From 3aca7fbc8ede0dd194317b2e3144815128ffb232 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Tue, 14 Aug 2012 14:34:00 -0400 Subject: 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: Konrad Rzeszutek Wilk --- arch/x86/xen/mmu.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index a640949..3f8e963 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -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(); } -- cgit v1.1