mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-27 14:58:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Start exploring graphical video modes for VGA console (#637)

Browse source
This commit is contained in:
tkchia 2022-10-02 16:50:16 +08:00 • committed by GitHub
parent 304cf8869c
commit ecb2ef7c39
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
8 changed files with 964 additions and 70 deletions
Download patch file Download diff file Expand all files Collapse all files

35
libc/intrin/mman.greg.c
View file

@ -112,19 +112,34 @@ static noasan textreal void __normalize_e820(struct mman *mm) {
mm->e820n = n;
}
/**
* Identity maps an area of physical memory to its negative address.
*/
noasan textreal void __invert_memory_area(struct mman *mm, uint64_t *pml4t,
uint64_t ps, uint64_t size,
uint64_t pte_flags) {
uint64_t pe = ps + size, p, *m;
ps = ROUNDDOWN(ps, 4096);
pe = ROUNDUP(pe, 4096);
for (p = ps; p != pe; p += 4096) {
m = __get_virtual(mm, pml4t, BANE + p, true);
if (m && !(*m & PAGE_V)) {
*m = p | PAGE_V | pte_flags;
}
}
}
/**
* Identity maps all usable physical memory to its negative address.
*/
static noasan textreal void __invert_memory(struct mman *mm, uint64_t *pml4t) {
uint64_t i, j, *m, p, pe;
for (i = 0; i < mm->e820n; ++i) {
for (p = mm->e820[i].addr, pe = mm->e820[i].addr + mm->e820[i].size;
p != pe + 0x200000; p += 4096) {
m = __get_virtual(mm, pml4t, BANE + p, true);
if (m && !(*m & PAGE_V)) {
*m = p | PAGE_V | PAGE_RW;
}
}
uint64_t ps = mm->e820[i].addr, size = mm->e820[i].size;
/* ape/ape.S has already mapped the first 2 MiB of physical memory. */
if (ps < 0x200000 && ps + size <= 0x200000)
continue;
__invert_memory_area(mm, pml4t, ps, size, PAGE_RW);
}
}
@ -148,6 +163,12 @@ noasan textreal void __setup_mman(struct mman *mm, uint64_t *pml4t) {
export_offsetof(struct mman, e820);
export_offsetof(struct mman, e820_end);
export_offsetof(struct mman, bad_idt);
export_offsetof(struct mman, pc_video_type);
export_offsetof(struct mman, pc_video_stride);
export_offsetof(struct mman, pc_video_width);
export_offsetof(struct mman, pc_video_height);
export_offsetof(struct mman, pc_video_framebuffer);
export_offsetof(struct mman, pc_video_framebuffer_size);
__normalize_e820(mm);
__invert_memory(mm, pml4t);
}