objtool, modules: Discard objtool annotation sections for modules
The '__unreachable' and '__func_stack_frame_non_standard' sections are
only used at compile time. They're discarded for vmlinux but they
should also be discarded for modules.
Since this is a recurring pattern, prefix the section names with
".discard.". It's a nice convention and vmlinux.lds.h already discards
such sections.
Also remove the 'a' (allocatable) flag from the __unreachable section
since it doesn't make sense for a discarded section.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: d1091c7fa3
("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
55149d0653
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@ -345,8 +345,6 @@ SECTIONS
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DISCARDS
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/DISCARD/ : {
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*(.eh_frame)
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*(__func_stack_frame_non_standard)
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*(__unreachable)
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}
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}
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@ -200,7 +200,7 @@
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#ifdef CONFIG_STACK_VALIDATION
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#define annotate_unreachable() ({ \
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asm("%c0:\t\n" \
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".pushsection __unreachable, \"a\"\t\n" \
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".pushsection .discard.unreachable\t\n" \
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".long %c0b - .\t\n" \
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".popsection\t\n" : : "i" (__LINE__)); \
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})
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@ -11,7 +11,7 @@
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* For more information, see tools/objtool/Documentation/stack-validation.txt.
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*/
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#define STACK_FRAME_NON_STANDARD(func) \
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static void __used __section(__func_stack_frame_non_standard) \
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static void __used __section(.discard.func_stack_frame_non_standard) \
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*__func_stack_frame_non_standard_##func = func
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#else /* !CONFIG_STACK_VALIDATION */
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@ -854,6 +854,7 @@ static const char *const section_white_list[] =
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".cmem*", /* EZchip */
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".fmt_slot*", /* EZchip */
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".gnu.lto*",
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".discard.*",
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NULL
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};
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@ -4,7 +4,10 @@
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* combine them automatically.
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*/
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SECTIONS {
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/DISCARD/ : { *(.discard) }
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/DISCARD/ : {
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*(.discard)
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*(.discard.*)
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}
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__ksymtab 0 : { *(SORT(___ksymtab+*)) }
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__ksymtab_gpl 0 : { *(SORT(___ksymtab_gpl+*)) }
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@ -339,13 +339,13 @@ static int add_dead_ends(struct objtool_file *file)
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struct instruction *insn;
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bool found;
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sec = find_section_by_name(file->elf, ".rela__unreachable");
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sec = find_section_by_name(file->elf, ".rela.discard.unreachable");
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if (!sec)
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return 0;
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list_for_each_entry(rela, &sec->rela_list, list) {
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if (rela->sym->type != STT_SECTION) {
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WARN("unexpected relocation symbol type in .rela__unreachable");
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WARN("unexpected relocation symbol type in %s", sec->name);
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return -1;
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}
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insn = find_insn(file, rela->sym->sec, rela->addend);
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@ -1272,7 +1272,7 @@ int cmd_check(int argc, const char **argv)
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INIT_LIST_HEAD(&file.insn_list);
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hash_init(file.insn_hash);
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file.whitelist = find_section_by_name(file.elf, "__func_stack_frame_non_standard");
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file.whitelist = find_section_by_name(file.elf, ".discard.func_stack_frame_non_standard");
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file.rodata = find_section_by_name(file.elf, ".rodata");
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file.ignore_unreachables = false;
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file.c_file = find_section_by_name(file.elf, ".comment");
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