From nobody Thu Nov 28 12:33:16 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A6FB02207A; Tue, 1 Oct 2024 23:02:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727823758; cv=none; b=l14c6ZnJGzewzYPBgR6nzWBaUk9P1Q+DiADCRvWPjWrn42AF0ApurND5GeBL4XCXhg8pLknxSm/GPRO6f+u0HpZGD4HjDD112DMttiJ4Zr1UhHGTXtMZlHRp/lTPms7bI0xgrAYdG4P7m5LabEHoHGl7QN1f1F9ac+I3wnvNzCo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727823758; c=relaxed/simple; bh=iaOo/eHnt7nVAYYY04s0CJoGcZR71Wh0L0z0tfAjj5s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JVun44LcetMuAWsYEnGDdj2rX9Pbt+e7D1SPBfTXjQUTvC03Tx46BXJ0QVV/gvYNAb7zEDOi/NBePE+92u8wCXJin4tpQCHTolMHjxwjRibQKheKenWXun/hBlH1qrig9uYrLujhljcHMS/a3VFYLTso8es5dfjwSF5MXbiTZ1Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gUqqh7nY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gUqqh7nY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32691C4CEC6; Tue, 1 Oct 2024 23:02:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727823758; bh=iaOo/eHnt7nVAYYY04s0CJoGcZR71Wh0L0z0tfAjj5s=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=gUqqh7nY8DifOXx4W85pnErZS2D1gnTtAy+3DgFxNMmQtLboM/sTyjbKi0UGUvxYE MnPV6ZCsIIJ6o7qGezeh+gI3YMVvc9Jb6VGhEpr3Ph1WOsyCPsnWO/QMsj4eHdpx20 P5298HT7y+dw1g1P5hyBAQlmS4D34zxnf2h9aYrrJGJtHSPGXczECZxbvomv0JSMEI 2brqU6kp7yqRC63sx+2NCcxw7ZEYrBATr3AqXdUwFLg8qnmQ0HQYdQ5eBj99fc3UTK 3WHErdya4+QHcjBF9VZIutYVj3Booae9dNtS22ZpYGEV1wpuiYpI32CInMnHzD7Phl eZsvlvNUlqAyQ== From: Mark Brown Date: Tue, 01 Oct 2024 23:58:54 +0100 Subject: [PATCH v13 15/40] arm64/mm: Map pages for guarded control stack 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: <20241001-arm64-gcs-v13-15-222b78d87eee@kernel.org> References: <20241001-arm64-gcs-v13-0-222b78d87eee@kernel.org> In-Reply-To: <20241001-arm64-gcs-v13-0-222b78d87eee@kernel.org> To: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , Kees Cook Cc: "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , Ross Burton , David Spickett , Yury Khrustalev , Wilco Dijkstra , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Brown X-Mailer: b4 0.15-dev-99b12 X-Developer-Signature: v=1; a=openpgp-sha256; l=1824; i=broonie@kernel.org; h=from:subject:message-id; bh=iaOo/eHnt7nVAYYY04s0CJoGcZR71Wh0L0z0tfAjj5s=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBm/H7P1EJJZsPfYIE0QBq/tINqmBg6uzvjA9MNO4G2 WFi9f7CJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZvx+zwAKCRAk1otyXVSH0IY5B/ 9I4+JyQBe97ebsZEscKo1qo7/m+PT10LjgI7Sgz+xOEzztCrZMsOVvxpJOfRz9LSx3HXo7l/r2fMhO o70EbKlG3Ndfo8ukorzVw/0u/VlVIE+M0+uxJE46CJS+gaJLEvLlTr/mr9roUwkqHeI5YJ3u1qCxDg sfdiVWbdejibK6kkPIsuDcMl7qLDgPPgfGyCaCEVo58dYkq5niIfdflsydhtntcNM/C56Pa+c0aUx3 c1CWAKMjvXY1Y+G6FwbVbqON1ejk1JFXdCKgSslWxH6sD1MB8vblGF7f9LD5Jkj1AV8uIM49MW5V/u qCNkmAnsAgQFFEoUsAkeMHuk7yKJ/0 X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Map pages flagged as being part of a GCS as such rather than using the full set of generic VM flags. This is done using a conditional rather than extending the size of protection_map since that would make for a very sparse array. Reviewed-by: Thiago Jung Bauermann Reviewed-by: Catalin Marinas Signed-off-by: Mark Brown --- arch/arm64/include/asm/mman.h | 9 +++++++++ arch/arm64/mm/mmap.c | 9 ++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index 03b790fd0ad8..f6d784f8e6e0 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -71,6 +71,15 @@ static inline bool arch_validate_flags(unsigned long vm_= flags) return false; } =20 + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { + /* An executable GCS isn't a good idea. */ + if (vm_flags & VM_EXEC) + return false; + + /* The memory management core should prevent this */ + VM_WARN_ON(vm_flags & VM_SHARED); + } + return true; =20 } diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 7e3ad97e27d8..07aeab8a7606 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -83,8 +83,15 @@ arch_initcall(adjust_protection_map); =20 pgprot_t vm_get_page_prot(unsigned long vm_flags) { - pteval_t prot =3D pgprot_val(protection_map[vm_flags & + pteval_t prot; + + /* Short circuit GCS to avoid bloating the table. */ + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { + prot =3D _PAGE_GCS_RO; + } else { + prot =3D pgprot_val(protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]); + } =20 if (vm_flags & VM_ARM64_BTI) prot |=3D PTE_GP; --=20 2.39.2