From patchwork Wed Dec 6 19:01:30 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 10096815 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1EDC560210 for ; Wed, 6 Dec 2017 19:19:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0C898291A9 for ; Wed, 6 Dec 2017 19:19:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0022629C74; Wed, 6 Dec 2017 19:19:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6971E291A9 for ; Wed, 6 Dec 2017 19:19:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=Vopc4B4HOootW73bSUaJQObzO9tzL1yIve0m63cp9Vw=; b=gxI0VtR3dsv2vJGFipWAeAAYxB CkJ/gGuXXndfzocIXHm7jkC7zh1xZX7UqAOhxhYN51rQiSIBA4+6avcWuGHKaR0VQkVtpg/jK2KsA XNf9zYpe+O7l7hGJmzu/M0vyuaD1CWp1TuAxAAJc7KMHZzyR/zPmlvHq7vVLfWobYa/TBZZVjKCRw DrWcWcasA7sJFHIHUSVgJmN/2H9Lqh/HTEZDJRDPCJVxdwsvySg/rOxLjnobjzsmXg2KpvbYOaOHT 6v0H7TIaQNnA4OR8gcDzqU8t6B/s8MZEn6OibijN3Kpth5E25fVmca8LSEFSAsGVRsXkA2VyNunla 3ElFU0rQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1eMfEM-00046A-Fy; Wed, 06 Dec 2017 19:19:42 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1eMezV-000458-O8 for linux-arm-kernel@lists.infradead.org; Wed, 06 Dec 2017 19:04:30 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D115A164F; Wed, 6 Dec 2017 11:04:02 -0800 (PST) Received: from melchizedek.cambridge.arm.com (melchizedek.cambridge.arm.com [10.1.207.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BEA083F487; Wed, 6 Dec 2017 11:04:00 -0800 (PST) From: James Morse To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 04/16] arm64: alternatives: use tpidr_el2 on VHE hosts Date: Wed, 6 Dec 2017 19:01:30 +0000 Message-Id: <20171206190142.9246-5-james.morse@arm.com> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171206190142.9246-1-james.morse@arm.com> References: <20171206190142.9246-1-james.morse@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171206_110422_427801_03EFB61A X-CRM114-Status: GOOD ( 14.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree@vger.kernel.org, Lorenzo Pieralisi , Marc Zyngier , Catalin Marinas , Will Deacon , Rob Herring , Loc Ho , Heyi Guo , kvmarm@lists.cs.columbia.edu, Christoffer Dall MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Now that KVM uses tpidr_el2 in the same way as Linux's cpu_offset in tpidr_el1, merge the two. This saves KVM from save/restoring tpidr_el1 on VHE hosts, and allows future code to blindly access per-cpu variables without triggering world-switch. Signed-off-by: James Morse Reviewed-by: Christoffer Dall Reviewed-by: Catalin Marinas --- Changes since v3: * Moved 'alternatives_applied' test all into C, * Made enable method static and dragged up before first-use. Changes since v1: * cpu_copy_el2regs()'s 'have I been patched' test now always sets a register, just in case the compiler optimises out part of the logic. arch/arm64/include/asm/alternative.h | 2 ++ arch/arm64/include/asm/assembler.h | 8 ++++++++ arch/arm64/include/asm/percpu.h | 11 +++++++++-- arch/arm64/kernel/alternative.c | 9 +++++---- arch/arm64/kernel/cpufeature.c | 17 +++++++++++++++++ arch/arm64/mm/proc.S | 8 ++++++++ 6 files changed, 49 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h index 4a85c6952a22..669028172fd6 100644 --- a/arch/arm64/include/asm/alternative.h +++ b/arch/arm64/include/asm/alternative.h @@ -12,6 +12,8 @@ #include #include +extern int alternatives_applied; + struct alt_instr { s32 orig_offset; /* offset to original instruction */ s32 alt_offset; /* offset to replacement instruction */ diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index c45bc94f15d0..c070c263021e 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -254,7 +254,11 @@ lr .req x30 // link register #else adr_l \dst, \sym #endif +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN mrs \tmp, tpidr_el1 +alternative_else + mrs \tmp, tpidr_el2 +alternative_endif add \dst, \dst, \tmp .endm @@ -265,7 +269,11 @@ lr .req x30 // link register */ .macro ldr_this_cpu dst, sym, tmp adr_l \dst, \sym +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN mrs \tmp, tpidr_el1 +alternative_else + mrs \tmp, tpidr_el2 +alternative_endif ldr \dst, [\dst, \tmp] .endm diff --git a/arch/arm64/include/asm/percpu.h b/arch/arm64/include/asm/percpu.h index 3bd498e4de4c..43393208229e 100644 --- a/arch/arm64/include/asm/percpu.h +++ b/arch/arm64/include/asm/percpu.h @@ -16,11 +16,15 @@ #ifndef __ASM_PERCPU_H #define __ASM_PERCPU_H +#include #include static inline void set_my_cpu_offset(unsigned long off) { - asm volatile("msr tpidr_el1, %0" :: "r" (off) : "memory"); + asm volatile(ALTERNATIVE("msr tpidr_el1, %0", + "msr tpidr_el2, %0", + ARM64_HAS_VIRT_HOST_EXTN) + :: "r" (off) : "memory"); } static inline unsigned long __my_cpu_offset(void) @@ -31,7 +35,10 @@ static inline unsigned long __my_cpu_offset(void) * We want to allow caching the value, so avoid using volatile and * instead use a fake stack read to hazard against barrier(). */ - asm("mrs %0, tpidr_el1" : "=r" (off) : + asm(ALTERNATIVE("mrs %0, tpidr_el1", + "mrs %0, tpidr_el2", + ARM64_HAS_VIRT_HOST_EXTN) + : "=r" (off) : "Q" (*(const unsigned long *)current_stack_pointer)); return off; diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c index 6dd0a3a3e5c9..414288a558c8 100644 --- a/arch/arm64/kernel/alternative.c +++ b/arch/arm64/kernel/alternative.c @@ -32,6 +32,8 @@ #define ALT_ORIG_PTR(a) __ALT_PTR(a, orig_offset) #define ALT_REPL_PTR(a) __ALT_PTR(a, alt_offset) +int alternatives_applied; + struct alt_region { struct alt_instr *begin; struct alt_instr *end; @@ -143,7 +145,6 @@ static void __apply_alternatives(void *alt_region, bool use_linear_alias) */ static int __apply_alternatives_multi_stop(void *unused) { - static int patched = 0; struct alt_region region = { .begin = (struct alt_instr *)__alt_instructions, .end = (struct alt_instr *)__alt_instructions_end, @@ -151,14 +152,14 @@ static int __apply_alternatives_multi_stop(void *unused) /* We always have a CPU 0 at this point (__init) */ if (smp_processor_id()) { - while (!READ_ONCE(patched)) + while (!READ_ONCE(alternatives_applied)) cpu_relax(); isb(); } else { - BUG_ON(patched); + BUG_ON(alternatives_applied); __apply_alternatives(®ion, true); /* Barriers provided by the cache flushing */ - WRITE_ONCE(patched, 1); + WRITE_ONCE(alternatives_applied, 1); } return 0; diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 98e6563015a4..cb9c4e5a72f8 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -879,6 +879,22 @@ static int __init parse_kpti(char *str) __setup("kpti=", parse_kpti); #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ +static int cpu_copy_el2regs(void *__unused) +{ + /* + * Copy register values that aren't redirected by hardware. + * + * Before code patching, we only set tpidr_el1, all CPUs need to copy + * this value to tpidr_el2 before we patch the code. Once we've done + * that, freshly-onlined CPUs will set tpidr_el2, so we don't need to + * do anything here. + */ + if (!alternatives_applied) + write_sysreg(read_sysreg(tpidr_el1), tpidr_el2); + + return 0; +} + static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "GIC system register CPU interface", @@ -948,6 +964,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .capability = ARM64_HAS_VIRT_HOST_EXTN, .def_scope = SCOPE_SYSTEM, .matches = runs_at_el2, + .enable = cpu_copy_el2regs, }, { .desc = "32-bit EL0 Support", diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 3146dc96f05b..2f5051411783 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -70,7 +70,11 @@ ENTRY(cpu_do_suspend) mrs x8, mdscr_el1 mrs x9, oslsr_el1 mrs x10, sctlr_el1 +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN mrs x11, tpidr_el1 +alternative_else + mrs x11, tpidr_el2 +alternative_endif mrs x12, sp_el0 stp x2, x3, [x0] stp x4, xzr, [x0, #16] @@ -116,7 +120,11 @@ ENTRY(cpu_do_resume) msr mdscr_el1, x10 msr sctlr_el1, x12 +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN msr tpidr_el1, x13 +alternative_else + msr tpidr_el2, x13 +alternative_endif msr sp_el0, x14 /* * Restore oslsr_el1 by writing oslar_el1