From: Jeremy Fitzhardinge <jeremy@goop.org> Date: Thu, 26 Jun 2008 19:02:49 +0000 (-0700) Subject: x86/paravirt: groundwork for 64-bit Xen support, fix #2 X-Git-Tag: firefly_0821_release~19697^2~116 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=22b45144f67dbaf0705992dc1462de2813fb83a1;p=firefly-linux-kernel-4.4.55.git x86/paravirt: groundwork for 64-bit Xen support, fix #2 Ingo Molnar wrote: > that fixed the build but now we've got a boot crash with this config: > > time.c: Detected 2010.304 MHz processor. > spurious 8259A interrupt: IRQ7. > BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 > IP: [<0000000000000000>] > PGD 0 > Thread overran stack, or stack corrupted > Oops: 0010 [1] SMP > CPU 0 > I don't know if this will fix this bug, but it's definitely a bugfix. It was trashing random pages by overwriting them with pagetables... Don't trash a large pmd's data when mapping physical memory. This is a bugfix for "x86_64: adjust mapping of physical pagetables to work with Xen". Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: xen-devel <xen-devel@lists.xensource.com> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 5c3305e05078..b10b7f17ea58 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -320,7 +320,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end) } if (pmd_val(*pmd)) { - phys_pte_update(pmd, address, end); + if (!pmd_large(*pmd)) + phys_pte_update(pmd, address, end); continue; }