Hi Tyler,
On 16/01/17 11:53, Will Deacon wrote:
> On Thu, Jan 12, 2017 at 11:15:18AM -0700, Tyler Baicar wrote:
>> SEA exceptions are often caused by an uncorrected hardware
>> error, and are handled when data abort and instruction abort
>> exception classes have specific values for their Fault Status
>> Code.
>> When SEA occurs, before killing the process, go through
>> the handlers registered in the notification list.
>> Update fault_info[] with specific SEA faults so that the
>> new SEA handler is used.
>> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
>> index 05d2bd7..81039c7 100644
>> --- a/arch/arm64/mm/fault.c
>> +++ b/arch/arm64/mm/fault.c
>> @@ -480,6 +496,28 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
>> return 1;
>> }
>>
>> +/*
>> + * This abort handler deals with Synchronous External Abort.
>> + * It calls notifiers, and then returns "fault".
>> + */
>> +static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
>> +{
>> + struct siginfo info;
>> +
>> + atomic_notifier_call_chain(&sea_handler_chain, 0, NULL);
>> +
>> + pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
>> + fault_name(esr), esr, addr);
>> +
>> + info.si_signo = SIGBUS;
>> + info.si_errno = 0;
>> + info.si_code = 0;
>> + info.si_addr = (void __user *)addr;
>> + arm64_notify_die("", regs, &info, esr);
>> +
>> + return 0;
>> +}
>> +
>> static const struct fault_info {
>> int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
>> int sig;
>> @@ -502,22 +540,22 @@ static const struct fault_info {
>> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" },
>> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" },
>> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" },
>> - { do_bad, SIGBUS, 0, "synchronous external abort" },
>> + { do_sea, SIGBUS, 0, "synchronous external abort" },
>> { do_bad, SIGBUS, 0, "unknown 17" },
>> { do_bad, SIGBUS, 0, "unknown 18" },
>> { do_bad, SIGBUS, 0, "unknown 19" },
>> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
>> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
>> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
>> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
>> - { do_bad, SIGBUS, 0, "synchronous parity error" },
>> + { do_sea, SIGBUS, 0, "level 0 SEA (translation table walk)" },
>> + { do_sea, SIGBUS, 0, "level 1 SEA (translation table walk)" },
>> + { do_sea, SIGBUS, 0, "level 2 SEA (translation table walk)" },
>> + { do_sea, SIGBUS, 0, "level 3 SEA (translation table walk)" },
>
> Perhaps I wasn't clear enough in my previous review, but please expand the
> acronym for strings and comments.
The 'SEA' in this user-string doesn't add anything. Now that these use do_sea()
instead of do_bad(), when they are printed won't it be:
> Synchronous External Abort: level 3 SEA (translation table walk) (...) at ....
Thanks,
James
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