svn commit: r340678 - head/sys/arm64/arm64

[Rodney W. Grimes]

> Author: markj
> Date: Tue Nov 20 15:12:37 2018
> New Revision: 340678
> URL: https://svnweb.freebsd.org/changeset/base/340678
> 
> Log:
>   Handle kernel superpage mappings in pmap_remove_l2().
>   
>   PR:		233088
>   Reviewed by:	alc, andrew, kib
>   Tested by:	sbruno
>   MFC after:	3 days
>   Sponsored by:	The FreeBSD Foundation
>   Differential Revision:	https://reviews.freebsd.org/D17981

Mark,
	If this is the fix for the aarch64/arm64 build
cluster failure could you *please* make sure it gets
MFC and MFS to releng/12 before this thursdays builds
of RC2?  Ie, about the next 24 hours?

Consider this an RE approval for immediate MFC to
stable/12 so that you can send an MFS RFA to merge it
to releng/12 which well take another re to approve.


Thanks,
Rod <RE

> Modified:
>   head/sys/arm64/arm64/pmap.c
> 
> Modified: head/sys/arm64/arm64/pmap.c
> ==============================================================================
> --- head/sys/arm64/arm64/pmap.c	Tue Nov 20 14:59:27 2018	(r340677)
> +++ head/sys/arm64/arm64/pmap.c	Tue Nov 20 15:12:37 2018	(r340678)
> @@ -2382,8 +2382,40 @@ pmap_pv_insert_l2(pmap_t pmap, vm_offset_t va, pd_entr
>  	return (true);
>  }
>  
> +static void
> +pmap_remove_kernel_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_t va)
> +{
> +	pt_entry_t newl2, oldl2;
> +	vm_page_t ml3;
> +	vm_paddr_t ml3pa;
> +
> +	KASSERT(!VIRT_IN_DMAP(va), ("removing direct mapping of %#lx", va));
> +	KASSERT(pmap == kernel_pmap, ("pmap %p is not kernel_pmap", pmap));
> +	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
> +
> +	ml3 = pmap_remove_pt_page(pmap, va);
> +	if (ml3 == NULL)
> +		panic("pmap_remove_kernel_l2: Missing pt page");
> +
> +	ml3pa = VM_PAGE_TO_PHYS(ml3);
> +	newl2 = ml3pa | L2_TABLE;
> +
> +	/*
> +	 * Initialize the page table page.
> +	 */
> +	pagezero((void *)PHYS_TO_DMAP(ml3pa));
> +
> +	/*
> +	 * Demote the mapping.  The caller must have already invalidated the
> +	 * mapping (i.e., the "break" in break-before-make).
> +	 */
> +	oldl2 = pmap_load_store(l2, newl2);
> +	KASSERT(oldl2 == 0, ("%s: found existing mapping at %p: %#lx",
> +	    __func__, l2, oldl2));
> +}
> +
>  /*
> - * pmap_remove_l2: do the things to unmap a level 2 superpage in a process
> + * pmap_remove_l2: Do the things to unmap a level 2 superpage.
>   */
>  static int
>  pmap_remove_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_t sva,
> @@ -2419,16 +2451,18 @@ pmap_remove_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_
>  				vm_page_aflag_clear(m, PGA_WRITEABLE);
>  		}
>  	}
> -	KASSERT(pmap != kernel_pmap,
> -	    ("Attempting to remove an l2 kernel page"));
> -	ml3 = pmap_remove_pt_page(pmap, sva);
> -	if (ml3 != NULL) {
> -		pmap_resident_count_dec(pmap, 1);
> -		KASSERT(ml3->wire_count == NL3PG,
> -		    ("pmap_remove_l2: l3 page wire count error"));
> -		ml3->wire_count = 1;
> -		vm_page_unwire_noq(ml3);
> -		pmap_add_delayed_free_list(ml3, free, FALSE);
> +	if (pmap == kernel_pmap) {
> +		pmap_remove_kernel_l2(pmap, l2, sva);
> +	} else {
> +		ml3 = pmap_remove_pt_page(pmap, sva);
> +		if (ml3 != NULL) {
> +			pmap_resident_count_dec(pmap, 1);
> +			KASSERT(ml3->wire_count == NL3PG,
> +			    ("pmap_remove_l2: l3 page wire count error"));
> +			ml3->wire_count = 1;
> +			vm_page_unwire_noq(ml3);
> +			pmap_add_delayed_free_list(ml3, free, FALSE);
> +		}
>  	}
>  	return (pmap_unuse_pt(pmap, sva, l1e, free));
>  }
> 
> 

-- 
Rod Grimes                                                 rgrimes at freebsd.org