rulimine/stage23/protos/stivale.c
2021-03-12 00:04:37 +01:00

309 lines
9.9 KiB
C

#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <protos/stivale.h>
#include <lib/libc.h>
#include <lib/elf.h>
#include <lib/blib.h>
#include <lib/acpi.h>
#include <lib/config.h>
#include <lib/time.h>
#include <lib/print.h>
#include <lib/rand.h>
#include <lib/real.h>
#include <lib/uri.h>
#include <lib/fb.h>
#include <lib/term.h>
#include <sys/pic.h>
#include <sys/cpu.h>
#include <sys/gdt.h>
#include <fs/file.h>
#include <mm/vmm.h>
#include <mm/pmm.h>
#include <mm/mtrr.h>
#include <stivale/stivale.h>
#define KASLR_SLIDE_BITMASK 0x000FFF000u
struct stivale_struct stivale_struct = {0};
void stivale_load(char *config, char *cmdline) {
// BIOS or UEFI?
#if defined (bios)
stivale_struct.flags |= (1 << 0);
#endif
stivale_struct.flags |= (1 << 1); // we give colour information
struct file_handle *kernel = ext_mem_alloc(sizeof(struct file_handle));
char *kernel_path = config_get_value(config, 0, "KERNEL_PATH");
if (kernel_path == NULL)
panic("KERNEL_PATH not specified");
if (!uri_open(kernel, kernel_path))
panic("Could not open kernel resource");
struct stivale_header stivale_hdr;
int bits = elf_bits(kernel);
int ret;
uint64_t slide = 0;
bool level5pg = false;
switch (bits) {
case 64: {
// Check if 64 bit CPU
uint32_t eax, ebx, ecx, edx;
if (!cpuid(0x80000001, 0, &eax, &ebx, &ecx, &edx) || !(edx & (1 << 29))) {
panic("stivale: This CPU does not support 64-bit mode.");
}
// Check if 5-level paging is available
if (cpuid(0x00000007, 0, &eax, &ebx, &ecx, &edx) && (ecx & (1 << 16))) {
print("stivale: CPU has 5-level paging support\n");
level5pg = true;
}
char *s_kaslr = config_get_value(config, 0, "KASLR");
if (s_kaslr != NULL && !strcmp(s_kaslr, "yes")) {
// KASLR is enabled, set the slide
slide = rand64() & KASLR_SLIDE_BITMASK;
}
ret = elf64_load_section(kernel, &stivale_hdr, ".stivalehdr", sizeof(struct stivale_header), slide);
break;
}
case 32:
ret = elf32_load_section(kernel, &stivale_hdr, ".stivalehdr", sizeof(struct stivale_header));
break;
default:
panic("stivale: Not 32 nor 64 bit x86 ELF file.");
}
print("stivale: %u-bit ELF file detected\n", bits);
switch (ret) {
case 1:
panic("stivale: File is not a valid ELF.");
case 2:
panic("stivale: Section .stivalehdr not found.");
case 3:
panic("stivale: Section .stivalehdr exceeds the size of the struct.");
case 4:
panic("stivale: Section .stivalehdr is smaller than size of the struct.");
}
print("stivale: Requested stack at %X\n", stivale_hdr.stack);
uint64_t entry_point = 0;
uint64_t top_used_addr = 0;
switch (bits) {
case 64:
elf64_load(kernel, &entry_point, &top_used_addr, slide, 10);
break;
case 32:
elf32_load(kernel, (uint32_t *)&entry_point, (uint32_t *)&top_used_addr, 10);
break;
}
if (stivale_hdr.entry_point != 0)
entry_point = stivale_hdr.entry_point;
print("stivale: Kernel slide: %X\n", slide);
print("stivale: Top used address in ELF: %X\n", top_used_addr);
stivale_struct.module_count = 0;
uint64_t *prev_mod_ptr = &stivale_struct.modules;
for (int i = 0; ; i++) {
char *module_path = config_get_value(config, i, "MODULE_PATH");
if (module_path == NULL)
break;
stivale_struct.module_count++;
struct stivale_module *m = ext_mem_alloc(sizeof(struct stivale_module));
char *module_string = config_get_value(config, i, "MODULE_STRING");
if (module_string == NULL) {
m->string[0] = '\0';
} else {
// TODO perhaps change this to be a pointer
size_t str_len = strlen(module_string);
if (str_len > 127)
str_len = 127;
memcpy(m->string, module_string, str_len);
}
print("stivale: Loading module `%s`...\n", module_path);
struct file_handle f;
if (!uri_open(&f, module_path))
panic("Requested module with path \"%s\" not found!", module_path);
m->begin = (uint64_t)(size_t)freadall(&f, STIVALE_MMAP_KERNEL_AND_MODULES);
m->end = m->begin + f.size;
m->next = 0;
*prev_mod_ptr = (uint64_t)(size_t)m;
prev_mod_ptr = &m->next;
print("stivale: Requested module %u:\n", i);
print(" Path: %s\n", module_path);
print(" String: %s\n", m->string);
print(" Begin: %X\n", m->begin);
print(" End: %X\n", m->end);
}
stivale_struct.rsdp = (uint64_t)(size_t)acpi_get_rsdp();
stivale_struct.cmdline = (uint64_t)(size_t)cmdline;
stivale_struct.epoch = time();
print("stivale: Current epoch: %U\n", stivale_struct.epoch);
term_deinit();
if (stivale_hdr.flags & (1 << 0)) {
int req_width = stivale_hdr.framebuffer_width;
int req_height = stivale_hdr.framebuffer_height;
int req_bpp = stivale_hdr.framebuffer_bpp;
char *resolution = config_get_value(config, 0, "RESOLUTION");
if (resolution != NULL)
parse_resolution(&req_width, &req_height, &req_bpp, resolution);
struct fb_info fbinfo;
if (!fb_init(&fbinfo, req_width, req_height, req_bpp))
panic("stivale: Unable to set video mode");
stivale_struct.framebuffer_addr = (uint64_t)fbinfo.framebuffer_addr;
stivale_struct.framebuffer_width = fbinfo.framebuffer_width;
stivale_struct.framebuffer_height = fbinfo.framebuffer_height;
stivale_struct.framebuffer_bpp = fbinfo.framebuffer_bpp;
stivale_struct.framebuffer_pitch = fbinfo.framebuffer_pitch;
stivale_struct.fb_memory_model = STIVALE_FBUF_MMODEL_RGB;
stivale_struct.fb_red_mask_size = fbinfo.red_mask_size;
stivale_struct.fb_red_mask_shift = fbinfo.red_mask_shift;
stivale_struct.fb_green_mask_size = fbinfo.green_mask_size;
stivale_struct.fb_green_mask_shift = fbinfo.green_mask_shift;
stivale_struct.fb_blue_mask_size = fbinfo.blue_mask_size;
stivale_struct.fb_blue_mask_shift = fbinfo.blue_mask_shift;
}
#if defined (uefi)
efi_exit_boot_services();
#endif
bool want_5lv = level5pg && (stivale_hdr.flags & (1 << 1));
pagemap_t pagemap = stivale_build_pagemap(want_5lv);
size_t memmap_entries;
struct e820_entry_t *memmap = get_memmap(&memmap_entries);
stivale_struct.memory_map_entries = (uint64_t)memmap_entries;
stivale_struct.memory_map_addr = (uint64_t)(size_t)memmap;
stivale_spinup(bits, want_5lv, &pagemap,
entry_point, &stivale_struct, stivale_hdr.stack);
}
pagemap_t stivale_build_pagemap(bool level5pg) {
pagemap_t pagemap = new_pagemap(level5pg ? 5 : 4);
uint64_t higher_half_base = level5pg ? 0xff00000000000000 : 0xffff800000000000;
// Map 0 to 2GiB at 0xffffffff80000000
for (uint64_t i = 0; i < 0x80000000; i += PAGE_SIZE) {
map_page(pagemap, 0xffffffff80000000 + i, i, 0x03);
}
// Map 0 to 4GiB at higher half base and 0
for (uint64_t i = 0; i < 0x100000000; i += PAGE_SIZE) {
map_page(pagemap, i, i, 0x03);
map_page(pagemap, higher_half_base + i, i, 0x03);
}
size_t _memmap_entries = memmap_entries;
struct e820_entry_t *_memmap =
ext_mem_alloc(_memmap_entries * sizeof(struct e820_entry_t));
for (size_t i = 0; i < _memmap_entries; i++)
_memmap[i] = memmap[i];
// Map any other region of memory from the memmap
for (size_t i = 0; i < _memmap_entries; i++) {
uint64_t base = _memmap[i].base;
uint64_t length = _memmap[i].length;
uint64_t top = base + length;
uint64_t aligned_base = ALIGN_DOWN(base, PAGE_SIZE);
uint64_t aligned_top = ALIGN_UP(top, PAGE_SIZE);
uint64_t aligned_length = aligned_top - aligned_base;
for (uint64_t i = 0; i < aligned_length; i += PAGE_SIZE) {
uint64_t page = aligned_base + i;
map_page(pagemap, page, page, 0x03);
map_page(pagemap, higher_half_base + page, page, 0x03);
}
}
return pagemap;
}
#if defined (uefi)
extern symbol ImageBase;
#endif
__attribute__((noreturn)) void stivale_spinup_32(
int bits, bool level5pg, uint32_t pagemap_top_lv,
uint32_t entry_point_lo, uint32_t entry_point_hi,
void *stivale_struct, uint32_t stack_lo, uint32_t stack_hi);
__attribute__((noreturn)) void stivale_spinup(
int bits, bool level5pg, pagemap_t *pagemap,
uint64_t entry_point, void *stivale_struct, uint64_t stack) {
mtrr_restore();
#if defined (bios)
if (bits == 64) {
// If we're going 64, we might as well call this BIOS interrupt
// to tell the BIOS that we are entering Long Mode, since it is in
// the specification.
struct rm_regs r = {0};
r.eax = 0xec00;
r.ebx = 0x02; // Long mode only
rm_int(0x15, &r, &r);
}
#endif
pic_mask_all();
pic_flush();
#if defined (uefi)
asm volatile (
"lgdt %0\n\t"
:
: "m"(gdt)
: "memory"
);
do_32(stivale_spinup_32, 8,
bits, level5pg, (uint32_t)(uintptr_t)pagemap->top_level,
(uint32_t)entry_point, (uint32_t)(entry_point >> 32),
stivale_struct,
(uint32_t)stack, (uint32_t)(stack >> 32));
#endif
#if defined (bios)
stivale_spinup_32(bits, level5pg, (uint32_t)(uintptr_t)pagemap->top_level,
(uint32_t)entry_point, (uint32_t)(entry_point >> 32),
stivale_struct,
(uint32_t)stack, (uint32_t)(stack >> 32));
#endif
__builtin_unreachable();
}