Implement page allocation

This commit is contained in:
Mathieu Maret 2018-08-09 22:19:34 +02:00
parent 0930f2664a
commit 6cb8b4372a
5 changed files with 70 additions and 11 deletions

View File

@ -9,3 +9,11 @@ void *memcpy(void *dst, const void *src, size_t n)
} }
return dst; return dst;
} }
void *memset(void *src, int c, size_t n)
{
for (char *ptr = (char *)src; n > 0; n--, ptr++) {
*ptr = (char)c;
}
return src;
}

View File

@ -2,3 +2,4 @@
#include "stdarg.h" #include "stdarg.h"
void *memcpy(void *dest, const void *src, size_t n ); void *memcpy(void *dest, const void *src, size_t n );
void *memset(void *s, int c, size_t n);

View File

@ -4,20 +4,21 @@
#include "interrupt.h" #include "interrupt.h"
#include "io.h" #include "io.h"
#include "irq.h" #include "irq.h"
#include "klibc.h"
#include "mem.h" #include "mem.h"
#include "multiboot.h" #include "multiboot.h"
#include "pit.h" #include "pit.h"
#include "stdarg.h" #include "stdarg.h"
#include "vga.h" #include "vga.h"
#define CHECK_FLAG(flags,bit) ((flags) & (1 << (bit))) #define CHECK_FLAG(flags, bit) ((flags) & (1 << (bit)))
void cpuid(int code, uint32_t *a, uint32_t *d) void cpuid(int code, uint32_t *a, uint32_t *d)
{ {
asm volatile("cpuid" : "=a"(*a), "=d"(*d) : "0"(code) : "ebx", "ecx"); asm volatile("cpuid" : "=a"(*a), "=d"(*d) : "0"(code) : "ebx", "ecx");
} }
// Multiboot information available here :
// Multiboot information available here : https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#kernel_002ec // https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#kernel_002ec
void kmain(unsigned long magic, unsigned long addr) void kmain(unsigned long magic, unsigned long addr)
{ {
unsigned long upper_mem = 0; unsigned long upper_mem = 0;
@ -31,23 +32,23 @@ void kmain(unsigned long magic, unsigned long addr)
if (magic == MULTIBOOT_BOOTLOADER_MAGIC) { // Get loaded by Grub wuth mutliboot version 1 if (magic == MULTIBOOT_BOOTLOADER_MAGIC) { // Get loaded by Grub wuth mutliboot version 1
multiboot_info_t *mbi = (multiboot_info_t *)addr; multiboot_info_t *mbi = (multiboot_info_t *)addr;
/* Are mem_* valid? */ /* Are mem_* valid? */
if (CHECK_FLAG(mbi->flags, 0)){ if (CHECK_FLAG(mbi->flags, 0)) {
printf("mem_lower = %dKB mem_upper %dKB\n", mbi->mem_lower, mbi->mem_upper); printf("mem_lower = %dKB mem_upper %dKB\n", mbi->mem_lower, mbi->mem_upper);
upper_mem = mbi->mem_upper; upper_mem = mbi->mem_upper;
} }
/* Is boot_device valid? */ /* Is boot_device valid? */
if (CHECK_FLAG(mbi->flags, 1)){ if (CHECK_FLAG(mbi->flags, 1)) {
printf("boot_device = %d\n", mbi->boot_device); printf("boot_device = %d\n", mbi->boot_device);
} }
/* Is the command line passed? */ /* Is the command line passed? */
if (CHECK_FLAG(mbi->flags, 2)){ if (CHECK_FLAG(mbi->flags, 2)) {
printf("cmdline = %s\n", (char *)mbi->cmdline); printf("cmdline = %s\n", (char *)mbi->cmdline);
} }
} }
if(upper_mem == 0){ if (upper_mem == 0) {
printf("Cannot get upper phy mem bound. Using default value 32MB\n"); printf("Cannot get upper phy mem bound. Using default value 32MB\n");
upper_mem = 32 * 1024; upper_mem = 32 * 1024;
} }

View File

@ -1,22 +1,68 @@
#include "mem.h" #include "mem.h"
#include "list.h"
#include "vga.h" #include "vga.h"
struct mem_desc *page_desc = (struct mem_desc *)&__ld_kernel_end; static struct mem_desc *page_desc = (struct mem_desc *)&__ld_kernel_end;
static struct mem_desc *free_page;
static struct mem_desc *used_page;
static unsigned long bottom_mem;
static unsigned long top_mem;
int memInit(unsigned long upper_mem) int memInit(unsigned long upper_mem)
{ {
printf("Free Mem going from %d to %d\n", &__ld_kernel_end, upper_mem *1024); printf("Free Mem going from %d to %d\n", &__ld_kernel_end, upper_mem * 1024);
unsigned long memdesc_end = unsigned long memdesc_end =
(unsigned long)page_desc + (unsigned long)page_desc +
((upper_mem) / (PAGE_SIZE / 1024)) * sizeof(struct mem_desc); ((upper_mem) / (PAGE_SIZE / 1024)) * sizeof(struct mem_desc);
uint lastUsed = (memdesc_end >> PAGE_SHIFT) + 1; uint lastUsed = (memdesc_end >> PAGE_SHIFT) + 1;
list_init(free_page);
list_init(used_page);
bottom_mem = lastUsed;
top_mem = upper_mem;
for (uint i = 0; i < (upper_mem / (PAGE_SIZE / 1024)); i++) { for (uint i = 0; i < (upper_mem / (PAGE_SIZE / 1024)); i++) {
struct mem_desc *mem = &page_desc[i]; struct mem_desc *mem = &page_desc[i];
if (i < lastUsed) if (i < lastUsed) {
mem->ref = 1; mem->ref = 1;
else list_add_tail(used_page, mem);
} else {
mem->ref = 0; mem->ref = 0;
list_add_tail(free_page, mem);
}
mem->phy_addr = i * PAGE_SIZE; mem->phy_addr = i * PAGE_SIZE;
} }
return 0; return 0;
} }
struct mem_desc *addr2memDesc(unsigned long addr)
{
if (addr > top_mem || addr < bottom_mem)
return NULL;
int idx = addr >> PAGE_SHIFT;
return page_desc + idx;
}
unsigned long allocPage(void)
{
if (list_is_empty(free_page))
return (unsigned long)NULL;
struct mem_desc *mem = list_pop_head(free_page);
mem->ref = 1;
list_add_tail(used_page, mem);
return mem->phy_addr;
}
int unrefPage(unsigned long addr)
{
struct mem_desc *mem = addr2memDesc(addr);
if (!mem) {
return -1;
}
mem->ref--;
if (mem->ref == 0) {
list_add_tail(free_page, mem);
}
return 0;
}

View File

@ -12,7 +12,10 @@ extern uint32_t __ld_kernel_end;
struct mem_desc{ struct mem_desc{
unsigned long phy_addr; unsigned long phy_addr;
unsigned long ref; unsigned long ref;
struct mem_desc *next, *prev;
}; };
int memInit(unsigned long upper_mem); int memInit(unsigned long upper_mem);
unsigned long allocPage(void);
int unrefPage(unsigned long addr);