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Alloc'ing from the memory map

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This commit is contained in:
Thomas Oltmann 2025-07-08 15:59:52 +02:00
parent 51502e07d4
commit 5fab4ba6c3
2 changed files with 20 additions and 10 deletions
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9
lboot.S
View file

@ -108,7 +108,7 @@ _start: cli
call print
mov $fn_initrd, %esi
call read_file
mov %ebx, initrd_ptr
mov %ebx, bb_ird_ptr
mov $msg_long, %si
call print
@ -503,8 +503,6 @@ server_ip: .space 4
heap_ptr: .long 0
heap_end: .long 0
initrd_ptr: .long 0
// Long mode initial page tables
pd_ptr: .long 0
pdp_ptr: .long 0
@ -541,8 +539,8 @@ trampo64:
mov $2, %ebx
2: mov type_table(%rbx), %bl
and $-16, %rax
or %rbx, %rax
and $-16, %rcx
or %rbx, %rcx
mov %rax, 0(%rdi)
mov %rcx, 8(%rdi)
@ -568,7 +566,6 @@ type_table: .byte 0
// ToDo List:
// - Sorting the memmap
// - Sanitizing the memmap
// - Translating the memmap to bootboot format
// - Parsing a config file
.section .data.bootboot

21
loader.c
View file

@ -185,13 +185,24 @@ load_elf(file_t file, uintptr_t *entry)
return 0;
}
/*
static void *
alloc(size_t size, size_t align)
alloc(BOOTBOOT *bootboot_ptr, size_t size, size_t align)
{
MMapEnt *mmap_end = (MMapEnt *)((char *)bootboot_ptr + bootboot_ptr->size);
for (MMapEnt *ent = &bootboot_ptr->mmap; ent < mmap_end; ent++) {
if (!MMapEnt_IsFree(ent)) continue;
int64_t mstart = MMapEnt_Ptr(ent);
int64_t msize = MMapEnt_Size(ent);
int64_t mend = mstart + msize;
mend -= size;
mend &= -align;
if (mend < mstart) continue;
ent->size = ((mend - mstart) & INT64_C(-16)) | MMAP_FREE;
return (void *)mend;
}
panic("panic: Could not allocate from memory map.");
return NULL;
}
*/
void
loader_main(BOOTBOOT *bootboot_ptr)
@ -202,6 +213,8 @@ loader_main(BOOTBOOT *bootboot_ptr)
panic("panic: Malformed ELF64 executable");
}
alloc(bootboot_ptr, PAGES(1), PAGES(1));
uint64_t stack = 0;
__asm__ __volatile__ (