[Devel] Re: [PATCH] c/r: enclose arch_setup_additional_pages() call between #ifdefs

[Oren Laadan]

Serge E. Hallyn wrote:
> Quoting Oren Laadan (orenl at cs.columbia.edu):
>> Invocation of arch_setup_additional_pages() should occur only for
>> those architectures that provide it:
>>
>> #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
>> ...
>> #endif
>>
>> Signed-off-by: Oren Laadan <orenl at cs.columbia.edu>
> 
> Acked-by: Serge Hallyn <serue at us.ibm.com>
> 
> (one query below)
> 
>> ---
>>  mm/mmap.c |   15 +++++++++++++--
>>  1 files changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/mmap.c b/mm/mmap.c
>> index 6aa606a..6aadf2e 100644
>> --- a/mm/mmap.c
>> +++ b/mm/mmap.c
>> @@ -2394,17 +2394,28 @@ int special_mapping_restore(struct ckpt_ctx *ctx,
>>  			    struct mm_struct *mm,
>>  			    struct ckpt_hdr_vma *h)
>>  {
>> +	int ret = 0;
>> +
>>  	/*
>>  	 * FIX:
>>  	 * Currently, we only handle VDSO/vsyscall special handling.
>>  	 * Even that, is very basic - call arch_setup_additional_pages
>>  	 * requiring the same mapping (start address) as before.
>>  	 */
>> +
>> +	if (h->vma_type != CKPT_VMA_VDSO)
>> +		return -EINVAL;
> 
> Well this really should just be a BUG_ON, right?  Since this only
> gets called for the VDSO restore_vma_ops.

Sure. Will fix and push.

Thanks,

Oren.

> 
>> +#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
>>  #if defined(CONFIG_X86_64) && defined(CONFIG_COMPAT)
> 
> (aside: I would have liked to make this more generic, but for reasons
> i never quite tracked down that didn't end up working, and x86 is the
> only one which defines compat_arch_setup_additional_pages())
> 
>>  	if (test_thread_flag(TIF_IA32))
>> -		return syscall32_setup_pages(NULL, h->vm_start, 0);
>> +		ret = syscall32_setup_pages(NULL, h->vm_start, 0);
>> +	else
>> +#endif
>> +	ret = arch_setup_additional_pages(NULL, h->vm_start, 0);
>>  #endif
>> -	return arch_setup_additional_pages(NULL, h->vm_start, 0);
>> +
>> +	return ret;
>>  }
>>  #else /* !CONFIG_CHECKPOINT */
>>  #define special_mapping_checkpoint NULL
>> -- 
>> 1.6.3.3
>>
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> 
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