kbuild: Allow for ',' in file names

The dependency generation broke on files with a comma in their name,
i.e. 53c7,8xx.c

This patches fixes the limitation. However, using commas in filenames
is strongly discouraged, there are other places where this case cannot
be handled cleanly (e.g. section names in include/linux/spinlock.h).

Rules.make

@@ -85,6 +85,10 @@ real-objs-m := $(foreach m, $(obj-m), $(if $($(m:.o=-objs)),$($(m:.o=-objs)),$(m
 # Only build module versions for files which are selected to be built
 export-objs := $(filter $(export-objs),$(real-objs-y) $(real-objs-m))
 
+# The temporary file to save gcc -MD generated dependencies must not
+# contain a comma
+depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
+
 # We're called for one of three purposes:
 # o fastdep: build module version files (.ver) for $(export-objs) in
 #   the current directory
@@ -131,7 +135,7 @@ $(MODVERDIR)/$(real-objs-y:.o=.ver): modkern_cflags := $(CFLAGS_KERNEL)
 $(MODVERDIR)/$(real-objs-m:.o=.ver): modkern_cflags := $(CFLAGS_MODULE)
 $(MODVERDIR)/$(export-objs:.o=.ver): export_flags   := -D__GENKSYMS__
 
-c_flags = -Wp,-MD,$(@D)/.$(@F).d $(CFLAGS) $(NOSTDINC_FLAGS) \
+c_flags = -Wp,-MD,$(depfile) $(CFLAGS) $(NOSTDINC_FLAGS) \
 	  $(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o) \
 	  -DKBUILD_BASENAME=$(subst $(comma),_,$(subst -,_,$(*F))) \
 	  $(export_flags) 
@@ -216,7 +220,7 @@ $(export-objs:.o=.i)  : export_flags   := $(EXPORT_FLAGS)
 $(export-objs:.o=.s)  : export_flags   := $(EXPORT_FLAGS)
 $(export-objs:.o=.lst): export_flags   := $(EXPORT_FLAGS)
 
-c_flags = -Wp,-MD,$(@D)/.$(@F).d $(CFLAGS) $(NOSTDINC_FLAGS) \
+c_flags = -Wp,-MD,$(depfile) $(CFLAGS) $(NOSTDINC_FLAGS) \
 	  $(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o) \
 	  -DKBUILD_BASENAME=$(subst $(comma),_,$(subst -,_,$(*F))) \
 	  $(export_flags) 
@@ -253,7 +257,7 @@ modkern_aflags := $(AFLAGS_KERNEL)
 $(real-objs-m)      : modkern_aflags := $(AFLAGS_MODULE)
 $(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE)
 
-a_flags = -Wp,-MD,$(@D)/.$(@F).d $(AFLAGS) $(NOSTDINC_FLAGS) \
+a_flags = -Wp,-MD,$(depfile) $(AFLAGS) $(NOSTDINC_FLAGS) \
 	  $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)
 
 quiet_cmd_as_s_S = CPP    $(RELDIR)/$@
@@ -447,8 +451,8 @@ if_changed_dep = $(if $(strip $? \
 	@set -e; \
 	$(if $($(quiet)cmd_$(1)),echo '  $($(quiet)cmd_$(1))';) \
 	$(cmd_$(1)); \
-	$(TOPDIR)/scripts/fixdep $(@D)/.$(@F).d $@ $(TOPDIR) '$(cmd_$(1))' > $(@D)/.$(@F).tmp; \
-	rm -f $(@D)/.$(@F).d; \
+	$(TOPDIR)/scripts/fixdep $(depfile) $@ $(TOPDIR) '$(cmd_$(1))' > $(@D)/.$(@F).tmp; \
+	rm -f $(depfile); \
 	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
 
 # If quiet is set, only print short version of command