10 files changed, 37 insertions, 10 deletions
diff --git a/arch/um/os-Linux/drivers/ethertap_kern.c b/arch/um/os-Linux/drivers/ethertap_kern.c
index 3182e759d8de..5e5ee40680ce 100644
--- a/arch/um/os-Linux/drivers/ethertap_kern.c
+++ b/arch/um/os-Linux/drivers/ethertap_kern.c
@@ -63,7 +63,7 @@ const struct net_kern_info ethertap_kern_info = {
 	.write 			= etap_write,
 };
 
-int ethertap_setup(char *str, char **mac_out, void *data)
+static int ethertap_setup(char *str, char **mac_out, void *data)
 {
 	struct ethertap_init *init = data;
 
diff --git a/arch/um/os-Linux/drivers/tuntap_kern.c b/arch/um/os-Linux/drivers/tuntap_kern.c
index adcb6717be6f..ff022d9cf0dd 100644
--- a/arch/um/os-Linux/drivers/tuntap_kern.c
+++ b/arch/um/os-Linux/drivers/tuntap_kern.c
@@ -53,7 +53,7 @@ const struct net_kern_info tuntap_kern_info = {
 	.write 			= tuntap_write,
 };
 
-int tuntap_setup(char *str, char **mac_out, void *data)
+static int tuntap_setup(char *str, char **mac_out, void *data)
 {
 	struct tuntap_init *init = data;
 
diff --git a/arch/um/os-Linux/elf_aux.c b/arch/um/os-Linux/elf_aux.c
index 344ac403fb5d..0a0f91cf4d6d 100644
--- a/arch/um/os-Linux/elf_aux.c
+++ b/arch/um/os-Linux/elf_aux.c
@@ -13,6 +13,7 @@
 #include <init.h>
 #include <elf_user.h>
 #include <mem_user.h>
+#include "internal.h"
 
 typedef Elf32_auxv_t elf_auxv_t;
 
diff --git a/arch/um/os-Linux/internal.h b/arch/um/os-Linux/internal.h
new file mode 100644
index 000000000000..317fca190c2b
--- /dev/null
+++ b/arch/um/os-Linux/internal.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_OS_LINUX_INTERNAL_H
+#define __UM_OS_LINUX_INTERNAL_H
+
+/*
+ * elf_aux.c
+ */
+void scan_elf_aux(char **envp);
+
+/*
+ * mem.c
+ */
+void check_tmpexec(void);
+
+/*
+ * skas/process.c
+ */
+void wait_stub_done(int pid);
+
+#endif /* __UM_OS_LINUX_INTERNAL_H */
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index c8a42ecbd7a2..f98ff79cdbf7 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -16,6 +16,7 @@
 #include <kern_util.h>
 #include <os.h>
 #include <um_malloc.h>
+#include "internal.h"
 
 #define PGD_BOUND (4 * 1024 * 1024)
 #define STACKSIZE (8 * 1024 * 1024)
@@ -102,8 +103,6 @@ static void setup_env_path(void)
 	}
 }
 
-extern void scan_elf_aux( char **envp);
-
 int __init main(int argc, char **argv, char **envp)
 {
 	char **new_argv;
@@ -184,6 +183,11 @@ int __init main(int argc, char **argv, char **envp)
 
 extern void *__real_malloc(int);
 
+/* workaround for -Wmissing-prototypes warnings */
+void *__wrap_malloc(int size);
+void *__wrap_calloc(int n, int size);
+void __wrap_free(void *ptr);
+
 void *__wrap_malloc(int size)
 {
 	void *ret;
diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index 8530b2e08604..cf44d386f23c 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -15,7 +15,9 @@
 #include <sys/vfs.h>
 #include <linux/magic.h>
 #include <init.h>
+#include <kern_util.h>
 #include <os.h>
+#include "internal.h"
 
 /*
  * kasan_map_memory - maps memory from @start with a size of @len.
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 24a403a70a02..787cfb9a0308 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -72,7 +72,7 @@ static int signals_blocked;
 static unsigned int signals_pending;
 static unsigned int signals_active = 0;
 
-void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
+static void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
 {
 	int enabled = signals_enabled;
 
@@ -108,7 +108,7 @@ static void timer_real_alarm_handler(mcontext_t *mc)
 	timer_handler(SIGALRM, NULL, &regs);
 }
 
-void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
+static void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
 {
 	int enabled;
 
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 953fb10f3f93..1f9c1bffc3a6 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -17,11 +17,10 @@
 #include <skas.h>
 #include <sysdep/ptrace.h>
 #include <sysdep/stub.h>
+#include "../internal.h"
 
 extern char batch_syscall_stub[], __syscall_stub_start[];
 
-extern void wait_stub_done(int pid);
-
 static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
 					      unsigned long *stack)
 {
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 1f5c3f2523d1..41a288dcfc34 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -23,6 +23,7 @@
 #include <skas.h>
 #include <sysdep/stub.h>
 #include <linux/threads.h>
+#include "../internal.h"
 
 int is_skas_winch(int pid, int fd, void *data)
 {
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 8b0e98ab842c..89ad9f4f865c 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -20,10 +20,12 @@
 #include <asm/unistd.h>
 #include <init.h>
 #include <os.h>
+#include <kern_util.h>
 #include <mem_user.h>
 #include <ptrace_user.h>
 #include <registers.h>
 #include <skas.h>
+#include "internal.h"
 
 static void ptrace_child(void)
 {
@@ -221,8 +223,6 @@ static void __init check_ptrace(void)
 	check_sysemu();
 }
 
-extern void check_tmpexec(void);
-
 static void __init check_coredump_limit(void)
 {
 	struct rlimit lim;