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| author | Peter Zijlstra <peterz@infradead.org> | 2021-10-26 14:01:34 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-25 11:26:23 +0200 |
| commit | 023e78bbf13c15a55013ca25641509a6697170e1 (patch) | |
| tree | 96b9c4a7e017d4b0b9f01feda962718214e26933 | |
| parent | 6e4676f438f8a454d85c12ffa2abf613f9a8f75c (diff) | |
| download | linux-stable-023e78bbf13c15a55013ca25641509a6697170e1.tar.gz linux-stable-023e78bbf13c15a55013ca25641509a6697170e1.tar.bz2 linux-stable-023e78bbf13c15a55013ca25641509a6697170e1.zip | |
objtool: Explicitly avoid self modifying code in .altinstr_replacement
commit dd003edeffa3cb87bc9862582004f405d77d7670 upstream.
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@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120309.722511775@infradead.org
[cascardo: context adjustment]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[bwh: Backported to 5.10: objtool doesn't have any mcount handling]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | tools/objtool/check.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 01b064b6182d..a70f3811918b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -870,18 +870,27 @@ 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; } /* @@ -889,7 +898,7 @@ 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); @@ -901,7 +910,16 @@ 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; } +} + +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 @@ -911,6 +929,8 @@ 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); } /* |