tcg/aarch64: Detect have_lse, have_lse2 for linux

Notice when the host has additional atomic instructions.
The new variables will also be used in generated code.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/aarch64/tcg-target.c.inc

@@ -13,6 +13,9 @@
 #include "../tcg-ldst.c.inc"
 #include "../tcg-pool.c.inc"
 #include "qemu/bitops.h"
+#ifdef __linux__
+#include <asm/hwcap.h>
+#endif
 
 /* We're going to re-use TCGType in setting of the SF bit, which controls
    the size of the operation performed.  If we know the values match, it
@@ -71,6 +74,9 @@ static TCGReg tcg_target_call_oarg_reg(TCGCallReturnKind kind, int slot)
     return TCG_REG_X0 + slot;
 }
 
+bool have_lse;
+bool have_lse2;
+
 #define TCG_REG_TMP TCG_REG_X30
 #define TCG_VEC_TMP TCG_REG_V31
 
@@ -2899,6 +2905,12 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
 
 static void tcg_target_init(TCGContext *s)
 {
+#ifdef __linux__
+    unsigned long hwcap = qemu_getauxval(AT_HWCAP);
+    have_lse = hwcap & HWCAP_ATOMICS;
+    have_lse2 = hwcap & HWCAP_USCAT;
+#endif
+
     tcg_target_available_regs[TCG_TYPE_I32] = 0xffffffffu;
     tcg_target_available_regs[TCG_TYPE_I64] = 0xffffffffu;
     tcg_target_available_regs[TCG_TYPE_V64] = 0xffffffff00000000ull;

tcg/aarch64/tcg-target.h

@@ -57,6 +57,9 @@ typedef enum {
 #define TCG_TARGET_CALL_ARG_I128        TCG_CALL_ARG_EVEN
 #define TCG_TARGET_CALL_RET_I128        TCG_CALL_RET_NORMAL
 
+extern bool have_lse;
+extern bool have_lse2;
+
 /* optional instructions */
 #define TCG_TARGET_HAS_div_i32          1
 #define TCG_TARGET_HAS_rem_i32          1