diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2021-06-24 11:41:00 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-25 09:14:38 +0200 |
| commit | 10a221e2d3d8cf53be4e55c92257197688cfe54f (patch) | |
| tree | 634604f1097ec17785d7aa0dbf10e314436111cb | |
| parent | a12884ff43400e94b109bf4aa9fa5eed47ef5241 (diff) | |
x86/xen: Mark cpu_bringup_and_idle() as dead_end_function
commit 9af9dcf11bda3e2c0e24c1acaacb8685ad974e93 upstream.
The asm_cpu_bringup_and_idle() function is required to push the return
value on the stack in order to make ORC happy, but the only reason
objtool doesn't complain is because of a happy accident.
The thing is that asm_cpu_bringup_and_idle() doesn't return, so
validate_branch() never terminates and falls through to the next
function, which in the normal case is the hypercall_page. And that, as
it happens, is 4095 NOPs and a RET.
Make asm_cpu_bringup_and_idle() terminate on it's own, by making the
function it calls as a dead-end. This way we no longer rely on what
code happens to come after.
Fixes: c3881eb58d56 ("x86/xen: Make the secondary CPU idle tasks reliable")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20210624095147.693801717@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | tools/objtool/check.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 06aaf04e629c..bae6b261481d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -144,6 +144,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "usercopy_abort", "machine_real_restart", "rewind_stack_do_exit", + "cpu_bringup_and_idle", }; if (!func) |