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westeros: Remove libkern dependency from early boot stage. Dangerous...
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Signed-off-by: TunaCici <[email protected]>
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@TunaCici
TunaCici committed Apr 15, 2024
1 parent e16f016 commit 7ec5b2a
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Showing 2 changed files with 89 additions and 65 deletions.
2 changes: 1 addition & 1 deletion Kernel/Main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,7 @@ void kmain(void)
}

/* X. Setup vector tables */
MSR("vbar_el1", vector_table);
MSR("VBAR_EL1", vector_table);
isb();

/* 1. Init BootMem */
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152 changes: 88 additions & 64 deletions Kernel/Start.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,70 +12,116 @@

#include "MemoryLayout.h"

#include "LibKern/DeviceTree.h"
#include "LibKern/Time.h"
#include "LibKern/Console.h"

extern void kmain(void);

void _utoa(uint64_t uval, char *buff, uint8_t base) {
const char digits[] = "0123456789ABCDEF";
int i = 0;

/* Convert to string. Digits are in reverse order */
do {
buff[i++] = digits[uval % base];
} while((uval /= base) != 0);
buff[i--] = '\0';

/* Reverse the string */
for (int j = 0; j < i; j++, i--) {
char tmp = buff[j];

buff[j] = buff[i];
buff[i] = tmp;
}
}

void _uart_putc(const int c)
{
volatile uint8_t *uart0 = (uint8_t*) PL011_BASE;
*uart0 = c;
}


void _puts(const char *s)
{
while (*s != '\0') {
_uart_putc(*s);
s++;
}
}

void _halt(const char *s)
{
klog("Halting due to: %s", s);
_puts("Halting due to: ");
_puts(s);

wfi();
}

void start(void)
{
volatile uint32_t arch;
volatile uint32_t val32;
volatile uint64_t val64;
volatile uint32_t arch = 0;
volatile uint32_t val32 = 0;
volatile uint64_t val64 = 0;

char buff[64] = {0};

/* Hard-coded device/board info */
/* TODO: Replace this with a DTB parser */
const char *_cpuModel = "Cortex A-72";
const uint32_t _coreCount = 2u;

klog("WesterOS early boot stage\n");
klog("Running sanity checks...\n");
_puts("WesterOS early boot stage\n");
_puts("Running sanity checks\n");

/* TODO: Any better way to early print? */
klog("WARN: Raw printing directly to PL011 @ 0x%x\n", PL011_BASE);
_puts("WARN: Raw printing directly to PL011 @ 0x");
_utoa(PL011_BASE, buff, 16);
_puts(buff);
_puts("\n");

/* -------- CPU -------- */
klog("Checking CPU\n");
_puts("Checking CPU\n");
MRS("MIDR_EL1", val32);
arch = (val32 & 0xFF000000) >> 24;

if (arch == 0x41) {
klog("---- Implementer: ARM\n");
_puts("---- Implementer: ARM\n");
} else {
_halt("---- Unknown Implementer\n");
}

klog("---- Model: %s\n", _cpuModel);
klog("---- SMP: %u\n", _coreCount);
_puts("---- Model: ");
_puts(_cpuModel);
_puts("\n");

_puts("---- SMP: ");
_utoa(_coreCount, buff, 10);
_puts(buff);
_puts("\n");

MRS("CNTFRQ_EL0", val64);
val64 = val64 / 1000000; /* Hz to MHz */

klog("---- Running @ %lu MHz\n", val64);
_puts("---- Running @ ");
_utoa(val64, buff, 10);
_puts(buff);
_puts(" MHz\n");

klog("---- Current exception level: ");
_puts("---- Current exception level: ");
MRS("CurrentEL", val32);
val32 = (val32 & 0x0C) >> 2;

switch(val32) {
case 0:
kprintf("EL0 (User mode)\n");
_puts("EL0 (User mode)\n");
break;
case 1:
kprintf("EL1 (Kernel mode)\n");
_puts("EL1 (Kernel mode)\n");
break;
case 2:
kprintf("EL2 (Hypervisor mode)\n");
_puts("EL2 (Hypervisor mode)\n");
break;
case 3:
kprintf("EL3 (Secure Monitor mode)\n");
_puts("EL3 (Secure Monitor mode)\n");
break;
default:
_halt("Unknown exception level\n");
Expand All @@ -89,71 +135,49 @@ void start(void)
serror_enable();
isb();

klog("---- IRQ: ");
_puts("---- IRQ: ");
MRS("DAIF", val32);

if (val32 & DAIF_IRQ) {
kprintf("Masked\n");
_puts("Masked\n");
} else {
kprintf("Unmasked\n");
_puts("Unmasked\n");
}

klog("---- FIQ: ");
_puts("---- FIQ: ");

if (val32 & DAIF_FIQ) {
kprintf("Masked\n");
_puts("Masked\n");
} else {
kprintf("Unmasked\n");
_puts("Unmasked\n");
}

klog("---- Debug: ");
_puts("---- Debug: ");

if (val32 & DAIF_DEBUG) {
kprintf("Masked\n");
_puts("Masked\n");
} else {
kprintf("Unmasked\n");
_puts("Unmasked\n");
}

klog("---- SError: ");
_puts("---- SError: ");

if (val32 & DAIF_SERROR) {
kprintf("Masked\n");
_puts("Masked\n");
} else {
kprintf("Unmasked\n");
_puts("Unmasked\n");
}

/* -------- Machine Layout -------- */
klog("QEMU ARM Virt Machine memory layout:\n");

klog("---- BootROM Code: 0x%x - 0x%x (reserved)\n",
BOOTROM_START, BOOTROM_END
);

klog ("---- GICv2: 0x%x - 0x%x (controller)\n",
GIC_BASE, GIC_END
);

klog ("---- PL011 UART: 0x%x - 0x%x (mmio)\n",
PL011_BASE, PL011_END
);

klog ("---- PL031 RTC: 0x%x - 0x%x (mmio)\n",
PL031_BASE, PL031_END
);

klog ("---- PL061 GPIO: 0x%x - 0x%x (mmio)\n",
PL061_BASE, PL061_END
);

klog ("---- QEMU fw_cfg: 0x%x - 0x%x (qemu)\n",
FW_CFG_BASE, FW_CFG_END
);

klog ("---- Device Tree Blob: 0x%x - 0x%x (reserved)\n",
DTB_START, DTB_END
);
/*TODO: Initialize page tables here */

_puts("+----------------------------------------------------+\n");
_puts("| __ _______ __, ____________ _ __ ___ __, |\n");
_puts("| ( / /( / ( ( / ( / ( / ) / ()( |\n");
_puts("| / / / /-- `. / /-- /--< / / `. |\n");
_puts("| (_/_/ (/____/(___)_/ (/____// \\_(___/ (___) |\n");
_puts("| |\n");
_puts("| Everything is OK. Calling the kernel now... |\n");
_puts("+----------------------------------------------------+\n");

klog("Everything's OK. Calling the Kernel now...\n");
kmain();
}

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