From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Subject: Re: [PATCH v2 10/11] PM / Hibernate: clean cached pages on
 architectures that require it
Date: Wed, 11 Nov 2015 11:40:39 +0000
Message-ID: <20151111114039.GA8375@red-moon>
References: <1445966960-31724-1-git-send-email-james.morse@arm.com>
 <1445966960-31724-11-git-send-email-james.morse@arm.com>
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To: James Morse <james.morse@arm.com>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Pavel Machek <pavel@ucw.cz>
Cc: linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, Will Deacon <will.deacon@arm.com>, Sudeep Holla <sudeep.holla@arm.com>, Kevin Kang <kkang@intrinsyc.com>, Geoff Levand <geoff@infradead.org>, Catalin Marinas <catalin.marinas@arm.com>, Mark Rutland <mark.rutland@arm.com>, AKASHI Takahiro <takahiro.akashi@linaro.org>, wangfei <w.f@huawei.com>, Marc Zyngier <marc.zyngier@arm.com>

Hi Pavel, Rafael,

Do you have any feedback on this patch ?

It is fundamental to this series and affects Hibernate core code so if you
have any feedback that would be much appreciated.

Thanks a lot,
Lorenzo

On Tue, Oct 27, 2015 at 05:29:19PM +0000, James Morse wrote:
> Some architectures require code written to memory as if it were data to be
> 'cleaned' from any data caches so that the processor can fetch them as new
> instructions.
> 
> During resume from hibernate, the snapshot code copies some pages directly,
> meaning these architectures do not get a chance to perform their cache
> maintenance. Add a call to flush_icache_range(), which is provided by
> architectures that require it, to perform the maintenance.
> 
> This mirrors the kernel's behaviour when loading kernel modules and when
> mapping executable pages to user space.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>  kernel/power/snapshot.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
> index 5235dd4e1e2f..139fc449ad75 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -31,6 +31,7 @@
>  #include <linux/ktime.h>
>  
>  #include <asm/uaccess.h>
> +#include <asm/cacheflush.h>
>  #include <asm/mmu_context.h>
>  #include <asm/pgtable.h>
>  #include <asm/tlbflush.h>
> @@ -1196,9 +1197,12 @@ static unsigned int count_data_pages(void)
>  static inline void do_copy_page(long *dst, long *src)
>  {
>  	int n;
> +	unsigned long __maybe_unused start = (unsigned long)dst;
>  
>  	for (n = PAGE_SIZE / sizeof(long); n; n--)
>  		*dst++ = *src++;
> +
> +	flush_icache_range(start, start+PAGE_SIZE);
>  }
>  
>  
> -- 
> 2.1.4
>