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Subject: Re: [RFC V2] mm: Generalize notify_page_fault()
References: <1559630046-12940-1-git-send-email-anshuman.khandual@arm.com>
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From: Anshuman Khandual <anshuman.khandual@arm.com>
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Date: Tue, 4 Jun 2019 13:42:10 +0530
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To: Peter Zijlstra <peterz@infradead.org>
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On 06/04/2019 12:24 PM, Peter Zijlstra wrote:
> On Tue, Jun 04, 2019 at 12:04:06PM +0530, Anshuman Khandual wrote:
>> diff --git a/mm/memory.c b/mm/memory.c
>> index ddf20bd..b6bae8f 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -52,6 +52,7 @@
>>  #include <linux/pagemap.h>
>>  #include <linux/memremap.h>
>>  #include <linux/ksm.h>
>> +#include <linux/kprobes.h>
>>  #include <linux/rmap.h>
>>  #include <linux/export.h>
>>  #include <linux/delayacct.h>
>> @@ -141,6 +142,21 @@ static int __init init_zero_pfn(void)
>>  core_initcall(init_zero_pfn);
>>  
>>  
>> +int __kprobes notify_page_fault(struct pt_regs *regs, unsigned int trap)
>> +{
>> +	int ret = 0;
>> +
>> +	/*
>> +	 * To be potentially processing a kprobe fault and to be allowed
>> +	 * to call kprobe_running(), we have to be non-preemptible.
>> +	 */
>> +	if (kprobes_built_in() && !preemptible() && !user_mode(regs)) {
>> +		if (kprobe_running() && kprobe_fault_handler(regs, trap))
>> +			ret = 1;
>> +	}
>> +	return ret;
>> +}
> 
> That thing should be called kprobe_page_fault() or something,
> notify_page_fault() is a horribly crap name for this function.

Agreed. kprobe_page_fault() sounds good.