Kexec on arm64

[Arun Chandran]

On Wed, Jul 30, 2014 at 2:49 AM, Geoff Levand <geoff at infradead.org> wrote:
> Hi Mark,
>
> On Tue, 2014-07-29 at 14:35 +0100, Mark Rutland wrote:
>> Since c218bca74eea (arm64: Relax the kernel cache requirements for
>> boot), the kernel will flush the cache for anything outside of the Image
>> that it writes to before enabling the MMU and caches (e.g. the idmap and
>> swapper page tables). Once caches are up we shouldn't care.
>>
>> Assuming that the existing kernel code is correct, the only region we
>> should need to flush out to the PoC is the region from _text to _edata
>> (i.e. just the contents of the Image).
>
> If the new kernel will overwrite the old one, then we do the final copy
> of the new kernel in the relocate_new_kernel routine.  relocate_new_kernel
> is executed after the dcache is disabled, so that should write it directly
> to the PoC.  It seems the protocol expects us to invalidate the dcache
> for that range though, so I added code to do this, essentially what Arun
> had added.
>
> Arun, please try.
>
It works without any hiccups :)..
I have attached the log.

I will try with big-endian UP configuration next.

Just had to comment the crashdump code to compile with
defconfig.

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 233cd04..6f4ebd8 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -377,6 +377,7 @@ static void __init __maybe_unused reserve_crashkernel(void)
        insert_resource(&iomem_resource, &crashk_res);
 }

+#ifdef CONFIG_CRASH_DUMP
 static void __init __maybe_unused reserve_elfcorehdr(void)
 {
        struct resource res;
@@ -402,6 +403,7 @@ static void __init __maybe_unused reserve_elfcorehdr(void)
        res.end = elfcorehdr_addr + elfcorehdr_size - 1;
        insert_resource(&iomem_resource, &res);
 }
+#endif

 static void __init request_standard_resources(void)
 {

--Arun
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