Subject: Re: PS3: Strange issue with kexec and FreeBSD loader

From: Phileas Fogg <[email-masked]>
Date: Sat, 23 Feb 2013 00:53:16 +0100

Benjamin Herrenschmidt wrote:
> On Sat, 2013-02-23 at 00:41 +0100, Phileas Fogg wrote:
>> Benjamin Herrenschmidt wrote:
>>> On Fri, 2013-02-22 at 21:49 +0100, Phileas Fogg wrote:
>>>> i wanted to let you know that i tested your advice. And let me say, it's was a
>>>> damn good advice :) I can boot FreeBSD loader on Linux 3.8 now, no SHA256
>>>> checksum failures. And no panics with FreeBSD LiveCD anymore too.
>>>>
>>>> I just inserted hard_irq_disable() after each local_irq_disable() in
>>>> arch/powerpc/kernel/machine_kexec_64.c
>>>
>>> Awesome ! :-)
>>>
>>> Care to send a patch with a Signed-off-by: ?
>>
>> No problem, but as i said it was your idea how to fix the issue with kexec.
>> Anyways here is the patch which i tested on my PS3 console with Linux 3.8.
>> After applying this patch i can boot any Linux kernel starting with 2.6,
>> FreeBSD loader, FreeBSD LiveCD and my own tiny ELF kernels too.
>> Even OpenBSD bootloader starts now too :)
>> And i don't see any failed SHA256 checksums in the purgatory code.
>
> Thanks, but I still need the Signed-off-by: line before i can apply
> it :-) (legal...)
>
> Cheers,
> Ben.
>
>> regards
>>
>>   From c17cdf38dfe180b4a571827bb547aaf9b678cf29 Mon Sep 17 00:00:00 2001
>> From: Phileas Fogg <[email-masked]>
>> Date: Sat, 23 Feb 2013 00:32:19 +0100
>> Subject: [PATCH] kexec: disable hard IRQ before kexec
>>
>> Disable hard IRQ before kexec a new kernel image.
>> Not doing it can result in corrupted data in the memory segments
>> reserved for the new kernel.
>> ---
>>    arch/powerpc/kernel/machine_kexec_64.c | 3 +++
>>    1 file changed, 3 insertions(+)
>>
>> diff --git a/arch/powerpc/kernel/machine_kexec_64.c
>> b/arch/powerpc/kernel/machine_kexec_64.c
>> index 7206701..e08b9d0 100644
>> --- a/arch/powerpc/kernel/machine_kexec_64.c
>> +++ b/arch/powerpc/kernel/machine_kexec_64.c
>> @@ -162,6 +162,7 @@ static int kexec_all_irq_disabled = 0;
>>    static void kexec_smp_down(void *arg)
>>    {
>>    	local_irq_disable();
>> +	hard_irq_disable();
>>    	mb(); /* make sure our irqs are disabled before we say they are */
>>    	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
>>    	while(kexec_all_irq_disabled == 0)
>> @@ -244,6 +245,7 @@ static void kexec_prepare_cpus(void)
>>    	wake_offline_cpus();
>>    	smp_call_function(kexec_smp_down, NULL, /* wait */0);
>>    	local_irq_disable();
>> +	hard_irq_disable();
>>    	mb(); /* make sure IRQs are disabled before we say they are */
>>    	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
>>
>> @@ -281,6 +283,7 @@ static void kexec_prepare_cpus(void)
>>    	if (ppc_md.kexec_cpu_down)
>>    		ppc_md.kexec_cpu_down(0, 0);
>>    	local_irq_disable();
>> +	hard_irq_disable();
>>    }
>>
>>    #endif /* SMP */
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> [email-masked]
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>

Next attempt.

Signed-off-by: Phileas Fogg <[email-masked]>
---

 From c17cdf38dfe180b4a571827bb547aaf9b678cf29 Mon Sep 17 00:00:00 2001
From: Phileas Fogg <[email-masked]>
Date: Sat, 23 Feb 2013 00:32:19 +0100
Subject: [PATCH] kexec: disable hard IRQ before kexec

Disable hard IRQ before kexec a new kernel image.
Not doing it can result in corrupted data in the memory segments
reserved for the new kernel.
---
  arch/powerpc/kernel/machine_kexec_64.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kernel/machine_kexec_64.c 
b/arch/powerpc/kernel/machine_kexec_64.c
index 7206701..e08b9d0 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -162,6 +162,7 @@ static int kexec_all_irq_disabled = 0;
  static void kexec_smp_down(void *arg)
  {
  	local_irq_disable();
+	hard_irq_disable();
  	mb(); /* make sure our irqs are disabled before we say they are */
  	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
  	while(kexec_all_irq_disabled == 0)
@@ -244,6 +245,7 @@ static void kexec_prepare_cpus(void)
  	wake_offline_cpus();
  	smp_call_function(kexec_smp_down, NULL, /* wait */0);
  	local_irq_disable();
+	hard_irq_disable();
  	mb(); /* make sure IRQs are disabled before we say they are */
  	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;

@@ -281,6 +283,7 @@ static void kexec_prepare_cpus(void)
  	if (ppc_md.kexec_cpu_down)
  		ppc_md.kexec_cpu_down(0, 0);
  	local_irq_disable();
+	hard_irq_disable();
  }

  #endif /* SMP */
-- 
1.8.1.4