util: Add cpuinfo-aarch64.c

Move the code from tcg/.  The only use of these bits so far
is with respect to the atomicity of tcg operations.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

host/include/aarch64/host/cpuinfo.h

@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Host specific cpu indentification for AArch64.
+ */
+
+#ifndef HOST_CPUINFO_H
+#define HOST_CPUINFO_H
+
+#define CPUINFO_ALWAYS          (1u << 0)  /* so cpuinfo is nonzero */
+#define CPUINFO_LSE             (1u << 1)
+#define CPUINFO_LSE2            (1u << 2)
+
+/* Initialized with a constructor. */
+extern unsigned cpuinfo;
+
+/*
+ * We cannot rely on constructor ordering, so other constructors must
+ * use the function interface rather than the variable above.
+ */
+unsigned cpuinfo_init(void);
+
+#endif /* HOST_CPUINFO_H */

tcg/aarch64/tcg-target.c.inc

@@ -13,12 +13,6 @@
 #include "../tcg-ldst.c.inc"
 #include "../tcg-pool.c.inc"
 #include "qemu/bitops.h"
-#ifdef __linux__
-#include <asm/hwcap.h>
-#endif
-#ifdef CONFIG_DARWIN
-#include <sys/sysctl.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
@@ -77,9 +71,6 @@ 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
 
@@ -2878,39 +2869,8 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
     }
 }
 
-#ifdef CONFIG_DARWIN
-static bool sysctl_for_bool(const char *name)
-{
-    int val = 0;
-    size_t len = sizeof(val);
-
-    if (sysctlbyname(name, &val, &len, NULL, 0) == 0) {
-        return val != 0;
-    }
-
-    /*
-     * We might in the future ask for properties not present in older kernels,
-     * but we're only asking about static properties, all of which should be
-     * 'int'.  So we shouln't see ENOMEM (val too small), or any of the other
-     * more exotic errors.
-     */
-    assert(errno == ENOENT);
-    return false;
-}
-#endif
-
 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
-#ifdef CONFIG_DARWIN
-    have_lse = sysctl_for_bool("hw.optional.arm.FEAT_LSE");
-    have_lse2 = sysctl_for_bool("hw.optional.arm.FEAT_LSE2");
-#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

@@ -13,6 +13,8 @@
 #ifndef AARCH64_TCG_TARGET_H
 #define AARCH64_TCG_TARGET_H
 
+#include "host/cpuinfo.h"
+
 #define TCG_TARGET_INSN_UNIT_SIZE  4
 #define TCG_TARGET_TLB_DISPLACEMENT_BITS 24
 #define MAX_CODE_GEN_BUFFER_SIZE  ((size_t)-1)
@@ -57,8 +59,8 @@ 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;
+#define have_lse    (cpuinfo & CPUINFO_LSE)
+#define have_lse2   (cpuinfo & CPUINFO_LSE2)
 
 /* optional instructions */
 #define TCG_TARGET_HAS_div_i32          1

util/cpuinfo-aarch64.c

@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Host specific cpu indentification for AArch64.
+ */
+
+#include "qemu/osdep.h"
+#include "host/cpuinfo.h"
+
+#ifdef CONFIG_LINUX
+# ifdef CONFIG_GETAUXVAL
+#  include <sys/auxv.h>
+# else
+#  include <asm/hwcap.h>
+#  include "elf.h"
+# endif
+#endif
+#ifdef CONFIG_DARWIN
+# include <sys/sysctl.h>
+#endif
+
+unsigned cpuinfo;
+
+#ifdef CONFIG_DARWIN
+static bool sysctl_for_bool(const char *name)
+{
+    int val = 0;
+    size_t len = sizeof(val);
+
+    if (sysctlbyname(name, &val, &len, NULL, 0) == 0) {
+        return val != 0;
+    }
+
+    /*
+     * We might in the future ask for properties not present in older kernels,
+     * but we're only asking about static properties, all of which should be
+     * 'int'.  So we shouln't see ENOMEM (val too small), or any of the other
+     * more exotic errors.
+     */
+    assert(errno == ENOENT);
+    return false;
+}
+#endif
+
+/* Called both as constructor and (possibly) via other constructors. */
+unsigned __attribute__((constructor)) cpuinfo_init(void)
+{
+    unsigned info = cpuinfo;
+
+    if (info) {
+        return info;
+    }
+
+    info = CPUINFO_ALWAYS;
+
+#ifdef CONFIG_LINUX
+    unsigned long hwcap = qemu_getauxval(AT_HWCAP);
+    info |= (hwcap & HWCAP_ATOMICS ? CPUINFO_LSE : 0);
+    info |= (hwcap & HWCAP_USCAT ? CPUINFO_LSE2 : 0);
+#endif
+#ifdef CONFIG_DARWIN
+    info |= sysctl_for_bool("hw.optional.arm.FEAT_LSE") * CPUINFO_LSE;
+    info |= sysctl_for_bool("hw.optional.arm.FEAT_LSE2") * CPUINFO_LSE2;
+#endif
+
+    cpuinfo = info;
+    return info;
+}

util/meson.build

@@ -109,6 +109,8 @@ if have_block
   util_ss.add(when: 'CONFIG_LINUX', if_true: files('vfio-helpers.c'))
 endif
 
-if cpu in ['x86', 'x86_64']
+if cpu == 'aarch64'
+  util_ss.add(files('cpuinfo-aarch64.c'))
+elif cpu in ['x86', 'x86_64']
   util_ss.add(files('cpuinfo-i386.c'))
 endif