)
@@ -236,79 +236,37 @@ find_next_zero_bit(const unsigned long *addr, unsigned 
long size,
        return (bit);
 }
 
-#define        __set_bit(i, a)                                                 
\
-       atomic_set_long(&((volatile unsigned long *)(a))[BIT_WORD(i)], 
BIT_MASK(i))
-
-#define        set_bit(i, a)                                                   
\
-       atomic_set_long(&((volatile unsigned long *)(a))[BIT_WORD(i)], 
BIT_MASK(i))
-
-#define        __clear_bit(i, a)                                               
\
-       atomic_clear_long(&((volatile unsigned long *)(a))[BIT_WORD(i)], 
BIT_MASK(i))
-
-#define        clear_bit(i, a)                                                 
\
-       atomic_clear_long(&((volatile unsigned long *)(a))[BIT_WORD(i)], 
BIT_MASK(i))
-
-#define        test_bit(i, a)                                                  
\
-       !!(READ_ONCE(((volatile unsigned long *)(a))[BIT_WORD(i)]) & 
BIT_MASK(i))
+/* set_bit and clear_bit are atomic and protected against
+ * reordering (do barriers), while the underscored (__*) versions of
+ * them don't (not atomic).
+ */
+#define __set_bit(i, a)        ukarch_set_bit(i, a)
+#define set_bit(i, a)          ukarch_set_bit_sync(i, a)
+#define __clear_bit(i, a)      ukarch_clr_bit(i, a)
+#define clear_bit(i, a)        ukarch_clr_bit_sync(i, a)
 
 static inline int
 test_and_clear_bit(long bit, volatile unsigned long *var)
 {
-       long val;
-
-       var += BIT_WORD(bit);
-       bit %= BITS_PER_LONG;
-       bit = (1UL << bit);
-       do {
-               val = *var;
-       } while (atomic_cmpset_long(var, val, val & ~bit) == 0);
-
-       return !!(val & bit);
+       return ukarch_test_and_clr_bit_sync(bit, (volatile void *) var);
 }
 
 static inline int
 __test_and_clear_bit(long bit, volatile unsigned long *var)
 {
-       long val;
-
-       var += BIT_WORD(bit);
-       bit %= BITS_PER_LONG;
-       bit = (1UL << bit);
-
-       val = *var;
-       *var &= ~bit;
-
-       return !!(val & bit);
+       return ukarch_test_and_clr_bit(bit, (volatile void *) var);
 }
 
 static inline int
 test_and_set_bit(long bit, volatile unsigned long *var)
 {
-       long val;
-
-       var += BIT_WORD(bit);
-       bit %= BITS_PER_LONG;
-       bit = (1UL << bit);
-       do {
-               val = *var;
-       } while (atomic_cmpset_long(var, val, val | bit) == 0);
-
-       return !!(val & bit);
+       return ukarch_test_and_set_bit_sync(bit, (volatile void *) var);
 }
 
 static inline int
 __test_and_set_bit(long bit, volatile unsigned long *var)
 {
-       long val;
-
-       var += BIT_WORD(bit);
-       bit %= BITS_PER_LONG;
-       bit = (1UL << bit);
-
-       val = *var;
-       *var |= bit;
-
-       return !!(val & bit);
+       return ukarch_test_and_set_bit(bit, (volatile void *) var);
 }
 
 enum {
-- 
2.18.0


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