ck_pr/sparcv9: use the correct address space for atomics on FreeBSD

On FreeBSD, atomic operations in the kernel must access the nucleus
address space. Userland may use either the atomic instruction set
which goes without an ASI (address space identifier) or specify the
primary address space.
To avoid hardcoding the address space here, we grab the corresponding
identifier from the appropriate machine header but also only for the
kernel so the namespace doesn't get polluted for userland.

include/gcc/sparcv9/ck_pr.h

@@ -136,11 +136,26 @@ CK_PR_STORE_S(int, int, "stsw")
 #undef CK_PR_STORE_S
 #undef CK_PR_STORE
 
+/* Use the appropriate address space for atomics within the FreeBSD kernel. */
+#if defined(__FreeBSD__) && defined(_KERNEL)
+#include <sys/cdefs.h>
+#include <machine/atomic.h>
+#define CK_PR_INS_CAS "casa"
+#define CK_PR_INS_CASX "casxa"
+#define CK_PR_INS_SWAP "swapa"
+#define CK_PR_ASI_ATOMIC __XSTRING(__ASI_ATOMIC)
+#else
+#define CK_PR_INS_CAS "cas"
+#define CK_PR_INS_CASX "casx"
+#define CK_PR_INS_SWAP "swap"
+#define CK_PR_ASI_ATOMIC ""
+#endif
+
 CK_CC_INLINE static bool
 ck_pr_cas_64_value(uint64_t *target, uint64_t compare, uint64_t set, uint64_t *value)
 {
 
-	__asm__ __volatile__("casx [%1], %2, %0"
+	__asm__ __volatile__(CK_PR_INS_CASX " [%1] " CK_PR_ASI_ATOMIC ", %2, %0"
 				: "+&r" (set)
 				: "r"   (target),
 				  "r"   (compare)
@@ -154,7 +169,7 @@ CK_CC_INLINE static bool
 ck_pr_cas_64(uint64_t *target, uint64_t compare, uint64_t set)
 {
 
-	__asm__ __volatile__("casx [%1], %2, %0"
+	__asm__ __volatile__(CK_PR_INS_CASX " [%1] " CK_PR_ASI_ATOMIC ", %2, %0"
 				: "+&r" (set)
 				: "r" (target),
 				  "r" (compare)
@@ -181,7 +196,7 @@ ck_pr_cas_ptr_value(void *target, void *compare, void *set, void *previous)
 	CK_CC_INLINE static bool					\
 	ck_pr_cas_##N##_value(T *target, T compare, T set, T *value)	\
 	{								\
-		__asm__ __volatile__("cas [%1], %2, %0"			\
+		__asm__ __volatile__(CK_PR_INS_CAS " [%1] " CK_PR_ASI_ATOMIC ", %2, %0" \
 					: "+&r" (set)			\
 					: "r"   (target),		\
 					  "r"   (compare)		\
@@ -192,7 +207,7 @@ ck_pr_cas_ptr_value(void *target, void *compare, void *set, void *previous)
 	CK_CC_INLINE static bool					\
 	ck_pr_cas_##N(T *target, T compare, T set)			\
 	{								\
-		__asm__ __volatile__("cas [%1], %2, %0"			\
+		__asm__ __volatile__(CK_PR_INS_CAS " [%1] " CK_PR_ASI_ATOMIC ", %2, %0" \
 					: "+&r" (set)			\
 					: "r" (target),			\
 					  "r" (compare)			\
@@ -211,7 +226,7 @@ CK_PR_CAS(int, int)
 	ck_pr_fas_##N(T *target, T update)			\
 	{							\
 								\
-		__asm__ __volatile__("swap [%1], %0"		\
+		__asm__ __volatile__(CK_PR_INS_SWAP " [%1] " CK_PR_ASI_ATOMIC ", %0"		\
 					: "+&r" (update)	\
 					: "r"   (target)	\
 					: "memory");		\
@@ -224,5 +239,10 @@ CK_PR_FAS(32, uint32_t)
 
 #undef CK_PR_FAS
 
+#undef CK_PR_INS_CAS
+#undef CK_PR_INS_CASX
+#undef CK_PR_INS_SWAP
+#undef CK_PR_ASI_ATOMIC
+
 #endif /* CK_PR_SPARCV9_H */