From cb4349edce6ce360436f10da8b6aa32e68fb778d Mon Sep 17 00:00:00 2001
From: Jerome Forissier <jerome.forissier@linaro.org>
Date: Tue, 23 Aug 2022 11:41:00 +0000
Subject: [PATCH] core, ldelf: link: add -z execstack

When building for arm32 with GNU binutils 2.39, the linker outputs
warnings when generating some TEE core binaries (all_obj.o, init.o,
unpaged.o and tee.elf) as well as ldelf.elf:

 arm-poky-linux-gnueabi-ld.bfd: warning: atomic_a32.o: missing .note.GNU-stack section implies executable stack
 arm-poky-linux-gnueabi-ld.bfd: NOTE: This behaviour is deprecated and will be removed in a future version of the linker

The permissions used when mapping the TEE core stacks do not depend on
any metadata found in the ELF file. Similarly when the TEE core loads
ldelf it already creates a non-executable stack regardless of ELF
information. Therefore we can safely ignore the warnings. This is done
by adding the '-z execstack' option.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>

Signed-off-by: Anton Antonov <Anton.Antonov@arm.com>
Upstream-Status: Backport [https://github.com/OP-TEE/optee_os/pull/5499]

---
 core/arch/arm/kernel/link.mk | 13 +++++++++----
 ldelf/link.mk                |  4 ++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/core/arch/arm/kernel/link.mk b/core/arch/arm/kernel/link.mk
index 3dc459d6..85cde58e 100644
--- a/core/arch/arm/kernel/link.mk
+++ b/core/arch/arm/kernel/link.mk
@@ -9,6 +9,11 @@ link-script-dep = $(link-out-dir)/.kern.ld.d
 
 AWK	 = awk
 
+link-ldflags-common += $(call ld-option,--no-warn-rwx-segments)
+ifeq ($(CFG_ARM32_core),y)
+link-ldflags-common += $(call ld-option,--no-warn-execstack)
+endif
+
 link-ldflags  = $(LDFLAGS)
 ifeq ($(CFG_CORE_ASLR),y)
 link-ldflags += -pie -Bsymbolic -z notext -z norelro $(ldflag-apply-dynamic-relocs)
@@ -17,7 +22,7 @@ link-ldflags += -T $(link-script-pp) -Map=$(link-out-dir)/tee.map
 link-ldflags += --sort-section=alignment
 link-ldflags += --fatal-warnings
 link-ldflags += --gc-sections
-link-ldflags += $(call ld-option,--no-warn-rwx-segments)
+link-ldflags += $(link-ldflags-common)
 
 link-ldadd  = $(LDADD)
 link-ldadd += $(ldflags-external)
@@ -39,7 +44,7 @@ link-script-cppflags := \
 		$(cppflagscore))
 
 ldargs-all_objs := -T $(link-script-dummy) --no-check-sections \
-		   $(call ld-option,--no-warn-rwx-segments) \
+		   $(link-ldflags-common) \
 		   $(link-objs) $(link-ldadd) $(libgcccore)
 cleanfiles += $(link-out-dir)/all_objs.o
 $(link-out-dir)/all_objs.o: $(objs) $(libdeps) $(MAKEFILE_LIST)
@@ -53,7 +58,7 @@ $(link-out-dir)/unpaged_entries.txt: $(link-out-dir)/all_objs.o
 		$(AWK) '/ ____keep_pager/ { printf "-u%s ", $$3 }' > $@
 
 unpaged-ldargs := -T $(link-script-dummy) --no-check-sections --gc-sections \
-		 $(call ld-option,--no-warn-rwx-segments)
+		 $(link-ldflags-common)
 unpaged-ldadd := $(objs) $(link-ldadd) $(libgcccore)
 cleanfiles += $(link-out-dir)/unpaged.o
 $(link-out-dir)/unpaged.o: $(link-out-dir)/unpaged_entries.txt
@@ -82,7 +87,7 @@ $(link-out-dir)/init_entries.txt: $(link-out-dir)/all_objs.o
 		$(AWK) '/ ____keep_init/ { printf "-u%s ", $$3 }' > $@
 
 init-ldargs := -T $(link-script-dummy) --no-check-sections --gc-sections \
-	       $(call ld-option,--no-warn-rwx-segments)
+	       $(link-ldflags-common)
 init-ldadd := $(link-objs-init) $(link-out-dir)/version.o  $(link-ldadd) \
 	      $(libgcccore)
 cleanfiles += $(link-out-dir)/init.o
diff --git a/ldelf/link.mk b/ldelf/link.mk
index 8fafc879..d8a05ea6 100644
--- a/ldelf/link.mk
+++ b/ldelf/link.mk
@@ -19,6 +19,10 @@ link-ldflags += --sort-section=alignment
 link-ldflags += -z max-page-size=4096 # OP-TEE always uses 4K alignment
 link-ldflags += $(link-ldflags$(sm))
 
+ifeq ($(CFG_ARM32_$(sm)), y)
+link-ldflags += $(call ld-option,--no-warn-execstack)
+endif
+
 link-ldadd  = $(addprefix -L,$(libdirs))
 link-ldadd += --start-group $(addprefix -l,$(libnames)) --end-group
 ldargs-ldelf.elf := $(link-ldflags) $(objs) $(link-ldadd) $(libgcc$(sm))