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Kernel: Allow kmalloc_aligned() alignment up to 4096

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This allows us to get kmalloc() memory aligned to the VM page size.
This commit is contained in:
Andreas Kling 2021-03-11 13:02:01 +01:00
parent a7b6282086
commit 40f2abf7c3
1 changed files with 5 additions and 5 deletions
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10
Kernel/Heap/kmalloc.h
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@ -58,18 +58,18 @@ inline void* operator new[](size_t, void* p) { return p; }
template<size_t ALIGNMENT> template<size_t ALIGNMENT>
[[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] inline void* kmalloc_aligned(size_t size) [[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] inline void* kmalloc_aligned(size_t size)
{ {
static_assert(ALIGNMENT > 1); static_assert(ALIGNMENT > sizeof(ptrdiff_t));
static_assert(ALIGNMENT < 255); static_assert(ALIGNMENT <= 4096);
void* ptr = kmalloc(size + ALIGNMENT + sizeof(u8)); void* ptr = kmalloc(size + ALIGNMENT + sizeof(ptrdiff_t));
size_t max_addr = (size_t)ptr + ALIGNMENT; size_t max_addr = (size_t)ptr + ALIGNMENT;
void* aligned_ptr = (void*)(max_addr - (max_addr % ALIGNMENT)); void* aligned_ptr = (void*)(max_addr - (max_addr % ALIGNMENT));
((u8*)aligned_ptr)[-1] = (u8)((u8*)aligned_ptr - (u8*)ptr); ((ptrdiff_t*)aligned_ptr)[-1] = (ptrdiff_t)((u8*)aligned_ptr - (u8*)ptr);
return aligned_ptr; return aligned_ptr;
} }
inline void kfree_aligned(void* ptr) inline void kfree_aligned(void* ptr)
{ {
kfree((u8*)ptr - ((u8*)ptr)[-1]); kfree((u8*)ptr - ((const ptrdiff_t*)ptr)[-1]);
} }
void kmalloc_enable_expand(); void kmalloc_enable_expand();