From 5f56cb030e4bcf14be2233332d5cd83fff62a376 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Wed, 1 Nov 2023 03:11:57 +0900
Subject: [PATCH] kbuild: support 'userldlibs' syntax
This syntax is useful to specify libraries linked to all userspace
programs in the Makefile.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
Documentation/kbuild/makefiles.rst | 4 ++++
scripts/Makefile.userprogs | 6 +++---
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index d88d4f0f4f895..e9299971220a0 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -937,6 +937,10 @@ Example::
# net/bpfilter/Makefile
bpfilter_umh-userldflags += -static
+To specify libraries linked to a userspace program, you can use
+``<executable>-userldlibs``. The ``userldlibs`` syntax specifies libraries
+linked to all userspace programs created in the current Makefile.
+
When linking bpfilter_umh, it will be passed the extra option -static.
From command line, :ref:`USERCFLAGS and USERLDFLAGS <userkbuildflags>` will also be used.
diff --git a/scripts/Makefile.userprogs b/scripts/Makefile.userprogs
index fb415297337ab..f3a7e1ef3753b 100644
--- a/scripts/Makefile.userprogs
+++ b/scripts/Makefile.userprogs
@@ -19,19 +19,19 @@ user-cobjs := $(addprefix $(obj)/, $(user-cobjs))
user_ccflags = -Wp,-MMD,$(depfile) $(KBUILD_USERCFLAGS) $(userccflags) \
$($(target-stem)-userccflags)
user_ldflags = $(KBUILD_USERLDFLAGS) $(userldflags) $($(target-stem)-userldflags)
+user_ldlibs = $(userldlibs) $($(target-stem)-userldlibs)
# Create an executable from a single .c file
quiet_cmd_user_cc_c = CC [U] $@
cmd_user_cc_c = $(CC) $(user_ccflags) $(user_ldflags) -o $@ $< \
- $($(target-stem)-userldlibs)
+ $(user_ldlibs)
$(user-csingle): $(obj)/%: $(src)/%.c FORCE
$(call if_changed_dep,user_cc_c)
# Link an executable based on list of .o files
quiet_cmd_user_ld = LD [U] $@
cmd_user_ld = $(CC) $(user_ldflags) -o $@ \
- $(addprefix $(obj)/, $($(target-stem)-objs)) \
- $($(target-stem)-userldlibs)
+ $(addprefix $(obj)/, $($(target-stem)-objs)) $(user_ldlibs)
$(user-cmulti): FORCE
$(call if_changed,user_ld)
$(call multi_depend, $(user-cmulti), , -objs)
--
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