45 lines
1.3 KiB
C
45 lines
1.3 KiB
C
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include "kprintf.h"
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#include "memory.h"
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#define MAX_FRAMES 1048319
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#define CEIL(x, y) (((x) + (y) - 1) / (y))
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#define GET_FRAME(i) (frame_table[i / 8] & (1 << (i % 8)))
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#define SET_FRAME(i, used) \
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do { \
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if (used) \
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frame_table[i / 8] |= (1 << (i % 8)); \
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else \
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frame_table[i / 8] &= ~(1 << (i % 8)); \
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} while (0)
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extern uint32_t end_kernel;
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static uint8_t frame_table[CEIL(MAX_FRAMES, 8)];
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uintptr_t kalloc_frame(uint32_t nb_frames)
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{
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if (nb_frames > MAX_FRAMES)
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kprintf(KERN_CRIT, "Not enough frames (max: %d)\n", MAX_FRAMES);
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size_t i = 0;
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while (i < MAX_FRAMES) {
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size_t free_frames = 1;
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while (!GET_FRAME(i + free_frames) && free_frames < nb_frames)
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free_frames++;
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if (free_frames == nb_frames)
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goto end;
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i += free_frames;
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}
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end:
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if (i != MAX_FRAMES) {
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for (size_t j = 0; j < nb_frames; j++)
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SET_FRAME(j + i, 1);
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return (uintptr_t)&end_kernel + i * PAGE_SIZE;
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}
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kprintf(KERN_WARNING, "Not enough frames available\n", MAX_FRAMES);
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return 0;
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}
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