Replace the C implementation of __aeabi_read_tp with an assembly version.

This ensures we follow the ABI by preserving registers r1-r3.

Reviewed by:	jmallett, imp

2 files changed, 9 insertions, 14 deletions

diff --git a/lib/libc/arm/gen/Makefile.inc b/lib/libc/arm/gen/Makefile.inc
index e0ebd988846f..a78cbb94260d 100644
--- a/lib/libc/arm/gen/Makefile.inc
+++ b/lib/libc/arm/gen/Makefile.inc
@@ -3,4 +3,4 @@
 
 SRCS+=	_ctx_start.S _setjmp.S _set_tp.c alloca.S fabs.c \
 	getcontextx.c infinity.c ldexp.c makecontext.c \
-	__aeabi_read_tp.c setjmp.S signalcontext.c sigsetjmp.S divsi3.S flt_rounds.c
+	__aeabi_read_tp.S setjmp.S signalcontext.c sigsetjmp.S divsi3.S flt_rounds.c
diff --git a/lib/libc/arm/gen/__aeabi_read_tp.c b/lib/libc/arm/gen/__aeabi_read_tp.S
index c2dd9789ef54..228acff9dbf0 100644
--- a/lib/libc/arm/gen/__aeabi_read_tp.c
+++ b/lib/libc/arm/gen/__aeabi_read_tp.S
@@ -23,23 +23,18 @@
  * 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.
- *
- *	$FreeBSD$
  */
 
-#include <sys/cdefs.h>
+#include <machine/asm.h>
 __FBSDID("$FreeBSD$");
 
-#include <sys/types.h>
-
-#include "machine/sysarch.h"
+#include <machine/sysarch.h>
 
-void *
-__aeabi_read_tp()
-{
-	void *_tp;
+ENTRY(__aeabi_read_tp)
+	ldr	r0, .Larm_tp_address
+	ldr	r0, [r0]
+	RET
 
-	asm("ldr %0, [%1]\n" : "=r"(_tp) : "r"(ARM_TP_ADDRESS));
+.Larm_tp_address:
+	.word ARM_TP_ADDRESS
 
-	return _tp;
-}