objtool: Remove --lto and --vmlinux in favor of --link

The '--lto' option is a confusing way of telling objtool to do stack
validation despite it being a linked object.  It's no longer needed now
that an explicit '--stackval' option exists.  The '--vmlinux' option is
also redundant.

Remove both options in favor of a straightforward '--link' option which
identifies a linked object.

Also, implicitly set '--link' with a warning if the user forgets to do
so and we can tell that it's a linked object.  This makes it easier for
manual vmlinux runs.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/dcd3ceffd15a54822c6183e5766d21ad06082b45.1650300597.git.jpoimboe@redhat.com
This commit is contained in:
Josh Poimboeuf
2022-04-18 09:50:43 -07:00
committed by Peter Zijlstra
parent 489e355b42
commit 753da4179d
7 changed files with 70 additions and 39 deletions

View File

@@ -229,7 +229,7 @@ objtool := $(objtree)/tools/objtool/objtool
objtool_args = \
$(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label) \
$(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \
$(if $(CONFIG_X86_KERNEL_IBT), --lto --ibt) \
$(if $(CONFIG_X86_KERNEL_IBT), --ibt) \
$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
$(if $(CONFIG_UNWINDER_ORC), --orc) \
$(if $(CONFIG_RETPOLINE), --retpoline) \
@@ -237,6 +237,7 @@ objtool_args = \
$(if $(CONFIG_STACK_VALIDATION), --stackval) \
$(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call) \
$(if $(CONFIG_X86_SMAP), --uaccess) \
$(if $(linked-object), --link) \
$(if $(part-of-module), --module) \
$(if $(CONFIG_GCOV_KERNEL), --no-unreachable)
@@ -306,6 +307,7 @@ quiet_cmd_cc_prelink_modules = LD [M] $@
# modules into native code
$(obj)/%.prelink.o: objtool-enabled = y
$(obj)/%.prelink.o: part-of-module := y
$(obj)/%.prelink.o: linked-object := y
$(obj)/%.prelink.o: $(obj)/%.o FORCE
$(call if_changed,cc_prelink_modules)

View File

@@ -114,8 +114,8 @@ objtool_link()
if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
# Don't perform vmlinux validation unless explicitly requested,
# but run objtool on vmlinux.o now that we have an object file.
# For LTO and IBT, objtool doesn't run on individual
# translation units. Run everything on vmlinux instead.
if is_enabled CONFIG_HAVE_JUMP_LABEL_HACK; then
objtoolopt="${objtoolopt} --hacks=jump_label"
@@ -156,8 +156,6 @@ objtool_link()
if is_enabled CONFIG_X86_SMAP; then
objtoolopt="${objtoolopt} --uaccess"
fi
objtoolopt="${objtoolopt} --lto"
fi
if is_enabled CONFIG_NOINSTR_VALIDATION; then
@@ -170,7 +168,7 @@ objtool_link()
objtoolopt="${objtoolopt} --no-unreachable"
fi
objtoolopt="${objtoolopt} --vmlinux"
objtoolopt="${objtoolopt} --link"
info OBJTOOL ${1}
tools/objtool/objtool ${objtoolopt} ${1}