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| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2021-03-05 10:27:07 +0100 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2021-04-24 22:12:26 +0200 |
| commit | 5cc1247204616528b427e276c97c5bc4c9612347 (patch) | |
| tree | eba8bcc358486f5d2a030ef1742e52849e2019a5 | |
| parent | kbuild: show warning if 'make headers_check' is used (diff) | |
| download | linux-5cc1247204616528b427e276c97c5bc4c9612347.tar.xz linux-5cc1247204616528b427e276c97c5bc4c9612347.zip | |
kbuild: add CONFIG_VMLINUX_MAP expert option
It can be quite useful to have ld emit a link map file, in order to
debug or verify that special sections end up where they are supposed
to, and to see what LD_DEAD_CODE_DATA_ELIMINATION manages to get rid
of.
The only reason I'm not just adding this unconditionally is that the
.map file can be rather large (several MB), and that's a waste of
space when one isn't interested in these things. Also make it depend
on CONFIG_EXPERT.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
| -rw-r--r-- | .gitignore | 1 | ||||
| -rw-r--r-- | Documentation/dontdiff | 1 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 10 | ||||
| -rwxr-xr-x | scripts/link-vmlinux.sh | 8 |
4 files changed, 20 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore index 3af66272d6f1..3adea59847ce 100644 --- a/.gitignore +++ b/.gitignore @@ -59,6 +59,7 @@ modules.order /linux /vmlinux /vmlinux.32 +/vmlinux.map /vmlinux.symvers /vmlinux-gdb.py /vmlinuz diff --git a/Documentation/dontdiff b/Documentation/dontdiff index e361fc95ca29..ac42ad8d430d 100644 --- a/Documentation/dontdiff +++ b/Documentation/dontdiff @@ -252,6 +252,7 @@ vmlinux-* vmlinux.aout vmlinux.bin.all vmlinux.lds +vmlinux.map vmlinux.symvers vmlinuz voffset.h diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2779c29d9981..b479ae609a31 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -449,6 +449,16 @@ config VMLINUX_VALIDATION depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT default y +config VMLINUX_MAP + bool "Generate vmlinux.map file when linking" + depends on EXPERT + help + Selecting this option will pass "-Map=vmlinux.map" to ld + when linking vmlinux. That file can be useful for verifying + and debugging magic section games, and for seeing which + pieces of code get eliminated with + CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. + config DEBUG_FORCE_WEAK_PER_CPU bool "Force weak per-cpu definitions" depends on DEBUG_KERNEL diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 3b261b0f74f0..855fd4e6f03e 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -155,6 +155,7 @@ vmlinux_link() local output=${1} local objects local strip_debug + local map_option info LD ${output} @@ -166,6 +167,10 @@ vmlinux_link() strip_debug=-Wl,--strip-debug fi + if [ -n "${CONFIG_VMLINUX_MAP}" ]; then + map_option="-Map=${output}.map" + fi + if [ "${SRCARCH}" != "um" ]; then if [ -n "${CONFIG_LTO_CLANG}" ]; then # Use vmlinux.o instead of performing the slow LTO @@ -187,6 +192,7 @@ vmlinux_link() ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \ ${strip_debug#-Wl,} \ -o ${output} \ + ${map_option} \ -T ${lds} ${objects} else objects="-Wl,--whole-archive \ @@ -200,6 +206,7 @@ vmlinux_link() ${CC} ${CFLAGS_vmlinux} \ ${strip_debug} \ -o ${output} \ + ${map_option:+-Wl,${map_option}} \ -Wl,-T,${lds} \ ${objects} \ -lutil -lrt -lpthread @@ -303,6 +310,7 @@ cleanup() rm -f .tmp_vmlinux* rm -f System.map rm -f vmlinux + rm -f vmlinux.map rm -f vmlinux.o } |