[v2,20/29] modpost: generate vmlinux.symvers and reuse it for the second modpost
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Message ID 20200524154235.380482-21-masahiroy@kernel.org
State New
Headers show
  • modpost: various fixes, cleanups, optimizations
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Commit Message

Masahiro Yamada May 24, 2020, 3:42 p.m. UTC
The full build runs modpost twice, first for vmlinux.o and second for

The first pass dumps all the vmlinux symbols into Module.symvers, but
the second pass parses vmlinux again instead of reusing the dump file,
presumably because it needs to avoid accumulating stale symbols.

Loading symbol info from a dump file is faster than parsing an ELF object.
Besides, modpost deals with various issues to parse vmlinux in the second

A solution is to make the first pass dumps symbols into a separate file,
vmlinux.symvers. The second pass reads it, and parses module .o files.
The merged symbol information is dumped into Module.symvers as before.

This makes further modpost cleanups possible.

Also, it fixes the problem of 'make vmlinux', which previously overwrote
Module.symvers, throwing away module symbols.

I slightly touched scripts/link-vmlinux.sh so that vmlinux is re-linked
when you cross this commit. Otherwise, vmlinux.symvers would not be

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Changes in v2: None

 .gitignore               |  1 +
 Makefile                 |  2 +-
 scripts/Makefile.modpost | 11 +++++++----
 scripts/link-vmlinux.sh  |  2 --
 4 files changed, 9 insertions(+), 7 deletions(-)

diff mbox series

diff --git a/.gitignore b/.gitignore
index 2258e906f01c..87b9dd8a163b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -56,6 +56,7 @@  modules.order
diff --git a/Makefile b/Makefile
index 3b25a51132ea..0a3d3828f6eb 100644
--- a/Makefile
+++ b/Makefile
@@ -1408,7 +1408,7 @@  endif # CONFIG_MODULES
 # make distclean Remove editor backup files, patch leftover files and the like
 # Directories & files removed with 'make clean'
-CLEAN_FILES += include/ksym \
+CLEAN_FILES += include/ksym vmlinux.symvers \
 	       modules.builtin modules.builtin.modinfo modules.nsdeps
 # Directories & files removed with 'make mrproper'
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index d14143b30b7a..1c597999b6a0 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -43,17 +43,17 @@  __modpost:
 include include/config/auto.conf
 include scripts/Kbuild.include
-kernelsymfile := $(objtree)/Module.symvers
 MODPOST = scripts/mod/modpost								\
 	$(if $(CONFIG_MODVERSIONS),-m)							\
-	$(if $(KBUILD_EXTMOD),,-o $(kernelsymfile))					\
+# modpost options for vmlinux.o
+MODPOST += -o vmlinux.symvers
 quiet_cmd_modpost = MODPOST vmlinux.o
       cmd_modpost = $(MODPOST) vmlinux.o
@@ -68,7 +68,10 @@  MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s \
 ifeq ($(KBUILD_EXTMOD),)
-MODPOST += $(wildcard vmlinux)
+# modpost options for in-kernel modules
+MODPOST += -i vmlinux.symvers -o Module.symvers
 # set src + obj - they may be used in the modules's Makefile
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index d09ab4afbda4..d5af6be50b50 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -218,8 +218,6 @@  on_signals()
 trap on_signals HUP INT QUIT TERM
 # Use "make V=1" to debug this script
 case "${KBUILD_VERBOSE}" in