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Thu, 20 Sep 2018 02:48:34 +0000 Received: from CY4PR21MB0776.namprd21.prod.outlook.com ([fe80::54e2:88e0:b622:b36]) by CY4PR21MB0776.namprd21.prod.outlook.com ([fe80::54e2:88e0:b622:b36%5]) with mapi id 15.20.1185.010; Thu, 20 Sep 2018 02:48:34 +0000 From: Sasha Levin To: "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" CC: Marc Zyngier , Will Deacon , Sasha Levin Subject: [PATCH AUTOSEL 4.18 53/56] arm/arm64: smccc-1.1: Handle function result as parameters Thread-Topic: [PATCH AUTOSEL 4.18 53/56] arm/arm64: smccc-1.1: Handle function result as parameters Thread-Index: AQHUUIxaVd0jV/+AM0+NyNHeC1sJmQ== Date: Thu, 20 Sep 2018 02:48:05 +0000 Message-ID: <20180920024716.58490-53-alexander.levin@microsoft.com> References: <20180920024716.58490-1-alexander.levin@microsoft.com> In-Reply-To: <20180920024716.58490-1-alexander.levin@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [52.168.54.252] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;CY4PR21MB0119;6:n6VQJxBVQxB8q5e1AC06HfajhPXgbmtEr3G/Oym12BVy4PDJeK0BZ7t8OPLj01DxLqe1rdplrjzWHGNBrEMNxbq9SyDcpfuWY8fFOBmP0Vr17juRY/9Bs4SlsMEB+9kVDXc009b9sUWj3uW9pI/IINusA81LRas502o6+1tegIIARmWN/2RjMXjcTvWtFXdy3Udq/xksEPVdzwl1p6xBseHBbj5CiDbdMY94sp5Ob+8ofyPVG1drCiY+wg3cYOstLb68dISWqckKN2stjEUwPDS3PWXDrNJXx4efQ3R5qPOJsdFtq2JMQwmvqTeOdNgfRNFGMJFhchhiZGZtElXs+perSd9Y84F0Zkx/XyNrhUB80nUlp5sBfqIaus6KAZ6NzuLknu1IrJNSrN1gvexhFQFk3mAVw44biBdlJ1OGkRC8cB5s/0vODA3r6toJdVANlFN4kW/AnhbcabVUU1A3Ag==;5:oC3O5z8JLm24KKUeeY9/v6DxKN1s6h87NHug778DMqxA35AUWF5CtFikxJi1RoQKYU6Kf99M5pm2lUOir8SpafxcXm+k4Sq4g1J45Ne95fLx4QXcUFZbCeAojsFMdV9cgQpFIRuHB7lVlSF98SB9npXr8joDBSxWlh5Tx4Nq3Js=;7:9pK3EEbyKfB6wDEDE4+nZ/AHTIiyj/BGkpd7Fx8YdcnizbNHn7+/6aeHSuyqzZVTHzkjHlz83DSQSbWG19Mpc5/j5hI+AUz9a6mFoiyfJewMaTSP3UitM3Rx58H0lJt1gDEBnXwgwVIdki1XI0otBU89hCyPiCdpI9q+Qn1Pu9C6LAH9UiZlYlm7NBGgdmhPTGMUwYlaY++3bWgEXkmQ1Mr+cej59cMqEIBjziwWGEo05Cqo/Qr4P0pSptieF44S x-ms-office365-filtering-correlation-id: eb7e1b64-d7e8-468f-4aeb-08d61ea38ec1 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: BCL:0;PCL:0;RULEID:(7020095)(4652040)(8989299)(4534165)(4627221)(201703031133081)(201702281549075)(8990200)(5600074)(711020)(4618075)(2017052603328)(7193020);SRVR:CY4PR21MB0119; 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received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) x-microsoft-antispam-message-info: x+i+qlhWY3BHt12YTDoRYUr9w1RIgqSDXJ+EgMi12BmfPJfwwn5dwzzCSlZB/8DVfLU8+GzoAQwSYm/cesWJdydtkVsjoM+X3TO2d/vXLWROPSRhXMECPtsZQCErz+FIVtb53wvdShkfqvRFlKXreOzX32DvABvOXGSxe+9+ItRswIklkAeArAvx4UUB7NJaFaZp+tzhhv+r5ArBxgtZ9OHxvUuwcvmB4VT8c/y6/R0DmoX6A7C9jhIRD78ot3Cc8WfB61SkDbHfsadEoltLFPvrJtOGTBjJxWhYvOuz+nT/zXYFGkFcp6R8lROV1qolmVEl3G7M+7a7QEcNVHGYWq922W6sdh/yN6Nts37jV3o= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: eb7e1b64-d7e8-468f-4aeb-08d61ea38ec1 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Sep 2018 02:48:05.0229 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0119 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marc Zyngier [ Upstream commit 755a8bf5579d22eb5636685c516d8dede799e27b ] If someone has the silly idea to write something along those lines: extern u64 foo(void); void bar(struct arm_smccc_res *res) { arm_smccc_1_1_smc(0xbad, foo(), res); } they are in for a surprise, as this gets compiled as: 0000000000000588 : 588: a9be7bfd stp x29, x30, [sp, #-32]! 58c: 910003fd mov x29, sp 590: f9000bf3 str x19, [sp, #16] 594: aa0003f3 mov x19, x0 598: aa1e03e0 mov x0, x30 59c: 94000000 bl 0 <_mcount> 5a0: 94000000 bl 0 5a4: aa0003e1 mov x1, x0 5a8: d4000003 smc #0x0 5ac: b4000073 cbz x19, 5b8 5b0: a9000660 stp x0, x1, [x19] 5b4: a9010e62 stp x2, x3, [x19, #16] 5b8: f9400bf3 ldr x19, [sp, #16] 5bc: a8c27bfd ldp x29, x30, [sp], #32 5c0: d65f03c0 ret 5c4: d503201f nop The call to foo "overwrites" the x0 register for the return value, and we end up calling the wrong secure service. A solution is to evaluate all the parameters before assigning anything to specific registers, leading to the expected result: 0000000000000588 : 588: a9be7bfd stp x29, x30, [sp, #-32]! 58c: 910003fd mov x29, sp 590: f9000bf3 str x19, [sp, #16] 594: aa0003f3 mov x19, x0 598: aa1e03e0 mov x0, x30 59c: 94000000 bl 0 <_mcount> 5a0: 94000000 bl 0 5a4: aa0003e1 mov x1, x0 5a8: d28175a0 mov x0, #0xbad 5ac: d4000003 smc #0x0 5b0: b4000073 cbz x19, 5bc 5b4: a9000660 stp x0, x1, [x19] 5b8: a9010e62 stp x2, x3, [x19, #16] 5bc: f9400bf3 ldr x19, [sp, #16] 5c0: a8c27bfd ldp x29, x30, [sp], #32 5c4: d65f03c0 ret Reported-by: Julien Grall Signed-off-by: Marc Zyngier Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- include/linux/arm-smccc.h | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 5a91ff33720b..18863d56273c 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -205,41 +205,51 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, uns= igned long a1, register unsigned long r3 asm("r3") =20 #define __declare_arg_1(a0, a1, res) \ + typeof(a1) __a1 =3D a1; \ struct arm_smccc_res *___res =3D res; \ register unsigned long r0 asm("r0") =3D (u32)a0; \ - register unsigned long r1 asm("r1") =3D a1; \ + register unsigned long r1 asm("r1") =3D __a1; \ register unsigned long r2 asm("r2"); \ register unsigned long r3 asm("r3") =20 #define __declare_arg_2(a0, a1, a2, res) \ + typeof(a1) __a1 =3D a1; \ + typeof(a2) __a2 =3D a2; \ struct arm_smccc_res *___res =3D res; \ register unsigned long r0 asm("r0") =3D (u32)a0; \ - register unsigned long r1 asm("r1") =3D a1; \ - register unsigned long r2 asm("r2") =3D a2; \ + register unsigned long r1 asm("r1") =3D __a1; \ + register unsigned long r2 asm("r2") =3D __a2; \ register unsigned long r3 asm("r3") =20 #define __declare_arg_3(a0, a1, a2, a3, res) \ + typeof(a1) __a1 =3D a1; \ + typeof(a2) __a2 =3D a2; \ + typeof(a3) __a3 =3D a3; \ struct arm_smccc_res *___res =3D res; \ register unsigned long r0 asm("r0") =3D (u32)a0; \ - register unsigned long r1 asm("r1") =3D a1; \ - register unsigned long r2 asm("r2") =3D a2; \ - register unsigned long r3 asm("r3") =3D a3 + register unsigned long r1 asm("r1") =3D __a1; \ + register unsigned long r2 asm("r2") =3D __a2; \ + register unsigned long r3 asm("r3") =3D __a3 =20 #define __declare_arg_4(a0, a1, a2, a3, a4, res) \ + typeof(a4) __a4 =3D a4; \ __declare_arg_3(a0, a1, a2, a3, res); \ - register typeof(a4) r4 asm("r4") =3D a4 + register unsigned long r4 asm("r4") =3D __a4 =20 #define __declare_arg_5(a0, a1, a2, a3, a4, a5, res) \ + typeof(a5) __a5 =3D a5; \ __declare_arg_4(a0, a1, a2, a3, a4, res); \ - register typeof(a5) r5 asm("r5") =3D a5 + register unsigned long r5 asm("r5") =3D __a5 =20 #define __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res) \ + typeof(a6) __a6 =3D a6; \ __declare_arg_5(a0, a1, a2, a3, a4, a5, res); \ - register typeof(a6) r6 asm("r6") =3D a6 + register unsigned long r6 asm("r6") =3D __a6 =20 #define __declare_arg_7(a0, a1, a2, a3, a4, a5, a6, a7, res) \ + typeof(a7) __a7 =3D a7; \ __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res); \ - register typeof(a7) r7 asm("r7") =3D a7 + register unsigned long r7 asm("r7") =3D __a7 =20 #define ___declare_args(count, ...) __declare_arg_ ## count(__VA_ARGS__) #define __declare_args(count, ...) ___declare_args(count, __VA_ARGS__) --=20 2.17.1