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

SP: start plumbing CapPtr<>s

Browse Source
This commit is contained in:
Nathaniel Filardo
2021-03-05 16:46:25 +00:00
committed by Nathaniel Wesley Filardo
parent 313a682faf
commit 005f5787ef
10 changed files with 431 additions and 304 deletions
Download Patch File Download Diff File Expand all files Collapse all files

66
src/mem/freelist.h
View File

@@ -23,7 +23,8 @@ namespace snmalloc
* Used to turn a location into a key. This is currently
* just the slab address truncated to 16bits and offset by 1.
*/
inline static address_t initial_key(void* slab)
template<typename T, capptr_bounds B>
inline static address_t initial_key(CapPtr<T, B> slab)
{
#ifdef CHECK_CLIENT
/**
@@ -46,12 +47,15 @@ namespace snmalloc
return ((p1 ^ p2) >= SLAB_SIZE);
}
static inline bool different_slab(address_t p1, void* p2)
template<typename T>
static inline bool different_slab(address_t p1, CapPtr<T, CBArena> p2)
{
return different_slab(p1, address_cast(p2));
}
static inline bool different_slab(void* p1, void* p2)
template<typename T, typename U>
static inline bool
different_slab(CapPtr<T, CBArena> p1, CapPtr<U, CBArena> p2)
{
return different_slab(address_cast(p1), address_cast(p2));
}
@@ -60,7 +64,7 @@ namespace snmalloc
class EncodeFreeObjectReference
{
FreeObject* reference;
CapPtr<FreeObject, CBArena> reference;
/**
* On architectures which use IntegerPointers, we can obfuscate our free
@@ -78,8 +82,8 @@ namespace snmalloc
public:
#ifdef CHECK_CLIENT
template<typename T = FreeObject>
static std::enable_if_t<do_encode, T*>
encode(uint16_t local_key, T* next_object, LocalEntropy& entropy)
static std::enable_if_t<do_encode, CapPtr<T, CBArena>> encode(
uint16_t local_key, CapPtr<T, CBArena> next_object, LocalEntropy& entropy)
{
// Simple involutional encoding. The bottom half of each word is
// multiplied by a function of both global and local keys (the latter,
@@ -92,25 +96,28 @@ namespace snmalloc
address_t key = (local_key + 1) * entropy.get_constant_key();
next ^= (((next & MASK) + 1) * key) &
~(bits::one_at_bit(PRESERVE_BOTTOM_BITS) - 1);
return reinterpret_cast<FreeObject*>(next);
return CapPtr<T, CBArena>(reinterpret_cast<T*>(next));
}
#endif
template<typename T = FreeObject>
static std::enable_if_t<!do_encode, T*>
encode(uint16_t local_key, T* next_object, LocalEntropy& entropy)
static std::enable_if_t<!do_encode, CapPtr<T, CBArena>> encode(
uint16_t local_key, CapPtr<T, CBArena> next_object, LocalEntropy& entropy)
{
UNUSED(local_key);
UNUSED(entropy);
return next_object;
}
void store(FreeObject* value, uint16_t local_key, LocalEntropy& entropy)
void store(
CapPtr<FreeObject, CBArena> value,
uint16_t local_key,
LocalEntropy& entropy)
{
reference = encode(local_key, value, entropy);
}
FreeObject* read(uint16_t local_key, LocalEntropy& entropy)
CapPtr<FreeObject, CBArena> read(uint16_t local_key, LocalEntropy& entropy)
{
return encode(local_key, reference, entropy);
}
@@ -129,15 +136,15 @@ namespace snmalloc
public:
EncodeFreeObjectReference next_object;
static FreeObject* make(void* p)
static CapPtr<FreeObject, CBArena> make(CapPtr<void, CBArena> p)
{
return static_cast<FreeObject*>(p);
return p.template as_static<FreeObject>();
}
/**
* Read the next pointer handling any required decoding of the pointer
*/
FreeObject* read_next(uint16_t key, LocalEntropy& entropy)
CapPtr<FreeObject, CBArena> read_next(uint16_t key, LocalEntropy& entropy)
{
return next_object.read(key, entropy);
}
@@ -150,7 +157,7 @@ namespace snmalloc
*/
class FreeListIter
{
FreeObject* curr = nullptr;
CapPtr<FreeObject, CBArena> curr = nullptr;
#ifdef CHECK_CLIENT
address_t prev = 0;
#endif
@@ -170,7 +177,7 @@ namespace snmalloc
* Currently this is just the value of current before this call.
* Other schemes could be used.
*/
void update_cursor(FreeObject* next)
void update_cursor(CapPtr<FreeObject, CBArena> next)
{
#ifdef CHECK_CLIENT
# ifndef NDEBUG
@@ -187,7 +194,7 @@ namespace snmalloc
}
public:
FreeListIter(FreeObject* head)
FreeListIter(CapPtr<FreeObject, CBArena> head)
: curr(head)
#ifdef CHECK_CLIENT
,
@@ -210,7 +217,7 @@ namespace snmalloc
/**
* Returns current head without affecting the iterator.
*/
void* peek()
CapPtr<FreeObject, CBArena> peek()
{
return curr;
}
@@ -218,7 +225,7 @@ namespace snmalloc
/**
* Moves the iterator on, and returns the current value.
*/
void* take(LocalEntropy& entropy)
CapPtr<FreeObject, CBArena> take(LocalEntropy& entropy)
{
#ifdef CHECK_CLIENT
check_client(
@@ -309,7 +316,7 @@ namespace snmalloc
* Start building a new free list.
* Provide pointer to the slab to initialise the system.
*/
void open(void* p)
void open(CapPtr<void, CBArena> p)
{
SNMALLOC_ASSERT(empty());
for (size_t i = 0; i < LENGTH; i++)
@@ -331,17 +338,17 @@ namespace snmalloc
{
for (size_t i = 0; i < LENGTH; i++)
{
if (end[i] != &head[i])
if (address_cast(end[i]) != address_cast(&head[i]))
return false;
}
return true;
}
bool debug_different_slab(void* n)
bool debug_different_slab(CapPtr<FreeObject, CBArena> n)
{
for (size_t i = 0; i < LENGTH; i++)
{
if (!different_slab(end[i], n))
if (!different_slab(address_cast(end[i]), n))
return false;
}
return true;
@@ -350,18 +357,17 @@ namespace snmalloc
/**
* Adds an element to the builder
*/
void add(void* n, LocalEntropy& entropy)
void add(CapPtr<FreeObject, CBArena> n, LocalEntropy& entropy)
{
SNMALLOC_ASSERT(!debug_different_slab(n) || empty());
FreeObject* next = FreeObject::make(n);
auto index = RANDOM ? entropy.next_bit() : 0;
end[index]->store(next, get_prev(index), entropy);
end[index] = &(next->next_object);
end[index]->store(n, get_prev(index), entropy);
end[index] = &(n->next_object);
#ifdef CHECK_CLIENT
prev[index] = curr[index];
curr[index] = address_cast(next) & 0xffff;
curr[index] = address_cast(n) & 0xffff;
#endif
}
@@ -378,11 +384,11 @@ namespace snmalloc
{
uint16_t local_prev = HEAD_KEY;
EncodeFreeObjectReference* iter = &head[i];
FreeObject* prev_obj = iter->read(local_prev, entropy);
CapPtr<FreeObject, CBArena> prev_obj = iter->read(local_prev, entropy);
uint16_t local_curr = initial_key(prev_obj) & 0xffff;
while (end[i] != iter)
{
FreeObject* next = iter->read(local_prev, entropy);
CapPtr<FreeObject, CBArena> next = iter->read(local_prev, entropy);
check_client(!different_slab(next, prev_obj), "Heap corruption");
local_prev = local_curr;
local_curr = address_cast(next) & 0xffff;