[PATCH v4 12/24] x86/vdso: Enable the vdsocheck tool

["Thomas Weißschuh" <thomas.weissschuh@linutronix.de>]

The vdsocheck tool validates the object files and final .so library.
It can detect if the compiler created relocations which are incompatible
with the vDSO which need to be worked around.

Wire it up for the architecture.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 arch/x86/entry/vdso/Makefile |  6 +++---
 lib/vdso/Kconfig             |  1 +
 lib/vdso/check/vdsocheck.rs  | 12 ++++++++++++
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index f247f5f5cb44dad706701dd5344c9a8031deffc1..9da9cdf8c976ccebac1429afd244d4c9ea6ef5fa 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -35,7 +35,7 @@ CPPFLAGS_vdso.lds += -P -C
 VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 \
 			-z max-page-size=4096
 
-$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
+$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) $(vdsocheck) FORCE
 	$(call if_changed,vdso_and_check)
 
 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
@@ -108,7 +108,7 @@ $(obj)/%.so: OBJCOPYFLAGS := -S --remove-section __ex_table
 $(obj)/%.so: $(obj)/%.so.dbg FORCE
 	$(call if_changed,objcopy)
 
-$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
+$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) $(vdsocheck) FORCE
 	$(call if_changed,vdso_and_check)
 
 CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds)
@@ -144,7 +144,7 @@ endif
 
 $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 
-$(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE
+$(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) $(vdsocheck) FORCE
 	$(call if_changed,vdso_and_check)
 
 #
diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig
index b461e2be6db80eae957c8e0a1ab573a85d78fd15..e9215084462dfb33a5cd55a57171d2ec4295a270 100644
--- a/lib/vdso/Kconfig
+++ b/lib/vdso/Kconfig
@@ -51,6 +51,7 @@ config GENERIC_VDSO_DATA_STORE
 
 config HAVE_VDSOCHECK
 	bool
+	default y if X86
 	help
 	  Selected for architectures that are supported by the 'vdsocheck' progam.
 	  Only transitional.
diff --git a/lib/vdso/check/vdsocheck.rs b/lib/vdso/check/vdsocheck.rs
index 3c421100a91740ce3735edfbc9837ef49f55d8f8..c4feb75f93ec0a6a153a758ee7a51cc6f2f58bf1 100644
--- a/lib/vdso/check/vdsocheck.rs
+++ b/lib/vdso/check/vdsocheck.rs
@@ -34,6 +34,18 @@ fn is_ignored_section(&self, section: &elf::Section<'_>) -> bool {
 
 fn allowed_relocations_for_machine(machine: u16) -> Option<AllowedRelocations<'static>> {
     match machine as u32 {
+        bindings::EM_386 => Some(AllowedRelocations {
+            ignored_object_file_sections: None,
+            in_object_file: &[
+                bindings::R_386_PC32,
+                bindings::R_386_GOTOFF,
+                bindings::R_386_GOTPC,
+            ],
+        }),
+        bindings::EM_X86_64 => Some(AllowedRelocations {
+            ignored_object_file_sections: None,
+            in_object_file: &[bindings::R_X86_64_PC32, bindings::R_X86_64_PLT32],
+        }),
         _ => None,
     }
 }

-- 
2.50.1