sim-se, tests: add a new sim-se test

This changeset adds a test to check the redirection features
added in faux-filesystem changeset. The test contains a
"chdir" system call to "/proc" which should be redirected to
"$(gem5-dir)/m5out/fs/proc" (as specified by the config files).

After "chdir", the test subsequently outputs the "/proc/cpuinfo"
file which should output a configuration of a fake cpu with
values set by a Python configuration file.

Note, the test will call "clone" once. To avoid a runtime error,
make sure that you run this test with "-n2" supplied to the
"config/example/se.py" script.

Change-Id: I505b046b7a4feddfa93a6ef0f0773ac43078cc94
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17112
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

tests/test-progs/chdir-print/Makefile

@@ -0,0 +1,20 @@
+
+CPP := g++
+
+TEST_OBJS := chdir-print.o
+TEST_PROGS := $(TEST_OBJS:.o=)
+
+# ==== Rules ==================================================================
+
+.PHONY: default clean
+
+default: $(TEST_PROGS)
+
+clean:
+	$(RM)  $(TEST_OBJS) $(TEST_PROGS)
+
+$(TEST_PROGS): $(TEST_OBJS)
+	$(CPP)  -static -o $@  $@.o
+
+%.o: %.c Makefile
+	$(CPP) -c -o $@ $*.c -msse3

tests/test-progs/chdir-print/README.txt

@@ -0,0 +1,67 @@
+# example test compile and run parameters
+# Note: the absolute path to the chdir-print binary should be specified
+# in the run command even if running from the same folder. This is needed
+# because chdir is executed before triggering a clone for the file read,
+# and the cloned process won't be able to find the executable if a relative
+# path is provided.
+
+# compile examples
+scons --default=X86 ./build/X86/gem5.opt PROTOCOL=MOESI_hammer
+scons --default=X86 ./build/X86/gem5.opt PROTOCOL=MESI_Three_Level
+
+# run parameters
+<GEM5_ROOT>/build/X86/gem5.opt <GEM5_ROOT>/configs/example/se.py -c <GEM5_ROOT>/tests/test-progs/chdir-print/chdir-print -n2 --ruby
+
+
+# example successful output for MESI_Three_Level:
+
+<...>
+
+**** REAL SIMULATION ****
+info: Entering event queue @ 0.  Starting simulation...
+warn: Replacement policy updates recently became the responsibility of SLICC state machines. Make sure to setMRU() near callbacks in .sm files!
+cwd: /proj/research_simu/users/jalsop/gem5-mem_dif_debug/tests/test-progs/chdir-print/
+cwd: /proc
+
+<...>
+
+processor       : 0
+vendor_id       : Generic
+cpu family      : 0
+model           : 0
+model name      : Generic
+stepping        : 0
+cpu MHz         : 2000
+cache size:     : 2048K
+physical id     : 0
+siblings        : 2
+core id         : 0
+cpu cores       : 2
+fpu             : yes
+fpu exception   : yes
+cpuid level     : 1
+wp              : yes
+flags           : fpu
+cache alignment : 64
+
+processor       : 1
+vendor_id       : Generic
+cpu family      : 0
+model           : 0
+model name      : Generic
+stepping        : 0
+cpu MHz         : 2000
+cache size:     : 2048K
+physical id     : 0
+siblings        : 2
+core id         : 1
+cpu cores       : 2
+fpu             : yes
+fpu exception   : yes
+cpuid level     : 1
+wp              : yes
+flags           : fpu
+cache alignment : 64
+
+SUCCESS
+Exiting @ tick 2694923000 because exiting with last active thread context

tests/test-progs/chdir-print/chdir-print.c

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2011-2015 Advanced Micro Devices, Inc.
+ * All rights reserved.
+ *
+ * For use for simulation and test purposes only
+ *
+ * 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.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
+ *
+ * Authors: Brandon Potter,
+ *          John Alsop
+ */
+
+#include <linux/limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+const int BUFFER_SIZE = 64;
+
+// Tests the functionality of RegisterFilesystem
+int main(void)
+{
+    char *cwd = getcwd(NULL, PATH_MAX);
+    printf("cwd: %s\n", cwd);
+    free(cwd);
+
+    chdir("/proc");
+
+    cwd = getcwd(NULL, PATH_MAX);
+    printf("cwd: %s\n", cwd);
+    free(cwd);
+
+    FILE *fp;
+    char buffer[BUFFER_SIZE];
+
+    bool found_procline = false;
+    fp = popen("cat cpuinfo", "r");
+    if (fp != NULL) {
+        while (fgets(buffer, BUFFER_SIZE, fp) != NULL) {
+            printf("%s", buffer);
+            if (strstr(buffer, "processor")) {
+                found_procline = true;
+            }
+        }
+        pclose(fp);
+    }
+
+    if (found_procline) {
+        printf("SUCCESS\n");
+        return EXIT_SUCCESS;
+    }
+
+    printf("FAILURE\n");
+    return EXIT_FAILURE;
+}