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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 23B83C433F7 for ; Wed, 15 Jul 2020 17:09:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CA15020672 for ; Wed, 15 Jul 2020 17:09:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA15020672 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 1A61E8D0015; Wed, 15 Jul 2020 13:09:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 12F638D0002; Wed, 15 Jul 2020 13:09:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F3A198D0015; Wed, 15 Jul 2020 13:09:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0076.hostedemail.com [216.40.44.76]) by kanga.kvack.org (Postfix) with ESMTP id C8C648D0002 for ; Wed, 15 Jul 2020 13:09:35 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 8F24C824805A for ; Wed, 15 Jul 2020 17:09:35 +0000 (UTC) X-FDA: 77040946710.17.bone03_061271026efb Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id 4FA30180D0194 for ; Wed, 15 Jul 2020 17:09:35 +0000 (UTC) X-HE-Tag: bone03_061271026efb X-Filterd-Recvd-Size: 6736 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Wed, 15 Jul 2020 17:09:34 +0000 (UTC) Received: from localhost.localdomain (unknown [95.146.230.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2285C20672; Wed, 15 Jul 2020 17:09:32 +0000 (UTC) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: linux-mm@kvack.org, linux-arch@vger.kernel.org, Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , Andrew Morton Subject: [PATCH v7 19/29] arm64: mte: Allow user control of the generated random tags via prctl() Date: Wed, 15 Jul 2020 18:08:34 +0100 Message-Id: <20200715170844.30064-20-catalin.marinas@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200715170844.30064-1-catalin.marinas@arm.com> References: <20200715170844.30064-1-catalin.marinas@arm.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 4FA30180D0194 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 which tags can be generated by the above instruction (an include rather than exclude mask). Note that by default all non-zero tags are excluded. This setting is per-thread. Signed-off-by: Catalin Marinas Cc: Will Deacon --- Notes: v5: - Rename gcr_incl to gcr_user_incl (there will be a subsequent gcr_kernel when support for in-kernel MTE is added). =20 v2: - Switch from an exclude mask to an include one for the prctl() interface. - Reset the allowed tags mask during flush_thread(). arch/arm64/include/asm/processor.h | 1 + arch/arm64/include/asm/sysreg.h | 7 ++++++ arch/arm64/kernel/mte.c | 35 +++++++++++++++++++++++++++--- arch/arm64/kernel/process.c | 2 +- include/uapi/linux/prctl.h | 3 +++ 5 files changed, 44 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/= processor.h index 80e7f0573309..e1b1c2a6086e 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -153,6 +153,7 @@ struct thread_struct { #endif #ifdef CONFIG_ARM64_MTE u64 sctlr_tcf0; + u64 gcr_user_incl; #endif }; =20 diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sys= reg.h index 2e12d8049d1c..d6357c4ea015 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -1033,6 +1033,13 @@ 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/mte.c b/arch/arm64/kernel/mte.c index 375483a1f573..07798b8d5039 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -71,6 +71,25 @@ static void set_sctlr_el1_tcf0(u64 tcf0) preempt_enable(); } =20 +static void update_gcr_el1_excl(u64 incl) +{ + u64 excl =3D ~incl & SYS_GCR_EL1_EXCL_MASK; + + /* + * Note that 'incl' is an include mask (controlled by the user via + * prctl()) while GCR_EL1 accepts an exclude mask. + * 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); +} + +static void set_gcr_el1_excl(u64 incl) +{ + current->thread.gcr_user_incl =3D incl; + update_gcr_el1_excl(incl); +} + void flush_mte_state(void) { if (!system_supports_mte()) @@ -82,6 +101,8 @@ void flush_mte_state(void) clear_thread_flag(TIF_MTE_ASYNC_FAULT); /* disable tag checking */ set_sctlr_el1_tcf0(SCTLR_EL1_TCF0_NONE); + /* reset tag generation mask */ + set_gcr_el1_excl(0); } =20 void mte_thread_switch(struct task_struct *next) @@ -92,6 +113,7 @@ void mte_thread_switch(struct task_struct *next) /* 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_user_incl); } =20 long set_mte_ctrl(unsigned long arg) @@ -116,23 +138,30 @@ long set_mte_ctrl(unsigned long arg) } =20 set_sctlr_el1_tcf0(tcf0); + set_gcr_el1_excl((arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT); =20 return 0; } =20 long get_mte_ctrl(void) { + unsigned long ret; + if (!system_supports_mte()) return 0; =20 + ret =3D current->thread.gcr_user_incl << PR_MTE_TAG_SHIFT; + switch (current->thread.sctlr_tcf0) { case SCTLR_EL1_TCF0_NONE: return PR_MTE_TCF_NONE; 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; } diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index d19ce8053a03..b5c1c975d38e 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -616,7 +616,7 @@ 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_TAG_MASK; =20 if (arg & ~valid_mask) return -EINVAL; diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 2390ab324afa..7f0827705c9a 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -239,6 +239,9 @@ 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 inclusion mask */ +# define PR_MTE_TAG_SHIFT 3 +# define PR_MTE_TAG_MASK (0xffffUL << PR_MTE_TAG_SHIFT) =20 /* Control reclaim behavior when allocating memory */ #define PR_SET_IO_FLUSHER 57