1 files changed, 48 insertions, 0 deletions
diff --git a/arch/x86_64/boot/limine/framebuffer.c b/arch/x86_64/boot/limine/framebuffer.c
new file mode 100644
index 0000000..aa93496
--- /dev/null
+++ b/arch/x86_64/boot/limine/framebuffer.c
@@ -0,0 +1,48 @@
+#include "arch/x86_64/hal/paging.h"
+#include "jove.h"
+#include "config.h"
+#include "hal/framebuffer.h"
+#include "lib/printf.h"
+
+/*We don't know the size of the framebuffer until runtime, but at the same
+ * time we don't want to dynamically allocate from physical memory. In this
+ * case we allocate memory for the maximum supported framebuffer at compile
+ * time and only use what we need at runtime.*/
+#define FRAMEBUFFER_MAX_BYTES (FRAMEBUFFER_MAX_WIDTH * FRAMEBUFFER_MAX_WIDTH * 4)
+#define FRAMEBUFFER_MAX_PAGES ((FRAMEBUFFER_MAX_BYTES + 4095) / 0x1000)
+#define FRAMEBUFFER_MAX_HUGEPAGES ((FRAMEBUFFER_MAX_PAGES + 511) / 512)
+#define FRAMEBUFFER_MAX_GIANTPAGES ((FRAMEBUFFER_MAX_HUGEPAGES + 511) / 512)
+
+PAGEALIGN static page_t fb_pml2[FRAMEBUFFER_MAX_GIANTPAGES][512];
+
+extern page_t _kernel_pml3[512];
+
+void*
+fb_remap(uintptr_t fb_address,
+         size_t fb_bytes)
+{
+    fb_address &= ~IDENT_VIRT_BASE;
+    size_t fb_pages = (fb_bytes + 4095) >> 12;
+    size_t fb_hugepages = (fb_pages + 511) >> 9;
+    size_t fb_giantpages = (fb_hugepages + 511) >> 9;
+
+    if(fb_pages > FRAMEBUFFER_MAX_PAGES) {
+        kprintf("Framebuffer is too big! Please recompile the kernel with a bigger framebuffer allowance!");
+        return NULL;
+    }
+
+    for(size_t pml2 = 0; pml2 < fb_giantpages; pml2++) {
+        uintptr_t fb_pml2_pptr = KPTR_TOPHYS((uintptr_t)fb_pml2[pml2]);
+        _kernel_pml3[pml2].value = fb_pml2_pptr | PAGE_PRESENT | PAGE_GLOBAL | PAGE_WRITEABLE;
+    }
+
+    for(size_t pml1 = 0; pml1 < fb_hugepages; pml1++) {
+        size_t pml2 = pml1 >> 9;
+        size_t pml1_mod = pml1 % 512;
+        uintptr_t fb_off = fb_address + (pml1 << 21);
+        fb_pml2[pml2][pml1_mod].value = fb_off | PAGE_PRESENT | PAGE_GLOBAL | PAGE_WRITEABLE | PAGE_PS;
+    }
+
+    uintptr_t fb_virt = IDENT_VIRT_BASE | (511ULL << PMLI_SHL(3));
+    return (void*)fb_virt;
+}