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AJvYcCXaqqr2DOZ8Bfclru3zvp0VATb0Nt2VUoZZ7aXxMc8jNsw1hxskB/vBb4eADGnGyGvqzt6EL0g1lD0GISkWA3cQtHU= X-Gm-Message-State: AOJu0YzDAGWo5wq+bQSG6PYJnYA4Hr1T9zQNY5bmg9hFl/kByqjkNP5e YPYr+lX5GsRtG1R4Eo2G//SFDZm8r20JBr1tvWIacbIXFY27ou7CusA1wvnoioc= X-Google-Smtp-Source: AGHT+IHn70WZbF+jlCONe2EcRRr6ZCh1IRqHu+QHyp4yjMBW+7E5Ek9bYAqg4ymMIf0JA4HyBbr9VA== X-Received: by 2002:a17:902:e80e:b0:1e0:b677:293b with SMTP id u14-20020a170902e80e00b001e0b677293bmr5847942plg.29.1712187716595; Wed, 03 Apr 2024 16:41:56 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id b18-20020a170902d51200b001deeac592absm13899117plg.180.2024.04.03.16.41.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Apr 2024 16:41:56 -0700 (PDT) From: Deepak Gupta To: paul.walmsley@sifive.com, rick.p.edgecombe@intel.com, broonie@kernel.org, Szabolcs.Nagy@arm.com, kito.cheng@sifive.com, keescook@chromium.org, ajones@ventanamicro.com, conor.dooley@microchip.com, cleger@rivosinc.com, atishp@atishpatra.org, alex@ghiti.fr, bjorn@rivosinc.com, alexghiti@rivosinc.com, samuel.holland@sifive.com, conor@kernel.org Cc: linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, corbet@lwn.net, palmer@dabbelt.com, aou@eecs.berkeley.edu, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, oleg@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, ebiederm@xmission.com, Liam.Howlett@oracle.com, vbabka@suse.cz, lstoakes@gmail.com, shuah@kernel.org, brauner@kernel.org, debug@rivosinc.com, andy.chiu@sifive.com, jerry.shih@sifive.com, hankuan.chen@sifive.com, greentime.hu@sifive.com, evan@rivosinc.com, xiao.w.wang@intel.com, charlie@rivosinc.com, apatel@ventanamicro.com, mchitale@ventanamicro.com, dbarboza@ventanamicro.com, sameo@rivosinc.com, shikemeng@huaweicloud.com, willy@infradead.org, vincent.chen@sifive.com, guoren@kernel.org, samitolvanen@google.com, songshuaishuai@tinylab.org, gerg@kernel.org, heiko@sntech.de, bhe@redhat.com, jeeheng.sia@starfivetech.com, cyy@cyyself.name, maskray@google.com, ancientmodern4@gmail.com, mathis.salmen@matsal.de, cuiyunhui@bytedance.com, bgray@linux.ibm.com, mpe@ellerman.id.au, baruch@tkos.co.il, alx@kernel.org, david@redhat.com, catalin.marinas@arm.com, revest@chromium.org, josh@joshtriplett.org, shr@devkernel.io, deller@gmx.de, omosnace@redhat.com, ojeda@kernel.org, jhubbard@nvidia.com Subject: [PATCH v3 10/29] riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE Date: Wed, 3 Apr 2024 16:34:58 -0700 Message-ID: <20240403234054.2020347-11-debug@rivosinc.com> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240403234054.2020347-1-debug@rivosinc.com> References: <20240403234054.2020347-1-debug@rivosinc.com> MIME-Version: 1.0 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: BB6A51C000A X-Stat-Signature: xsrb8gjo6efqhwmmts535uhudtcaoti6 X-Rspam-User: X-HE-Tag: 1712187717-719015 X-HE-Meta: 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 oum9EIKs 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: `arch_calc_vm_prot_bits` is implemented on risc-v to return VM_READ | VM_WRITE if PROT_WRITE is specified. Similarly `riscv_sys_mmap` is updated to convert all incoming PROT_WRITE to (PROT_WRITE | PROT_READ). This is to make sure that any existing apps using PROT_WRITE still work. Earlier `protection_map[VM_WRITE]` used to pick read-write PTE encodings. Now `protection_map[VM_WRITE]` will always pick PAGE_SHADOWSTACK PTE encodings for shadow stack. Above changes ensure that existing apps continue to work because underneath kernel will be picking `protection_map[VM_WRITE|VM_READ]` PTE encodings. Signed-off-by: Deepak Gupta --- arch/riscv/include/asm/mman.h | 24 ++++++++++++++++++++++++ arch/riscv/include/asm/pgtable.h | 1 + arch/riscv/kernel/sys_riscv.c | 11 +++++++++++ arch/riscv/mm/init.c | 2 +- mm/mmap.c | 1 + 5 files changed, 38 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/include/asm/mman.h diff --git a/arch/riscv/include/asm/mman.h b/arch/riscv/include/asm/mman.h new file mode 100644 index 000000000000..ef9fedf32546 --- /dev/null +++ b/arch/riscv/include/asm/mman.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#include +#include +#include + +static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, + unsigned long pkey __always_unused) +{ + unsigned long ret = 0; + + /* + * If PROT_WRITE was specified, force it to VM_READ | VM_WRITE. + * Only VM_WRITE means shadow stack. + */ + if (prot & PROT_WRITE) + ret = (VM_READ | VM_WRITE); + return ret; +} +#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey) + +#endif /* ! __ASM_MMAN_H__ */ diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 6066822e7396..4d5983bc6766 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -184,6 +184,7 @@ extern struct pt_alloc_ops pt_ops __initdata; #define PAGE_READ_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC) #define PAGE_WRITE_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | \ _PAGE_EXEC | _PAGE_WRITE) +#define PAGE_SHADOWSTACK __pgprot(_PAGE_BASE | _PAGE_WRITE) #define PAGE_COPY PAGE_READ #define PAGE_COPY_EXEC PAGE_READ_EXEC diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c index f1c1416a9f1e..846c36b1b3d5 100644 --- a/arch/riscv/kernel/sys_riscv.c +++ b/arch/riscv/kernel/sys_riscv.c @@ -8,6 +8,8 @@ #include #include #include +#include +#include static long riscv_sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, @@ -17,6 +19,15 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len, if (unlikely(offset & (~PAGE_MASK >> page_shift_offset))) return -EINVAL; + /* + * If only PROT_WRITE is specified then extend that to PROT_READ + * protection_map[VM_WRITE] is now going to select shadow stack encodings. + * So specifying PROT_WRITE actually should select protection_map [VM_WRITE | VM_READ] + * If user wants to create shadow stack then they should use `map_shadow_stack` syscall. + */ + if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ))) + prot |= PROT_READ; + return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> (PAGE_SHIFT - page_shift_offset)); } diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index fa34cf55037b..98e5ece4052a 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -299,7 +299,7 @@ pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); static const pgprot_t protection_map[16] = { [VM_NONE] = PAGE_NONE, [VM_READ] = PAGE_READ, - [VM_WRITE] = PAGE_COPY, + [VM_WRITE] = PAGE_SHADOWSTACK, [VM_WRITE | VM_READ] = PAGE_COPY, [VM_EXEC] = PAGE_EXEC, [VM_EXEC | VM_READ] = PAGE_READ_EXEC, diff --git a/mm/mmap.c b/mm/mmap.c index d89770eaab6b..57a974f49b00 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include