10.0 BETA 3 with redports kernel panic

[Sean Bruno]

On Sat, 2013-12-21 at 16:55 +0200, Konstantin Belousov wrote:
> > The reason why the dmaplimit change originally exploded was becase
> > dmaplimit is set to zero for the duration of while we're running on
> > the page tables given to us by the loader.  I believe initializing
> > dmaplimit to DMAP_MAX_ADDRESS rather than zero would have solved the
> > original explosions.
> The dmaplimit is initialized in
> hammer_time->pmap_bootstrap->getmemsize->
> create_pagetable().  The backtrace above should be much later in the
> boot sequence, note that mi_startup() was already running.
> 
> I believe that my previous change just broke vsetslab()/vtoslab(). 

Currently running 2/4 machines with the following patch.  No data for
stability yet.  Still waiting.


> Index: amd64/amd64/mem.c
> ===================================================================
> --- amd64/amd64/mem.c   (revision 258554)
> +++ amd64/amd64/mem.c   (working copy)
> @@ -98,6 +98,10 @@
>  kmemphys:
>                         o = v & PAGE_MASK;
>                         c = min(uio->uio_resid, (u_int)(PAGE_SIZE - o));
> +                       v = PHYS_TO_DMAP(v);
> +                       if (v < DMAP_MIN_ADDRESS || v >= dmaplimit ||
> +                           pmap_kextract(v) == 0)
> +                               return (EFAULT);
>                         error = uiomove((void *)PHYS_TO_DMAP(v), (int)c, uio);
>                         continue;
>                 }
> Index: amd64/amd64/pmap.c
> ===================================================================
> --- amd64/amd64/pmap.c  (revision 258554)
> +++ amd64/amd64/pmap.c  (working copy)
> @@ -321,7 +321,7 @@
>      "Number of kernel page table pages allocated on bootup");
>  
>  static int ndmpdp;
> -static vm_paddr_t dmaplimit;
> +vm_paddr_t dmaplimit;
>  vm_offset_t kernel_vm_end = VM_MIN_KERNEL_ADDRESS;
>  pt_entry_t pg_nx;
>  
> Index: amd64/include/pmap.h
> ===================================================================
> --- amd64/include/pmap.h        (revision 258554)
> +++ amd64/include/pmap.h        (working copy)
> @@ -368,6 +368,7 @@
>  extern vm_paddr_t dump_avail[];
>  extern vm_offset_t virtual_avail;
>  extern vm_offset_t virtual_end;
> +extern vm_paddr_t dmaplimit;
>  
>  #define        pmap_page_get_memattr(m)        ((vm_memattr_t)(m)->md.pat_mode)
>  #define        pmap_page_is_write_mapped(m)    (((m)->aflags & PGA_WRITEABLE) != 0)