Add support for Altera's Nios-II softcore architecture

This commit adds strace support for Altera's Nios-II.  The architecture
is supported by Linux since v3.19, and it implements the generic syscall
ABI.

* configure.ac: Add nios2 support.
* cacheflush.c [NIOS2] (sys_cacheflush): New function.
* linux/nios2/*: New Nios-II specific files.
* Makefile.am (EXTRA_DIST): Add them.

Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

Makefile.am

@@ -341,6 +341,14 @@ EXTRA_DIST =				\
 	linux/mips/syscallent.h		\
 	linux/mips/userent.h		\
 	linux/mtd-abi.h			\
+	linux/nios2/arch_regs.c		\
+	linux/nios2/get_error.c		\
+	linux/nios2/get_scno.c		\
+	linux/nios2/get_syscall_args.c	\
+	linux/nios2/ioctls_arch0.h	\
+	linux/nios2/ioctls_inc0.h	\
+	linux/nios2/print_pc.c		\
+	linux/nios2/syscallent.h	\
 	linux/or1k/arch_regs.c		\
 	linux/or1k/get_error.c		\
 	linux/or1k/get_scno.c		\

cacheflush.c

@@ -89,3 +89,15 @@ SYS_FUNC(cacheflush)
 	return 0;
 }
 #endif /* SH */
+
+#ifdef NIOS2
+SYS_FUNC(cacheflush)
+{
+	if (entering(tcp)) {
+		/* addr and len */
+		tprintf("%#lx, %lu", tcp->u_arg[0], tcp->u_arg[3]);
+		/* scope and flags (cache type) are currently ignored */
+	}
+	return 0;
+}
+#endif /* NIOS2 */

configure.ac

@@ -125,6 +125,11 @@ microblaze*)
 	arch=microblaze
 	AC_DEFINE([MICROBLAZE], 1, [Define for the MicroBlaze architecture.])
 	;;
+nios2*)
+	arch=nios2
+	AC_DEFINE([NIOS2], 1, [Define for the Nios-II architecture.])
+	;;
+
 or1k*)
 	arch=or1k
 	AC_DEFINE([OR1K], 1, [Define for the OpenRISC 1000 architecture.])

linux/nios2/arch_regs.c

@@ -0,0 +1,2 @@
+static struct user_pt_regs nios2_regs;
+# define ARCH_REGS_FOR_GETREGSET nios2_regs

linux/nios2/get_error.c

@@ -0,0 +1,13 @@
+/*
+ * The system call convention specifies that r2 contains the return
+ * value on success or a positive error number on failure.  A flag
+ * indicating successful completion is written to r7; r7=0 indicates
+ * the system call success, r7=1 indicates an error.  The positive
+ * errno value written in r2.
+ */
+if (check_errno && nios2_regs.regs[7]) {
+	tcp->u_rval = -1;
+	tcp->u_error = nios2_regs.regs[2];
+} else {
+	tcp->u_rval = nios2_regs.regs[2];
+}

linux/nios2/get_scno.c

@@ -0,0 +1 @@
+scno = nios2_regs.regs[2];

linux/nios2/get_syscall_args.c

@@ -0,0 +1,6 @@
+tcp->u_arg[0] = nios2_regs.regs[4];
+tcp->u_arg[1] = nios2_regs.regs[5];
+tcp->u_arg[2] = nios2_regs.regs[6];
+tcp->u_arg[3] = nios2_regs.regs[7];
+tcp->u_arg[4] = nios2_regs.regs[8];
+tcp->u_arg[5] = nios2_regs.regs[9];

linux/nios2/ioctls_arch0.h

@@ -0,0 +1 @@
+/* Generated by ioctls_gen.sh from definitions found in $linux/arch/nios2/include/ tree. */

linux/nios2/ioctls_inc0.h

@@ -0,0 +1 @@
+#include "32/ioctls_inc.h"

linux/nios2/print_pc.c

@@ -0,0 +1 @@
+tprintf(fmt, nios2_regs.regs[PTR_EA]);

linux/nios2/syscallent.h

@@ -0,0 +1,4 @@
+#define ARCH_sys_mmap sys_mmap_pgoff
+#include "32/syscallent.h"
+[244] = {4,    0,	sys_cacheflush, "cacheflush"},
+[245 ... 259] = { },