arm64: vdso: Enable vDSO compat support

Add vDSO compat support to the arm64 build system.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Shijith Thotton <sthotton@marvell.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Huw Davies <huw@codeweavers.com>
Link: https://lkml.kernel.org/r/20190621095252.32307-16-vincenzo.frascino@arm.com

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 952c9f8..f5eb592 100644 (file)
--- 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 && COMPAT)
        select HANDLE_DOMAIN_IRQ
        select HARDIRQS_SW_RESEND
        select HAVE_PCI

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index e9d2e57..e3d3fd0 100644 (file)
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -49,10 +49,26 @@ $(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_CFLAGS  += $(call cc-disable-warning, psabi)
-KBUILD_AFLAGS  += $(lseinstr) $(brokengasinst)
+KBUILD_AFLAGS  += $(lseinstr) $(brokengasinst) $(compat_vdso)
 
 KBUILD_CFLAGS  += $(call cc-option,-mabi=lp64)
 KBUILD_AFLAGS  += $(call cc-option,-mabi=lp64)
@@ -164,6 +180,9 @@ ifeq ($(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 9e7dcb2..478491f 100644 (file)
--- 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