kbuild: complain about missing system calls

Most system calls seems to get added to i386 first. This patch
automatically generates a warning for any new system call which is
implemented on i386 but not the architecture currently being compiled.
On PowerPC at the moment, for example, it results in these warnings:
init/missing_syscalls.h:935:3: warning: #warning syscall sync_file_range not implemented
init/missing_syscalls.h:947:3: warning: #warning syscall getcpu not implemented
init/missing_syscalls.h:950:3: warning: #warning syscall epoll_pwait not implemented

The file scripts/checksyscalls.sh list a number of legacy system calls
that are ignored because they only makes sense on i386 systems.

Other contributors to this patch are Russell King <rmk+lkml@arm.linux.org.uk>
and Stéphane Jourdois <kwisatz@rubis.org>

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/Kbuild b/Kbuild
index 0451f69353ba..163f8cb020a4 100644
--- a/Kbuild
+++ b/Kbuild
@@ -2,6 +2,7 @@
 # Kbuild for top-level directory of the kernel
 # This file takes care of the following:
 # 1) Generate asm-offsets.h
+# 2) Check for missing system calls
 
 #####
 # 1) Generate asm-offsets.h
@@ -46,3 +47,13 @@ $(obj)/$(offsets-file): arch/$(ARCH)/kernel/asm-offsets.s Kbuild
         $(Q)mkdir -p $(dir $@)
         $(call cmd,offsets)
 
+#####
+# 2) Check for missing system calls
+#
+
+quiet_cmd_syscalls = CALL    $<
+      cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags)
+
+PHONY += missing-syscalls
+missing-syscalls: scripts/checksyscalls.sh FORCE
+        $(call cmd,syscalls)