From nobody Tue Feb 10 19:17:06 2026 Received: from mail-pj1-f52.google.com (mail-pj1-f52.google.com [209.85.216.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1DBD22A7EF for ; Wed, 5 Feb 2025 01:22:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.52 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738718531; cv=none; b=A92gwENi0/8etaplewU/RYvwva6Zv0tslsA9D2eX+c74nFectGBIHmZBd/tAylX6kkWQUTquEpqav9aMcDcQXFdyEhVdIr3L0m73mVdNF29GtsA+w1UoUB4TW+jkosdrIYvDxyywxnBE7/ruaUso8e3PAR9QpqXpt+Ks3HTaE84= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738718531; c=relaxed/simple; bh=HOQqOSPO+MhBbccjb2UbKqhOT3MYkxspDNQyPTpGYhw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=k0n0GFDUY444KehobdqRbxfdBYygVCOkbKroXGA5NHw3W/Iwu62DshsO3HOF2FYfaw/lpZI7pcVjujtiZCDbHw3xFZKLxPvyPNErkubnG5MyWqObQLn9L3VkhoL7E3pQ6bSA5Yx82Jvdme86B4Nb8QUsEjl8nhihQLkkvCXTu0M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com; spf=pass smtp.mailfrom=rivosinc.com; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b=GYWuKvhE; arc=none smtp.client-ip=209.85.216.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b="GYWuKvhE" Received: by mail-pj1-f52.google.com with SMTP id 98e67ed59e1d1-2f9d9f14a74so1154082a91.0 for ; Tue, 04 Feb 2025 17:22:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1738718529; x=1739323329; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=WPde6NcIQ47rHbegQG8dPMP+orPth983zEAPX8ktkAY=; b=GYWuKvhE5q6kewHJL2AeIOOIlbys8wkXYWo16hj7BUaqIY03Eod2piqVd+ZsLyjuEG XTQuQDJNVQEvwS3RSPWMFVbeXUlX6w00Akc0c7wVcGs1nJGa9I+bb68IYVacK3klMqvn oVgAnQAn0gurFpjdq1MdlYYFsKO2XkzLxSZStYgbzgnHL3y4OsgjQf6EK2Atv86K/Agd 30AICNnrIODMm1QtigZ0R29NyARO978AdDG72LXvUUWmEhhsZ1Y2OMQagb59O/jXGgVn dVGloyM0+1Gez+hSN62xGySydNKbomuA1jzk88uHevbjfgy38d2qsq4ftKq202byhT9d s4eg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738718529; x=1739323329; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WPde6NcIQ47rHbegQG8dPMP+orPth983zEAPX8ktkAY=; b=sws3P+FcUiJOy/Y+mgkYSRdQE4uX6rXP8lwhGmrrDPtbToVd6POZjXqRDUqSWIJWo5 FhXU1d3P0NuDpitkVmARjnpFBV2SAv5fPwTQWPjDbqBjtW0PHL5vD3xqqeqFQPf3va9X iaz6D8TGAZtBdOiMF15K0+wdftGXp6p7Mo8YTUDqXEucOQ93uXg+uYPDo4+CNr3NOkhh 2twywF+YTzdcNZM2FpE+vigyc4UXu2GMvYmYBuiDRK5iuS1O3BMp8yuZC0OSjc4JFN1S hK4zj3fJQbbqKcKghZua/ePmb2RaOo0+UIe7FQWexqDCwPzUE7G2cAqd9GRe032uso9p w77g== X-Gm-Message-State: AOJu0Ywdk3dbm4YV97wrpDxEaxTbAJJMCiSfNTzQHOPa/EhOq3F6tiGR 0EymRshMbkwNlCg9Os65GWlvQy/chUucLtMOFLXsFUieibBvhRaAPwKUye19HI0= X-Gm-Gg: ASbGncsFdWTXrEqBf5qu+/wJJEmGuD4RBR2kIrdg5In+0aVXRQbB7SFeL2KoSpi4J9e tojO1Niwnd+shVYQbyDh01oaBEo6GcwONA30XnvghvaXFebr2qb27H8LWKaBosrBRH/Hm+6HTDw waUAIGOePRUukyfpGwgdGHrTVKCgccxMdI01C2MlrhON41n/38mocf0eb/zjUvzrVkSIQ6qTBwS crmJ5qZxNuqTiCpqPfYLMTLHdaXRH6LTTRwl1yb4kt82dHwBei0i4etvXsF3TIpj6Qy7imhWJv8 2kmh2Kp3VWNQYOPgquPzGpt7LQ== X-Google-Smtp-Source: AGHT+IEPr/jAZdU1BeAv0MTLO4+mRSsOemI+fwwJ0UmsHYAhZKBwL5jRXw2/FSsvJQ9vrjQzGW+zkw== X-Received: by 2002:a05:6a00:35cb:b0:72d:8fa2:9999 with SMTP id d2e1a72fcca58-73035140b35mr1685541b3a.11.1738718529305; Tue, 04 Feb 2025 17:22:09 -0800 (PST) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-72fe69cec0fsm11457202b3a.137.2025.02.04.17.22.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Feb 2025 17:22:08 -0800 (PST) From: Deepak Gupta Date: Tue, 04 Feb 2025 17:21:55 -0800 Subject: [PATCH v9 08/26] riscv mmu: teach pte_mkwrite to manufacture shadow stack PTEs Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250204-v5_user_cfi_series-v9-8-b37a49c5205c@rivosinc.com> References: <20250204-v5_user_cfi_series-v9-0-b37a49c5205c@rivosinc.com> In-Reply-To: <20250204-v5_user_cfi_series-v9-0-b37a49c5205c@rivosinc.com> To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Lorenzo Stoakes , Paul Walmsley , Palmer Dabbelt , Albert Ou , Conor Dooley , Rob Herring , Krzysztof Kozlowski , Arnd Bergmann , Christian Brauner , Peter Zijlstra , Oleg Nesterov , Eric Biederman , Kees Cook , Jonathan Corbet , Shuah Khan , Jann Horn , Conor Dooley Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, alistair.francis@wdc.com, richard.henderson@linaro.org, jim.shu@sifive.com, andybnac@gmail.com, kito.cheng@sifive.com, charlie@rivosinc.com, atishp@rivosinc.com, evan@rivosinc.com, cleger@rivosinc.com, alexghiti@rivosinc.com, samitolvanen@google.com, broonie@kernel.org, rick.p.edgecombe@intel.com, Deepak Gupta X-Mailer: b4 0.14.0 pte_mkwrite creates PTEs with WRITE encodings for underlying arch. Underlying arch can have two types of writeable mappings. One that can be written using regular store instructions. Another one that can only be written using specialized store instructions (like shadow stack stores). pte_mkwrite can select write PTE encoding based on VMA range (i.e. VM_SHADOW_STACK) Signed-off-by: Deepak Gupta Reviewed-by: Alexandre Ghiti --- arch/riscv/include/asm/pgtable.h | 7 +++++++ arch/riscv/mm/pgtable.c | 17 +++++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgta= ble.h index ede43185ffdf..ccd2fa34afb8 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -416,6 +416,10 @@ static inline pte_t pte_wrprotect(pte_t pte) =20 /* static inline pte_t pte_mkread(pte_t pte) */ =20 +struct vm_area_struct; +pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma); +#define pte_mkwrite pte_mkwrite + static inline pte_t pte_mkwrite_novma(pte_t pte) { return __pte(pte_val(pte) | _PAGE_WRITE); @@ -749,6 +753,9 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd) return pte_pmd(pte_mkyoung(pmd_pte(pmd))); } =20 +pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); +#define pmd_mkwrite pmd_mkwrite + static inline pmd_t pmd_mkwrite_novma(pmd_t pmd) { return pte_pmd(pte_mkwrite_novma(pmd_pte(pmd))); diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c index 4ae67324f992..be5d38546bb3 100644 --- a/arch/riscv/mm/pgtable.c +++ b/arch/riscv/mm/pgtable.c @@ -155,3 +155,20 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, return pmd; } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma) +{ + if (vma->vm_flags & VM_SHADOW_STACK) + return pte_mkwrite_shstk(pte); + + return pte_mkwrite_novma(pte); +} + +pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) +{ + if (vma->vm_flags & VM_SHADOW_STACK) + return pmd_mkwrite_shstk(pmd); + + return pmd_mkwrite_novma(pmd); +} + --=20 2.34.1