From patchwork Mon May 23 15:57:24 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Hofmann X-Patchwork-Id: 809212 Received: from smtp1.linux-foundation.org (smtp1.linux-foundation.org [140.211.169.13]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p4NG04ZH015625 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for ; Mon, 23 May 2011 16:00:29 GMT Received: from daredevil.linux-foundation.org (localhost [127.0.0.1]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p4NFvUdp015024; Mon, 23 May 2011 08:57:32 -0700 Received: from mxvs2.esa.t-systems.com (mxvs2.esa.t-systems.com [81.7.202.143]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p4NFvPMR015007 for ; Mon, 23 May 2011 08:57:27 -0700 Received: from unknown (HELO nl-exc-01.intra.local) ([82.210.235.24]) by mx.esa.t-systems.com with ESMTP; 23 May 2011 15:57:25 +0000 Received: from magrathea ([10.101.8.37]) by nl-exc-01.intra.local with Microsoft SMTPSVC(6.0.3790.3959); Mon, 23 May 2011 17:57:24 +0200 Date: Mon, 23 May 2011 16:57:24 +0100 (BST) From: Frank Hofmann To: Russell King - ARM Linux In-Reply-To: <20110523143216.GA14131@n2100.arm.linux.org.uk> Message-ID: References: <3DCE2F529B282E4B8F53D4D8AA406A07014FFE@008-AM1MPN1-022.mgdnok.nokia.com> <20110520113758.GA3141@arm.com> <201105210027.17159.rjw@sisk.pl> <20110523095232.GB2370@arm.com> <20110523143216.GA14131@n2100.arm.linux.org.uk> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 X-OriginalArrivalTime: 23 May 2011 15:57:24.0830 (UTC) FILETIME=[1BA6AFE0:01CC1962] Received-SPF: pass (localhost is always allowed.) X-Spam-Status: No, hits=-3.408 required=5 tests=AWL, BAYES_00, OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.21 Cc: Dave Martin , tuxonice-devel@tuxonice.net, Frank Hofmann , linux-pm@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org Subject: [linux-pm] [RFC PATCH v2] ARM hibernation / suspend-to-disk support code X-BeenThere: linux-pm@lists.linux-foundation.org X-Mailman-Version: 2.1.9 Precedence: list Reply-To: frank.hofmann@tomtom.com List-Id: Linux power management List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Mon, 23 May 2011 16:00:30 +0000 (UTC) On Mon, 23 May 2011, Russell King - ARM Linux wrote: > On Mon, May 23, 2011 at 02:37:19PM +0100, Frank Hofmann wrote: >> What I've found necessary to save/restore via swsusp_arch_suspend/resume >> are the SYSTEM_MODE and SVC_MODE registers. >> Yesterday, I had thought that cpu_init() resets SVC_MODE sufficiently but >> that doesn't seem to be the case, if I leave that out, resume-from-disk >> doesn't work anymore. > > You will be running in SVC mode, so the SVC mode registers are your > current register set. At some point you need to do an effective > "context switch" between the kernel doing the resume and the kernel > which was running. That involves restoring the saved register state. > > System mode on the other hand is unused by the kernel. > Ah, and I had it the other way round ... that's why. Thanks ! I've tried that, saving/restoring just CPSR/SPSR and the reg set - and that seems sufficient, works fine ! All this means that the basic code has again become smaller. Attached is a new version, integrating all the feedback so far: * save/restore only those parts of the register set that the kernel cannot reinitialize from scratch * take care of FIQ disable/enable bracketing * use traditional stmfd/ldmfd instead of push/pop * don't rely on thread state, current->active_mm, but use global &init_mm * dump arch_prepare_suspend (skipping ahead of Rafael's suggested fix) * ditch the vmlinux.lds changes as they're not needed What other outstanding things are there to address for this ? All the best, FrankH. diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 6b6786c..859dd86 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -198,6 +198,9 @@ config VECTORS_BASE config ARCH_HAS_CPU_IDLE_WAIT def_bool y +config ARCH_HIBERNATION_POSSIBLE + def_bool n + source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h index 5421d82..23e93a6 100644 --- a/arch/arm/include/asm/memory.h +++ b/arch/arm/include/asm/memory.h @@ -191,6 +191,7 @@ static inline void *phys_to_virt(unsigned long x) */ #define __pa(x) __virt_to_phys((unsigned long)(x)) #define __va(x) ((void *)__phys_to_virt((unsigned long)(x))) +#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x),0)) #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) /* diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index c9b00bb..541ac3a 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -36,6 +36,7 @@ obj-$(CONFIG_ARM_THUMBEE) += thumbee.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_ARM_UNWIND) += unwind.o obj-$(CONFIG_HAVE_TCM) += tcm.o +obj-$(CONFIG_HIBERNATION) += cpu.o swsusp.o obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 diff --git a/arch/arm/kernel/cpu.c b/arch/arm/kernel/cpu.c new file mode 100644 index 0000000..0f1c31f --- /dev/null +++ b/arch/arm/kernel/cpu.c @@ -0,0 +1,64 @@ +/* + * Hibernation support specific for ARM + * + * Derived from work on ARM hibernation support by: + * + * Ubuntu project, hibernation support for mach-dove + * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu) + * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.) + * https://lkml.org/lkml/2010/6/18/4 + * https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html + * https://patchwork.kernel.org/patch/96442/ + * + * Copyright (C) 2006 Rafael J. Wysocki + * + * License terms: GNU General Public License (GPL) version 2 + */ + +#include +#include +#include +#include + +extern const void __nosave_begin, __nosave_end; + +int pfn_is_nosave(unsigned long pfn) +{ + unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT; + unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT; + + return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn); +} + +void save_processor_state(void) +{ + flush_thread(); + local_fiq_disable(); +} + +void restore_processor_state(void) +{ + local_flush_tlb_all(); + local_fiq_enable(); +} + +u8 __swsusp_arch_ctx[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE))); +u8 __swsusp_resume_stk[PAGE_SIZE/2] __nosavedata; + +/* + * The framework loads the hibernation image into this linked list, + * for swsusp_arch_resume() to copy back to the proper destinations. + * + * To make this work if resume is triggered from initramfs, the + * pagetables need to be switched to allow writes to kernel mem. + */ +void notrace __swsusp_arch_restore_image(void) +{ + extern struct pbe *restore_pblist; + struct pbe *pbe; + + cpu_switch_mm(__virt_to_phys(swapper_pg_dir), &init_mm); + + for (pbe = restore_pblist; pbe; pbe = pbe->next) + copy_page(pbe->orig_address, pbe->address); +} diff --git a/arch/arm/kernel/swsusp.S b/arch/arm/kernel/swsusp.S new file mode 100644 index 0000000..1fc0e33 --- /dev/null +++ b/arch/arm/kernel/swsusp.S @@ -0,0 +1,72 @@ +/* + * Hibernation support specific for ARM + * + * Based on work by: + * + * Ubuntu project, hibernation support for mach-dove, + * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu) + * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.) + * https://lkml.org/lkml/2010/6/18/4 + * https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html + * https://patchwork.kernel.org/patch/96442/ + * + * Copyright (C) 2006 Rafael J. Wysocki + * + * License terms: GNU General Public License (GPL) version 2 + */ + +#include +#include +#include + +/* + * Save the current CPU state before suspend / poweroff. + */ +ENTRY(swsusp_arch_suspend) + ldr r0, =__swsusp_arch_ctx + mrs r1, cpsr + mrs r2, spsr + stmia r0!, {r1-r11,lr} @ CPSR, SPSR, nonvolatile regs + str sp, [r0], #4 @ stack + stmfd sp!, {lr} + bl __save_processor_state @ machine-specific state + ldmfd sp!, {lr} + b swsusp_save @ let framework write snapshot out +ENDPROC(swsusp_arch_suspend) + +/* + * Restore the memory image from the pagelists, and load the CPU registers + * from saved state. + */ +ENTRY(swsusp_arch_resume) + /* + * Switch stack to a nosavedata region to make sure image restore + * doesn't clobber it underneath itself. + */ + ldr sp, =(__swsusp_resume_stk + PAGE_SIZE / 2) + bl __swsusp_arch_restore_image + + /* + * Restore the CPU registers. + */ + ldr r0, =__swsusp_arch_ctx + ldmia r0!, {r1,r2} @ CPSR / SPSR + msr cpsr, r1 + msr spsr, r2 + ldr r0, =__swsusp_arch_ctx @ reload in case regset switched + ldmia r0!, {r1-r11,lr} @ nonvolatile regs + ldr sp, [r0], #4 @ stack + + /* + * From here on we have a valid stack again. Core state is + * not restored yet, redirect to the machine-specific + * implementation to get that done. + * Resume has succeeded at this point; if the machine-specific + * code wants to fail it needs to panic. + */ + mov r1, #0 + stmfd sp!, {r1,lr} + bl __restore_processor_state @ machine-specific state + bl cpu_init @ reinitialize other modes + ldmfd sp!, {r0,pc} +ENDPROC(swsusp_arch_resume)