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| author | Peter Zijlstra <peterz@infradead.org> | 2022-09-15 14:11:13 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-10-17 17:41:08 +0300 |
| commit | 08ef8c40112b8cd157515cd532f65cb82c934a76 (patch) | |
| tree | 08ef77d8801a888a385cf97dcfd61f49599607b4 /tools/objtool | |
| parent | 5da6aea375cde499fdfac3cde4f26df4a840eb9f (diff) | |
| download | linux-08ef8c40112b8cd157515cd532f65cb82c934a76.tar.xz | |
objtool: Allow symbol range comparisons for IBT/ENDBR
A semi common pattern is where code checks if a code address is
within a specific range. All text addresses require either ENDBR or
ANNOTATE_ENDBR, however the ANNOTATE_NOENDBR past the range is
unnatural.
Instead, suppress this warning when this is exactly at the end of a
symbol that itself starts with either ENDBR/ANNOTATE_ENDBR.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111146.434642471@infradead.org
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/check.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 1461c8894fb7..3f46f46ab85c 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4033,6 +4033,24 @@ static void mark_endbr_used(struct instruction *insn) list_del_init(&insn->call_node); } +static bool noendbr_range(struct objtool_file *file, struct instruction *insn) +{ + struct symbol *sym = find_symbol_containing(insn->sec, insn->offset-1); + struct instruction *first; + + if (!sym) + return false; + + first = find_insn(file, sym->sec, sym->offset); + if (!first) + return false; + + if (first->type != INSN_ENDBR && !first->noendbr) + return false; + + return insn->offset == sym->offset + sym->len; +} + static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn) { struct instruction *dest; @@ -4105,9 +4123,19 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn continue; } + /* + * Accept anything ANNOTATE_NOENDBR. + */ if (dest->noendbr) continue; + /* + * Accept if this is the instruction after a symbol + * that is (no)endbr -- typical code-range usage. + */ + if (noendbr_range(file, dest)) + continue; + WARN_FUNC("relocation to !ENDBR: %s", insn->sec, insn->offset, offstr(dest->sec, dest->offset)); |