tests/tcg: add user version of dumb-as-bricks semiconsole test

There are linux-user users of semihosting so we'd better check things
work for them as well.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

tests/tcg/aarch64/Makefile.target

@@ -32,4 +32,11 @@ run-plugin-semihosting-with-%:
 		 $(call strip-plugin,$<) 2> $<.err, \
 		"$< on $(TARGET_NAME) with $*")
 
+AARCH64_TESTS += semiconsole
+run-semiconsole: semiconsole
+	$(call skip-test, $<, "MANUAL ONLY")
+
+run-plugin-semiconsole-with-%:
+	$(call skip-test, $<, "MANUAL ONLY")
+
 TESTS += $(AARCH64_TESTS)

tests/tcg/arm/Makefile.target

@@ -49,6 +49,25 @@ run-plugin-semihosting-with-%:
 		 $(call strip-plugin,$<) 2> $<.err, \
 		"$< on $(TARGET_NAME) with $*")
 
+ARM_TESTS += semiconsole semiconsole-arm
+
+semiconsole: CFLAGS += -mthumb
+run-semiconsole: semiconsole
+	$(call skip-test, $<, "MANUAL ONLY")
+
+run-plugin-semiconsole-with-%:
+	$(call skip-test, $<, "MANUAL ONLY")
+
+semiconsole-arm: CFLAGS += -marm
+semiconsole-arm: semiconsole.c
+	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $< -o $@ $(LDFLAGS)
+
+run-semiconsole-arm: semiconsole-arm
+	$(call skip-test, $<, "MANUAL ONLY")
+
+run-plugin-semiconsole-arm-with-%:
+	$(call skip-test, $<, "MANUAL ONLY")
+
 TESTS += $(ARM_TESTS)
 
 # On ARM Linux only supports 4k pages

tests/tcg/arm/semiconsole.c

@@ -0,0 +1,27 @@
+/*
+ * linux-user semihosting console
+ *
+ * Copyright (c) 2019
+ * Written by Alex Bennée <alex.bennee@linaro.org>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include "semicall.h"
+
+int main(void)
+{
+    char c;
+
+    printf("Semihosting Console Test\n");
+    printf("hit X to exit:");
+
+    do {
+        c = __semi_call(SYS_READC, 0);
+        printf("got '%c'\n", c);
+    } while (c != 'X');
+
+    return 0;
+}