From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5A0EC43603 for ; Wed, 11 Dec 2019 18:49:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 696C6206A5 for ; Wed, 11 Dec 2019 18:49:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 696C6206A5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C3F766B336E; Wed, 11 Dec 2019 13:48:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B776F6B3373; Wed, 11 Dec 2019 13:48:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9CA5A6B3371; Wed, 11 Dec 2019 13:48:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0142.hostedemail.com [216.40.44.142]) by kanga.kvack.org (Postfix) with ESMTP id 644F66B336A for ; Wed, 11 Dec 2019 13:48:52 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 44EA14DA8 for ; Wed, 11 Dec 2019 18:48:52 +0000 (UTC) X-FDA: 76253747304.04.hole04_13338b6e8f510 X-HE-Tag: hole04_13338b6e8f510 X-Filterd-Recvd-Size: 5660 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Wed, 11 Dec 2019 18:48:51 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DB91314FF; Wed, 11 Dec 2019 10:41:10 -0800 (PST) Received: from arrakis.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 729483F6CF; Wed, 11 Dec 2019 10:41:09 -0800 (PST) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon , Marc Zyngier , Vincenzo Frascino , Szabolcs Nagy , Richard Earnshaw , Kevin Brodsky , Andrey Konovalov , linux-mm@kvack.org, linux-arch@vger.kernel.org Subject: [PATCH 20/22] arm64: mte: Allow user control of the excluded tags via prctl() Date: Wed, 11 Dec 2019 18:40:25 +0000 Message-Id: <20191211184027.20130-21-catalin.marinas@arm.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191211184027.20130-1-catalin.marinas@arm.com> References: <20191211184027.20130-1-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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: The IRG, ADDG and SUBG instructions insert a random tag in the resulting address. Certain tags can be excluded via the GCR_EL1.Exclude bitmap when, for example, the user wants a certain colour for freed buffers. Since the GCR_EL1 register is not accessible at EL0, extend the prctl(PR_SET_TAGGED_ADDR_CTRL) interface to include a 16-bit field in the first argument for controlling the excluded tags. This setting is pre-thread. Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/processor.h | 1 + arch/arm64/include/asm/sysreg.h | 7 +++++++ arch/arm64/kernel/process.c | 27 +++++++++++++++++++++++---- include/uapi/linux/prctl.h | 3 +++ 4 files changed, 34 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/= processor.h index 91aa270afc7d..5b6988035334 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -150,6 +150,7 @@ struct thread_struct { #endif #ifdef CONFIG_ARM64_MTE u64 sctlr_tcf0; + u64 gcr_excl; #endif }; =20 diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sys= reg.h index 9e5753272f4b..b6bb6d31f1cd 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -901,6 +901,13 @@ write_sysreg(__scs_new, sysreg); \ } while (0) =20 +#define sysreg_clear_set_s(sysreg, clear, set) do { \ + u64 __scs_val =3D read_sysreg_s(sysreg); \ + u64 __scs_new =3D (__scs_val & ~(u64)(clear)) | (set); \ + if (__scs_new !=3D __scs_val) \ + write_sysreg_s(__scs_new, sysreg); \ +} while (0) + #endif =20 #endif /* __ASM_SYSREG_H */ diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 47ce98f47253..5ec6889795fc 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -502,6 +502,15 @@ static void update_sctlr_el1_tcf0(u64 tcf0) sysreg_clear_set(sctlr_el1, SCTLR_EL1_TCF0_MASK, tcf0); } =20 +static void update_gcr_el1_excl(u64 excl) +{ + /* + * No need for ISB since this only affects EL0 currently, implicit + * with ERET. + */ + sysreg_clear_set_s(SYS_GCR_EL1, SYS_GCR_EL1_EXCL_MASK, excl); +} + /* Handle MTE thread switch */ static void mte_thread_switch(struct task_struct *next) { @@ -511,6 +520,7 @@ static void mte_thread_switch(struct task_struct *nex= t) /* avoid expensive SCTLR_EL1 accesses if no change */ if (current->thread.sctlr_tcf0 !=3D next->thread.sctlr_tcf0) update_sctlr_el1_tcf0(next->thread.sctlr_tcf0); + update_gcr_el1_excl(next->thread.gcr_excl); } #else static void mte_thread_switch(struct task_struct *next) @@ -641,22 +651,31 @@ static long set_mte_ctrl(unsigned long arg) update_sctlr_el1_tcf0(tcf0); preempt_enable(); =20 + current->thread.gcr_excl =3D (arg & PR_MTE_EXCL_MASK) >> PR_MTE_EXCL_SH= IFT; + update_gcr_el1_excl(current->thread.gcr_excl); + return 0; } =20 static long get_mte_ctrl(void) { + unsigned long ret; + if (!system_supports_mte()) return 0; =20 + ret =3D current->thread.gcr_excl << PR_MTE_EXCL_SHIFT; + switch (current->thread.sctlr_tcf0) { case SCTLR_EL1_TCF0_SYNC: - return PR_MTE_TCF_SYNC; + ret |=3D PR_MTE_TCF_SYNC; + break; case SCTLR_EL1_TCF0_ASYNC: - return PR_MTE_TCF_ASYNC; + ret |=3D PR_MTE_TCF_ASYNC; + break; } =20 - return 0; + return ret; } #else static long set_mte_ctrl(unsigned long arg) @@ -684,7 +703,7 @@ long set_tagged_addr_ctrl(unsigned long arg) return -EINVAL; =20 if (system_supports_mte()) - valid_mask |=3D PR_MTE_TCF_MASK; + valid_mask |=3D PR_MTE_TCF_MASK | PR_MTE_EXCL_MASK; =20 if (arg & ~valid_mask) return -EINVAL; diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 5e9323e66a38..749de5ab4f9f 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -239,5 +239,8 @@ struct prctl_mm_map { # define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT) # define PR_MTE_TCF_ASYNC (2UL << PR_MTE_TCF_SHIFT) # define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT) +/* MTE tag exclusion mask */ +# define PR_MTE_EXCL_SHIFT 3 +# define PR_MTE_EXCL_MASK (0xffffUL << PR_MTE_EXCL_SHIFT) =20 #endif /* _LINUX_PRCTL_H */