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#include <stddef.h>
#include <apos/init.h>
#include <apos/sizes.h>
#include <pages.h>
#include <vmap.h>
struct page_ret {
size_t left;
size_t num;
void *top;
};
extern void main(struct mm_pagearr_info *pageinfo);
void __init init_zero(void *ptr, size_t bytes)
{
char *byte_ptr = ptr;
/* Not entirely sure if it would be faster to use a larget type than
* char, Linux seems to have memset16/32/64 but I guess I should check
* the generated assembly.
*/
while(bytes--)
*byte_ptr++ = 0;
}
struct page_ret __init init_pages(size_t ram_size, void *ram_top,
size_t page_size, size_t struct_size)
{
size_t num_pages = ram_size / page_size;
size_t size_pages = num_pages * struct_size;
struct page_ret pageret;
pageret.top = ram_top - size_pages;
pageret.num = num_pages;
pageret.left = ram_size - (size_pages * page_size);
init_zero(pageret.top, size_pages);
return pageret;
};
size_t __init init_align_down(size_t num, size_t a)
{
size_t rem = num % a;
return num - rem;
}
size_t __init init_align_up(size_t num, size_t a)
{
return init_align_down(num, a) + a;
}
void __init init_enter_vm(unsigned long *root_page)
{
asm volatile ("csrw 0x180, %0\n" "sfence.vma\n"
:
: "rK" (root_page)
: "memory");
}
void call_main()
{
}
void __init init(void *ram_base, void *ram_top, void *initrd, void *fdt, void *boot)
{
size_t ram_size = ram_top - ram_base;
struct mm_pagearr_info pagearr;
struct page_ret pageret;
/* create crude page status map at the top of physical RAM */
pageret = init_pages(ram_size, ram_top,
SZ_512G, sizeof(struct terapages));
pagearr.tera_num = pageret.num;
pagearr.tera_top = pageret.top;
pageret = init_pages(pageret.left, pageret.top,
SZ_1G, sizeof(struct gigapages));
pagearr.giga_num = pageret.num;
pagearr.giga_top = pageret.top;
pageret = init_pages(pageret.left, pageret.top,
SZ_2M, sizeof(struct megapages));
pagearr.mega_num = pageret.num;
pagearr.mega_top = pageret.top;
pageret = init_pages(pageret.left, pageret.top,
SZ_4K, sizeof(struct kilopages));
pagearr.kilo_num = pageret.num;
pagearr.kilo_top = pageret.top;
unsigned long *root_page = (unsigned long *)
(init_align_down((size_t)pagearr.kilo_top, SZ_4K) - SZ_4K);
/* TODO: should init insert page data into the created arrays? */
/* map .text.* into top part of RAM */
root_page[511] = ((unsigned long)&main & VM_AL) | VM_V | VM_R | VM_W | VM_X;
/* temporarily map .init.* so that our current physical address matches
* the virtual address */
root_page[0] = 0 | VM_V | VM_R | VM_W | VM_X;
/* enter virtual memory */
init_enter_vm(root_page);
/* enter main */
call_main();
}
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