x86,objtool: Create .return_sites

stable inclusion
from stable-v5.10.133
commit 8bdb25f7aee312450e9c9ac21ae209d9cf0602e5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5PTAS
CVE: CVE-2022-29900,CVE-2022-23816,CVE-2022-29901

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8bdb25f7aee312450e9c9ac21ae209d9cf0602e5



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commit d9e9d230 upstream.

Find all the return-thunk sites and record them in a .return_sites
section such that the kernel can undo this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
[cascardo: conflict fixup because of functions added to support IBT]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[bwh: Backported to 5.10: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lin Yujun <linyujun809@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>