Cheri-research/snmalloc
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Expose Entropy

Browse Source 
Define various parts of random that can be used to make the layout of
memory more random.  Thread this through the allocator.

Expose the concept as part of the Pal. Subsequent commits will expose
that on different platforms.
This commit is contained in:
Matthew Parkinson
2021-03-26 16:22:32 +00:00
committed by Matthew Parkinson
parent c5b65d07b8
commit f15dc6ee2e
8 changed files with 186 additions and 89 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
src/mem/slab.h
View File

@@ -29,8 +29,11 @@ namespace snmalloc
* worth of allocations, or one if the allocation size is larger than a
* page.
*/
static SNMALLOC_FAST_PATH void
alloc_new_list(void*& bumpptr, FreeListIter& fast_free_list, size_t rsize)
static SNMALLOC_FAST_PATH void alloc_new_list(
void*& bumpptr,
FreeListIter& fast_free_list,
size_t rsize,
LocalEntropy& entropy)
{
void* slab_end = pointer_align_up<SLAB_SIZE>(pointer_offset(bumpptr, 1));
@@ -48,14 +51,14 @@ namespace snmalloc
void* newbumpptr = pointer_offset(bumpptr, rsize * offset);
while (newbumpptr < slab_end)
{
b.add(newbumpptr);
b.add(newbumpptr, entropy);
newbumpptr = pointer_offset(newbumpptr, rsize * start_index.size());
}
}
bumpptr = slab_end;
SNMALLOC_ASSERT(!b.empty());
b.close(fast_free_list);
b.close(fast_free_list, entropy);
}
// Returns true, if it deallocation can proceed without changing any status
@@ -65,7 +68,7 @@ namespace snmalloc
// This is pre-factored to take an explicit self parameter so that we can
// eventually annotate that pointer with additional information.
static SNMALLOC_FAST_PATH bool
dealloc_fast(Slab* self, Superslab* super, void* p)
dealloc_fast(Slab* self, Superslab* super, void* p, LocalEntropy& entropy)
{
Metaslab& meta = super->get_meta(self);
SNMALLOC_ASSERT(!meta.is_unused());
@@ -74,7 +77,7 @@ namespace snmalloc
return false;
// Update the head and the next pointer in the free list.
meta.free_queue.add(p);
meta.free_queue.add(p, entropy);
return true;
}
@@ -86,11 +89,15 @@ namespace snmalloc
//
// This is pre-factored to take an explicit self parameter so that we can
// eventually annotate that pointer with additional information.
static SNMALLOC_SLOW_PATH typename Superslab::Action
dealloc_slow(Slab* self, SlabList* sl, Superslab* super, void* p)
static SNMALLOC_SLOW_PATH typename Superslab::Action dealloc_slow(
Slab* self,
SlabList* sl,
Superslab* super,
void* p,
LocalEntropy& entropy)
{
Metaslab& meta = super->get_meta(self);
meta.debug_slab_invariant(self);
meta.debug_slab_invariant(self, entropy);
if (meta.is_full())
{
@@ -106,7 +113,7 @@ namespace snmalloc
return super->dealloc_slab(self);
}
meta.free_queue.add(p);
meta.free_queue.add(p, entropy);
// Remove trigger threshold from how many we need before we have fully
// freed the slab.
meta.needed() =
@@ -114,7 +121,7 @@ namespace snmalloc
// Push on the list of slabs for this sizeclass.
sl->insert_prev(&meta);
meta.debug_slab_invariant(self);
meta.debug_slab_invariant(self, entropy);
return Superslab::NoSlabReturn;
}
@@ -123,11 +130,11 @@ namespace snmalloc
// Check free list is well-formed on platforms with
// integers as pointers.
FreeListIter fl;
meta.free_queue.close(fl);
meta.free_queue.close(fl, entropy);
while (!fl.empty())
{
fl.take();
fl.take(entropy);
count++;
}
#endif