From: Josh Poimboeuf <jpoimboe@redhat.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Nick Desaulniers <ndesaulniers@google.com>,
Arnd Bergmann <arnd@arndb.de>, Jann Horn <jannh@google.com>,
Randy Dunlap <rdunlap@infradead.org>
Subject: [PATCH 17/22] objtool: Refactor sibling call detection logic
Date: Sun, 14 Jul 2019 19:37:12 -0500 [thread overview]
Message-ID: <50a783c4ccc47479806e2147f0447315fd5be228.1563150885.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1563150885.git.jpoimboe@redhat.com>
Simplify the sibling call detection logic a bit.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
tools/objtool/check.c | 65 ++++++++++++++++++++++---------------------
1 file changed, 33 insertions(+), 32 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 3fb656ea96b9..a190a6e79a91 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -97,6 +97,20 @@ static struct instruction *next_insn_same_func(struct objtool_file *file,
for (insn = next_insn_same_sec(file, insn); insn; \
insn = next_insn_same_sec(file, insn))
+static bool is_sibling_call(struct instruction *insn)
+{
+ /* An indirect jump is either a sibling call or a jump to a table. */
+ if (insn->type == INSN_JUMP_DYNAMIC)
+ return list_empty(&insn->alts);
+
+ if (insn->type != INSN_JUMP_CONDITIONAL &&
+ insn->type != INSN_JUMP_UNCONDITIONAL)
+ return false;
+
+ /* add_jump_destinations() sets insn->call_dest for sibling calls. */
+ return !!insn->call_dest;
+}
+
/*
* This checks to see if the given function is a "noreturn" function.
*
@@ -167,34 +181,25 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
* of the sibling call returns.
*/
func_for_each_insn_all(file, func, insn) {
- if (insn->type == INSN_JUMP_UNCONDITIONAL) {
+ if (is_sibling_call(insn)) {
struct instruction *dest = insn->jump_dest;
if (!dest)
/* sibling call to another file */
return false;
- if (dest->func && dest->func->pfunc != insn->func->pfunc) {
-
- /* local sibling call */
- if (recursion == 5) {
- /*
- * Infinite recursion: two functions
- * have sibling calls to each other.
- * This is a very rare case. It means
- * they aren't dead ends.
- */
- return false;
- }
-
- return __dead_end_function(file, dest->func,
- recursion + 1);
+ /* local sibling call */
+ if (recursion == 5) {
+ /*
+ * Infinite recursion: two functions have
+ * sibling calls to each other. This is a very
+ * rare case. It means they aren't dead ends.
+ */
+ return false;
}
- }
- if (insn->type == INSN_JUMP_DYNAMIC && list_empty(&insn->alts))
- /* sibling call */
- return false;
+ return __dead_end_function(file, dest->func, recursion+1);
+ }
}
return true;
@@ -581,9 +586,8 @@ static int add_jump_destinations(struct objtool_file *file)
insn->retpoline_safe = true;
continue;
} else {
- /* sibling call */
+ /* external sibling call */
insn->call_dest = rela->sym;
- insn->jump_dest = NULL;
continue;
}
@@ -633,9 +637,8 @@ static int add_jump_destinations(struct objtool_file *file)
} else if (insn->jump_dest->func->pfunc != insn->func->pfunc &&
insn->jump_dest->offset == insn->jump_dest->func->offset) {
- /* sibling class */
+ /* internal sibling call */
insn->call_dest = insn->jump_dest->func;
- insn->jump_dest = NULL;
}
}
}
@@ -1889,7 +1892,7 @@ static inline bool func_uaccess_safe(struct symbol *func)
return false;
}
-static inline const char *insn_dest_name(struct instruction *insn)
+static inline const char *call_dest_name(struct instruction *insn)
{
if (insn->call_dest)
return insn->call_dest->name;
@@ -1901,13 +1904,13 @@ static int validate_call(struct instruction *insn, struct insn_state *state)
{
if (state->uaccess && !func_uaccess_safe(insn->call_dest)) {
WARN_FUNC("call to %s() with UACCESS enabled",
- insn->sec, insn->offset, insn_dest_name(insn));
+ insn->sec, insn->offset, call_dest_name(insn));
return 1;
}
if (state->df) {
WARN_FUNC("call to %s() with DF set",
- insn->sec, insn->offset, insn_dest_name(insn));
+ insn->sec, insn->offset, call_dest_name(insn));
return 1;
}
@@ -2088,14 +2091,12 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
case INSN_JUMP_CONDITIONAL:
case INSN_JUMP_UNCONDITIONAL:
- if (func && !insn->jump_dest) {
+ if (func && is_sibling_call(insn)) {
ret = validate_sibling_call(insn, &state);
if (ret)
return ret;
- } else if (insn->jump_dest &&
- (!func || !insn->jump_dest->func ||
- insn->jump_dest->func->pfunc == func)) {
+ } else if (insn->jump_dest) {
ret = validate_branch(file, func,
insn->jump_dest, state);
if (ret) {
@@ -2111,7 +2112,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
break;
case INSN_JUMP_DYNAMIC:
- if (func && list_empty(&insn->alts)) {
+ if (func && is_sibling_call(insn)) {
ret = validate_sibling_call(insn, &state);
if (ret)
return ret;
--
2.20.1
next prev parent reply other threads:[~2019-07-15 0:37 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 0:36 [PATCH 00/22] x86, objtool: several fixes/improvements Josh Poimboeuf
2019-07-15 0:36 ` [PATCH 01/22] x86/paravirt: Fix callee-saved function ELF sizes Josh Poimboeuf
2019-07-15 4:58 ` Juergen Gross
2019-07-15 12:43 ` Josh Poimboeuf
2019-07-15 0:36 ` [PATCH 02/22] x86/kvm: Fix fastop function ELF metadata Josh Poimboeuf
2019-07-15 9:05 ` Paolo Bonzini
2019-07-15 0:36 ` [PATCH 03/22] x86/kvm: Fix frame pointer usage in vmx_vmenter() Josh Poimboeuf
2019-07-15 9:04 ` Paolo Bonzini
2019-07-15 12:37 ` Josh Poimboeuf
2019-07-15 13:03 ` Paolo Bonzini
2019-07-15 13:35 ` Josh Poimboeuf
2019-07-15 18:17 ` Paolo Bonzini
2019-07-15 0:36 ` [PATCH 04/22] x86/kvm: Don't call kvm_spurious_fault() from .fixup Josh Poimboeuf
2019-07-15 9:07 ` Paolo Bonzini
2019-07-15 12:40 ` Josh Poimboeuf
2019-07-15 13:05 ` Paolo Bonzini
2019-07-15 13:25 ` Josh Poimboeuf
2019-07-15 18:16 ` Paolo Bonzini
2019-07-15 0:37 ` [PATCH 05/22] x86/entry: Fix thunk function ELF sizes Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 06/22] x86/head/64: Annotate start_cpu0() as non-callable Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 07/22] x86/uaccess: Remove ELF function annotation from copy_user_handle_tail() Josh Poimboeuf
2019-07-16 18:16 ` Nick Desaulniers
2019-07-16 18:51 ` Peter Zijlstra
2019-07-15 0:37 ` [PATCH 08/22] x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail() Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 09/22] x86/uaccess: Remove redundant CLACs in getuser/putuser error paths Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 10/22] bpf: Disable GCC -fgcse optimization for ___bpf_prog_run() Josh Poimboeuf
2019-07-16 18:15 ` Nick Desaulniers
2019-07-16 23:02 ` Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 11/22] objtool: Add mcsafe_handle_tail() to the uaccess safe list Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 12/22] objtool: Track original function across branches Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 13/22] objtool: Refactor function alias logic Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 14/22] objtool: Warn on zero-length functions Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 15/22] objtool: Change dead_end_function() to return boolean Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 16/22] objtool: Do frame pointer check before dead end check Josh Poimboeuf
2019-07-15 0:37 ` Josh Poimboeuf [this message]
2019-07-15 0:37 ` [PATCH 18/22] objtool: Refactor jump table code Josh Poimboeuf
2019-07-15 9:38 ` Peter Zijlstra
2019-07-15 0:37 ` [PATCH 19/22] objtool: Support repeated uses of the same C jump table Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 20/22] objtool: Fix seg fault on bad switch table entry Josh Poimboeuf
2019-07-15 17:24 ` Nick Desaulniers
2019-07-15 17:29 ` Josh Poimboeuf
2019-07-18 23:02 ` Nick Desaulniers
2019-07-15 0:37 ` [PATCH 21/22] objtool: convert insn type to enum Josh Poimboeuf
2019-07-15 0:37 ` [PATCH 22/22] objtool: Support conditional retpolines Josh Poimboeuf
2019-07-15 9:52 ` [PATCH 00/22] x86, objtool: several fixes/improvements Peter Zijlstra
2019-07-15 19:38 ` Josh Poimboeuf
2019-07-15 21:45 ` Nick Desaulniers
2019-07-16 23:17 ` Josh Poimboeuf
2019-07-18 22:26 ` Nick Desaulniers
2019-09-27 20:24 ` Nick Desaulniers
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