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Silva" , linux-kernel , "linux-hardening@vger.kernel.org" Subject: RE: [PATCH] linux/const.h: Explain how __is_constexpr() works Thread-Topic: [PATCH] linux/const.h: Explain how __is_constexpr() works Thread-Index: AQHYGHV8RL4oDGFcTkyEh79ubpGBJ6yBjFag Date: Thu, 3 Feb 2022 09:25:07 +0000 Message-ID: <8f41a0e40e78419d947ba322031acd2f@AcuMS.aculab.com> References: <20220131204357.1133674-1-keescook@chromium.org> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RnJvbTogTWlndWVsIE9qZWRhDQo+IFNlbnQ6IDAyIEZlYnJ1YXJ5IDIwMjIgMjA6NDMNCj4gDQo+ IE9uIE1vbiwgSmFuIDMxLCAyMDIyIGF0IDk6NDMgUE0gS2VlcyBDb29rIDxrZWVzY29va0BjaHJv bWl1bS5vcmc+IHdyb3RlOg0KPiA+DQo+ID4gKyAqIC0gVGhlIGNvbmRpdGlvbmFsIG9wZXJhdG9y ICgiLi4uID8gLi4uIDogLi4uIikgcmV0dXJucyB0aGUgdHlwZSBvZiB0aGUNCj4gPiArICogICBv cGVyYW5kIHRoYXQgaXNuJ3QgYSBudWxsIHBvaW50ZXIgY29uc3RhbnQuIFRoaXMgYmVoYXZpb3Ig aXMgdGhlDQo+IA0KPiBQZXJoYXBzIGNsYXJpZnkgdGhhdCB0aGlzIGhhcHBlbnMgb25seSBpZiBp dCBmaXRzIHRoYXQgY2FzZT8gLi4uDQo+IA0KPiA+ICsgKiAtIElmICh4KSBpcyBhbiBpbnRlZ2Vy IGNvbnN0YW50IGV4cHJlc3Npb24sIHRoZW4gdGhlICIqIDBsIiByZXNvbHZlcyBpdA0KPiA+ICsg KiAgIGludG8gYSBudWxsIHBvaW50ZXIgY29uc3RhbnQsIHdoaWNoIGZvcmNlcyB0aGUgY29uZGl0 aW9uYWwgb3BlcmF0b3INCj4gPiArICogICB0byByZXR1cm4gdGhlIHR5cGUgb2YgdGhlIGxhc3Qg b3BlcmFuZDogIihpbnQgKikiLg0KPiA+ICsgKiAtIElmICh4KSBpcyBub3QgYW4gaW50ZWdlciBj b25zdGFudCBleHByZXNzaW9uLCB0aGVuIHRoZSB0eXBlIG9mIHRoZQ0KPiA+ICsgKiAgIGNvbmRp dGlvbmFsIG9wZXJhdG9yIGlzIGZyb20gdGhlIGZpcnN0IG9wZXJhbmQ6ICIodm9pZCAqKSIuDQo+ IA0KPiAuLi4gaS5lLiB0aGlzIG9uZSBoYXBwZW5zIGJlY2F1c2UgaXQgaXMgc3BlY2lmaWVkIGFz IHJldHVybmluZyBhDQo+IHBvaW50ZXIgdG8gdm9pZCAob25lIGNvdWxkIHJlYWQgaXQgYXMgcmV0 dXJuaW5nIHRoZSB0eXBlIG9mIHRoZSBmaXJzdA0KPiBvcGVyYW5kKS4NCj4gDQo+IFdoYXQgYWJv dXQgc29tZXRoaW5nIGxpa2U6DQo+IA0KPiAgIC0gVGhlIGJlaGF2aW9yIChpbmNsdWRpbmcgaXRz IHJldHVybiB0eXBlKSBvZiB0aGUgY29uZGl0aW9uYWwNCj4gb3BlcmF0b3IgKCIuLi4gPyAuLi4g OiAuLi4iKSBkZXBlbmRzIG9uIHRoZSBraW5kIG9mIGV4cHJlc3Npb25zIGdpdmVuDQo+IGZvciB0 aGUgc2Vjb25kIGFuZCB0aGlyZCBvcGVyYW5kcy4gVGhpcyBpcyB0aGUgY2VudHJhbCBtZWNoYW5p c20gb2YNCj4gdGhlIG1hY3JvLg0KPiAgIC0gSWYgKHgpIGlzIGFuIGludGVnZXIgY29uc3RhbnQg ZXhwcmVzc2lvbiwgdGhlbiB0aGUgIiogMGwiIHJlc29sdmVzDQo+IGl0IGludG8gYSBudWxsIHBv aW50ZXIgY29uc3RhbnQuIFdoZW4gb25lIG9wZXJhbmQgaXMgYSBudWxsIHBvaW50ZXINCj4gY29u c3RhbnQgYW5kIHRoZSBvdGhlciBpcyBhIHBvaW50ZXIsIHRoZSBjb25kaXRpb25hbCBvcGVyYXRv ciByZXR1cm5zDQo+IHRoZSB0eXBlIG9mIHRoZSBwb2ludGVyIG9wZXJhbmQ7IHRoYXQgaXMsICJp bnQgKiIuDQo+ICAgLSBJZiAoeCkgaXMgbm90IGFuIGludGVnZXIgY29uc3RhbnQgZXhwcmVzc2lv biwgdGhlbiB0aGF0IG9wZXJhbmQgaXMNCj4gYSBwb2ludGVyIHRvIHZvaWQgKGJ1dCBub3QgYSBu dWxsIHBvaW50ZXIgY29uc3RhbnQpLiBXaGVuIG9uZSBvcGVyYW5kDQo+IGlzIGEgcG9pbnRlciB0 byB2b2lkIGFuZCB0aGUgb3RoZXIgYSBwb2ludGVyIHRvIGFuIG9iamVjdCB0eXBlLCB0aGUNCj4g Y29uZGl0aW9uYWwgb3BlcmF0b3IgcmV0dXJucyBhICJ2b2lkICoiIHR5cGUuDQoNCk5pY2sncyBx dW90ZSBmcm9tIHRoZSBDIHN0YW5kYXJkIGFjdHVhbGx5IHN1bXMgaXQgdXAgbmljZWx5Og0KDQog ICAgVGhlIGtleSBoZXJlIGlzIHRoYXQgdGhlIGNvbmRpdGlvbmFsIG9wZXJhdG9yIHJldHVybnMg YSBkaWZmZXJlbnQgdHlwZQ0KICAgIGRlcGVuZGluZyBvbiB3aGV0aGVyIG9uZSBvZiB0aGUgb3Bl cmFuZHMgaXMgYSBudWxsIHBvaW50ZXIgY29uc3RhbnQNCiAgICAoNi41LjE1LjYpOg0KDQogICAg Wy4uLl0gaWYgb25lIG9wZXJhbmQgaXMgYSBudWxsIHBvaW50ZXIgY29uc3RhbnQsIHRoZSByZXN1 bHQgaGFzIHRoZQ0KICAgIHR5cGUgb2YgdGhlIG90aGVyIG9wZXJhbmQ7IG90aGVyd2lzZSwgb25l IG9wZXJhbmQgaXMgYSBwb2ludGVyIHRvIHZvaWQNCiAgICBvciBhIHF1YWxpZmllZCB2ZXJzaW9u IG9mIHZvaWQsIGluIHdoaWNoIGNhc2UgdGhlIHJlc3VsdCB0eXBlIGlzIGENCiAgICBwb2ludGVy IHRvIGFuIGFwcHJvcHJpYXRlbHkgcXVhbGlmaWVkIHZlcnNpb24gb2Ygdm9pZC4NCg0KVGhhdCBm b2xsb3dlZCBieSBhIHJlbWluZGVyIHRoYXQgIih2b2lkICopeCBpcyBhIG51bGwgcG9pbnRlciBj b25zdGFudCBpZiB4DQppcyBhIGNvbXBpbGUgdGltZSBpbnRlZ2VyIGNvbnN0YW50IGV4cHJlc3Np b24iIGlzIGVub3VnaC4NCkFsbCB0aGUgcmVzdCBpcyBqdXN0IFRMO0RSLg0KDQpUaGUgJzgnIGFs c28ganVzdCBjb25mdXNlIHRoaW5ncywgdGhleSBhcmUgbm90IGltcG9ydGFudCBhdCBhbGwuDQpT byBpdCBjYW4gYmU6DQojZGVmaW5lIF9faXNfY29uc3RleHByKHgpIFwNCiAJKHNpemVvZigqKDAg PyAoKHZvaWQgKikoKGxvbmcpKHgpICogMCkpIDogKGludCAqKTApKSA9PSBzaXplb2YoaW50KSkN Cg0KCURhdmlkDQoNCi0NClJlZ2lzdGVyZWQgQWRkcmVzcyBMYWtlc2lkZSwgQnJhbWxleSBSb2Fk LCBNb3VudCBGYXJtLCBNaWx0b24gS2V5bmVzLCBNSzEgMVBULCBVSw0KUmVnaXN0cmF0aW9uIE5v OiAxMzk3Mzg2IChXYWxlcykNCg==