From: james.morse@arm•com (James Morse)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v7 15/16] arm64: kernel: Add support for hibernate/suspend-to-disk
Date: Mon, 25 Apr 2016 10:19:11 +0100 [thread overview]
Message-ID: <571DE10F.10905@arm.com> (raw)
In-Reply-To: <20160422102954.GB2998@e104818-lin.cambridge.arm.com>
Hi Catalin,
Thanks for your comments,
On 22/04/16 11:29, Catalin Marinas wrote:
> On Fri, Apr 01, 2016 at 05:53:39PM +0100, James Morse wrote:
>> --- /dev/null
>> +++ b/arch/arm64/kernel/hibernate-asm.S
>> + copy_page x0, x1, x2, x3, x4, x5, x6, x7, x8, x9
>> +
>> + add x1, x10, #PAGE_SIZE
>> + /* Clean the copied page to PoU - based on flush_icache_range() */
>> + dcache_line_size x2, x3
>> + sub x3, x2, #1
>> + bic x4, x10, x3
>> +2: dc cvau, x4 /* clean D line / unified line */
>> + add x4, x4, x2
>> + cmp x4, x1
>> + b.lo 2b
>> +
>> + ldr x19, [x19, #HIBERN_PBE_NEXT]
>> + cbnz x19, 1b
>> +
>> +
>> + /* switch to the restored kernels page tables, to reconfigure el2 */
>> + msr ttbr1_el1, x21 /* physical address of swapper page tables */
>> + isb
>> + tlbi vmalle1is /* invalidate intermediate caching entries */
>> + ic ialluis
>> + dsb ish /* also waits for PoU cleaning to finish */
>> + isb
>
> The waiting for PoU cleaning needs to happen before the IC instruction.
Done, to check I understand why:
The 'ic ialluis' may finish before the PoU cleaning, sharing a barrier means in
this case we may speculatively load stale values back into the icache while we
wait for the cleaning to finish.
[ ... ]
>> +
>> + /* Load our new page tables */
>> + asm volatile("msr ttbr0_el1, %0;"
>> + "isb;"
>> + "tlbi vmalle1is;"
>> + "dsb ish" : : "r"(virt_to_phys(pgd)));
>
> Do we expect anything to have used ttbr0_el1 at this point?
EFI for the virt_efi_get_time() call when we setup the rtc. There may also be
device drivers out there that try to load firmware before the
late_initcall_sync() call that triggers resume.
[ ... ]
>> +int swsusp_arch_suspend(void)
>> +{
>> + int ret = 0;
>> + unsigned long flags;
>> + struct sleep_stack_data state;
>> +
>> + local_dbg_save(flags);
>> +
>> + if (__cpu_suspend_enter(&state)) {
>> + ret = swsusp_save();
>> + } else {
>> + void *lm_kernel_start;
>> +
>> + /* Clean kernel to PoC for secondary core startup */
>> + lm_kernel_start = LMADDR(KERNEL_START);
>> + __flush_dcache_area(lm_kernel_start, KERNEL_END - KERNEL_START);
>
> We don't need to use LMADDR here. The KERNEL_START is already mapped at
> the caches are PIPT (-like), so flushing any of the aliases would do.
With kaslr the range KERNEL_START -> KERNEL_END has holes in it. I think this is
where the __init text or alternatives used to be. Cleaning the corresponding
range in the linear map avoids the fault...
> But I'm not sure we even need to flush the whole kernel. The secondary
> cores would only execute certain areas before they enable the MMU, at
> which point they have visibility over the whole cache. Is this needed
> for secondary core startup on resume from hibernate?
I haven't hit this as an issue, but I think its needed for any mmu-off code.
The list is:
* secondary startup after resume
* hyp-stub and kvm's el2-init code,
* and cpu_resume() (if a core goes into idle soon after resume).
I agree cleaning the whole kernel is excessive. I guess the right thing to do is
to collect all these functions into a single section and clean that.
[ ... ]
Thanks for the detailed comments!
James
next prev parent reply other threads:[~2016-04-25 9:19 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 16:53 [PATCH v7 00/16] arm64: kernel: Add support for hibernate/suspend-to-disk James Morse
2016-04-01 16:53 ` [PATCH v7 01/16] arm64: KVM: Register CPU notifiers when the kernel runs at HYP James Morse
2016-04-18 16:10 ` Catalin Marinas
2016-04-19 8:58 ` James Morse
2016-04-19 14:39 ` Marc Zyngier
2016-04-01 16:53 ` [PATCH v7 02/16] arm64: Fold proc-macros.S into assembler.h James Morse
2016-04-18 16:11 ` Catalin Marinas
2016-04-01 16:53 ` [PATCH v7 03/16] arm64: Cleanup SCTLR flags James Morse
2016-04-19 14:44 ` Marc Zyngier
2016-04-01 16:53 ` [PATCH v7 04/16] arm64: kvm: Move the do_el2_call macro to a header file James Morse
2016-04-19 15:02 ` Marc Zyngier
2016-04-19 15:05 ` James Morse
2016-04-19 15:10 ` Marc Zyngier
2016-04-01 16:53 ` [PATCH v7 05/16] arm64: kvm: Move lr save/restore from do_el2_call into EL1 James Morse
2016-04-19 15:11 ` Marc Zyngier
2016-04-01 16:53 ` [PATCH v7 06/16] arm64: hyp/kvm: Extend hyp-stub API to allow function calls at EL2 James Morse
2016-04-19 15:22 ` Marc Zyngier
2016-04-01 16:53 ` [PATCH v7 07/16] arm64: kvm: allows kvm cpu hotplug James Morse
2016-04-19 16:03 ` Marc Zyngier
2016-04-19 17:37 ` James Morse
2016-04-20 10:29 ` AKASHI Takahiro
2016-04-20 11:19 ` James Morse
2016-04-20 10:37 ` Marc Zyngier
2016-04-20 11:19 ` James Morse
2016-04-20 11:46 ` Marc Zyngier
2016-04-25 8:41 ` AKASHI Takahiro
2016-04-25 9:16 ` James Morse
2016-04-25 9:28 ` Marc Zyngier
2016-04-01 16:53 ` [PATCH v7 08/16] arm64: kernel: Rework finisher callback out of __cpu_suspend_enter() James Morse
2016-04-18 17:20 ` Catalin Marinas
2016-04-01 16:53 ` [PATCH v7 09/16] arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va James Morse
2016-04-20 16:24 ` Catalin Marinas
2016-04-01 16:53 ` [PATCH v7 10/16] arm64: kernel: Include _AC definition in page.h James Morse
2016-04-20 16:25 ` Catalin Marinas
2016-04-01 16:53 ` [PATCH v7 11/16] arm64: Promote KERNEL_START/KERNEL_END definitions to a header file James Morse
2016-04-20 16:26 ` Catalin Marinas
2016-04-01 16:53 ` [PATCH v7 12/16] arm64: Add new asm macro copy_page James Morse
2016-04-20 16:38 ` Catalin Marinas
2016-04-20 16:56 ` James Morse
2016-04-01 16:53 ` [PATCH v7 13/16] arm64: head.S: el2_setup() to accept sctlr_el1 as an argument James Morse
2016-04-20 17:12 ` Catalin Marinas
2016-04-20 17:35 ` James Morse
2016-04-22 10:36 ` Catalin Marinas
2016-04-01 16:53 ` [PATCH v7 14/16] PM / Hibernate: Call flush_icache_range() on pages restored in-place James Morse
2016-04-20 17:16 ` Catalin Marinas
2016-04-01 16:53 ` [PATCH v7 15/16] arm64: kernel: Add support for hibernate/suspend-to-disk James Morse
2016-04-22 10:29 ` Catalin Marinas
2016-04-25 9:19 ` James Morse [this message]
2016-04-01 16:53 ` [PATCH v7 16/16] arm64: hibernate: Prevent resume from a different kernel version James Morse
2016-04-10 12:16 ` Ard Biesheuvel
2016-04-13 16:35 ` James Morse
2016-04-13 16:31 ` [PATCH v7 17/16] arm64: hibernate: Refuse to hibernate if the boot cpu is offline James Morse
2016-04-21 11:33 ` Lorenzo Pieralisi
2016-04-21 11:44 ` Mark Rutland
2016-04-21 12:33 ` Mark Rutland
2016-04-21 16:28 ` Lorenzo Pieralisi
2016-04-22 10:41 ` Mark Rutland
2016-04-22 15:32 ` James Morse
2016-04-22 10:41 ` Catalin Marinas
2016-04-22 15:32 ` James Morse
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