Add support for usermode (vdso-like) gettimeofday(2) and

clock_gettime(2) on ARMv7 and ARMv8 systems which have architectural
generic timer hardware. It is similar how the RDTSC timer is used in
userspace on x86.

Fix a permission problem where generic timer access from EL0 (or
userspace on v7) was not properly initialized on APs.

For ARMv7, mark the stack non-executable. The shared page is added for
all arms (including ARMv8 64bit), and the signal trampoline code is
moved to the page.

Reviewed by:	andrew
Discussed with:	emaste, mmel
Sponsored by:	The FreeBSD Foundation
Differential revision:	https://reviews.freebsd.org/D4209

4 files changed, 155 insertions, 2 deletions

diff --git a/lib/libc/aarch64/sys/Makefile.inc b/lib/libc/aarch64/sys/Makefile.inc
index cb56f73..b33b568 100644
--- a/lib/libc/aarch64/sys/Makefile.inc
+++ b/lib/libc/aarch64/sys/Makefile.inc
@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-SRCS+=	trivial-vdso_tc.c
+SRCS+=	__vdso_gettc.c
 
 #MDASM= ptrace.S
 MDASM=	brk.S \
diff --git a/lib/libc/aarch64/sys/__vdso_gettc.c b/lib/libc/aarch64/sys/__vdso_gettc.c
new file mode 100644
index 0000000..f9015e2
--- /dev/null
+++ b/lib/libc/aarch64/sys/__vdso_gettc.c
@@ -0,0 +1,74 @@
+/*-
+ * Copyright (c) 2015 The FreeBSD Foundation
+ *
+ * This software was developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/elf.h>
+#include <sys/time.h>
+#include <sys/vdso.h>
+#include <machine/cpufunc.h>
+#include "libc_private.h"
+
+static inline uint64_t
+cp15_cntvct_get(void)
+{
+	uint64_t reg;
+
+	__asm __volatile("mrs %0, cntvct_el0" : "=r" (reg));
+	return (reg);
+}
+
+static inline uint64_t
+cp15_cntpct_get(void)
+{
+	uint64_t reg;
+
+	__asm __volatile("mrs %0, cntpct_el0" : "=r" (reg));
+	return (reg);
+}
+
+#pragma weak __vdso_gettc
+u_int
+__vdso_gettc(const struct vdso_timehands *th)
+{
+	uint64_t val;
+
+	__asm __volatile("isb" : : : "memory");
+	val = th->th_physical == 0 ? cp15_cntvct_get() : cp15_cntpct_get();
+	return (val);
+}
+
+#pragma weak __vdso_gettimekeep
+int
+__vdso_gettimekeep(struct vdso_timekeep **tk)
+{
+
+	return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
+}
diff --git a/lib/libc/arm/sys/Makefile.inc b/lib/libc/arm/sys/Makefile.inc
index 60c2dc3..5e89109 100644
--- a/lib/libc/arm/sys/Makefile.inc
+++ b/lib/libc/arm/sys/Makefile.inc
@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-SRCS+=	trivial-vdso_tc.c
+SRCS+=	__vdso_gettc.c
 
 MDASM= Ovfork.S brk.S cerror.S pipe.S ptrace.S sbrk.S shmat.S sigreturn.S syscall.S
 
diff --git a/lib/libc/arm/sys/__vdso_gettc.c b/lib/libc/arm/sys/__vdso_gettc.c
new file mode 100644
index 0000000..d75d866
--- /dev/null
+++ b/lib/libc/arm/sys/__vdso_gettc.c
@@ -0,0 +1,79 @@
+/*-
+ * Copyright (c) 2015 The FreeBSD Foundation
+ *
+ * This software was developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/elf.h>
+#include <sys/time.h>
+#include <sys/vdso.h>
+#include <machine/cpufunc.h>
+#include "libc_private.h"
+
+static inline uint64_t
+cp15_cntvct_get(void)
+{
+	uint64_t reg;
+
+	__asm __volatile("mrrc\tp15, 1, %Q0, %R0, c14" : "=r" (reg));
+	return (reg);
+}
+
+static inline uint64_t
+cp15_cntpct_get(void)
+{
+	uint64_t reg;
+
+	__asm __volatile("mrrc\tp15, 0, %Q0, %R0, c14" : "=r" (reg));
+	return (reg);
+}
+
+#pragma weak __vdso_gettc
+u_int
+__vdso_gettc(const struct vdso_timehands *th)
+{
+	uint64_t val;
+
+	/*
+	 * Userspace gettimeofday() is only enabled on ARMv7 CPUs, but
+	 * libc is compiled for ARMv6.  Due to clang issues, .arch
+	 * armv7-a directive does not work.
+	 */
+	__asm __volatile(".word\t0xf57ff06f" : : : "memory"); /* isb */
+	val = th->th_physical == 0 ? cp15_cntvct_get() : cp15_cntpct_get();
+	return (val);
+}
+
+#pragma weak __vdso_gettimekeep
+int
+__vdso_gettimekeep(struct vdso_timekeep **tk)
+{
+
+	return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
+}