test-user-mode: classify and skip all failing gem5 tests

Create userlan/posix/kill.c to better test signals.

README.adoc

@@ -15383,6 +15383,7 @@ The following examples end up testing that our setup is working:
 * link:userland/c/exit0.c[]
 * link:userland/c/exit1.c[]
 * link:userland/c/exit2.c[]
+* link:userland/posix/kill.c[]
 
 Beware that on Linux kernel simulations, you cannot even echo that string from userland, since userland stdout shows up on the serial.
 

path_properties.py

@@ -47,6 +47,7 @@ class PathProperties:
         'extra_objs_disable_baremetal_bootloader': False,
         # We should get rid of this if we ever properly implement dependency graphs.
         'extra_objs_lkmc_common': False,
+        'gem5_unimplemented_instruction': False,
         'interactive': False,
         # The script takes a perceptible amount of time to run. Possibly an infinite loop.
         'more_than_1s': False,
@@ -149,6 +150,7 @@ class PathProperties:
                     self['signal_generated_by_os']
                 )
             ) and
+            not self['disrupts_system'] and
             not self['interactive'] and
             not self['more_than_1s'] and
             not self['no_executable'] and
@@ -159,6 +161,9 @@ class PathProperties:
             not (
                 env['emulator'] == 'gem5' and
                 (
+                    self['gem5_unimplemented_instruction'] or
+                    # gem5 does not report signals properly.
+                    self['signal_received'] is not None or
                     self['requires_dynamic_library'] or
                     self['requires_semihosting'] or
                     self['requires_syscall_getcpu']
@@ -347,7 +352,10 @@ path_properties_tuples = (
                                     'signal_generated_by_os': True,
                                     'signal_received': signal.Signals.SIGILL,
                                 },
-                                'vcvta.S': {'arm_aarch32': True},
+                                'vcvta.S': {
+                                    'arm_aarch32': True,
+                                    'gem5_unimplemented_instruction': True,
+                                },
                             }
                         ),
                         'aarch64': (
@@ -452,6 +460,10 @@ path_properties_tuples = (
                     {},
                     {
                         'count.c': {'more_than_1s': True},
+                        'kill.c': {
+                            'baremetal': True,
+                            'signal_received': signal.Signals.SIGHUP,
+                        },
                         'sleep_forever.c': {'more_than_1s': True},
                         'virt_to_phys_test.c': {'more_than_1s': True},
                     }

userland/posix/kill.c

@@ -0,0 +1,16 @@
+/* A process that commits suicide by signal. */
+
+#define _XOPEN_SOURCE 700
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int main(int argc, char **argv) {
+    int sig;
+    if (argc <= 1) {
+        sig = 1;
+    } else {
+        sig = strtoull(argv[1], NULL, 0);
+    }
+    kill(getpid(), sig);
+}