From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754687AbbGTCc6 (ORCPT ); Sun, 19 Jul 2015 22:32:58 -0400 Received: from mail-pd0-f173.google.com ([209.85.192.173]:36195 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753780AbbGTCcm (ORCPT ); Sun, 19 Jul 2015 22:32:42 -0400 From: Olof Johansson To: will.deacon@arm.com, catalin.marinas@arm.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ingo Molnar , Olof Johansson , Dave Hansen Subject: [PATCH] arm64: Minor refactoring of cpu_switch_to() to fix build breakage Date: Sun, 19 Jul 2015 19:29:37 -0700 Message-Id: <1437359377-39932-1-git-send-email-olof@lixom.net> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 0c8c0f03e3a2 ("x86/fpu, sched: Dynamically allocate 'struct fpu'") moved the thread_struct to the bottom of task_struct. As a result, the offset is now too large to be used in an immediate add on arm64 with some kernel configs: arch/arm64/kernel/entry.S: Assembler messages: arch/arm64/kernel/entry.S:588: Error: immediate out of range arch/arm64/kernel/entry.S:597: Error: immediate out of range There's really no reason for cpu_switch_to to take a task_struct pointer in the first place, since all it does is access the thread.cpu_context member. So, just pass that in directly. Fixes: 0c8c0f03e3a2 ("x86/fpu, sched: Dynamically allocate 'struct fpu'") Cc: Dave Hansen Signed-off-by: Olof Johansson --- arch/arm64/include/asm/processor.h | 4 ++-- arch/arm64/kernel/asm-offsets.c | 2 -- arch/arm64/kernel/entry.S | 34 ++++++++++++++++------------------ arch/arm64/kernel/process.c | 3 ++- 4 files changed, 20 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index e4c893e..ba90764 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -152,8 +152,8 @@ static inline void cpu_relax(void) #define cpu_relax_lowlatency() cpu_relax() /* Thread switching */ -extern struct task_struct *cpu_switch_to(struct task_struct *prev, - struct task_struct *next); +extern struct task_struct *cpu_switch_to(struct cpu_context *prev, + struct cpu_context *next); #define task_pt_regs(p) \ ((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1) diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index c99701a..c9e13f6 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -39,8 +39,6 @@ int main(void) DEFINE(TI_TASK, offsetof(struct thread_info, task)); DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); BLANK(); - DEFINE(THREAD_CPU_CONTEXT, offsetof(struct task_struct, thread.cpu_context)); - BLANK(); DEFINE(S_X0, offsetof(struct pt_regs, regs[0])); DEFINE(S_X1, offsetof(struct pt_regs, regs[1])); DEFINE(S_X2, offsetof(struct pt_regs, regs[2])); diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index f860bfd..2216326 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -579,29 +579,27 @@ ENDPROC(el0_irq) /* * Register switch for AArch64. The callee-saved registers need to be saved * and restored. On entry: - * x0 = previous task_struct (must be preserved across the switch) - * x1 = next task_struct + * x0 = previous cpu_context (must be preserved across the switch) + * x1 = next cpu_context * Previous and next are guaranteed not to be the same. * */ ENTRY(cpu_switch_to) - add x8, x0, #THREAD_CPU_CONTEXT mov x9, sp - stp x19, x20, [x8], #16 // store callee-saved registers - stp x21, x22, [x8], #16 - stp x23, x24, [x8], #16 - stp x25, x26, [x8], #16 - stp x27, x28, [x8], #16 - stp x29, x9, [x8], #16 - str lr, [x8] - add x8, x1, #THREAD_CPU_CONTEXT - ldp x19, x20, [x8], #16 // restore callee-saved registers - ldp x21, x22, [x8], #16 - ldp x23, x24, [x8], #16 - ldp x25, x26, [x8], #16 - ldp x27, x28, [x8], #16 - ldp x29, x9, [x8], #16 - ldr lr, [x8] + stp x19, x20, [x0], #16 // store callee-saved registers + stp x21, x22, [x0], #16 + stp x23, x24, [x0], #16 + stp x25, x26, [x0], #16 + stp x27, x28, [x0], #16 + stp x29, x9, [x0], #16 + str lr, [x0] + ldp x19, x20, [x1], #16 // restore callee-saved registers + ldp x21, x22, [x1], #16 + ldp x23, x24, [x1], #16 + ldp x25, x26, [x1], #16 + ldp x27, x28, [x1], #16 + ldp x29, x9, [x1], #16 + ldr lr, [x1] mov sp, x9 ret ENDPROC(cpu_switch_to) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 223b093..6b9a09c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -325,7 +325,8 @@ struct task_struct *__switch_to(struct task_struct *prev, dsb(ish); /* the actual thread switch */ - last = cpu_switch_to(prev, next); + last = cpu_switch_to(&prev->thread.cpu_context, + &next->thread.cpu_context); return last; } -- 1.7.10.4