ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Virtual Memory System Architecture (VMSA)
physicaladdressext = ‘00000000’;
physicaladdress = l1desc : mva;
else // Supersection
domain = ‘0000’;
type = TLBRecType_Supersection;
physicaladdressext = l1desc;
physicaladdress = l1desc : mva;
when ‘10’ // Large page or Small page
domain = l1desc;
sectionnotpage = FALSE;
NS = l1desc;
// Obtain level 2 descriptor.
l2descaddr.paddress.physicaladdress = l1desc : mva : ‘00’;
l2descaddr.paddress.physicaladdressext = ‘00000000’;
l2descaddr.paddress.NS = if IsSecure() then ‘0’ else ‘1’;
l2descaddr.memattrs = l1descaddr.memattrs;
l2desc = _Mem[l2descaddr,4];
// Process level 2 descriptor.
if l2desc == ‘00’ then
DataAbort(mva, domain, sectionnotpage, is_write, DAbort_Translation);
S = l2desc;
ap = l2desc;
nG = l2desc;
if SCTLR.AFE == ‘1’ && l2desc == ‘0’ then
if SCTLR.HA == ‘0’ then
DataAbort(mva, domain, sectionnotpage, is_write, DAbort_AccessFlag);
else // Hardware-managed access flag must be set in memory
_Mem[l2descaddr,4] = ‘1’;
if l2desc == ‘0’ then // Large page
texcb = l2desc
xn = l2desc;
type = TLBRecType_LargePage;
physicaladdressext = ‘00000000’;
physicaladdress = l2desc : mva;
else // Small page
texcb = l2desc;
xn = l2desc;
type = TLBRecType_SmallPage;
physicaladdressext = ‘00000000’;
physicaladdress = l2desc : mva;
else // MMU is disabled
texcb = ‘00000’;
S = ‘1’;
ap = bits(3) UNKNOWN;
xn = bit UNKNOWN;
nG = bit UNKNOWN;
B3-160 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B