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mem: Add interleaving bits to the address ranges

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This patch adds support for interleaving bits for the address
ranges. What was previously just a start and end address, now has an
additional three fields, for the high bit, and number of bits to use
for interleaving, and a match value to compare against. If the number
of interleaving bits is set to zero it is effectively disabled.

A number of convenience functions are added to the range to enquire
about the interleaving, its granularity and the number of stripes it
is part of.
This commit is contained in:
Andreas Hansson 2013-01-07 13:05:38 -05:00
parent e6c57786a4
commit 01c5598373
4 changed files with 156 additions and 19 deletions
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119
src/base/addr_range.hh
View file

@ -45,7 +45,9 @@
#ifndef __BASE_ADDR_RANGE_HH__
#define __BASE_ADDR_RANGE_HH__
#include "base/bitfield.hh"
#include "base/cprintf.hh"
#include "base/misc.hh"
#include "base/types.hh"
class AddrRange
@ -53,27 +55,68 @@ class AddrRange
private:
/// Private fields for the start and end of the range. In the
/// future, these will be extended with interleaving functionality
/// and hence should never be manipulated directly.
/// Private fields for the start and end of the range
Addr _start;
Addr _end;
/// The high bit of the slice that is used for interleaving
uint8_t intlvHighBit;
/// The number of bits used for interleaving, set to 0 to disable
uint8_t intlvBits;
/// The value to compare the slice addr[high:(high - bits + 1)]
/// with.
uint8_t intlvMatch;
public:
AddrRange()
: _start(1), _end(0)
: _start(1), _end(0), intlvHighBit(0), intlvBits(0), intlvMatch(0)
{}
AddrRange(Addr _start, Addr _end, uint8_t _intlv_high_bit,
uint8_t _intlv_bits, uint8_t _intlv_match)
: _start(_start), _end(_end), intlvHighBit(_intlv_high_bit),
intlvBits(_intlv_bits), intlvMatch(_intlv_match)
{}
AddrRange(Addr _start, Addr _end)
: _start(_start), _end(_end)
: _start(_start), _end(_end), intlvHighBit(0), intlvBits(0),
intlvMatch(0)
{}
/**
* Get the size of the address range. For a case where
* interleaving is used this should probably cause a panic.
* Determine if the range is interleaved or not.
*
* @return true if interleaved
*/
Addr size() const { return _end - _start + 1; }
bool interleaved() const { return intlvBits != 0; }
/**
* Determing the interleaving granularity of the range.
*
* @return The size of the regions created by the interleaving bits
*/
uint64_t granularity() const { return ULL(1) << intlvHighBit; }
/**
* Determine the number of interleaved address stripes this range
* is part of.
*
* @return The number of stripes spanned by the interleaving bits
*/
uint32_t stripes() const { return ULL(1) << intlvBits; }
/**
* Get the size of the address range. For a case where
* interleaving is used we make the simplifying assumption that
* the size is a divisible by the size of the interleaving slice.
*/
Addr size() const
{
return (_end - _start + 1) >> intlvBits;
}
/**
* Determine if the range is valid.
@ -92,7 +135,27 @@ class AddrRange
*/
std::string to_string() const
{
return csprintf("[%#llx : %#llx]", _start, _end);
if (interleaved())
return csprintf("[%#llx : %#llx], [%d : %d] = %d", _start, _end,
intlvHighBit, intlvHighBit - intlvBits + 1,
intlvMatch);
else
return csprintf("[%#llx : %#llx]", _start, _end);
}
/**
* Determine if another range merges with the current one, i.e. if
* they are part of the same contigous range and have the same
* interleaving bits.
*
* @param r Range to evaluate merging with
* @return true if the two ranges would merge
*/
bool mergesWith(const AddrRange& r) const
{
return r._start == _start && r._end == _end &&
r.intlvHighBit == intlvHighBit &&
r.intlvBits == intlvBits;
}
/**
@ -105,7 +168,26 @@ class AddrRange
*/
bool intersects(const AddrRange& r) const
{
return _start <= r._end && _end >= r._start;
if (!interleaved()) {
return _start <= r._end && _end >= r._start;
}
// the current range is interleaved, split the check up in
// three cases
if (r.size() == 1)
// keep it simple and check if the address is within
// this range
return contains(r.start());
else if (!r.interleaved())
// be conservative and ignore the interleaving
return _start <= r._end && _end >= r._start;
else if (mergesWith(r))
// restrict the check to ranges that belong to the
// same chunk
return intlvMatch == r.intlvMatch;
else
panic("Cannot test intersection of interleaved range %s\n",
to_string());
}
/**
@ -118,6 +200,8 @@ class AddrRange
*/
bool isSubset(const AddrRange& r) const
{
if (interleaved())
panic("Cannot test subset of interleaved range %s\n", to_string());
return _start >= r._start && _end <= r._end;
}
@ -129,7 +213,13 @@ class AddrRange
*/
bool contains(const Addr& a) const
{
return a >= _start && a <= _end;
// check if the address is in the range and if there is either
// no interleaving, or with interleaving also if the selected
// bits from the address match the interleaving value
return a >= _start && a <= _end &&
(interleaved() ||
(bits(a, intlvHighBit, intlvHighBit - intlvBits + 1) ==
intlvMatch));
}
/**
@ -146,7 +236,12 @@ class AddrRange
*/
bool operator<(const AddrRange& r) const
{
return _start < r._start;
if (_start != r._start)
return _start < r._start;
else
// for now assume that the end is also the same, and that
// we are looking at the same interleaving bits
return intlvMatch < r.intlvMatch;
}
#endif // SWIG

25
src/base/addr_range_map.hh
View file

@ -74,11 +74,11 @@ class AddrRangeMap
const_iterator i = tree.upper_bound(r);
if (i == tree.begin()) {
if (i->first.intersects(r))
if (i->first.intersects(r)) {
return i;
else
// Nothing could match, so return end()
} else {
return tree.end();
}
}
--i;
@ -86,6 +86,25 @@ class AddrRangeMap
if (i->first.intersects(r))
return i;
// if we are looking at an interleaved range, also step
// backwards through the ranges while we are looking at ranges
// that are part of the same contigous chunk
if (i->first.interleaved()) {
AddrRange orig_range = i->first;
while (i != tree.begin() && i->first.mergesWith(orig_range)) {
--i;
if (i->first.intersects(r)) {
return i;
}
}
// we could leave the loop based on reaching the first
// element, so we must still check for an intersection
if (i->first.intersects(r))
return i;
}
return tree.end();
}

8
src/mem/physical.cc
View file

@ -119,9 +119,13 @@ void
PhysicalMemory::createBackingStore(AddrRange range,
const vector<AbstractMemory*>& _memories)
{
if (range.interleaved())
panic("Cannot create backing store for interleaved range %s\n",
range.to_string());
// perform the actual mmap
DPRINTF(BusAddrRanges, "Creating backing store for range %s\n",
range.to_string());
DPRINTF(BusAddrRanges, "Creating backing store for range %s with size %d\n",
range.to_string(), range.size());
int map_flags = MAP_ANON | MAP_PRIVATE;
uint8_t* pmem = (uint8_t*) mmap(NULL, range.size(),
PROT_READ | PROT_WRITE,

23
src/python/m5/params.py
View file

@ -553,7 +553,15 @@ class AddrRange(ParamValue):
cxx_type = 'AddrRange'
def __init__(self, *args, **kwargs):
# Disable interleaving by default
self.intlvHighBit = 0
self.intlvBits = 0
self.intlvMatch = 0
def handle_kwargs(self, kwargs):
# An address range needs to have an upper limit, specified
# either explicitly with an end, or as an offset using the
# size keyword.
if 'end' in kwargs:
self.end = Addr(kwargs.pop('end'))
elif 'size' in kwargs:
@ -561,6 +569,14 @@ class AddrRange(ParamValue):
else:
raise TypeError, "Either end or size must be specified"
# Now on to the optional bit
if 'intlvHighBit' in kwargs:
self.intlvHighBit = int(kwargs.pop('intlvHighBit'))
if 'intlvBits' in kwargs:
self.intlvBits = int(kwargs.pop('intlvBits'))
if 'intlvMatch' in kwargs:
self.intlvMatch = int(kwargs.pop('intlvMatch'))
if len(args) == 0:
self.start = Addr(kwargs.pop('start'))
handle_kwargs(self, kwargs)
@ -589,7 +605,8 @@ class AddrRange(ParamValue):
return '%s:%s' % (self.start, self.end)
def size(self):
return long(self.end) - long(self.start) + 1
# Divide the size by the size of the interleaving slice
return (long(self.end) - long(self.start) + 1) >> self.intlvBits
@classmethod
def cxx_predecls(cls, code):
@ -605,7 +622,9 @@ class AddrRange(ParamValue):
# by swig
from m5.internal.range import AddrRange
return AddrRange(long(self.start), long(self.end))
return AddrRange(long(self.start), long(self.end),
int(self.intlvHighBit), int(self.intlvBits),
int(self.intlvMatch))
# Boolean parameter type. Python doesn't let you subclass bool, since
# it doesn't want to let you create multiple instances of True and