Re: mp_machdep.c (was Re: [Fwd: Re: Bug reports requested - acpi])

John Baldwin:

>On Tuesday 21 September 2004 12:27 pm, Roman Kurakin wrote:
>  
>
>>My solution works for current so I am going to commit it and MFC after
>>a while. To be sure that I am not on the wrong way I need some
>>reviewed/approved signs ;-) I also hope to get one (or more) tested signs.
>>
>>Patch I plan to commit following patch:
>>
>>Index: mp_machdep.c
>>===================================================================
>>RCS file: /home/ncvs/src/sys/i386/i386/mp_machdep.c,v
>>retrieving revision 1.238
>>diff -u -r1.238 mp_machdep.c
>>--- mp_machdep.c        1 Sep 2004 06:42:01 -0000       1.238
>>+++ mp_machdep.c        21 Sep 2004 15:54:41 -0000
>>_at__at_ -743,10 +743,11 _at__at_
>>        u_int8_t *dst8;
>>        u_int16_t *dst16;
>>        u_int32_t *dst32;
>>+       vm_offset_t va = (vm_offset_t) dst;
>>
>>        POSTCODE(INSTALL_AP_TRAMP_POST);
>>
>>-       pmap_kenter(boot_address + KERNBASE, boot_address);
>>+       pmap_map(&va, boot_address, boot_address + size, 0);
>>        for (x = 0; x < size; ++x)
>>                *dst++ = *src++;
>>
>>Any signs for(or against)?
>>
>>Thanks!
>>
>>PS. John: I am against of pmap_kenter/pmap_invalidate_XXX since we could
>>get
>>the same problem if we would use atomic functions instead of composite
>>functions,
>>which, I hope, will track all changes in the future.
>>    
>>
>pmap_foo() doesn't change much. :)  One reason I would prefer the 
>kenter/invalidate is that we explicitly assume a single page for the boot 
>code when we go to allocate an address for it, so I'd kind of like to keep it 
>as an explicit assumption, but I'd be ok with just adding a KASSERT(size <=
>
Are you sure that some one who will add new features wouldn't forget 
about this
place? If you consider that we can ignore this I'll commit 
kenter/invalidate pair with
KASSERT().

>PAGE_SIZE, ("bewm"));  Also, I think your end va needs to be boot_address + 
>size -1 so that if size == PAGE_SIZE you don't bogusly try to map the first 
>page of Video RAM as read/write memory.
>
Tell me if I am wrong, but as I understand this code "end" is not really 
last, but next to
last. Hm, may be this is other (potential) bug, probably we should 
rename 'end' to smth
else? (va + psz < va + psz)

rik