e16f2aff6f
This change brings in a new approach to managing address space. It wraps the Pal with a power of two reservation system, that guarantees all returned blocks are naturally aligned to their size. It either lets the Pal perform aligned requests, or over allocates and splits into power of two blocks.
72 lines
1.7 KiB
C++
72 lines
1.7 KiB
C++
#pragma once
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#include "ds/address.h"
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#include "ds/flaglock.h"
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#include "pal_plain.h"
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#include <array>
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#ifdef OPEN_ENCLAVE
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extern "C" void* oe_memset_s(void* p, size_t p_size, int c, size_t size);
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extern "C" [[noreturn]] void oe_abort();
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namespace snmalloc
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{
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class PALOpenEnclave
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{
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/// Base of OE heap
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static inline void* heap_base = nullptr;
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/// Size of OE heap
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static inline size_t heap_size;
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// This is infrequently used code, a spin lock simplifies the code
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// considerably, and should never be on the fast path.
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static inline std::atomic_flag spin_lock;
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public:
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/**
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* This will be called by oe_allocator_init to set up enclave heap bounds.
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*/
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static void setup_initial_range(void* base, void* end)
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{
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heap_size = pointer_diff(base, end);
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heap_base = base;
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}
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/**
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* Bitmap of PalFeatures flags indicating the optional features that this
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* PAL supports.
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*/
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static constexpr uint64_t pal_features = 0;
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static constexpr size_t page_size = 0x1000;
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[[noreturn]] static void error(const char* const str)
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{
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UNUSED(str);
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oe_abort();
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}
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static std::pair<void*, size_t>
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reserve_at_least(size_t request_size) noexcept
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{
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// First call returns the entire address space
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// subsequent calls return {nullptr, 0}
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FlagLock lock(spin_lock);
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if (request_size > heap_size)
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return {nullptr, 0};
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auto result = std::make_pair(heap_base, heap_size);
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heap_size = 0;
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return result;
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}
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template<bool page_aligned = false>
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void zero(void* p, size_t size) noexcept
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{
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oe_memset_s(p, size, 0, size);
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}
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};
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}
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#endif
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