From: geoff@infradead.org (Geoff Levand)
To: linux-arm-kernel@lists.infradead.org
Subject: Kexec on arm64
Date: Mon, 28 Jul 2014 17:09:08 -0700 [thread overview]
Message-ID: <1406592548.28348.49.camel@smoke> (raw)
In-Reply-To: <20140728153812.GA2576@leverpostej>
Hi,
On Mon, 2014-07-28 at 16:38 +0100, Mark Rutland wrote:
> On Mon, Jul 28, 2014 at 04:00:18PM +0100, Arun Chandran wrote:
> > I have these changes to the code.
> > flush_icache_range((unsigned long)reboot_code_buffer,
> > - relocate_new_kernel_size);
> > + (unsigned long)(reboot_code_buffer + relocate_new_kernel_size));
Thanks, I introduced this in my last version in an attempt to clean up
the code, but on studying setup_restart(), I wonder if we even need to
do this icache flush here (see below).
> > /*
> > * Flush any data used by relocate_new_kernel in preparation for
> > #########
> > Passing of second variable to flush_icache_range() is wrong
> > it expects an address not length.
>
> A simpler option would be to nuke the entire icache before branching to
> the new image.
flush_cache_all(), which is called by setup_restart(), does a 'ic
ialluis'. The ARM says that this will invalidate all instruction caches
for the inner shareable domain. Do we need something more?
> > 2)
> >
> > #######
> > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> > index 9ed7327..e3fc8d6 100644
> > --- a/arch/arm64/kernel/process.c
> > +++ b/arch/arm64/kernel/process.c
> >
> > @@ -84,12 +91,17 @@ void soft_restart(unsigned long addr)
> > {
> > typedef void (*phys_reset_t)(unsigned long);
> > phys_reset_t phys_reset;
> > + unsigned long jump_addr = addr;
> > +
> > + phys_reset = (phys_reset_t)virt_to_phys(cpu_reset);
> > +
> > + __flush_dcache_area(&jump_addr, 8);
> > + __flush_dcache_area(&phys_reset, 8);
>
> Are these values really not getting stashed in registers?
Looking at the disassembled code of soft_restart() from my compiler,
addr is being saved on the stack over the call to setup_restart(), which
I would expect it to do.
> If the compiler is spilling, then we have absolutely no guarantee about
> any part of the stack. If that's the case, then we can't use the stack
> at all. These need to be rewritten in asm if the compiler is spilling.
I think we just need to put the restart addr in a variable and flush
that to the PoC.
Arun, I pushed out a fixed version of soft_restart(), so please try
another UP + L3 boot.
-Geoff
next prev parent reply other threads:[~2014-07-29 0:09 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
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 [this message]
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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