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authorSami Tolvanen <samitolvanen@google.com>2020-04-13 16:10:13 -0700
committerKees Cook <keescook@chromium.org>2021-02-23 12:46:57 -0800
commitb1a1a1a09b4606d41723a426110382d2077c26fb (patch)
tree4c6672f8aa90443585f2ceb4cb4e65425d800c6a /scripts/link-vmlinux.sh
parent41425ebe20245c99b44d6ba0f017be9bfc28414f (diff)
kbuild: lto: postpone objtool
With LTO, LLVM bitcode won't be compiled into native code until modpost_link, or modfinal for modules. This change postpones calls to objtool until after these steps, and moves objtool_args to Makefile.lib, so the arguments can be reused in Makefile.modfinal. As we didn't have objects to process earlier, we use --duplicate when processing vmlinux.o. This change also disables unreachable instruction warnings with LTO to avoid warnings about the int3 padding between functions. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'scripts/link-vmlinux.sh')
-rwxr-xr-xscripts/link-vmlinux.sh28
1 files changed, 25 insertions, 3 deletions
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 18aed761f9c0..3b261b0f74f0 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -103,14 +103,36 @@ modpost_link()
objtool_link()
{
+ local objtoolcmd;
local objtoolopt;
+ if [ "${CONFIG_LTO_CLANG} ${CONFIG_STACK_VALIDATION}" = "y y" ]; then
+ # Don't perform vmlinux validation unless explicitly requested,
+ # but run objtool on vmlinux.o now that we have an object file.
+ if [ -n "${CONFIG_UNWINDER_ORC}" ]; then
+ objtoolcmd="orc generate"
+ fi
+
+ objtoolopt="${objtoolopt} --duplicate"
+
+ if [ -n "${CONFIG_FTRACE_MCOUNT_USE_OBJTOOL}" ]; then
+ objtoolopt="${objtoolopt} --mcount"
+ fi
+ fi
+
if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
- objtoolopt="check --vmlinux --noinstr"
+ objtoolopt="${objtoolopt} --noinstr"
+ fi
+
+ if [ -n "${objtoolopt}" ]; then
+ if [ -z "${objtoolcmd}" ]; then
+ objtoolcmd="check"
+ fi
+ objtoolopt="${objtoolopt} --vmlinux"
if [ -z "${CONFIG_FRAME_POINTER}" ]; then
objtoolopt="${objtoolopt} --no-fp"
fi
- if [ -n "${CONFIG_GCOV_KERNEL}" ]; then
+ if [ -n "${CONFIG_GCOV_KERNEL}" ] || [ -n "${CONFIG_LTO_CLANG}" ]; then
objtoolopt="${objtoolopt} --no-unreachable"
fi
if [ -n "${CONFIG_RETPOLINE}" ]; then
@@ -120,7 +142,7 @@ objtool_link()
objtoolopt="${objtoolopt} --uaccess"
fi
info OBJTOOL ${1}
- tools/objtool/objtool ${objtoolopt} ${1}
+ tools/objtool/objtool ${objtoolcmd} ${objtoolopt} ${1}
fi
}