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13 Mar 2019 06:08:18 +0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sharedspace.onmicrosoft.com; s=selector1-wdc-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=ji/DS0clLT53VPloo9pNYI4u6s6ZtyNVjcXWLm8sxBM=; b=G4xWezoQtz+V7qktC7HsvuI+p0ksT1dIkfuecL4oGOmzUA7LP0pxQj/HhUg2CpWPTknqwcQI8sVYlO1zhtLowzMQ75b5PUS3i1B3dq0nERi3a3YoInEdDSEtxlm74tYhU+nvMHIXUHFc6ttYrodSixRYwsQRDQE59FoqZ2/Evew= Received: from DM6PR04MB6059.namprd04.prod.outlook.com (20.178.226.89) by DM6PR04MB4201.namprd04.prod.outlook.com (20.176.76.146) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.1709.13; Tue, 12 Mar 2019 22:08:16 +0000 Received: from DM6PR04MB6059.namprd04.prod.outlook.com ([fe80::447:8360:6df9:c934]) by DM6PR04MB6059.namprd04.prod.outlook.com ([fe80::447:8360:6df9:c934%3]) with mapi id 15.20.1686.021; Tue, 12 Mar 2019 22:08:16 +0000 From: Anup Patel To: Palmer Dabbelt , Albert Ou CC: Atish Patra , Paul Walmsley , Christoph Hellwig , Mike Rapoport , "linux-riscv@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Anup Patel Subject: [PATCH 2/3] RISC-V: Make setup_vm() independent of GCC code model Thread-Topic: [PATCH 2/3] RISC-V: Make setup_vm() independent of GCC code model Thread-Index: AQHU2SAXFOwCqD7TIUe3nwMe83Le9Q== Date: Tue, 12 Mar 2019 22:08:16 +0000 Message-ID: <20190312220752.128141-3-anup.patel@wdc.com> References: <20190312220752.128141-1-anup.patel@wdc.com> In-Reply-To: <20190312220752.128141-1-anup.patel@wdc.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: BY5PR13CA0028.namprd13.prod.outlook.com (2603:10b6:a03:180::41) To DM6PR04MB6059.namprd04.prod.outlook.com (2603:10b6:5:129::25) authentication-results: spf=none (sender IP is ) smtp.mailfrom=Anup.Patel@wdc.com; x-ms-exchange-messagesentrepresentingtype: 1 x-mailer: git-send-email 2.17.1 x-originating-ip: [199.255.44.250] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 6dd653cd-dcf9-441c-3a55-08d6a73739e2 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600127)(711020)(4605104)(4618075)(2017052603328)(7153060)(7193020);SRVR:DM6PR04MB4201; x-ms-traffictypediagnostic: DM6PR04MB4201: wdcipoutbound: EOP-TRUE x-microsoft-antispam-prvs: x-forefront-prvs: 09749A275C x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(366004)(346002)(396003)(376002)(136003)(39860400002)(199004)(189003)(71200400001)(478600001)(26005)(305945005)(106356001)(76176011)(7736002)(105586002)(72206003)(102836004)(6506007)(1076003)(386003)(71190400001)(66066001)(97736004)(36756003)(4326008)(5660300002)(14444005)(25786009)(186003)(14454004)(316002)(256004)(6116002)(53936002)(54906003)(99286004)(2906002)(110136005)(2171002)(8936002)(50226002)(486006)(446003)(476003)(11346002)(2616005)(44832011)(81156014)(6436002)(6512007)(8676002)(81166006)(68736007)(86362001)(52116002)(6486002)(3846002);DIR:OUT;SFP:1102;SCL:1;SRVR:DM6PR04MB4201;H:DM6PR04MB6059.namprd04.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: tiHj9PVfonobz1GaiyuAd9AepKi7R06MHRXEExm4b7BWIL5tAjQn0tw5nevgMX4QXUp4klgEUWMHBRRpIMUSEn9Gz5LEdE/3vBdjNNai+hQ37q2YFp6HPJV8M8EF8EBh8O31CFGID1DvY/HJELENjhzj3fQPvIUOh47dxnRtHCXw3A9nSWAFjda9jtnZ/XGjw7Ef12aNSPdO82YAv7ctQchKojsu3CSDhpEMHJEVaKuE4Dke1YCrhYHBGwTlvhVNiZHggcmpsPbD12/gAfA9f99hm1WB5GorBsRBWGjvg22Rg0mP2FM211oQSLcLFGr3F+P61L/lRFVkbK3ikycjue1IDWXTRPUgfuFKwA/5StiqJo7H50U4QJt6Sk5m4Felfc/bv7/hX0jZku9Wv3sEkdPAEK2om1hu0YFBFMF/j0A= Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6dd653cd-dcf9-441c-3a55-08d6a73739e2 X-MS-Exchange-CrossTenant-originalarrivaltime: 12 Mar 2019 22:08:16.2065 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR04MB4201 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The setup_vm() must access kernel symbols in a position independent way because it will be called from head.S with MMU off. If we compile kernel with cmodel=3Dmedany then PC-relative addressing will be used in setup_vm() to access kernel symbols so it works perfectly fine. Although, if we compile kernel with cmodel=3Dmedlow then either absolute addressing or PC-relative addressing (based on whichever requires fewer instructions) is used to access kernel symbols in setup_vm(). This can break setup_vm() whenever any absolute addressing is used to access kernel symbols. With the movement of setup_vm() from kernel/setup.c to mm/init.c, the setup_vm() is now broken for cmodel=3Dmedlow but it works perfectly fine for cmodel=3Dmedany. This patch fixes setup_vm() and makes it independent of GCC code model by accessing kernel symbols relative to kernel load address instead of assuming PC-relative addressing. Fixes: 6f1e9e946f0b ("RISC-V: Move setup_vm() to mm/init.c") Signed-off-by: Anup Patel --- arch/riscv/kernel/head.S | 1 + arch/riscv/mm/init.c | 71 ++++++++++++++++++++++++++-------------- 2 files changed, 47 insertions(+), 25 deletions(-) diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index fe884cd69abd..7966262b4f9d 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -62,6 +62,7 @@ clear_bss_done: =20 /* Initialize page tables and relocate to virtual addresses */ la sp, init_thread_union + THREAD_SIZE + la a0, _start call setup_vm call relocate =20 diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index b379a75ac6a6..f35299f2f3d5 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -172,55 +172,76 @@ void __set_fixmap(enum fixed_addresses idx, phys_addr= _t phys, pgprot_t prot) } } =20 -asmlinkage void __init setup_vm(void) +static inline void *__early_va(void *ptr, uintptr_t load_pa) { extern char _start; + uintptr_t va =3D (uintptr_t)ptr; + uintptr_t sz =3D (uintptr_t)(&_end) - (uintptr_t)(&_start); + + if (va >=3D PAGE_OFFSET && va < (PAGE_OFFSET + sz)) + return (void *)(load_pa + (va - PAGE_OFFSET)); + return (void *)va; +} + +asmlinkage void __init setup_vm(uintptr_t load_pa) +{ uintptr_t i; - uintptr_t pa =3D (uintptr_t) &_start; +#ifndef __PAGETABLE_PMD_FOLDED + pmd_t *pmdp; +#endif + pgd_t *pgdp; + phys_addr_t map_pa; + pgprot_t tableprot =3D __pgprot(_PAGE_TABLE); pgprot_t prot =3D __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC); =20 - va_pa_offset =3D PAGE_OFFSET - pa; - pfn_base =3D PFN_DOWN(pa); + va_pa_offset =3D PAGE_OFFSET - load_pa; + pfn_base =3D PFN_DOWN(load_pa); =20 /* Sanity check alignment and size */ BUG_ON((PAGE_OFFSET % PGDIR_SIZE) !=3D 0); - BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) !=3D 0); + BUG_ON((load_pa % (PAGE_SIZE * PTRS_PER_PTE)) !=3D 0); =20 #ifndef __PAGETABLE_PMD_FOLDED - trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D - pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd), - __pgprot(_PAGE_TABLE)); - trampoline_pmd[0] =3D pfn_pmd(PFN_DOWN(pa), prot); + pgdp =3D __early_va(trampoline_pg_dir, load_pa); + map_pa =3D (uintptr_t)__early_va(trampoline_pmd, load_pa); + pgdp[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D + pfn_pgd(PFN_DOWN(map_pa), tableprot); + trampoline_pmd[0] =3D pfn_pmd(PFN_DOWN(load_pa), prot); + + pgdp =3D __early_va(swapper_pg_dir, load_pa); =20 for (i =3D 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) { size_t o =3D (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i; =20 - swapper_pg_dir[o] =3D - pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i, - __pgprot(_PAGE_TABLE)); + map_pa =3D (uintptr_t)__early_va(swapper_pmd, load_pa); + pgdp[o] =3D pfn_pgd(PFN_DOWN(map_pa) + i, tableprot); } + pmdp =3D __early_va(swapper_pmd, load_pa); for (i =3D 0; i < ARRAY_SIZE(swapper_pmd); i++) - swapper_pmd[i] =3D pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot); + pmdp[i] =3D pfn_pmd(PFN_DOWN(load_pa + i * PMD_SIZE), prot); =20 - swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D - pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pmd), - __pgprot(_PAGE_TABLE)); + map_pa =3D (uintptr_t)__early_va(fixmap_pmd, load_pa); + pgdp[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D + pfn_pgd(PFN_DOWN(map_pa), tableprot); + pmdp =3D __early_va(fixmap_pmd, load_pa); + map_pa =3D (uintptr_t)__early_va(fixmap_pte, load_pa); fixmap_pmd[(FIXADDR_START >> PMD_SHIFT) % PTRS_PER_PMD] =3D - pfn_pmd(PFN_DOWN((uintptr_t)fixmap_pte), - __pgprot(_PAGE_TABLE)); + pfn_pmd(PFN_DOWN(map_pa), tableprot); #else - trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D - pfn_pgd(PFN_DOWN(pa), prot); + pgdp =3D __early_va(trampoline_pg_dir, load_pa); + pgdp[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D + pfn_pgd(PFN_DOWN(load_pa), prot); + + pgdp =3D __early_va(swapper_pg_dir, load_pa); =20 for (i =3D 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) { size_t o =3D (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i; =20 - swapper_pg_dir[o] =3D - pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot); + pgdp[o] =3D pfn_pgd(PFN_DOWN(load_pa + i * PGDIR_SIZE), prot); } =20 - swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D - pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pte), - __pgprot(_PAGE_TABLE)); + map_pa =3D (uintptr_t)__early_va(fixmap_pte, load_pa); + pgdp[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =3D + pfn_pgd(PFN_DOWN(map_pa), tableprot); #endif } --=20 2.17.1