From: m-karicheri2@ti•com (Murali Karicheri)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: keystone: add a work around to handle asynchronous external abort
Date: Mon, 17 Aug 2015 10:11:11 -0400 [thread overview]
Message-ID: <55D1EB7F.4030905@ti.com> (raw)
In-Reply-To: <1439561519.13210.55.camel@pengutronix.de>
On 08/14/2015 10:11 AM, Lucas Stach wrote:
> Am Freitag, den 14.08.2015, 10:04 -0400 schrieb Murali Karicheri:
>> On 08/11/2015 03:13 PM, Murali Karicheri wrote:
>>> Currently on some devices, an asynchronous external abort exception
>>> happens during boot up when exception handlers are enabled in kernel
>>> before switching to user space. This patch adds a workaround to handle
>>> this once during boot. Many customers are already using this
>>> with out any issues and is required to workaround the above issue.
>>>
>>> Signed-off-by: Murali Karicheri <m-karicheri2@ti•com>
>>> ---
>>> arch/arm/mach-keystone/keystone.c | 26 ++++++++++++++++++++++++++
>>> 1 file changed, 26 insertions(+)
>>>
>>> diff --git a/arch/arm/mach-keystone/keystone.c b/arch/arm/mach-keystone/keystone.c
>>> index e2880105..c1d0fe5 100644
>>> --- a/arch/arm/mach-keystone/keystone.c
>>> +++ b/arch/arm/mach-keystone/keystone.c
>>> @@ -15,6 +15,7 @@
>>> #include <linux/of_platform.h>
>>> #include <linux/of_address.h>
>>> #include <linux/memblock.h>
>>> +#include <linux/signal.h>
>>>
>>> #include <asm/setup.h>
>>> #include <asm/mach/map.h>
>>> @@ -52,6 +53,24 @@ static struct notifier_block platform_nb = {
>>> .notifier_call = keystone_platform_notifier,
>>> };
>>>
>>> +static bool ignore_first = true;
>>> +static int keystone_async_ext_abort_fault(unsigned long addr, unsigned int fsr,
>>> + struct pt_regs *regs)
>>> +{
>>> + /*
>>> + * if first time, ignore this as this is a asynchronous external abort
>>> + * happening only some devices that couldn't be root caused and we add
>>> + * this work around to handle this first time.
>>> + */
>>> + if (ignore_first) {
>>> + ignore_first = false;
>>> + return 0;
>>> + }
>>> +
>>> + /* Subsequent ones should be handled as fault */
>>> + return 1;
>>> +}
>>> +
>>> static void __init keystone_init(void)
>>> {
>>> if (PHYS_OFFSET >= KEYSTONE_HIGH_PHYS_START) {
>>> @@ -61,6 +80,13 @@ static void __init keystone_init(void)
>>> }
>>> keystone_pm_runtime_init();
>>> of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
>>> +
>>> + /*
>>> + * Add a one time exception handler to catch asynchronous external
>>> + * abort
>>> + */
>>> + hook_fault_code(17, keystone_async_ext_abort_fault, SIGBUS, 0,
>>> + "async external abort handler");
>>> }
>>>
>>> static phys_addr_t keystone_virt_to_idmap(unsigned long x)
>>>
>> Can this be applied if it looks good?
>>
> The keystone PCIe host driver already hooks the same fault code. Those
> hooks are no chain, but a simple pointer, so one of those handlers is
> going to loose out.
>
> This likely isn't what you intended.
You are right. I will try to debug this further based on your patch and
as per RMK's suggestion.
Thanks and regards,
Murali
>
> Regards,
> Lucas
>
--
Murali Karicheri
Linux Kernel, Keystone
prev parent reply other threads:[~2015-08-17 14:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-11 19:13 [PATCH] ARM: keystone: add a work around to handle asynchronous external abort Murali Karicheri
2015-08-14 14:04 ` Murali Karicheri
2015-08-14 14:09 ` Russell King - ARM Linux
2015-08-14 14:20 ` Lucas Stach
2015-08-14 21:55 ` Murali Karicheri
2015-08-14 21:56 ` Russell King - ARM Linux
2015-08-17 14:09 ` Murali Karicheri
2015-08-14 15:14 ` santosh shilimkar
2015-08-14 21:53 ` Murali Karicheri
2015-08-14 21:56 ` Russell King - ARM Linux
2015-08-17 22:12 ` Murali Karicheri
2015-08-17 22:47 ` Russell King - ARM Linux
2015-08-18 3:09 ` santosh.shilimkar at oracle.com
2015-08-18 8:13 ` Russell King - ARM Linux
2015-08-18 8:28 ` Lucas Stach
2015-08-18 12:06 ` Afzal Mohammed
2015-08-18 8:28 ` Jisheng Zhang
2015-08-18 14:49 ` Murali Karicheri
2015-08-18 20:25 ` Murali Karicheri
2015-08-15 0:01 ` santosh.shilimkar at oracle.com
2015-08-14 14:11 ` Lucas Stach
2015-08-17 14:11 ` Murali Karicheri [this message]
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