From patchwork Fri Nov 24 16:34:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joey Gouly X-Patchwork-Id: 13467951 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9A2ECC636CB for ; Fri, 24 Nov 2023 16:36:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3+Z+EPGGnFgOCTbPU5jn6v26VwM+9fwy4wp+n3jz8hE=; b=zis2Tkv+rTO4BC LI9uRXEdFexRPbWMeYHGH7KMLzhGiJRR2JR1crZTRuq0wtxlIqMLHSMgA95ABRgE9EfMVU4hGQhFc SOaELvmkYOzrRfeaEVMy+HSot4fq/3uSTiwHT6MiJWMI2BwvIoALOL+7uF1YwqoGyNKi7Uxq36HG6 2+5ghTalIj6yef4BRb2PU4q6Dh1eFrcmgKGwk/y+lswUJ2f+PVRujAGfniZw1QTsYtUWDyN18KnZ5 5F4ySAZB2WhkjHMY/gedDJnAAIdvzZukVy8Uk1qptKG/oUDxY/xbzt5jar+M/hWb5GTlEf6nD0XhD uEiuzWEwpfCWa42s0vwQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r6Z9m-007fAk-0E; Fri, 24 Nov 2023 16:35:54 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r6Z9Y-007f3f-2J for linux-arm-kernel@lists.infradead.org; Fri, 24 Nov 2023 16:35:42 +0000 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 5D8C81BD0; Fri, 24 Nov 2023 08:36:21 -0800 (PST) Received: from e124191.cambridge.arm.com (e124191.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AE04C3F73F; Fri, 24 Nov 2023 08:35:32 -0800 (PST) From: Joey Gouly To: linux-arm-kernel@lists.infradead.org Cc: akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, broonie@kernel.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, joey.gouly@arm.com, maz@kernel.org, oliver.upton@linux.dev, shuah@kernel.org, will@kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, James Morse , Suzuki K Poulose , Zenghui Yu Subject: [PATCH v3 05/25] arm64: context switch POR_EL0 register Date: Fri, 24 Nov 2023 16:34:50 +0000 Message-Id: <20231124163510.1835740-6-joey.gouly@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231124163510.1835740-1-joey.gouly@arm.com> References: <20231124163510.1835740-1-joey.gouly@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231124_083540_847049_263E4893 X-CRM114-Status: GOOD ( 13.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org POR_EL0 is a register that can be modified by userspace directly, so it must be context switched. Signed-off-by: Joey Gouly Cc: Catalin Marinas Cc: Will Deacon --- arch/arm64/include/asm/cpufeature.h | 6 ++++++ arch/arm64/include/asm/processor.h | 1 + arch/arm64/include/asm/sysreg.h | 3 +++ arch/arm64/kernel/process.c | 22 ++++++++++++++++++++++ 4 files changed, 32 insertions(+) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index f6d416fe49b0..6870e4d46334 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -819,6 +819,12 @@ static inline bool system_supports_tlb_range(void) return alternative_has_cap_unlikely(ARM64_HAS_TLB_RANGE); } +static inline bool system_supports_poe(void) +{ + return IS_ENABLED(CONFIG_ARM64_POE) && + alternative_has_cap_unlikely(ARM64_HAS_S1POE); +} + int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); bool try_emulate_mrs(struct pt_regs *regs, u32 isn); diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index e5bc54522e71..b3ad719c2d0c 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -179,6 +179,7 @@ struct thread_struct { u64 sctlr_user; u64 svcr; u64 tpidr2_el0; + u64 por_el0; }; static inline unsigned int thread_get_vl(struct thread_struct *thread, diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 9c2caf0efdc7..77a4797d0d54 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -1052,6 +1052,9 @@ #define POE_RXW UL(0x7) #define POE_MASK UL(0xf) +/* Initial value for Permission Overlay Extension for EL0 */ +#define POR_EL0_INIT POE_RXW + #define ARM64_FEATURE_FIELD_BITS 4 /* Defined for compatibility only, do not add new users. */ diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 7387b68c745b..fc899c12d759 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -271,12 +271,19 @@ static void flush_tagged_addr_state(void) clear_thread_flag(TIF_TAGGED_ADDR); } +static void flush_poe(void) +{ + if (system_supports_poe()) + write_sysreg_s(POR_EL0_INIT, SYS_POR_EL0); +} + void flush_thread(void) { fpsimd_flush_thread(); tls_thread_flush(); flush_ptrace_hw_breakpoint(current); flush_tagged_addr_state(); + flush_poe(); } void arch_release_task_struct(struct task_struct *tsk) @@ -374,6 +381,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) if (system_supports_tpidr2()) p->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0); + if (system_supports_poe()) + p->thread.por_el0 = read_sysreg_s(SYS_POR_EL0); + if (stack_start) { if (is_compat_thread(task_thread_info(p))) childregs->compat_sp = stack_start; @@ -498,6 +508,17 @@ static void erratum_1418040_new_exec(void) preempt_enable(); } +static void permission_overlay_switch(struct task_struct *next) +{ + if (system_supports_poe()) { + current->thread.por_el0 = read_sysreg_s(SYS_POR_EL0); + if (current->thread.por_el0 != next->thread.por_el0) { + write_sysreg_s(next->thread.por_el0, SYS_POR_EL0); + isb(); + } + } +} + /* * __switch_to() checks current->thread.sctlr_user as an optimisation. Therefore * this function must be called with preemption disabled and the update to @@ -533,6 +554,7 @@ struct task_struct *__switch_to(struct task_struct *prev, ssbs_thread_switch(next); erratum_1418040_thread_switch(next); ptrauth_thread_switch_user(next); + permission_overlay_switch(next); /* * Complete any pending TLB or cache maintenance on this CPU in case