The following commit has been merged into the objtool/core branch of tip:
Commit-ID: dd003edeffa3cb87bc9862582004f405d77d7670
Gitweb: https://git.kernel.org/tip/dd003edeffa3cb87bc9862582004f405d77d7670
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 26 Oct 2021 14:01:34 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Thu, 28 Oct 2021 23:25:25 +02:00
objtool: Explicitly avoid self modifying code in .altinstr_replacement
Assume ALTERNATIVE()s know what they're doing and do not change, or
cause to change, instructions in .altinstr_replacement sections.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Tested-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211026120309.722511775@xxxxxxxxxxxxx
---
tools/objtool/check.c | 42 +++++++++++++++++++++++++++++++-----------
1 file changed, 31 insertions(+), 11 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index fdbc6d2..8ab6f24 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -993,18 +993,27 @@ static void remove_insn_ops(struct instruction *insn)
}
}
-static void add_call_dest(struct objtool_file *file, struct instruction *insn,
- struct symbol *dest, bool sibling)
+static void annotate_call_site(struct objtool_file *file,
+ struct instruction *insn, bool sibling)
{
struct reloc *reloc = insn_reloc(file, insn);
+ struct symbol *sym = insn->call_dest;
- insn->call_dest = dest;
- if (!dest)
+ if (!sym)
+ sym = reloc->sym;
+
+ /*
+ * Alternative replacement code is just template code which is
+ * sometimes copied to the original instruction. For now, don't
+ * annotate it. (In the future we might consider annotating the
+ * original instruction if/when it ever makes sense to do so.)
+ */
+ if (!strcmp(insn->sec->name, ".altinstr_replacement"))
return;
- if (insn->call_dest->static_call_tramp) {
- list_add_tail(&insn->call_node,
- &file->static_call_list);
+ if (sym->static_call_tramp) {
+ list_add_tail(&insn->call_node, &file->static_call_list);
+ return;
}
/*
@@ -1012,7 +1021,7 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn,
* so they need a little help, NOP out any KCOV calls from noinstr
* text.
*/
- if (insn->sec->noinstr && insn->call_dest->kcov) {
+ if (insn->sec->noinstr && sym->kcov) {
if (reloc) {
reloc->type = R_NONE;
elf_write_reloc(file->elf, reloc);
@@ -1024,9 +1033,10 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn,
: arch_nop_insn(insn->len));
insn->type = sibling ? INSN_RETURN : INSN_NOP;
+ return;
}
- if (mcount && insn->call_dest->fentry) {
+ if (mcount && sym->fentry) {
if (sibling)
WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset);
@@ -1041,9 +1051,17 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn,
insn->type = INSN_NOP;
- list_add_tail(&insn->mcount_loc_node,
- &file->mcount_loc_list);
+ list_add_tail(&insn->mcount_loc_node, &file->mcount_loc_list);
+ return;
}
+}
+
+static void add_call_dest(struct objtool_file *file, struct instruction *insn,
+ struct symbol *dest, bool sibling)
+{
+ insn->call_dest = dest;
+ if (!dest)
+ return;
/*
* Whatever stack impact regular CALLs have, should be undone
@@ -1053,6 +1071,8 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn,
* are converted to JUMP, see read_intra_function_calls().
*/
remove_insn_ops(insn);
+
+ annotate_call_site(file, insn, sibling);
}
/*
|