x86: Update the check for Forbidden global variables
Add a section .illegal_globals to romstage and check that the section does not
contain any variables while creating romstage.
BUG=None
BRANCH=None
TEST=Compiles for falco and boots to kernel. No size change for romstage with
and without this check.
Change-Id: Ib2ac0c9b8106547f286f5202682a431e2ce886f9
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/226190
Reviewed-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc
index c408cd2..28f8105 100644
--- a/src/arch/x86/Makefile.inc
+++ b/src/arch/x86/Makefile.inc
@@ -211,9 +211,10 @@
$(objcbfs)/romstage_null.debug: $$(romstage-objs) $(LIBGCC_FILE_NAME_romstage) $(objgenerated)/romstage_null.ld
@printf " LINK $(subst $(obj)/,,$(@))\n"
$(call link,romstage,$(filter %.o %.a,$(^)),-o $(@) -L$(obj) -T $(objgenerated)/romstage_null.ld,$(LIBGCC_WRAP_LDFLAGS))
- $(NM_romstage) $@ | grep -q " [DdBb] "; if [ $$? -eq 0 ]; then \
+ $(OBJCOPY_romstage) --only-section .illegal_globals $(@) $(objcbfs)/romstage_null.offenders && \
+ $(NM_romstage) $(objcbfs)/romstage_null.offenders | grep -q ""; if [ $$? -eq 0 ]; then \
echo "Forbidden global variables in romstage:"; \
- $(NM_romstage) $@ | grep " [DdBb] "; test "$(CONFIG_CPU_AMD_AGESA)" = y; \
+ $(NM_romstage) $(objcbfs)/romstage_null.offenders; test "$(CONFIG_CPU_AMD_AGESA)" = y; \
else true; fi
$(objcbfs)/romstage_xip.debug: $$(romstage-objs) $(LIBGCC_FILE_NAME_romstage) $(objgenerated)/romstage_xip.ld
diff --git a/src/arch/x86/init/romstage.ld b/src/arch/x86/init/romstage.ld
index aa5bf44..fb7e877 100644
--- a/src/arch/x86/init/romstage.ld
+++ b/src/arch/x86/init/romstage.ld
@@ -42,6 +42,21 @@
_erom = .;
}
+#if !IS_ENABLED(CONFIG_CPU_AMD_AGESA)
+ /* Global variables are not allowed in romstage
+ * This section is checked during stage creation to ensure
+ * that there are no global variables present
+ */
+ .illegal_globals . : {
+ *(.data)
+ *(.data.*)
+ *(.bss)
+ *(.bss.*)
+ *(.sbss)
+ *(.sbss.*)
+ }
+#endif
+
/DISCARD/ : {
*(.comment)
*(.note)
