From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752773AbdGLWeU (ORCPT ); Wed, 12 Jul 2017 18:34:20 -0400 Received: from foss.arm.com ([217.140.101.70]:59114 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752523AbdGLWeT (ORCPT ); Wed, 12 Jul 2017 18:34:19 -0400 From: Mark Rutland To: ard.biesheuvel@linaro.org, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: akashi.takahiro@linaro.org, catalin.marinas@arm.com, dave.martin@arm.com, james.morse@arm.com, labbott@fedoraproject.org, will.deacon@arm.com, keescook@chromium.org, Mark Rutland Subject: [RFC PATCH 4/6] arm64: pass stack base to secondary_start_kernel Date: Wed, 12 Jul 2017 23:33:01 +0100 Message-Id: <1499898783-25732-5-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1499898783-25732-1-git-send-email-mark.rutland@arm.com> References: <1499898783-25732-1-git-send-email-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In subsequent patches, we'll want the base of the secondary stack in secondary_start_kernel. Pass the stack base down, as we do in the primary path, and add the offset in secondary_start_kernel. Unfortunately, we can't encode STACK_START_SP in an add immediate, so use a mov immedaite, which has greater range. This is far from a hot path, so the overhead shouldn't matter. Signed-off-by: Mark Rutland --- arch/arm64/kernel/head.S | 3 ++- arch/arm64/kernel/smp.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index a58ecda..db77cac 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -613,7 +613,8 @@ __secondary_switched: adr_l x0, secondary_data ldr x1, [x0, #CPU_BOOT_STACK] // get secondary_data.stack - mov sp, x1 + mov x3, #THREAD_START_SP + add sp, x1, x3 ldr x2, [x0, #CPU_BOOT_TASK] msr tpidr_el1, x2 mov x29, #0 diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 6e0e16a..269c957 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -154,7 +154,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) * page tables. */ secondary_data.task = idle; - secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; + secondary_data.stack = task_stack_page(idle); update_cpu_boot_status(CPU_MMU_OFF); __flush_dcache_area(&secondary_data, sizeof(secondary_data)); -- 1.9.1