[tip: timers/vdso] x86/vdso: Always reject undefined references during linking

["tip-bot2 for Thomas Weißschuh" <tip-bot2@linutronix.de>]

The following commit has been merged into the timers/vdso branch of tip:

Commit-ID:     c080f2b8a2e44077aed15f1b4f0fbc0f4a912a66
Gitweb:        https://git.kernel.org/tip/c080f2b8a2e44077aed15f1b4f0fbc0f4a912a66
Author:        Thomas Weißschuh <thomas.weissschuh@linutronix.de>
AuthorDate:    Thu, 06 Mar 2025 15:07:20 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 11 Mar 2025 09:49:15 +01:00

x86/vdso: Always reject undefined references during linking

Instead of using a custom script to detect and fail on undefined
references, use --no-undefined for all VDSO linker invocations.

Drop the now unused checkundef.sh script.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250306-vdso-checkundef-v2-1-a26cc315fd73@linutronix.de
---
 arch/x86/entry/vdso/Makefile      |  7 +++----
 arch/x86/entry/vdso/checkundef.sh | 10 ----------
 2 files changed, 3 insertions(+), 14 deletions(-)
 delete mode 100755 arch/x86/entry/vdso/checkundef.sh

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 1c00723..a6430c5 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -32,7 +32,7 @@ targets += $(foreach x, 64 x32 32, vdso-image-$(x).c vdso$(x).so vdso$(x).so.dbg
 
 CPPFLAGS_vdso.lds += -P -C
 
-VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
+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
@@ -151,10 +151,9 @@ $(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE
 quiet_cmd_vdso = VDSO    $@
       cmd_vdso = $(LD) -o $@ \
 		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
-		       -T $(filter %.lds,$^) $(filter %.o,$^) && \
-		 sh $(src)/checkundef.sh '$(NM)' '$@'
+		       -T $(filter %.lds,$^) $(filter %.o,$^)
 
-VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 \
+VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 --no-undefined \
 	$(call ld-option, --eh-frame-hdr) -Bsymbolic -z noexecstack
 
 quiet_cmd_vdso_and_check = VDSO    $@
diff --git a/arch/x86/entry/vdso/checkundef.sh b/arch/x86/entry/vdso/checkundef.sh
deleted file mode 100755
index 7ee90a9..0000000
--- a/arch/x86/entry/vdso/checkundef.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/bin/sh
-nm="$1"
-file="$2"
-$nm "$file" | grep '^ *U' > /dev/null 2>&1
-if [ $? -eq 1 ]; then
-    exit 0
-else
-    echo "$file: undefined symbols found" >&2
-    exit 1
-fi