From: achandran@mvista.com (Arun Chandran)
To: linux-arm-kernel@lists.infradead.org
Subject: Kexec on arm64
Date: Fri, 25 Jul 2014 17:18:04 +0530 [thread overview]
Message-ID: <CAFdej01w_pE6vv+13cCCyfDs4Rbdkzx4CMUj9q97HBKV0B53ow@mail.gmail.com> (raw)
In-Reply-To: <1406247468.4062.59.camel@smoke>
Hi Geoff,
On Fri, Jul 25, 2014 at 5:47 AM, Geoff Levand <geoff@infradead.org> wrote:
> Hi,
>
> On Thu, 2014-07-24 at 10:36 +0100, Mark Rutland wrote:
>> On Thu, Jul 24, 2014 at 01:38:07AM +0100, Geoff Levand wrote:
>
>> > All memory management for the main cpu is done by the arch code. Kexec
>> > and cpu hot plug only work with the secondary cpus, so the problem would
>> > be in the arch memory code, either in setup_restart() for shutdown, or
>> > in the startup code.
>>
>> It's possible that soft_restart and setup_restart are a little dodgy, as
>> they also rely on the compiler being smart and not touching the stack
>> after setup_restart().
>>
>> However, they provide absolutely no guarantee that any data has been
>> flushed out to the PoC [1]. If you require any data to be flushed out to the
>> PoC so as to be visible to noncacheable accesses, you will need to
>> ensure that this is flushed by VA before soft_restart is called. Data
>> may have migrated to another cache (e.g. another CPU, or the L3) where
>> it is not visible.
>
> OK, kexec's reset routine relocate_new_kernel does use a few global
> variables that are set by the main kexec routines. I added a call to
> __flush_dcache_area(), which uses 'dc civac' for those.
>
> I had thought the call to __flush_dcache_all, which uses 'dc cisw', in
> flush_cache_all() would be enough.
>
> Arun, I also fixed UP builds. Could you pull my latest and try with L3
> enabled?
>
I got this working. As 'Mark Rutland' pointed in another mail that
it could be problem with flushing the cache; I did a read of
1GB data from start of RAM to a volatile var. I assume that
this will clear and invalidate all that in cache (L1=32K, L2=256 K, L3=8M)
###################
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 786daa6..90418f3 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -63,6 +63,10 @@ static inline void smp_secondary_shutdown(void) {}
static void setup_restart(void)
{
+ volatile u64 tmp;
+ volatile u64 *addr;
+
+ addr = (u64 *)(0xffffffc000000000);
/*
* Tell the mm system that we are going to reboot -
* we may need it to insert some 1:1 mappings so that
@@ -75,6 +79,11 @@ static void setup_restart(void)
/* Clean and invalidate caches */
flush_cache_all();
+ for ( ;addr < (u64 *)0xffffffc040000000; addr++)
+ {
+ tmp = *addr;
+ }
+
/* Turn D-cache off */
cpu_cache_off();
###################
With the above change latest kernel @
https://git.linaro.org/people/geoff.levand/linux-kexec.git
is able to do kexec with L3 enabled in UP scenario.
--Arun
> -Geoff
>
next prev parent reply other threads:[~2014-07-25 11:48 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAFdej006OSyhgDcJ2iZdbjt+PtysN=i_+9Dr4GTmr=+t5yg4Kw@mail.gmail.com>
2014-07-15 17:04 ` Kexec on arm64 Geoff Levand
2014-07-16 17:57 ` Feng Kan
2014-07-16 23:04 ` Geoff Levand
2014-07-22 9:44 ` Arun Chandran
2014-07-22 13:25 ` Arun Chandran
2014-07-24 0:38 ` Geoff Levand
2014-07-24 9:36 ` Mark Rutland
2014-07-24 12:49 ` Arun Chandran
2014-07-25 0:17 ` Geoff Levand
2014-07-25 10:31 ` Arun Chandran
2014-07-25 10:36 ` Mark Rutland
2014-07-25 11:48 ` Arun Chandran [this message]
2014-07-25 12:14 ` Mark Rutland
2014-07-25 15:29 ` Arun Chandran
2014-07-26 0:18 ` Geoff Levand
2014-07-28 15:00 ` Arun Chandran
2014-07-28 15:38 ` Mark Rutland
2014-07-29 0:09 ` Geoff Levand
2014-07-29 9:10 ` Mark Rutland
2014-07-29 12:32 ` Arun Chandran
2014-07-29 13:35 ` Mark Rutland
2014-07-29 21:19 ` Geoff Levand
2014-07-30 7:22 ` Arun Chandran
2014-08-01 11:13 ` Arun Chandran
2014-08-03 14:47 ` Mark Rutland
2014-08-04 10:16 ` Arun Chandran
2014-08-04 11:35 ` Mark Rutland
2014-08-07 0:40 ` Geoff Levand
2014-08-07 9:59 ` Mark Rutland
2014-08-07 17:09 ` Geoff Levand
2014-08-04 17:21 ` Geoff Levand
2014-08-06 13:54 ` Arun Chandran
2014-08-06 15:51 ` Arun Chandran
2014-08-07 20:07 ` Geoff Levand
2014-08-08 5:46 ` Arun Chandran
2014-08-08 10:03 ` Arun Chandran
2014-08-12 5:42 ` Arun Chandran
2014-08-13 11:09 ` Arun Chandran
2014-08-26 22:32 ` Geoff Levand
2014-08-27 4:56 ` Arun Chandran
2014-07-30 5:46 ` Arun Chandran
2014-07-30 9:16 ` Mark Rutland
2014-07-30 7:01 ` Arun Chandran
2014-07-25 10:26 ` Arun Chandran
2014-07-25 11:29 ` Mark Rutland
2014-07-24 11:50 ` Arun Chandran
2014-07-30 3:26 ` Feng Kan
2014-07-24 0:10 ` Geoff Levand
2014-07-24 9:13 ` Mark Rutland
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