From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F7F2423A61; Tue, 31 Mar 2026 16:29:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774974599; cv=none; b=e9aypG+S8v3+fw0ufkaSFqX+TqUzb8tqkuUqyo9McaUFttYlTBnOUJNClHy4iyoapWOC/UqACX4RnENZ6Cgo2Q2QYd52Ikeust+PCQcp85dwsZMtBtyWi1tGU9wTEqlmAbK2QhTjsUSAJoDx3l1l+uVNmV6Hzg20P3ek2xCrDXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774974599; c=relaxed/simple; bh=QBc+Ye484imVi7a0vX9K7pcAOGxRYqS+dlW9ym24mGk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oNApWWCtMq1Y7AumEJMzK9n07AXVSwqD5WxG539CgprHboFtANiDjhrz7yxkjP8Jy5jJ07F2etE/qdmQWyghJlAbqTvj0AcI7GMjWg32Kwk4m6xIjlRhlSyXXyvvQNz3iI9CvAE7nsAfRjV+VUEuXCJ6Iv8G6CbfxJgm9ySJm/I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PvjVItF4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PvjVItF4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27A17C19423; Tue, 31 Mar 2026 16:29:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774974599; bh=QBc+Ye484imVi7a0vX9K7pcAOGxRYqS+dlW9ym24mGk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PvjVItF4O5zLJg7SvueEsH1wCsTZX+f6zHCs2grMqg1jk5+IL975cB95nTyMTICV3 3J10ACGVIhvOvB7IU1jGTQH2EDmmU9prQJwta/ZzjX8n7K8XxxX2P0TiEaa0fIkKzQ j+NoX1qmpuz7LAtdi9z21+4s42x0orlKGh4OeCpU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Ilya Leoshkevich , Vasily Gorbik Subject: [PATCH 6.6 115/175] s390/entry: Scrub r12 register on kernel entry Date: Tue, 31 Mar 2026 18:21:39 +0200 Message-ID: <20260331161734.006218967@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161729.779738837@linuxfoundation.org> References: <20260331161729.779738837@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vasily Gorbik commit 0738d395aab8fae3b5a3ad3fc640630c91693c27 upstream. Before commit f33f2d4c7c80 ("s390/bp: remove TIF_ISOLATE_BP"), all entry handlers loaded r12 with the current task pointer (lg %r12,__LC_CURRENT) for use by the BPENTER/BPEXIT macros. That commit removed TIF_ISOLATE_BP, dropping both the branch prediction macros and the r12 load, but did not add r12 to the register clearing sequence. Add the missing xgr %r12,%r12 to make the register scrub consistent across all entry points. Fixes: f33f2d4c7c80 ("s390/bp: remove TIF_ISOLATE_BP") Cc: stable@kernel.org Reviewed-by: Ilya Leoshkevich Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/entry.S | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -300,6 +300,7 @@ SYM_CODE_START(system_call) xgr %r9,%r9 xgr %r10,%r10 xgr %r11,%r11 + xgr %r12,%r12 la %r2,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs mvc __PT_R8(64,%r2),__LC_SAVE_AREA_SYNC MBEAR %r2 @@ -378,6 +379,7 @@ SYM_CODE_START(pgm_check_handler) xgr %r5,%r5 xgr %r6,%r6 xgr %r7,%r7 + xgr %r12,%r12 lgr %r2,%r11 brasl %r14,__do_pgm_check tmhh %r8,0x0001 # returning to user space? @@ -439,6 +441,7 @@ SYM_CODE_START(\name) xgr %r6,%r6 xgr %r7,%r7 xgr %r10,%r10 + xgr %r12,%r12 xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC MBEAR %r11 @@ -547,6 +550,7 @@ SYM_CODE_START(mcck_int_handler) xgr %r6,%r6 xgr %r7,%r7 xgr %r10,%r10 + xgr %r12,%r12 mvc __PT_R8(64,%r11),0(%r14) stmg %r8,%r9,__PT_PSW(%r11) xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)