[Qemu-devel] [PATCH v3 2/2] semihosting: add --semihosting-config arg sub-argument

[Leon Alrae <leon.alrae@imgtec.com>]

Add new "arg" sub-argument to the --semihosting-config allowing to pass
multiple input argument separately. It is required for example by UHI
semihosting to construct argc and argv.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
---
 include/exec/semihost.h | 12 ++++++++++++
 qemu-options.hx         | 19 ++++++++++++++-----
 vl.c                    | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/include/exec/semihost.h b/include/exec/semihost.h
index c2f0bcb..6e4e8c0 100644
--- a/include/exec/semihost.h
+++ b/include/exec/semihost.h
@@ -36,9 +36,21 @@ static inline SemihostingTarget semihosting_get_target(void)
 {
     return SEMIHOSTING_TARGET_AUTO;
 }
+
+static inline const char *semihosting_get_arg(int i)
+{
+    return NULL;
+}
+
+static inline int semihosting_get_argc(void)
+{
+    return 0;
+}
 #else
 bool semihosting_enabled(void);
 SemihostingTarget semihosting_get_target(void);
+const char *semihosting_get_arg(int i);
+int semihosting_get_argc(void);
 #endif
 
 #endif
diff --git a/qemu-options.hx b/qemu-options.hx
index ec356f6..84ae6c2 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3296,14 +3296,23 @@ STEXI
 Enable semihosting mode (ARM, M68K, Xtensa only).
 ETEXI
 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
-    "-semihosting-config [enable=on|off,]target=native|gdb|auto   semihosting configuration\n",
+    "-semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
+    "                semihosting configuration\n",
 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32)
 STEXI
-@item -semihosting-config [enable=on|off,]target=native|gdb|auto
+@item -semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]
 @findex -semihosting-config
-Enable semihosting and define where the semihosting calls will be addressed,
-to QEMU (@code{native}) or to GDB (@code{gdb}). The default is @code{auto}, which means
-@code{gdb} during debug sessions and @code{native} otherwise (ARM, M68K, Xtensa only).
+Enable and configure semihosting (ARM, M68K, Xtensa only).
+@table @option
+@item target=@code{native|gdb|auto}
+Defines where the semihosting calls will be addressed, to QEMU (@code{native})
+or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb}
+during debug sessions and @code{native} otherwise.
+@item arg=@var{str1},arg=@var{str2},...
+Allows the user to pass input arguments, can be used multiple times to build up
+a list. This is a replacement for the old-style -kernel/-append method of
+passing a command line to semihosting.
+@end table
 ETEXI
 DEF("old-param", 0, QEMU_OPTION_old_param,
     "-old-param      old param mode\n", QEMU_ARCH_ARM)
diff --git a/vl.c b/vl.c
index f3319a9..c8ac1e6 100644
--- a/vl.c
+++ b/vl.c
@@ -486,6 +486,9 @@ static QemuOptsList qemu_semihosting_config_opts = {
         }, {
             .name = "target",
             .type = QEMU_OPT_STRING,
+        }, {
+            .name = "arg",
+            .type = QEMU_OPT_STRING,
         },
         { /* end of list */ }
     },
@@ -1230,6 +1233,8 @@ static void configure_msg(QemuOpts *opts)
 typedef struct SemihostingConfig {
     bool enabled;
     SemihostingTarget target;
+    const char **argv;
+    int argc;
 } SemihostingConfig;
 
 static SemihostingConfig semihosting;
@@ -1244,6 +1249,31 @@ 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;
+}
+
+static int add_semihosting_arg(const char *name, const char *val, void *opaque)
+{
+    SemihostingConfig *s = opaque;
+    if (strcmp(name, "arg") == 0) {
+        s->argc++;
+        s->argv = g_realloc(s->argv, s->argc * sizeof(void *));
+        s->argv[s->argc - 1] = val;
+    }
+    return 0;
+}
+
 /***********************************************************/
 /* USB devices */
 
@@ -3592,6 +3622,9 @@ int main(int argc, char **argv, char **envp)
                     } else {
                         semihosting.target = SEMIHOSTING_TARGET_AUTO;
                     }
+                    /* Set semihosting argument count and vector */
+                    qemu_opt_foreach(opts, add_semihosting_arg,
+                                     &semihosting, 0);
                 } else {
                     fprintf(stderr, "Unsupported semihosting-config %s\n",
                             optarg);