Kuteedzera Linus Torvalds: Gadzira yako yega yekushandisa system kubva pakutanga (I)

Chekutanga pane zvese, taura kuti ichi ndicho chinyorwa changu chekutanga uye kuti ndinovimba mese munochida.

Mune dzino dzakateedzana tiri kuenda kutevedzera Linus Torvalds, tichagadzira yedu yekushandisa system kubva ku0.Muchikamu chino chekutanga tichaona bhuti uye tichaisa chinyorwa pachiratidziri kubva pane yedu kernel.

Mune yangu kesi iyo inoshanda system inonzi NextDivel. Sarudzo yekutanga yatinofanirwa kuita nekukurumidza isu patinofunga nezve mashandiro sisitimu ndiyo ichave iyo bootloader ichave iri?

Pano pane zvakawanda zvakasiyana, uye isu tinogona kana kugadzira imwe pachedu; zvisinei mune ino dzidzo ini ndiri kuzoshandisa GRUB, nekuti vazhinji vanoziva zvimwe kana zvishoma chimwe chinhu nezvake. Isu tinogadzira dhairekitori iyo ichave mudzi wesystem yedu yekushandisa uye ipapo tinogadzira iyo / boot / grub dhairekitori

mkdir nextroot && cd nextroot

mkdir -p boot/grub

Ikoko tinogadzira iyo grub.cfg faira seinotevera:

menuentry "NextDivel" {
echo "Booting NextDivel"
multiboot /next/START.ELF
boot
}


Mune ino faira taona sei GRUB inotakura kernel yedu, mune iyi kesi, mu /next/START.ELF. Iye zvino isu tinofanirwa kugadzira yedu kernel.

Kune izvi isu tichada iyo GCC y GAS (iko kuunganidza kweprojekiti GNU, kazhinji inouya neiyo gcc). Saka isu tichagadzira iyo kernel.

Kutanga tinoita faira inonzi kernel.asm. Iyi faira ichave neinotangira kernel yedu uye zvakare ichajekesa iyo multiboot (chimwe chinhu chevamwe bootloaders senge GRUB). Zviri mukati mekernel.asm zvichave:

.text
.globl start
start:
jmp multiboot_entry
.align 4
multiboot_header:
.long 0x1BADB002
.long 0x00000003
.long -(0x1BADB002+0x00000003)
multiboot_entry:
movl $(stack + 0x4000), %esp
call NextKernel_Main
loop: hlt
jmp loop
.section ".bss"
.comm stack,0x4000

Zvese zvine chekuita ne multiboot ndeye kungoteedzera iwo maratidziro hapana chimwezve. Zvese zvichatanga pakutanga, zvinodaidza multiboot_entry, isu tichava tatsanangura iyo multiboot musoro mune yekutanga 4k uye isu tichaiisa (ne movl)

Gare gare tinodaidza NextKernel_Main inova yedu kernel C inoshanda. Muchiuno tinomira kumisa komputa. Izvi zvinosangana ne:

as -o kernel.o -c kernel.asm

Iye zvino tave kuzopinda muchirongwa muC. Iwe uchafunga kuti izvozvi zvese chidimbu chekeke, tinoisa a kudhinda en kuru uye ndizvozvo, tazviita.

Zvakanaka kwete, kubvira kudhinda y kuru aya mabasa anotsanangurwa neiyo inoshanda system, asi isu tiri kuigadzira! Tinogona chete kushandisa mabasa atinozvitsanangura isu pachedu.

Muzvitsauko zvinotevera ini ndichataura nezve maitiro ekuisa edu C raibhurari (glibc, bionic, newlibc) asi nguva nenguva. Takakurukura kuti tinoda kuisa zvinyorwa pachiratidziri, zvakanaka tichaona kuti tinozviita sei.

Pane sarudzo mbiri, imwe ndeye kudaidza iyo Bios uye imwe ndeye kubata screen memory zvakananga. Tichaita zvekupedzisira nekuti zviri pachena kubva kuC uye zvinotibvumidzawo kuti tizviite kana tapinda yakachengetedzwa maitiro.

Isu tinogadzira iyo faira inonzi NextKernel_Main.c ine zvinotevera zvirimo:

int NextKernel_Main()
{
char *str = "NextDivel says Hello World", *ch;
unsigned short *vidmem = (unsigned short*) 0xb8000;
unsigned i;
for (ch = str, i = 0; *ch; ch++, i++)
vidmem[i] = (unsigned char) *ch | 0x0700;
return 0;
}

Naizvozvi isu tinonyengera chiyeuchidzo VGA uye hunhu nehunhu isu tiri kuzvinyora. Isu tinounganidza nekuremadza iyo stdlib:
gcc -o NextKernel_Main.o -c NextKernel_Main.c -nostdlib -fPIC -ffreestanding

Kana iwe wakazviita kusvika pano, iwe uchazoda kuedza yako nyowani sisitimu yekushandisa izvozvi, asi isu hatisati tapedza izvozvi. Isu tinoda diki faira rinotaurira muunganidzi kuti mune iyo faira kusiya chikamu chimwe nechimwe. Izvi zvinoitwa nechinongedzo script. Isu tinogadzira link.ld:

ENTRY(start)
SECTIONS
{
. = 0x00100000;
.multiboot_header :
{
*(.multiboot_header)
}
.text :
{
code = .; _code = .; __code = .;
*(.text)
. = ALIGN(4096);
}
.data :
{
data = .; _data = .; __data = .;
*(.data)
*(.rodata)
. = ALIGN(4096);
}
.bss :
{
bss = .; _bss = .; __bss = .;
*(.bss)
. = ALIGN(4096);
}
end = .; _end = .; __end = .;
}


Nezvo isu tinotsanangura chinzvimbo chechikamu chimwe nechimwe nenzvimbo yekupinda, kutanga, yatakatsanangura mu kernel.asm. Iye zvino tinogona kubatanidza zvese izvi concoction:

gcc -o START.ELF kernel.o NextKernel_Main.o -Tlink.ld -nostdlib -fPIC -ffreestanding -lgcc

Iye zvino isu tinoteedzera START.ELF ku / inotevera mukati medu folda iyo inoteedzera mudzi wesisitimu yedu yekushandisa. Isu tinoenda kumudzi dhairekitori reedu nyowani yekushandisa sisitimu pamwe neconsole uye tiongorore kuti kune mafaera maviri: imwe / boot / grub / grub.cfg uye imwe / / inotevera / START.ELF.

Isu tinoenda kune yekumusoro dhairekitori uye tinodaidza iyo ISO yekushandisa inobatsira ine GRUB inonzi grub-mkrescue

grub-mkrescue -o nextdivel.iso nextroot

Kana tangoita izvi tichava ne ISO. Iyi ISO inogona kuvhurwa pamakomputa x86 (64 bits zvakare) uye chaiwo michina. Kuti ndizviedze, ndiri kuzoshandisa QEMU. Tinoshevedza QEMU kubva pamutsetse wekuraira:

qemu-system-i386 nextdivel.iso

Unotanga GungwaBIOS uye gare gare tichava nazvo GRUB. Gare gare kana zvese zviri chokwadi tichaona mutsara wedu.
Iwe uchafunga kuti izvi zvakaoma, ndinopindura, hongu zviripo.

Chaizvoizvo kugadzira iyo inoshanda sisitimu inonetsa uye kuti iyi pano haina kuita chero chinhu chinobatsira. Muzvitsauko zvinotevera tichaona mabatiro amungaita mavara pachiratidziri, chengetedza ndangariro uye kana ndichigona, maitiro ekuwana data kubva kubhodhi.

Kana mumwe munhu asingade kuteedzera zvese apa, ndine repodhi pa GitHub (zvakanyanyisa) nehurongwa hwekushandisa NextDivel. Kana iwe uchida kuumbiridza NextDivel iwe unongofanirwa kunge uine git uye cmake:

git clone https://github.com/AdrianArroyoCalle/next-divel
cd next-divel
mkdir build && cd build
cmake ..
make
make DESTDIR=next install
chmod +x iso.sh
./iso.sh
qemu-system-i386 nextdivel.iso


Ini ndinokukurudzira kuti ubatsirane paNextDivel kana iwe uine nguva uye chishuwo chekugadzira inoshanda sisitimu. Zvichida kunyange zvakakwirira kune Linux ... nguva ichataura.