From e8c6577617bffa4402c07c7aa20e3c24f03c1c20 Mon Sep 17 00:00:00 2001 From: Benji Dial Date: Sun, 6 Sep 2020 00:48:07 -0400 Subject: program loading, others big kernel additions: paging, elf loading, separate kernel and user page allocation it now properly loads and runs sd0:bin/init.elf still need to determine which disk was booted from, and start the init on that disk --- src/kernel/mem.c | 63 -------------------------------------------------------- 1 file changed, 63 deletions(-) delete mode 100644 src/kernel/mem.c (limited to 'src/kernel/mem.c') diff --git a/src/kernel/mem.c b/src/kernel/mem.c deleted file mode 100644 index d3baad3..0000000 --- a/src/kernel/mem.c +++ /dev/null @@ -1,63 +0,0 @@ -#include -#include "panic.h" -#include "mem.h" - -#define DYNAMIC_START (0x10000000) -#define DYNAMIC_END (DYNAMIC_START + 65536 * 4096) -#define PAGE_TO_ADDR(n) ((void *)(DYNAMIC_START | ((n) << 12))) -#define ADDR_TO_PAGE(n) (((uint32_t)(n) & ~DYNAMIC_START) >> 12) - -#define MMAP_START (0x00010000) -#define PAGE_USED(n) ((*(uint8_t *)(MMAP_START + (n >> 3)) >> (n & 7)) & 1) -#define CLEAR_PAGE(n) *(uint8_t *)(MMAP_START + (n >> 3)) &= ~(1 << (n & 7)) -#define SET_PAGE(n) *(uint8_t *)(MMAP_START + (n >> 3)) |= 1 << (n & 7) - -extern const void kernel_bss_end; - -uint16_t pages_left; - -void init_mmap() { - volatile uint8_t *end_ptr = (uint8_t *)(DYNAMIC_END - 1); - uint8_t end_val = *end_ptr; - *end_ptr = (uint8_t)~end_val; - if (*end_ptr != (uint8_t)~end_val) - panic("Not enough memory. Must have at least 512MiB."); - - for (uint32_t *m = (uint32_t *)MMAP_START; m < (uint32_t *)(MMAP_START + (65536 / 8)); ++m) - *m = 0; - - uint16_t kernel_bss_pages = (((uint32_t)&kernel_bss_end - DYNAMIC_START - 1) >> 12) + 1; - for (uint16_t i = 0; i < kernel_bss_pages; ++i) - SET_PAGE(i); - - pages_left = 65536 - kernel_bss_pages; -} - -//very inneficient algorithm, just returns first hole big enough. -//a smarter algorithm might pick the smallest one available, -//and go by bytes (or dwords) instead of bits where possible. -void *allocate_pages(uint16_t n) { - uint16_t run = 0; - - for (uint32_t page = 0; page < 65536; ++page) { - if (PAGE_USED(page)) - run = 0; - else if (++run == n) { - uint16_t start = page - run + 1; - for (uint32_t i = start; i <= page; ++i) - SET_PAGE(i); - pages_left -= n; - return PAGE_TO_ADDR(start); - } - } - - return 0; -} - -//in the future, change this to go by bytes or dwords instead of bits. -void free_pages(const void *ptr, uint16_t n) { - uint16_t page = ADDR_TO_PAGE(ptr); - for (uint32_t i = page; i < page + n; ++i) - CLEAR_PAGE(i); - pages_left += n; -} \ No newline at end of file -- cgit v1.2.3