util/cpuinfo-aarch64: Add CPUINFO_BTI

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

host/include/aarch64/host/cpuinfo.h

@@ -10,6 +10,7 @@
 #define CPUINFO_LSE             (1u << 1)
 #define CPUINFO_LSE2            (1u << 2)
 #define CPUINFO_AES             (1u << 3)
+#define CPUINFO_BTI             (1u << 4)
 
 /* Initialized with a constructor. */
 extern unsigned cpuinfo;

util/cpuinfo-aarch64.c

@@ -13,6 +13,9 @@
 #  include <asm/hwcap.h>
 #  include "elf.h"
 # endif
+# ifndef HWCAP2_BTI
+#  define HWCAP2_BTI 0  /* added in glibc 2.32 */
+# endif
 #endif
 #ifdef CONFIG_DARWIN
 # include <sys/sysctl.h>
@@ -57,11 +60,15 @@ unsigned __attribute__((constructor)) cpuinfo_init(void)
     info |= (hwcap & HWCAP_ATOMICS ? CPUINFO_LSE : 0);
     info |= (hwcap & HWCAP_USCAT ? CPUINFO_LSE2 : 0);
     info |= (hwcap & HWCAP_AES ? CPUINFO_AES: 0);
+
+    unsigned long hwcap2 = qemu_getauxval(AT_HWCAP2);
+    info |= (hwcap2 & HWCAP2_BTI ? CPUINFO_BTI : 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;
     info |= sysctl_for_bool("hw.optional.arm.FEAT_AES") * CPUINFO_AES;
+    info |= sysctl_for_bool("hw.optional.arm.FEAT_BTI") * CPUINFO_BTI;
 #endif
 
     cpuinfo = info;