aboutsummaryrefslogtreecommitdiffstatshomepage
diff options
context:
space:
mode:
-rw-r--r--arch/x86/kernel/traps.c18
-rw-r--r--tools/objtool/check.c31
2 files changed, 18 insertions, 31 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 2dbadf347b5f..5e3e036e6e53 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -380,6 +380,21 @@ __visible void __noreturn handle_stack_overflow(struct pt_regs *regs,
#endif
/*
+ * Prevent the compiler and/or objtool from marking the !CONFIG_X86_ESPFIX64
+ * version of exc_double_fault() as noreturn. Otherwise the noreturn mismatch
+ * between configs triggers objtool warnings.
+ *
+ * This is a temporary hack until we have compiler or plugin support for
+ * annotating noreturns.
+ */
+#ifdef CONFIG_X86_ESPFIX64
+#define always_true() true
+#else
+bool always_true(void);
+bool __weak always_true(void) { return true; }
+#endif
+
+/*
* Runs on an IST stack for x86_64 and on a special task stack for x86_32.
*
* On x86_64, this is more or less a normal kernel entry. Notwithstanding the
@@ -514,7 +529,8 @@ DEFINE_IDTENTRY_DF(exc_double_fault)
pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
die("double fault", regs, error_code);
- panic("Machine halted.");
+ if (always_true())
+ panic("Machine halted.");
instrumentation_end();
}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 7dbf22c6da9d..12bf6c1f5071 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4460,35 +4460,6 @@ static int validate_sls(struct objtool_file *file)
return warnings;
}
-static bool ignore_noreturn_call(struct instruction *insn)
-{
- struct symbol *call_dest = insn_call_dest(insn);
-
- /*
- * FIXME: hack, we need a real noreturn solution
- *
- * Problem is, exc_double_fault() may or may not return, depending on
- * whether CONFIG_X86_ESPFIX64 is set. But objtool has no visibility
- * to the kernel config.
- *
- * Other potential ways to fix it:
- *
- * - have compiler communicate __noreturn functions somehow
- * - remove CONFIG_X86_ESPFIX64
- * - read the .config file
- * - add a cmdline option
- * - create a generic objtool annotation format (vs a bunch of custom
- * formats) and annotate it
- */
- if (!strcmp(call_dest->name, "exc_double_fault")) {
- /* prevent further unreachable warnings for the caller */
- insn->sym->warned = 1;
- return true;
- }
-
- return false;
-}
-
static int validate_reachable_instructions(struct objtool_file *file)
{
struct instruction *insn, *prev_insn;
@@ -4505,7 +4476,7 @@ static int validate_reachable_instructions(struct objtool_file *file)
prev_insn = prev_insn_same_sec(file, insn);
if (prev_insn && prev_insn->dead_end) {
call_dest = insn_call_dest(prev_insn);
- if (call_dest && !ignore_noreturn_call(prev_insn)) {
+ if (call_dest) {
WARN_INSN(insn, "%s() is missing a __noreturn annotation",
call_dest->name);
warnings++;