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charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 3382f82d-3ab9-406f-bc63-08d72be01078 X-MS-Exchange-CrossTenant-originalarrivaltime: 28 Aug 2019 17:49:24.4101 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: FqGmoFCVH/b7nzUdBd2IuhmAHKpGSLMZ4fY2f1a2SXm535Y4RbOWuVBJw0ld1g28UN/Zt9Niim9jyuxikbXJxA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR15MB1854 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.70,1.0.8 definitions=2019-08-28_08:2019-08-28,2019-08-28 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 priorityscore=1501 mlxscore=0 mlxlogscore=827 clxscore=1015 malwarescore=0 spamscore=0 lowpriorityscore=0 bulkscore=0 phishscore=0 impostorscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1906280000 definitions=main-1908280174 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Aug 28, 2019, at 7:24 AM, Thomas Gleixner wrote: >=20 > When PTI is disabled at boot time either because the CPU is not affected = or > PTI has been disabled on the command line, the boot code still calls into > pti_finalize() which then unconditionally invokes: >=20 > pti_clone_entry_text() > pti_clone_kernel_text() >=20 > pti_clone_kernel_text() was called unconditionally before the 32bit suppo= rt > was added and 32bit added the call to pti_clone_entry_text(). >=20 > The call has no side effects as cloning the page tables into the availabl= e > second one, which was allocated for PTI does not create damage. But it do= es > not make sense either and in case that this functionality would be extend= ed > later this might actually lead to hard to diagnose issue. >=20 > Neither function should be called when PTI is runtime disabled. Make the > invocation conditional. >=20 > Signed-off-by: Thomas Gleixner Acked-by: Song Liu