1 files changed, 110 insertions, 0 deletions

diff --git a/platforms/chibios/syscall-fallbacks.c b/platforms/chibios/syscall-fallbacks.c
new file mode 100644
index 000000000..4569879c7
--- /dev/null
+++ b/platforms/chibios/syscall-fallbacks.c
@@ -0,0 +1,110 @@
+/* Copyright 2021 Nick Brassel, QMK
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+/* To compile the ChibiOS syscall stubs with picolibc
+ * the _reent struct has to be defined. */
+#if defined(USE_PICOLIBC)
+struct _reent;
+#endif
+
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+
+__attribute__((weak, used)) int _open_r(struct _reent *r, const char *path, int flag, int m) {
+    __errno_r(r) = ENOENT;
+    return -1;
+}
+
+__attribute__((weak, used)) int _lseek_r(struct _reent *r, int file, int ptr, int dir) {
+    __errno_r(r) = EBADF;
+    return -1;
+}
+
+__attribute__((weak, used)) int _read_r(struct _reent *r, int file, char *ptr, int len) {
+    __errno_r(r) = EBADF;
+    return -1;
+}
+
+__attribute__((weak, used)) int _write_r(struct _reent *r, int file, char *ptr, int len) {
+    __errno_r(r) = EBADF;
+    return -1;
+}
+
+__attribute__((weak, used)) int _close_r(struct _reent *r, int file) {
+    __errno_r(r) = EBADF;
+    return -1;
+}
+
+__attribute__((weak, used)) int _link_r(struct _reent *r, const char *oldpath, const char *newpath) {
+    __errno_r(r) = EPERM;
+    return -1;
+}
+
+__attribute__((weak, used)) int _unlink_r(struct _reent *r, const char *path) {
+    __errno_r(r) = EPERM;
+    return -1;
+}
+
+__attribute__((weak, used)) clock_t _times_r(struct _reent *r, void *t) {
+    __errno_r(r) = EFAULT;
+    return -1;
+}
+
+__attribute__((weak, used)) int _fstat_r(struct _reent *r, int file, struct stat *st) {
+    __errno_r(r) = EBADF;
+    return -1;
+}
+
+__attribute__((weak, used)) int _isatty_r(struct _reent *r, int fd) {
+    __errno_r(r) = EBADF;
+    return 0;
+}
+
+__attribute__((weak, used)) caddr_t _sbrk_r(struct _reent *r, int incr) {
+    __errno_r(r) = ENOMEM;
+    return (caddr_t)-1;
+}
+
+__attribute__((weak, used)) int _kill(int pid, int sig) {
+    errno = EPERM;
+    return -1;
+}
+
+__attribute__((weak, used)) pid_t _getpid(void) { return 1; }
+
+__attribute__((weak, used)) void _fini(void) { return; }
+
+__attribute__((weak, used, noreturn)) void _exit(int i) {
+    while (1)
+        ;
+}
+
+__attribute__((weak, used)) int _gettimeofday_r(struct _reent *r, struct timeval *t, void *tzp) {
+    __errno_r(r) = EPERM;
+    return -1;
+}
+
+__attribute__((weak, used)) void *__dso_handle;
+
+__attribute__((weak, used)) void __cxa_pure_virtual(void) {
+    while (1)
+        ;
+}
+
+#pragma GCC diagnostic pop