x86/alternative: Relax text_poke_bp() constraint
stable inclusion from stable-v5.10.133 commit 1f6e6683c46612baf01555e214d863aaa03c399b 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=1f6e6683c46612baf01555e214d863aaa03c399b -------------------------------- commit 26c44b77 upstream. Currently, text_poke_bp() is very strict to only allow patching a single instruction; however with straight-line-speculation it will be required to patch: ret; int3, which is two instructions. As such, relax the constraints a little to allow int3 padding for all instructions that do not imply the execution of the next instruction, ie: RET, JMP.d8 and JMP.d32. While there, rename the text_poke_loc::rel32 field to ::disp. Note: this fills up the text_poke_loc structure which is now a round 16 bytes big. [ bp: Put comments ontop instead of on the side. ] Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: NBorislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211204134908.082342723@infradead.orgSigned-off-by: NSasha Levin <sashal@kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: NBen Hutchings <ben@decadent.org.uk> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: NLin Yujun <linyujun809@huawei.com> Reviewed-by: NZhang Jianhua <chris.zjh@huawei.com> Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
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