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| author | Peter Zijlstra <peterz@infradead.org> | 2021-06-24 11:41:00 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-09-15 15:51:44 +0200 |
| commit | 9af9dcf11bda3e2c0e24c1acaacb8685ad974e93 (patch) | |
| tree | 179b8ed6ba33d8297ddb28ce3c6a0719c983f6a7 | |
| parent | 6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f (diff) | |
| download | linux-9af9dcf11bda3e2c0e24c1acaacb8685ad974e93.tar.bz2 | |
x86/xen: Mark cpu_bringup_and_idle() as dead_end_function
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
| -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 e5947fbb9e7a..0e3981d91afc 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -173,6 +173,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "rewind_stack_do_exit", "kunit_try_catch_throw", "xen_start_kernel", + "cpu_bringup_and_idle", }; if (!func) |