diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c
--- a/sys/amd64/linux/linux_sysvec.c
+++ b/sys/amd64/linux/linux_sysvec.c
@@ -233,7 +233,7 @@
 
 	AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
 	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, cpu_feature);
-	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, 0);
+	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, linux_x86_elf_hwcap2());
 	AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform));
 }
 
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -146,7 +146,7 @@
 	AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO, __kernel_vsyscall);
 	AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
 	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, cpu_feature);
-	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, 0);
+	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, linux_x86_elf_hwcap2());
 	AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform));
 }
 
diff --git a/sys/i386/linux/linux.h b/sys/i386/linux/linux.h
--- a/sys/i386/linux/linux.h
+++ b/sys/i386/linux/linux.h
@@ -94,7 +94,7 @@
 /*
  * Miscellaneous
  */
-#define LINUX_AT_COUNT		21	/* Count of used aux entry types.
+#define LINUX_AT_COUNT		22	/* Count of used aux entry types.
 					 * Keep this synchronized with
 					 * linux_copyout_auxargs() code.
 					 */
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -145,6 +145,7 @@
 	AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
 	AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO, __kernel_vsyscall);
 	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, cpu_feature);
+	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, linux_x86_elf_hwcap2());
 	AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform));
 }
 
diff --git a/sys/x86/linux/linux_x86.h b/sys/x86/linux/linux_x86.h
--- a/sys/x86/linux/linux_x86.h
+++ b/sys/x86/linux/linux_x86.h
@@ -32,10 +32,16 @@
 #define	LINUX_VDSO_CPU_RDPID		1
 #define	LINUX_VDSO_CPU_RDTSCP		2
 
+/* More machine dependent hints about processor capabilities. */
+#define	LINUX_HWCAP2_RING3MWAIT		0x00000001
+#define	LINUX_HWCAP2_FSGSBASE		0x00000002
+
 int	linux_vdso_tsc_selector_idx(void);
 int	linux_vdso_cpu_selector_idx(void);
 
 int	linux_translate_traps(int, int);
 int	bsd_to_linux_trapcode(int);
 
+u_int	linux_x86_elf_hwcap2(void);
+
 #endif /* _X86_INCLUDE_LINUX_LINUX_X86_H_ */
diff --git a/sys/x86/linux/linux_x86.c b/sys/x86/linux/linux_x86.c
--- a/sys/x86/linux/linux_x86.c
+++ b/sys/x86/linux/linux_x86.c
@@ -31,7 +31,9 @@
 
 #include <sys/param.h>
 #include <sys/signal.h>
+#include <x86/specialreg.h>
 #include <x86/trap.h>
+#include <x86/x86_var.h>
 
 #include <x86/linux/linux_x86.h>
 
@@ -96,4 +98,18 @@
 
 	return (code < nitems(_bsd_to_linux_trapcode) ?
 	    _bsd_to_linux_trapcode[code] : LINUX_T_UNKNOWN);
-}
\ No newline at end of file
+}
+
+u_int
+linux_x86_elf_hwcap2(void)
+{
+	static u_int elf_hwcap2 = 0;
+	static bool elf_hwcap2_valid = false;
+
+	if (!elf_hwcap2_valid) {
+		if ((cpu_stdext_feature & CPUID_STDEXT_FSGSBASE) != 0)
+			elf_hwcap2 |= LINUX_HWCAP2_FSGSBASE;
+		elf_hwcap2_valid = true;
+	}
+	return (elf_hwcap2);
+}