4 files changed, 275 insertions, 0 deletions
diff --git a/hw/semihosting/Kconfig b/hw/semihosting/Kconfig
new file mode 100644
index 0000000000..efe0a30734
--- /dev/null
+++ b/hw/semihosting/Kconfig
@@ -0,0 +1,3 @@
+
+config SEMIHOSTING
+       bool
diff --git a/hw/semihosting/Makefile.objs b/hw/semihosting/Makefile.objs
new file mode 100644
index 0000000000..4ad47c05c0
--- /dev/null
+++ b/hw/semihosting/Makefile.objs
@@ -0,0 +1,2 @@
+obj-$(CONFIG_SEMIHOSTING) += config.o
+obj-$(CONFIG_SEMIHOSTING) += console.o
diff --git a/hw/semihosting/config.c b/hw/semihosting/config.c
new file mode 100644
index 0000000000..2a8e7e1045
--- /dev/null
+++ b/hw/semihosting/config.c
@@ -0,0 +1,186 @@
+/*
+ * Semihosting configuration
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Copyright (c) 2019 Linaro Ltd
+ *
+ * This controls the configuration of semihosting for all guest
+ * targets that support it. Architecture specific handling is handled
+ * in target/HW/HW-semi.c
+ *
+ * Semihosting is sightly strange in that it is also supported by some
+ * linux-user targets. However in that use case no configuration of
+ * the outputs and command lines is supported.
+ *
+ * The config module is common to all softmmu targets however as vl.c
+ * needs to link against the helpers.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/option.h"
+#include "qemu/config-file.h"
+#include "qemu/error-report.h"
+#include "hw/semihosting/semihost.h"
+#include "chardev/char.h"
+
+QemuOptsList qemu_semihosting_config_opts = {
+    .name = "semihosting-config",
+    .implied_opt_name = "enable",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_semihosting_config_opts.head),
+    .desc = {
+        {
+            .name = "enable",
+            .type = QEMU_OPT_BOOL,
+        }, {
+            .name = "target",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "chardev",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "arg",
+            .type = QEMU_OPT_STRING,
+        },
+        { /* end of list */ }
+    },
+};
+
+typedef struct SemihostingConfig {
+    bool enabled;
+    SemihostingTarget target;
+    Chardev *chardev;
+    const char **argv;
+    int argc;
+    const char *cmdline; /* concatenated argv */
+} SemihostingConfig;
+
+static SemihostingConfig semihosting;
+static const char *semihost_chardev;
+
+bool semihosting_enabled(void)
+{
+    return semihosting.enabled;
+}
+
+SemihostingTarget semihosting_get_target(void)
+{
+    return semihosting.target;
+}
+
+const char *semihosting_get_arg(int i)
+{
+    if (i >= semihosting.argc) {
+        return NULL;
+    }
+    return semihosting.argv[i];
+}
+
+int semihosting_get_argc(void)
+{
+    return semihosting.argc;
+}
+
+const char *semihosting_get_cmdline(void)
+{
+    if (semihosting.cmdline == NULL && semihosting.argc > 0) {
+        semihosting.cmdline = g_strjoinv(" ", (gchar **)semihosting.argv);
+    }
+    return semihosting.cmdline;
+}
+
+static int add_semihosting_arg(void *opaque,
+                               const char *name, const char *val,
+                               Error **errp)
+{
+    SemihostingConfig *s = opaque;
+    if (strcmp(name, "arg") == 0) {
+        s->argc++;
+        /* one extra element as g_strjoinv() expects NULL-terminated array */
+        s->argv = g_realloc(s->argv, (s->argc + 1) * sizeof(void *));
+        s->argv[s->argc - 1] = val;
+        s->argv[s->argc] = NULL;
+    }
+    return 0;
+}
+
+/* Use strings passed via -kernel/-append to initialize semihosting.argv[] */
+void semihosting_arg_fallback(const char *file, const char *cmd)
+{
+    char *cmd_token;
+
+    /* argv[0] */
+    add_semihosting_arg(&semihosting, "arg", file, NULL);
+
+    /* split -append and initialize argv[1..n] */
+    cmd_token = strtok(g_strdup(cmd), " ");
+    while (cmd_token) {
+        add_semihosting_arg(&semihosting, "arg", cmd_token, NULL);
+        cmd_token = strtok(NULL, " ");
+    }
+}
+
+Chardev *semihosting_get_chardev(void)
+{
+    return semihosting.chardev;
+}
+
+void qemu_semihosting_enable(void)
+{
+    semihosting.enabled = true;
+    semihosting.target = SEMIHOSTING_TARGET_AUTO;
+}
+
+int qemu_semihosting_config_options(const char *optarg)
+{
+    QemuOptsList *opt_list = qemu_find_opts("semihosting-config");
+    QemuOpts *opts = qemu_opts_parse_noisily(opt_list, optarg, false);
+
+    semihosting.enabled = true;
+
+    if (opts != NULL) {
+        semihosting.enabled = qemu_opt_get_bool(opts, "enable",
+                                                true);
+        const char *target = qemu_opt_get(opts, "target");
+        /* setup of chardev is deferred until they are initialised */
+        semihost_chardev = qemu_opt_get(opts, "chardev");
+        if (target != NULL) {
+            if (strcmp("native", target) == 0) {
+                semihosting.target = SEMIHOSTING_TARGET_NATIVE;
+            } else if (strcmp("gdb", target) == 0) {
+                semihosting.target = SEMIHOSTING_TARGET_GDB;
+            } else  if (strcmp("auto", target) == 0) {
+                semihosting.target = SEMIHOSTING_TARGET_AUTO;
+            } else {
+                error_report("unsupported semihosting-config %s",
+                             optarg);
+                return 1;
+            }
+        } else {
+            semihosting.target = SEMIHOSTING_TARGET_AUTO;
+        }
+        /* Set semihosting argument count and vector */
+        qemu_opt_foreach(opts, add_semihosting_arg,
+                         &semihosting, NULL);
+    } else {
+        error_report("unsupported semihosting-config %s", optarg);
+        return 1;
+    }
+
+    return 0;
+}
+
+void qemu_semihosting_connect_chardevs(void)
+{
+    /* We had to defer this until chardevs were created */
+    if (semihost_chardev) {
+        Chardev *chr = qemu_chr_find(semihost_chardev);
+        if (chr == NULL) {
+            error_report("semihosting chardev '%s' not found",
+                         semihost_chardev);
+            exit(1);
+        }
+        semihosting.chardev = chr;
+    }
+}
diff --git a/hw/semihosting/console.c b/hw/semihosting/console.c
new file mode 100644
index 0000000000..466ea6dade
--- /dev/null
+++ b/hw/semihosting/console.c
@@ -0,0 +1,84 @@
+/*
+ * Semihosting Console Support
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Copyright (c) 2019 Linaro Ltd
+ *
+ * This provides support for outputting to a semihosting console.
+ *
+ * While most semihosting implementations support reading and writing
+ * to arbitrary file descriptors we treat the console as something
+ * specifically for debugging interaction. This means messages can be
+ * re-directed to gdb (if currently being used to debug) or even
+ * re-directed elsewhere.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "hw/semihosting/semihost.h"
+#include "hw/semihosting/console.h"
+#include "exec/gdbstub.h"
+#include "qemu/log.h"
+#include "chardev/char.h"
+
+int qemu_semihosting_log_out(const char *s, int len)
+{
+    Chardev *chardev = semihosting_get_chardev();
+    if (chardev) {
+        return qemu_chr_write_all(chardev, (uint8_t *) s, len);
+    } else {
+        return write(STDERR_FILENO, s, len);
+    }
+}
+
+/*
+ * A re-implementation of lock_user_string that we can use locally
+ * instead of relying on softmmu-semi. Hopefully we can deprecate that
+ * in time. We either copy len bytes if specified or until we find a NULL.
+ */
+static GString *copy_user_string(CPUArchState *env, target_ulong addr, int len)
+{
+    CPUState *cpu = ENV_GET_CPU(env);
+    GString *s = g_string_sized_new(len ? len : 128);
+    uint8_t c;
+    bool done;
+
+    do {
+        if (cpu_memory_rw_debug(cpu, addr++, &c, 1, 0) == 0) {
+            s = g_string_append_c(s, c);
+            done = len ? s->len == len : c == 0;
+        } else {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: passed inaccessible address " TARGET_FMT_lx,
+                          __func__, addr);
+            done = true;
+        }
+    } while (!done);
+
+    return s;
+}
+
+static void semihosting_cb(CPUState *cs, target_ulong ret, target_ulong err)
+{
+    if (ret == (target_ulong) -1) {
+        qemu_log("%s: gdb console output failed ("TARGET_FMT_ld")",
+                 __func__, err);
+    }
+}
+
+int qemu_semihosting_console_out(CPUArchState *env, target_ulong addr, int len)
+{
+    GString *s = copy_user_string(env, addr, len);
+    int out = s->len;
+
+    if (use_gdb_syscalls()) {
+        gdb_do_syscall(semihosting_cb, "write,2,%x,%x", addr, s->len);
+    } else {
+        out = qemu_semihosting_log_out(s->str, s->len);
+    }
+
+    g_string_free(s, true);
+    return out;
+}