semihosting/guestfd: compile once for system/user

We move relevant code to semihosting/arm-compat-semi.c, and add
functions to query CONFIG_ARM_COMPATIBLE_SEMIHOSTING at runtime.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-ID: <20250822150058.18692-4-pierrick.bouvier@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-ID: <20250922093711.2768983-7-alex.bennee@linaro.org>

include/semihosting/guestfd.h

@@ -35,13 +35,6 @@ typedef struct GuestFD {
     };
 } GuestFD;
 
-/*
- * For ARM semihosting, we have a separate structure for routing
- * data for the console which is outside the guest fd address space.
- */
-extern GuestFD console_in_gf;
-extern GuestFD console_out_gf;
-
 /**
  * alloc_guestfd:
  *

include/semihosting/semihost.h

@@ -33,6 +33,8 @@ typedef enum SemihostingTarget {
  * Return true if guest code is allowed to make semihosting calls.
  */
 bool semihosting_enabled(bool is_user);
+bool semihosting_arm_compatible(void);
+void semihosting_arm_compatible_init(void);
 
 SemihostingTarget semihosting_get_target(void);
 const char *semihosting_get_arg(int i);

semihosting/arm-compat-semi-stub.c

@@ -0,0 +1,19 @@
+/*
+ * Stubs for platforms different from ARM
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "semihosting/semihost.h"
+#include <glib.h>
+
+bool semihosting_arm_compatible(void)
+{
+    return false;
+}
+
+void semihosting_arm_compatible_init(void)
+{
+    g_assert_not_reached();
+}

semihosting/arm-compat-semi.c

@@ -101,6 +101,13 @@ static int gdb_open_modeflags[12] = {
     GDB_O_RDWR | GDB_O_CREAT | GDB_O_APPEND,
 };
 
+/*
+ * For ARM semihosting, we have a separate structure for routing
+ * data for the console which is outside the guest fd address space.
+ */
+static GuestFD console_in_gf;
+static GuestFD console_out_gf;
+
 #ifndef CONFIG_USER_ONLY
 
 /**
@@ -353,6 +360,25 @@ static const uint8_t featurefile_data[] = {
     SH_EXT_EXIT_EXTENDED | SH_EXT_STDOUT_STDERR, /* Feature byte 0 */
 };
 
+bool semihosting_arm_compatible(void)
+{
+    return true;
+}
+
+void semihosting_arm_compatible_init(void)
+{
+    /* For ARM-compat, the console is in a separate namespace. */
+    if (use_gdb_syscalls()) {
+        console_in_gf.type = GuestFDGDB;
+        console_in_gf.hostfd = 0;
+        console_out_gf.type = GuestFDGDB;
+        console_out_gf.hostfd = 2;
+    } else {
+        console_in_gf.type = GuestFDConsole;
+        console_out_gf.type = GuestFDConsole;
+    }
+}
+
 /*
  * Do a semihosting call.
  *

semihosting/guestfd.c

@@ -12,35 +12,20 @@
 #include "gdbstub/syscalls.h"
 #include "semihosting/semihost.h"
 #include "semihosting/guestfd.h"
-#ifndef CONFIG_USER_ONLY
-#include CONFIG_DEVICES
-#endif
 
 static GArray *guestfd_array;
 
-#ifdef CONFIG_ARM_COMPATIBLE_SEMIHOSTING
-GuestFD console_in_gf;
-GuestFD console_out_gf;
-#endif
-
 void qemu_semihosting_guestfd_init(void)
 {
     /* New entries zero-initialized, i.e. type GuestFDUnused */
     guestfd_array = g_array_new(FALSE, TRUE, sizeof(GuestFD));
 
-#ifdef CONFIG_ARM_COMPATIBLE_SEMIHOSTING
-    /* For ARM-compat, the console is in a separate namespace. */
-    if (use_gdb_syscalls()) {
-        console_in_gf.type = GuestFDGDB;
-        console_in_gf.hostfd = 0;
-        console_out_gf.type = GuestFDGDB;
-        console_out_gf.hostfd = 2;
-    } else {
-        console_in_gf.type = GuestFDConsole;
-        console_out_gf.type = GuestFDConsole;
+    if (semihosting_arm_compatible()) {
+        semihosting_arm_compatible_init();
+        return;
     }
-#else
-    /* Otherwise, the stdio file descriptors apply. */
+
+    /* Out of ARM, the stdio file descriptors apply. */
     guestfd_array = g_array_set_size(guestfd_array, 3);
 #ifndef CONFIG_USER_ONLY
     if (!use_gdb_syscalls()) {
@@ -54,7 +39,6 @@ void qemu_semihosting_guestfd_init(void)
     associate_guestfd(0, 0);
     associate_guestfd(1, 1);
     associate_guestfd(2, 2);
-#endif
 }
 
 /*

semihosting/meson.build

@@ -1,17 +1,18 @@
-specific_ss.add(when: 'CONFIG_SEMIHOSTING', if_true: files(
-  'guestfd.c',
-))
-
 common_ss.add(when: 'CONFIG_SEMIHOSTING', if_false: files('stubs-all.c'))
-user_ss.add(when: 'CONFIG_SEMIHOSTING', if_true: files('user.c'))
+user_ss.add(when: 'CONFIG_SEMIHOSTING', if_true: files(
+  'user.c',
+  'guestfd.c'))
 system_ss.add(when: 'CONFIG_SEMIHOSTING', if_true: files(
   'config.c',
   'console.c',
+  'guestfd.c',
   'uaccess.c',
   'syscalls.c',
 ), if_false: files(
   'stubs-system.c',
 ))
+system_ss.add(when: 'CONFIG_ARM_COMPATIBLE_SEMIHOSTING',
+  if_false: files('arm-compat-semi-stub.c'))
 
 specific_ss.add(when: ['CONFIG_SEMIHOSTING', 'CONFIG_USER_ONLY'],
                 if_true: files('syscalls.c'))