forked from PoliEcho-holding-org/kern
106 lines
3.0 KiB
C
106 lines
3.0 KiB
C
#ifndef _KMALLOC_H
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#define _KMALLOC_H
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#include "types.h"
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// This function allocates size bytes of contiguous memory.
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// Returns a pointer to allocated memory or NULL.
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void* kmalloc(size_t size);
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// This function allocates size bytes of contiguous, zeroed-out memory.
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// Returns a pointer to allocated memory or NULL.
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void* kzalloc(size_t size);
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// This function allocates memory for count elements each of size bytes,
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// zeroed-out memory. Returns a pointer to allocated memory or NULL.
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void* kcalloc(size_t count, size_t size);
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// 9 bytes in 8 bytes
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#define TAG_SHIFT 56
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#define TAG_MASK ((uintptr_t)0xFF << TAG_SHIFT)
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#define SIGN_BIT ((uintptr_t)1 << 55)
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typedef struct {
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uintptr_t bits;
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} tagged_ptr;
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static inline tagged_ptr tp_make(void* p, uint8_t tag) {
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uintptr_t addr = (uintptr_t)p & ~TAG_MASK;
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return (tagged_ptr){addr | ((uintptr_t)tag << TAG_SHIFT)};
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}
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static inline uint8_t tp_tag(tagged_ptr t) {
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return (uint8_t)(t.bits >> TAG_SHIFT);
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}
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static inline void* tp_ptr(tagged_ptr t) {
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/* Bits 48..55 were untouched and still equal the canonical sign.
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Copy bit 55 into bits 56..63. */
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uintptr_t addr =
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(t.bits & SIGN_BIT) ? (t.bits | TAG_MASK) : (t.bits & ~TAG_MASK);
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return (void*)addr;
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}
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// powers of 2
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#define KMALLOC_MAX_SIZE 17
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#define LOWEST_POWER 3
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struct freelist {
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struct freelist* nextnode;
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};
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struct partialy_freelist {
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struct freelist* freelist_nextnode;
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struct partialy_freelist* partialy_freelist_nextnode;
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};
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// this is used when object is too small to hold the big one in this case we use
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// first object as pointer storage and dont allocate it
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struct partialy_freelist_short {
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struct partialy_freelist_short* partialy_freelist_nextnode;
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};
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union freelists_list {
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struct freelist* freelists[KMALLOC_MAX_SIZE];
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struct {
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struct freelist* kmalloc_8;
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struct freelist* kmalloc_16;
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struct freelist* kmalloc_32;
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struct freelist* kmalloc_64;
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struct freelist* kmalloc_128;
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struct freelist* kmalloc_256;
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struct freelist* kmalloc_512;
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struct freelist* kmalloc_1024;
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struct freelist* kmalloc_2048;
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struct freelist* kmalloc_4096;
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struct freelist* kmalloc_8192;
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struct freelist* kmalloc_16384;
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struct freelist* kmalloc_32768;
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struct freelist* kmalloc_65536;
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struct freelist* kmalloc_131072;
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};
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};
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union partialy_freelists_list {
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struct partialy_freelist* partialy_freelists[KMALLOC_MAX_SIZE];
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struct {
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struct partialy_freelist* kmalloc_8;
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struct partialy_freelist* kmalloc_16;
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struct partialy_freelist* kmalloc_32;
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struct partialy_freelist* kmalloc_64;
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struct partialy_freelist* kmalloc_128;
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struct partialy_freelist* kmalloc_256;
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struct partialy_freelist* kmalloc_512;
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struct partialy_freelist* kmalloc_1024;
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struct partialy_freelist* kmalloc_2048;
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struct partialy_freelist* kmalloc_4096;
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struct partialy_freelist* kmalloc_8192;
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struct partialy_freelist* kmalloc_16384;
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struct partialy_freelist* kmalloc_32768;
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struct partialy_freelist* kmalloc_65536;
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struct partialy_freelist* kmalloc_131072;
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};
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};
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#endif
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