From: Vasily Gorbik <gor@linux.ibm.com>
Date: Mon, 27 Jun 2022 12:50:53 +0000 (+0200)
Subject: s390/nospec: build expoline.o for modules_prepare target
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c4e789572557aa147b13bf7fe09cc99663ed0cf5;p=linux.git

s390/nospec: build expoline.o for modules_prepare target

When CONFIG_EXPOLINE_EXTERN is used expoline thunks are generated
from arch/s390/lib/expoline.S and postlinked into every module.
This is also true for external modules. Add expoline.o build to
the modules_prepare target.

Fixes: 1d2ad084800e ("s390/nospec: add an option to use thunk-extern")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Tested-by: C. Erastus Toe <ctoe@redhat.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://lore.kernel.org/r/patch-1.thread-d13b6c.git-a2387a74dc49.your-ad-here.call-01656331067-ext-4899@work.hours
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---

diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 495c68a4df1e9..fc72a35a1f074 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -82,7 +82,7 @@ endif
 
 ifdef CONFIG_EXPOLINE
   ifdef CONFIG_EXPOLINE_EXTERN
-    KBUILD_LDFLAGS_MODULE += arch/s390/lib/expoline.o
+    KBUILD_LDFLAGS_MODULE += arch/s390/lib/expoline/expoline.o
     CC_FLAGS_EXPOLINE := -mindirect-branch=thunk-extern
     CC_FLAGS_EXPOLINE += -mfunction-return=thunk-extern
   else
@@ -163,6 +163,12 @@ vdso_prepare: prepare0
 	$(Q)$(MAKE) $(build)=arch/s390/kernel/vdso64 include/generated/vdso64-offsets.h
 	$(if $(CONFIG_COMPAT),$(Q)$(MAKE) \
 		$(build)=arch/s390/kernel/vdso32 include/generated/vdso32-offsets.h)
+
+ifdef CONFIG_EXPOLINE_EXTERN
+modules_prepare: expoline_prepare
+expoline_prepare: prepare0
+	$(Q)$(MAKE) $(build)=arch/s390/lib/expoline arch/s390/lib/expoline/expoline.o
+endif
 endif
 
 # Don't use tabs in echo arguments
diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
index 5d415b3db6d14..580d2e3265cb2 100644
--- a/arch/s390/lib/Makefile
+++ b/arch/s390/lib/Makefile
@@ -7,7 +7,6 @@ lib-y += delay.o string.o uaccess.o find.o spinlock.o
 obj-y += mem.o xor.o
 lib-$(CONFIG_KPROBES) += probes.o
 lib-$(CONFIG_UPROBES) += probes.o
-obj-$(CONFIG_EXPOLINE_EXTERN) += expoline.o
 obj-$(CONFIG_S390_KPROBES_SANITY_TEST) += test_kprobes_s390.o
 test_kprobes_s390-objs += test_kprobes_asm.o test_kprobes.o
 
@@ -22,3 +21,5 @@ obj-$(CONFIG_S390_MODULES_SANITY_TEST) += test_modules.o
 obj-$(CONFIG_S390_MODULES_SANITY_TEST_HELPERS) += test_modules_helpers.o
 
 lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
+
+obj-$(CONFIG_EXPOLINE_EXTERN) += expoline/
diff --git a/arch/s390/lib/expoline.S b/arch/s390/lib/expoline.S
deleted file mode 100644
index 92ed8409a7a44..0000000000000
--- a/arch/s390/lib/expoline.S
+++ /dev/null
@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-#include <asm/nospec-insn.h>
-#include <linux/linkage.h>
-
-.macro GEN_ALL_BR_THUNK_EXTERN
-	.irp r1,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
-	GEN_BR_THUNK_EXTERN %r\r1
-	.endr
-.endm
-
-GEN_ALL_BR_THUNK_EXTERN
diff --git a/arch/s390/lib/expoline/Makefile b/arch/s390/lib/expoline/Makefile
new file mode 100644
index 0000000000000..854631d9cb03a
--- /dev/null
+++ b/arch/s390/lib/expoline/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-y += expoline.o
diff --git a/arch/s390/lib/expoline/expoline.S b/arch/s390/lib/expoline/expoline.S
new file mode 100644
index 0000000000000..92ed8409a7a44
--- /dev/null
+++ b/arch/s390/lib/expoline/expoline.S
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <asm/nospec-insn.h>
+#include <linux/linkage.h>
+
+.macro GEN_ALL_BR_THUNK_EXTERN
+	.irp r1,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
+	GEN_BR_THUNK_EXTERN %r\r1
+	.endr
+.endm
+
+GEN_ALL_BR_THUNK_EXTERN