mips: Add support for generic vDSO

The mips vDSO library requires some adaptations to take advantage of the
newly introduced generic vDSO library.

Introduce the following changes:
 - Modification of vdso.c to be compliant with the common vdso datapage
 - Use of lib/vdso for gettimeofday

Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
[paul.burton@mips.com: Prepend $(src) to config-n32-o32-env.c path.]
Signed-off-by: Paul Burton <paul.burton@mips.com>

1 files changed, 30 insertions, 3 deletions

diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index 7221df24cb23..de853c6aab28 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -1,6 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0
 # Objects to go into the VDSO.
-obj-vdso-y := elf.o gettimeofday.o sigreturn.o
+
+# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
+# the inclusion of generic Makefile.
+ARCH_REL_TYPE_ABS := R_MIPS_JUMP_SLOT|R_MIPS_GLOB_DAT
+include $(srctree)/lib/vdso/Makefile
+
+obj-vdso-y := elf.o vgettimeofday.o sigreturn.o
 
 # Common compiler flags between ABIs.
 ccflags-vdso := \
@@ -15,15 +21,31 @@ ifdef CONFIG_CC_IS_CLANG
 ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS))
 endif
 
+#
+# The -fno-jump-tables flag only prevents the compiler from generating
+# jump tables but does not prevent the compiler from emitting absolute
+# offsets.
 cflags-vdso := $(ccflags-vdso) \
 	$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
-	-O2 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
-	-DDISABLE_BRANCH_PROFILING \
+	-O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
+	-fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \
 	$(call cc-option, -fno-asynchronous-unwind-tables) \
 	$(call cc-option, -fno-stack-protector)
 aflags-vdso := $(ccflags-vdso) \
 	-D__ASSEMBLY__ -Wa,-gdwarf-2
 
+ifneq ($(c-gettimeofday-y),)
+CFLAGS_vgettimeofday.o = -include $(c-gettimeofday-y)
+
+# config-n32-o32-env.c prepares the environment to build a 32bit vDSO
+# library on a 64bit kernel.
+# Note: Needs to be included before than the generic library.
+CFLAGS_vgettimeofday-o32.o = -include $(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
+CFLAGS_vgettimeofday-n32.o = -include $(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
+endif
+
+CFLAGS_REMOVE_vgettimeofday.o = -pg
+
 #
 # For the pre-R6 code in arch/mips/vdso/vdso.h for locating
 # the base address of VDSO, the linker will emit a R_MIPS_PC32
@@ -48,6 +70,8 @@ VDSO_LDFLAGS := \
 	$(addprefix -Wl$(comma),$(filter -E%,$(KBUILD_CFLAGS))) \
 	-nostdlib -shared -Wl,--hash-style=sysv -Wl,--build-id
 
+CFLAGS_REMOVE_vdso.o = -pg
+
 GCOV_PROFILE := n
 UBSAN_SANITIZE := n
 
@@ -96,6 +120,7 @@ $(obj)/vdso.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) $(native-abi)
 
 $(obj)/vdso.so.dbg.raw: $(obj)/vdso.lds $(obj-vdso) FORCE
 	$(call if_changed,vdsold)
+	$(call if_changed,vdso_check)
 
 $(obj)/vdso-image.c: $(obj)/vdso.so.dbg.raw $(obj)/vdso.so.raw \
                      $(obj)/genvdso FORCE
@@ -134,6 +159,7 @@ $(obj)/vdso-o32.lds: $(src)/vdso.lds.S FORCE
 
 $(obj)/vdso-o32.so.dbg.raw: $(obj)/vdso-o32.lds $(obj-vdso-o32) FORCE
 	$(call if_changed,vdsold)
+	$(call if_changed,vdso_check)
 
 $(obj)/vdso-o32-image.c: VDSO_NAME := o32
 $(obj)/vdso-o32-image.c: $(obj)/vdso-o32.so.dbg.raw $(obj)/vdso-o32.so.raw \
@@ -174,6 +200,7 @@ $(obj)/vdso-n32.lds: $(src)/vdso.lds.S FORCE
 
 $(obj)/vdso-n32.so.dbg.raw: $(obj)/vdso-n32.lds $(obj-vdso-n32) FORCE
 	$(call if_changed,vdsold)
+	$(call if_changed,vdso_check)
 
 $(obj)/vdso-n32-image.c: VDSO_NAME := n32
 $(obj)/vdso-n32-image.c: $(obj)/vdso-n32.so.dbg.raw $(obj)/vdso-n32.so.raw \