kbuild: unify vdso_install rules

Currently, there is no standard implementation for vdso_install,
leading to various issues:

 1. Code duplication

    Many architectures duplicate similar code just for copying files
    to the install destination.

    Some architectures (arm, sparc, x86) create build-id symlinks,
    introducing more code duplication.

 2. Unintended updates of in-tree build artifacts

    The vdso_install rule depends on the vdso files to install.
    It may update in-tree build artifacts. This can be problematic,
    as explained in commit 19514fc665ff ("arm, kbuild: make
    "make install" not depend on vmlinux").

 3. Broken code in some architectures

    Makefile code is often copied from one architecture to another
    without proper adaptation.

    'make vdso_install' for parisc does not work.

    'make vdso_install' for s390 installs vdso64, but not vdso32.

To address these problems, this commit introduces a generic vdso_install
rule.

Architectures that support vdso_install need to define vdso-install-y
in arch/*/Makefile. vdso-install-y lists the files to install.

For example, arch/x86/Makefile looks like this:

  vdso-install-$(CONFIG_X86_64)           += arch/x86/entry/vdso/vdso64.so.dbg
  vdso-install-$(CONFIG_X86_X32_ABI)      += arch/x86/entry/vdso/vdsox32.so.dbg
  vdso-install-$(CONFIG_X86_32)           += arch/x86/entry/vdso/vdso32.so.dbg
  vdso-install-$(CONFIG_IA32_EMULATION)   += arch/x86/entry/vdso/vdso32.so.dbg

These files will be installed to $(MODLIB)/vdso/ with the .dbg suffix,
if exists, stripped away.

vdso-install-y can optionally take the second field after the colon
separator. This is needed because some architectures install a vdso
file as a different base name.

The following is a snippet from arch/arm64/Makefile.

  vdso-install-$(CONFIG_COMPAT_VDSO)      += arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so

This will rename vdso.so.dbg to vdso32.so during installation. If such
architectures change their implementation so that the base names match,
this workaround will go away.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Guo Ren <guoren@kernel.org>
Acked-by: Helge Deller <deller@gmx.de>  # parisc
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

3 files changed, 3 insertions, 26 deletions

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 2d49aea0ff67..4bd85cc0d32b 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -169,12 +169,6 @@ install: KBUILD_IMAGE := $(boot)/Image
 install zinstall:
 	$(call cmd,install)
 
-PHONY += vdso_install
-vdso_install:
-	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso $@
-	$(if $(CONFIG_COMPAT_VDSO), \
-		$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso32 $@)
-
 archprepare:
 	$(Q)$(MAKE) $(build)=arch/arm64/tools kapi
 ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
@@ -205,6 +199,9 @@ ifdef CONFIG_COMPAT_VDSO
 endif
 endif
 
+vdso-install-y				+= arch/arm64/kernel/vdso/vdso.so.dbg
+vdso-install-$(CONFIG_COMPAT_VDSO)	+= arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so
+
 include $(srctree)/scripts/Makefile.defconf
 
 PHONY += virtconfig
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index fe7a53c6781f..8818287f1095 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -78,13 +78,3 @@ include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
 # Actual build commands
 quiet_cmd_vdsold_and_vdso_check = LD      $@
       cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
-
-# Install commands for the unstripped file
-quiet_cmd_vdso_install = INSTALL $@
-      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
-
-vdso.so: $(obj)/vdso.so.dbg
-	@mkdir -p $(MODLIB)/vdso
-	$(call cmd,vdso_install)
-
-vdso_install: vdso.so
diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
index 2f73e5bca213..1f911a76c5af 100644
--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile
@@ -172,13 +172,3 @@ gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
 quiet_cmd_vdsosym = VDSOSYM $@
 # The AArch64 nm should be able to read an AArch32 binary
       cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
-
-# Install commands for the unstripped file
-quiet_cmd_vdso_install = INSTALL32 $@
-      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so
-
-vdso.so: $(obj)/vdso.so.dbg
-	@mkdir -p $(MODLIB)/vdso
-	$(call cmd,vdso_install)
-
-vdso_install: vdso.so