Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild

* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild:
  kbuild: explain why DEBUG_SECTION_MISMATCH is UNDEFINED
  kbuild: fix building vmlinux.o
  kbuild: allow -fstack-protector to take effect
  kconfig: fix select in combination with default

Makefile

@@ -507,6 +507,10 @@ else
 KBUILD_CFLAGS	+= -O2
 endif
 
+# Force gcc to behave correct even for buggy distributions
+# Arch Makefiles may override this setting
+KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
+
 include $(srctree)/arch/$(SRCARCH)/Makefile
 
 ifdef CONFIG_FRAME_POINTER
@@ -525,9 +529,6 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH
 KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
 endif
 
-# Force gcc to behave correct even for buggy distributions
-KBUILD_CFLAGS         += $(call cc-option, -fno-stack-protector)
-
 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 CHECKFLAGS     += $(NOSTDINC_FLAGS)
@@ -810,7 +811,9 @@ endif
 	$(Q)rm -f .old_version
 
 # build vmlinux.o first to catch section mismatch errors early
-$(kallsyms.o): vmlinux.o
+ifdef CONFIG_KALLSYMS
+.tmp_vmlinux1: vmlinux.o
+endif
 vmlinux.o: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) FORCE
 	$(call if_changed_rule,vmlinux-modpost)
 

lib/Kconfig.debug

@@ -82,6 +82,9 @@ config HEADERS_CHECK
 config DEBUG_SECTION_MISMATCH
 	bool "Enable full Section mismatch analysis"
 	depends on UNDEFINED
+	# This option is on purpose disabled for now.
+	# It will be enabled when we are down to a resonable number
+	# of section mismatch warnings (< 10 for an allyesconfig build)
 	help
 	  The section mismatch analysis checks if there are illegal
 	  references from one section to another section.

scripts/kconfig/symbol.c

@@ -298,22 +298,30 @@ void sym_calc_value(struct symbol *sym)
 		if (sym_is_choice_value(sym) && sym->visible == yes) {
 			prop = sym_get_choice_prop(sym);
 			newval.tri = (prop_get_symbol(prop)->curr.val == sym) ? yes : no;
-		} else if (EXPR_OR(sym->visible, sym->rev_dep.tri) != no) {
-			sym->flags |= SYMBOL_WRITE;
-			if (sym_has_value(sym))
-				newval.tri = sym->def[S_DEF_USER].tri;
-			else if (!sym_is_choice(sym)) {
-				prop = sym_get_default_prop(sym);
-				if (prop)
-					newval.tri = expr_calc_value(prop->expr);
+		} else {
+			if (sym->visible != no) {
+				/* if the symbol is visible use the user value
+				 * if available, otherwise try the default value
+				 */
+				sym->flags |= SYMBOL_WRITE;
+				if (sym_has_value(sym)) {
+					newval.tri = EXPR_AND(sym->def[S_DEF_USER].tri,
+							      sym->visible);
+					goto calc_newval;
+				}
 			}
-			newval.tri = EXPR_OR(EXPR_AND(newval.tri, sym->visible), sym->rev_dep.tri);
-		} else if (!sym_is_choice(sym)) {
-			prop = sym_get_default_prop(sym);
-			if (prop) {
+			if (sym->rev_dep.tri != no)
 				sym->flags |= SYMBOL_WRITE;
-				newval.tri = expr_calc_value(prop->expr);
+			if (!sym_is_choice(sym)) {
+				prop = sym_get_default_prop(sym);
+				if (prop) {
+					sym->flags |= SYMBOL_WRITE;
+					newval.tri = EXPR_AND(expr_calc_value(prop->expr),
+							      prop->visible.tri);
+				}
 			}
+		calc_newval:
+			newval.tri = EXPR_OR(newval.tri, sym->rev_dep.tri);
 		}
 		if (newval.tri == mod && sym_get_type(sym) == S_BOOLEAN)
 			newval.tri = yes;