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Commit 3aca7fbc authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen/mmu: Remove from __ka space PMD entries for pagetables. 



Please first read the description in "xen/mmu: Copy and revector the
P2M tree."

At this stage, the __ka address space (which is what the old
P2M tree was using) is partially disassembled. The cleanup_highmap
has removed the PMD entries from 0-16MB and anything past _brk_end
up to the max_pfn_mapped (which is the end of the ramdisk).

The xen_remove_p2m_tree and code around has ripped out the __ka for
the old P2M array.

Here we continue on doing it to where the Xen page-tables were.
It is safe to do it, as the page-tables are addressed using __va.
For good measure we delete anything that is within MODULES_VADDR
and up to the end of the PMD.

At this point the __ka only contains PMD entries for the start
of the kernel up to __brk.

[v1: Per Stefano's suggestion wrapped the MODULES_VADDR in debug]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 7f914062

arch/x86/xen/mmu.c

+19 −0
Original line number Diff line number Diff line
@@ -1240,6 +1240,25 @@ static void __init xen_pagetable_setup_done(pgd_t *base) 
			xen_start_info->mfn_list = new_mfn_list;

		}

	}

	/* At this stage, cleanup_highmap has already cleaned __ka space

	 * from _brk_limit way up to the max_pfn_mapped (which is the end of

	 * the ramdisk). We continue on, erasing PMD entries that point to page

	 * tables - do note that they are accessible at this stage via __va.

	 * For good measure we also round up to the PMD - which means that if

	 * anybody is using __ka address to the initial boot-stack - and try

	 * to use it - they are going to crash. The xen_start_info has been

	 * taken care of already in xen_setup_kernel_pagetable. */

	addr = xen_start_info->pt_base;

	size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);



	xen_cleanhighmap(addr, addr + size);

	xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));

#ifdef DEBUG

	/* This is superflous and is not neccessary, but you know what

	 * lets do it. The MODULES_VADDR -> MODULES_END should be clear of

	 * anything at this stage. */

	xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);

#endif

#endif

	xen_post_allocator_init();

}