fix: use Hermit's sys malloc and fix uninitialised global data

newlib/configure.host

@@ -595,7 +595,7 @@ case "${host}" in
 	syscall_dir=syscalls
 	;;
   *-*-hermit*)
-	newlib_cflags="${newlib_cflags} -DREENTRANT_SYSCALLS_PROVIDED -D__DYNAMIC_REENT__ -DSIGNAL_PROVIDED -DHAVE_NANOSLEEP"
+	newlib_cflags="${newlib_cflags} -DREENTRANT_SYSCALLS_PROVIDED -D__DYNAMIC_REENT__ -DSIGNAL_PROVIDED -DHAVE_NANOSLEEP -DMALLOC_PROVIDED"
 +	;;
 # RTEMS supplies its own versions of some routines:
 #       malloc()            (reentrant version)

newlib/libc/include/sys/config.h

@@ -137,7 +137,7 @@
 #endif
 #endif
 
-#if defined(__mips__) && !defined(__rtems__)
+#if (defined(__mips__) || defined(__hermit__)) && !defined(__rtems__)
 #define __ATTRIBUTE_IMPURE_PTR__ __attribute__((__section__(".sdata")))
 #endif
 

newlib/libc/sys/hermit/crt0.c

@@ -28,17 +28,74 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <getopt.h>
+#include <reent.h>
+#include "syscall.h"
 
 extern int main(int argc, char** argv);
 extern void __libc_init_array(void);
 extern void __libc_fini_array (void);
 extern int _init_signal(void);
 extern char** environ;
+extern void   __sinit (struct _reent *);
+extern struct _glue __sglue;
+extern __FILE __sf[3];
+
+typedef struct layout {
+   size_t size;
+} layout_t;
+
+#define HERMIT_MALLOC_ALIGN ((size_t)8)
+
+void* malloc(size_t s) {
+   return _malloc_r(_REENT, s);
+}
+
+void* _malloc_r(struct _reent* _r, size_t size) {
+   uint8_t *ptr = sys_malloc(size + sizeof(layout_t), HERMIT_MALLOC_ALIGN);
+   if (!ptr)
+      return NULL;
+
+   ((layout_t*)ptr)->size = size;
+   return (void*)(ptr + sizeof(layout_t));
+}
+
+void* calloc(size_t nmemb, size_t size) {
+   return _calloc_r(_REENT, nmemb, size);
+}
+
+void* _calloc_r(struct _reent* r, size_t nmemb, size_t size) {
+   return NULL;
+}
+
+void* realloc(void* ptr, size_t size) {
+   return _realloc_r(_REENT, ptr, size);
+}
+
+void* _realloc_r(struct _reent* r, void* ptr, size_t size) {
+   return NULL;
+}
+
+void free(void* ptr) {
+   _free_r(_REENT, ptr);
+}
+
+void _free_r(struct _reent* r, void* ptr) {
+   if (ptr) {
+      uint8_t* p = (uint8_t*)ptr - sizeof(layout_t);
+      sys_free(p, ((layout_t*)p)->size + sizeof(layout_t), HERMIT_MALLOC_ALIGN);
+   }
+}
 
 void runtime_entry(int argc, char** argv, char** env)
 {
    int ret;
 
+   // For some reason, the newlib symbol for _impure_ptr is NULL.
+   _impure_ptr = &_impure_data;
+   _REENT_INIT_PTR(_impure_ptr);
+   __sglue = (struct _glue){ NULL, 3, &__sf[0] };
+
+
    /* call init function */
    __libc_init_array();
 

newlib/libc/sys/hermit/syscall.h

@@ -146,6 +146,11 @@ int sys_kill(tid_t dest, int signum);
 int sys_signal(signal_handler_t handler);
 unsigned int sys_rand();
 
+uint8_t *sys_malloc(size_t size, size_t align);
+uint8_t *sys_alloc(size_t size, size_t align);
+uint8_t *sys_realloc(uint8_t *ptr, size_t size, size_t align, size_t new_size);
+void sys_free(uint8_t *ptr, size_t size, size_t align);
+
 struct ucontext;
 typedef struct ucontext ucontext_t;