[PATCH v6 15/19] arm64: Add vDSO compat support

Vincenzo Frascino
2019-05-30T14:16:39Z

Add vDSO compat support to the arm64 building system.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
arch/arm64/Kconfig | 1 +
arch/arm64/Makefile | 23 +++++++++++++++++++++--
arch/arm64/kernel/Makefile | 6 +++++-
3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 952c9f8cf3b8..3e1d4f8347f4 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -108,6 +108,7 @@ config ARM64
select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
select GENERIC_GETTIMEOFDAY
+ select GENERIC_COMPAT_VDSO if !CPU_BIG_ENDIAN
select HANDLE_DOMAIN_IRQ
select HARDIRQS_SW_RESEND
select HAVE_PCI
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index b025304bde46..4db50d4b2476 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -49,9 +49,25 @@ $(warning Detected assembler with broken .inst; disassembly will be unreliable)
endif
endif

-KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst)
+ifeq ($(CONFIG_GENERIC_COMPAT_VDSO), y)
+ CROSS_COMPILE_COMPAT ?= $(CONFIG_CROSS_COMPILE_COMPAT_VDSO:"%"=%)
+
+ ifeq ($(CONFIG_CC_IS_CLANG), y)
+ $(warning CROSS_COMPILE_COMPAT is clang, the compat vDSO will not be built)
+ else ifeq ($(CROSS_COMPILE_COMPAT),)
+ $(warning CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built)
+ else ifeq ($(shell which $(CROSS_COMPILE_COMPAT)gcc 2> /dev/null),)
+ $(error $(CROSS_COMPILE_COMPAT)gcc not found, check CROSS_COMPILE_COMPAT)
+ else
+ export CROSS_COMPILE_COMPAT
+ export CONFIG_COMPAT_VDSO := y
+ compat_vdso := -DCONFIG_COMPAT_VDSO=1
+ endif
+endif
+
+KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) $(compat_vdso)
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
-KBUILD_AFLAGS += $(lseinstr) $(brokengasinst)
+KBUILD_AFLAGS += $(lseinstr) $(brokengasinst) $(compat_vdso)

KBUILD_CFLAGS += $(call cc-option,-mabi=lp64)
KBUILD_AFLAGS += $(call cc-option,-mabi=lp64)
@@ -163,6 +179,9 @@ ifeq ($(KBUILD_EXTMOD),)
prepare: vdso_prepare
vdso_prepare: prepare0
$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h
+ $(if $(CONFIG_COMPAT_VDSO),$(Q)$(MAKE) \
+ $(build)=arch/arm64/kernel/vdso32 \
+ include/generated/vdso32-offsets.h)
endif

define archhelp
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 9e7dcb2c31c7..478491f07b4f 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -28,7 +28,10 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
$(call if_changed,objcopy)

obj-$(CONFIG_COMPAT) += sys32.o signal32.o \
- sigreturn32.o sys_compat.o
+ sys_compat.o
+ifneq ($(CONFIG_COMPAT_VDSO), y)
+obj-$(CONFIG_COMPAT) += sigreturn32.o
+endif
obj-$(CONFIG_KUSER_HELPERS) += kuser32.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
obj-$(CONFIG_MODULES) += module.o
@@ -62,6 +65,7 @@ obj-$(CONFIG_ARM64_SSBD) += ssbd.o
obj-$(CONFIG_ARM64_PTR_AUTH) += pointer_auth.o

obj-y += vdso/ probes/
+obj-$(CONFIG_COMPAT_VDSO) += vdso32/
head-y := head.o
extra-y += $(head-y) vmlinux.lds

--
2.21.0