Implement atomic_testandset_{32,int,long,64} for ARMv6. Only

little-endian configuration for 64-bit variant is supported.

Reviewed by:	mmel
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D4113

diff --git a/sys/arm/include/atomic-v6.h b/sys/arm/include/atomic-v6.h
index d22f7e169e29350a9cd96c287f35774a701def48..aa1780f29ff9e625b0451a22aee0b4b2b0438138 100644 (file)
--- a/sys/arm/include/atomic-v6.h
+++ b/sys/arm/include/atomic-v6.h
@@ -593,6 +593,54 @@ atomic_store_rel_long(volatile u_long *p, u_long v)
        *p = v;
 }
 
+static __inline int
+atomic_testandset_32(volatile uint32_t *p, u_int v)
+{
+       uint32_t tmp, tmp2, res, mask;
+
+       mask = 1u << (v & 0x1f);
+       tmp = tmp2 = 0;
+       __asm __volatile(
+       "1:     ldrex   %0, [%4]        \n"
+       "       orr     %1, %0, %3      \n"
+       "       strex   %2, %1, [%4]    \n"
+       "       cmp     %2, #0          \n"
+       "       it      ne              \n"
+       "       bne     1b              \n"
+       : "=&r" (res), "=&r" (tmp), "=&r" (tmp2)
+       : "r" (mask), "r" (p)
+       : "cc", "memory");
+       return ((res & mask) != 0);
+}
+
+static __inline int
+atomic_testandset_int(volatile u_int *p, u_int v)
+{
+
+       return (atomic_testandset_32((volatile uint32_t *)p, v));
+}
+
+static __inline int
+atomic_testandset_long(volatile u_long *p, u_int v)
+{
+
+       return (atomic_testandset_32((volatile uint32_t *)p, v));
+}
+
+static __inline int
+atomic_testandset_64(volatile uint64_t *p, u_int v)
+{
+       volatile uint32_t *p32;
+
+       p32 = (volatile uint32_t *)p;
+       /* Assume little-endian */
+       if (v >= 32) {
+               v &= 0x1f;
+               p32++;
+       }
+       return (atomic_testandset_32(p32, v));
+}
+
 #undef ATOMIC_ACQ_REL
 #undef ATOMIC_ACQ_REL_LONG