Add x86 and generic implementations of atomic_test_and_set_bit() to allow
KVM selftests to atomically manage bitmaps.
Note, the generic version is taken from arch_test_and_set_bit() as of
commit
415d83249709 ("locking/atomic: Make test_and_*_bit() ordered on
failure").
Signed-off-by: Peter Gonda <pgonda@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-5-seanjc@google.com
#define LOCK_PREFIX "\n\tlock; "
+#include <asm/asm.h>
#include <asm/cmpxchg.h>
/*
return cmpxchg(&v->counter, old, new);
}
+static inline int atomic_test_and_set_bit(long nr, unsigned long *addr)
+{
+ GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, "Ir", nr, "%0", "c");
+
+}
+
#endif /* _TOOLS_LINUX_ASM_X86_ATOMIC_H */
#include <linux/compiler.h>
#include <linux/types.h>
+#include <linux/bitops.h>
/*
* Atomic operations that C can't guarantee us. Useful for
return cmpxchg(&(v)->counter, oldval, newval);
}
+static inline int atomic_test_and_set_bit(long nr, unsigned long *addr)
+{
+ unsigned long mask = BIT_MASK(nr);
+ long old;
+
+ addr += BIT_WORD(nr);
+
+ old = __sync_fetch_and_or(addr, mask);
+ return !!(old & mask);
+}
+
#endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */