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authorJosh Poimboeuf <jpoimboe@redhat.com>2021-01-22 00:29:18 +0300
committerJosh Poimboeuf <jpoimboe@redhat.com>2021-01-26 20:11:59 +0300
commit1f9a1b74942485a0a29e7c4a9a9f2fe8aea17766 (patch)
treefed5d10db74d928885cbac6c194893a21ca34556 /tools/objtool
parent6f567c9300a5ebd7b18c26dda1c8d6ffbdd0debd (diff)
downloadlinux-1f9a1b74942485a0a29e7c4a9a9f2fe8aea17766.tar.xz
objtool: Fix retpoline detection in asm code
The JMP_NOSPEC macro branches to __x86_retpoline_*() rather than the __x86_indirect_thunk_*() wrappers used by C code. Detect jumps to __x86_retpoline_*() as retpoline dynamic jumps. Presumably this doesn't trigger a user-visible bug. I only found it when testing vmlinux.o validation. Fixes: 39b735332cb8 ("objtool: Detect jumps to retpoline thunks") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/31f5833e2e4f01e3d755889ac77e3661e906c09f.1611263461.git.jpoimboe@redhat.com
Diffstat (limited to 'tools/objtool')
-rw-r--r--tools/objtool/arch/x86/special.c2
-rw-r--r--tools/objtool/check.c3
-rw-r--r--tools/objtool/include/objtool/check.h11
3 files changed, 14 insertions, 2 deletions
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index b4bd3505fc94..e707d9bcd161 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -48,7 +48,7 @@ bool arch_support_alt_relocation(struct special_alt *special_alt,
* replacement group.
*/
return insn->offset == special_alt->new_off &&
- (insn->type == INSN_CALL || is_static_jump(insn));
+ (insn->type == INSN_CALL || is_jump(insn));
}
/*
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 3bdd946c2027..081572170f6b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -785,7 +785,8 @@ static int add_jump_destinations(struct objtool_file *file)
dest_sec = reloc->sym->sec;
dest_off = reloc->sym->sym.st_value +
arch_dest_reloc_offset(reloc->addend);
- } else if (strstr(reloc->sym->name, "_indirect_thunk_")) {
+ } else if (!strncmp(reloc->sym->name, "__x86_indirect_thunk_", 21) ||
+ !strncmp(reloc->sym->name, "__x86_retpoline_", 16)) {
/*
* Retpoline jumps are really dynamic jumps in
* disguise, so convert them accordingly.
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index f4e041fbdab2..b408636c0201 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -68,6 +68,17 @@ static inline bool is_static_jump(struct instruction *insn)
insn->type == INSN_JUMP_UNCONDITIONAL;
}
+static inline bool is_dynamic_jump(struct instruction *insn)
+{
+ return insn->type == INSN_JUMP_DYNAMIC ||
+ insn->type == INSN_JUMP_DYNAMIC_CONDITIONAL;
+}
+
+static inline bool is_jump(struct instruction *insn)
+{
+ return is_static_jump(insn) || is_dynamic_jump(insn);
+}
+
struct instruction *find_insn(struct objtool_file *file,
struct section *sec, unsigned long offset);