drivers: add basic framebuffer support

Makefile

@@ -123,7 +123,7 @@ ifeq ($(CONFIG_ACPICA),y)
 COMMON_FLAGS += -DKTF_ACPICA
 endif
 
-AFLAGS  := $(COMMON_FLAGS) -D__ASSEMBLY__ -nostdlib -nostdinc
+AFLAGS  := $(COMMON_FLAGS) -DASM_FILE -D__ASSEMBLY__ -nostdlib -nostdinc
 CFLAGS  := $(COMMON_FLAGS) -std=gnu99 -O2 -g -Wall -Wextra -ffreestanding -nostdlib -nostdinc
 CFLAGS  += -mno-red-zone -mno-mmx -mno-sse -mno-sse2
 CFLAGS  += -fno-stack-protector -fno-exceptions -fno-builtin -fomit-frame-pointer -fcf-protection="none"

arch/x86/boot/boot.S

@@ -1,5 +1,6 @@
 /*
  * Copyright © 2020 Amazon.com, Inc. or its affiliates.
+ * Copyright © 2022 Open Source Security, Inc.
  * All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -23,16 +24,38 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <asm-macros.h>
+#include <multiboot.h>
 
 SECTION(.multiboot, "a", 4)
-#define MULTIBOOT_PAGE_ALIGN (1<<0)
-#define MULTIBOOT_MEMORY_INFO (1<<1)
-#define MULTIBOOT_HEADER_MAGIC (0x1BADB002)
-#define MULTIBOOT_HEADER_FLAGS (MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO)
+#define MULTIBOOT_HEADER_FLAGS (MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_VIDEO_MODE)
 #define MULTIBOOT_CHECKSUM -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
 
+#define MULTIBOOT_VIDEO_MODE_GFX 0
+#define MULTIBOOT_VIDEO_MODE_TEXT 1
+
+#define MULTIBOOT_MODE_TYPE MULTIBOOT_VIDEO_MODE_GFX
+
+#define MULTIBOOT_HEADER_ADDR      0
+#define MULTIBOOT_LOAD_ADDRESS     0
+#define MULTIBOOT_LOAD_END_ADDRESS 0
+#define MULTIBOOT_BSS_END_ADDRESS  0
+#define MULTIBOOT_ENTRY_ADDRESS    0
+
+#define MULTIBOOT_FB_WIDTH  1024
+#define MULTIBOOT_FB_HEIGHT  768
+#define MULTIBOOT_FB_BPP      32
+
 .code32
 multiboot_header:
     .long MULTIBOOT_HEADER_MAGIC
     .long MULTIBOOT_HEADER_FLAGS
     .long MULTIBOOT_CHECKSUM
+    .long MULTIBOOT_HEADER_ADDR
+    .long MULTIBOOT_LOAD_ADDRESS
+    .long MULTIBOOT_LOAD_END_ADDRESS
+    .long MULTIBOOT_BSS_END_ADDRESS
+    .long MULTIBOOT_ENTRY_ADDRESS
+    .long MULTIBOOT_MODE_TYPE
+    .long MULTIBOOT_FB_WIDTH
+    .long MULTIBOOT_FB_HEIGHT
+    .long MULTIBOOT_FB_BPP

arch/x86/boot/multiboot.c

@@ -194,3 +194,19 @@ int mbi_get_memory_range(paddr_t pa, addr_range_t *r) {
 
     return 0;
 }
+
+bool mbi_has_framebuffer(void) {
+    if (!has_mbi_flag(MULTIBOOT_INFO_FRAMEBUFFER_INFO))
+        return false;
+
+    switch (multiboot_info->framebuffer_type) {
+    case MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED:
+    case MULTIBOOT_FRAMEBUFFER_TYPE_RGB:
+        return true;
+    case MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT:
+    default:
+        return false;
+    }
+
+    return false;
+}

common/console.c

@@ -30,6 +30,7 @@
 #include <spinlock.h>
 #include <string.h>
 
+#include <drivers/fb.h>
 #include <drivers/serial.h>
 #include <drivers/vga.h>
 
@@ -98,6 +99,10 @@ void vga_console_write(void *vga_memory, const char *buf, size_t len) {
     vga_write(vga_memory, buf, len, VGA_WHITE);
 }
 
+void fb_console_write(void *fb_memory, const char *buf, size_t len) {
+    fb_write(fb_memory, buf, len, FB_WHITE);
+}
+
 void register_console_callback(console_callback_t cb, void *arg) {
     console_callbacks[num_console_callbacks].cb = cb;
     console_callbacks[num_console_callbacks++].arg = arg;

common/setup.c

@@ -50,6 +50,7 @@
 #include <smp/mptables.h>
 #include <smp/smp.h>
 
+#include <drivers/fb.h>
 #include <drivers/hpet.h>
 #include <drivers/pic.h>
 #include <drivers/pit.h>
@@ -137,6 +138,8 @@ static void display_cpu_info(void) {
         printk("Frequency: %lu MHz\n", freq / MHZ(1));
 }
 
+static void display_banner(void) { draw_logo(); }
+
 static void __text_init init_vga_console(void) {
     if (!boot_flags.vga)
         return;
@@ -194,6 +197,11 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic,
     if (opt_debug)
         dump_pagetables();
 
+    if (init_framebuffer(mbi))
+        display_banner();
+    else
+        init_vga_console();
+
     init_percpu();
 
     init_traps(get_bsp_cpu_id());
@@ -213,8 +221,6 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic,
             BUG();
     }
 
-    init_vga_console();
-
     init_apic(get_bsp_cpu_id(), APIC_MODE_XAPIC);
 
     init_tasks();

drivers/fb/fb.c

@@ -0,0 +1,181 @@
+/*
+ * Copyright © 2022 Open Source Security, Inc.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <console.h>
+#include <drivers/fb.h>
+#include <drivers/logo.h>
+#include <ktf.h>
+#include <multiboot.h>
+#include <page.h>
+#include <string.h>
+
+extern uint64_t fonts[];
+
+static uint32_t width;
+static uint32_t height;
+static uint32_t pitch;
+static uint8_t bpp;
+
+static size_t buffer_size;
+static size_t banner_size;
+static void *video_memory;
+
+static void (*put_pixel)(uint32_t x, uint32_t y, uint32_t color);
+
+static void map_fb_area(paddr_t start, size_t size) {
+    for (mfn_t video_mfn = paddr_to_mfn(start); video_mfn < paddr_to_mfn(start + size);
+         video_mfn++) {
+        vmap_4k(mfn_to_virt(video_mfn), video_mfn, L1_PROT_NOCACHE);
+        kmap_4k(video_mfn, L1_PROT_NOCACHE);
+    }
+}
+
+static void put_pixel8(uint32_t x, uint32_t y, uint32_t color) {
+    *(uint8_t *) (video_memory + (y * pitch) + x) = color;
+}
+
+static void put_pixel16(uint32_t x, uint32_t y, uint32_t color) {
+    *(uint16_t *) (video_memory + (y * pitch) + (x * 2)) = color;
+}
+
+static void put_pixel24(uint32_t x, uint32_t y, uint32_t color) {
+    uint32_t *px = video_memory + (y * pitch) + (x * 3);
+
+    *px = (color & 0x00ffffff) | (*px & 0xff000000);
+}
+
+static void put_pixel32(uint32_t x, uint32_t y, uint32_t color) {
+    *(uint32_t *) (video_memory + (y * pitch) + (x * 4)) = color;
+}
+
+bool init_framebuffer(const multiboot_info_t *mbi) {
+    if (!mbi_has_framebuffer())
+        return false;
+
+    video_memory = (void *) mbi->framebuffer_addr;
+    if (!video_memory)
+        return false;
+
+    width = mbi->framebuffer_width;
+    height = mbi->framebuffer_height;
+    pitch = mbi->framebuffer_pitch;
+    bpp = mbi->framebuffer_bpp;
+
+    buffer_size = (size_t) width * height;
+    banner_size = (size_t) width * LOGO_HEIGHT;
+
+    switch (bpp) {
+    case 0 ... 7:
+        printk("FB: Unsupported framebuffer BPP: %u\n", bpp);
+        return false;
+    case 8:
+        put_pixel = put_pixel8;
+        break;
+    case 15:
+    case 16:
+        put_pixel = put_pixel16;
+        buffer_size *= 2;
+        banner_size *= 2;
+        break;
+    case 24:
+        put_pixel = put_pixel24;
+        buffer_size *= 3;
+        banner_size *= 3;
+        break;
+    case 32:
+        put_pixel = put_pixel32;
+        buffer_size *= 4;
+        banner_size *= 4;
+        break;
+    default:
+        BUG();
+    }
+
+    map_fb_area(mbi->framebuffer_addr, buffer_size);
+    memset(video_memory, 0, buffer_size);
+
+    register_console_callback(fb_console_write, video_memory);
+    return true;
+}
+
+void put_char(char c, uint32_t x, uint32_t y, uint32_t color) {
+    uint64_t font = fonts[(uint8_t) c];
+
+    for (int yy = 0; yy < 8; yy++) {
+        for (int xx = 0; xx < 8; xx++, font >>= 1) {
+            if (font & 1)
+                put_pixel(x + xx, y + yy, color);
+        }
+    }
+}
+
+void draw_line(uint32_t x1, uint32_t y1, uint32_t x2, uint32_t y2, uint32_t color) {
+    while (x1 <= x2 || y1 <= y2) {
+        put_pixel(x1, y1, color);
+        if (x1 <= x2)
+            x1++;
+        if (y1 <= y2)
+            y1++;
+    }
+}
+
+void draw_logo(void) {
+    uint32_t *px = (uint32_t *) logo;
+
+    for (int y = LOGO_HEIGHT; y > 0; y--) {
+        for (int x = 0; x < LOGO_WIDTH; x++)
+            put_pixel(x, y, *px++);
+    }
+
+    draw_line(0, LOGO_HEIGHT + 4, width, LOGO_HEIGHT + 4, FB_WHITE);
+}
+
+static void clear_screen(void *fb_addr) {
+    memset((uint8_t *) video_memory + banner_size, 0, buffer_size - banner_size);
+}
+
+void fb_write(void *fb_addr, const char *buf, size_t len, uint32_t color) {
+    static uint32_t row = LOGO_HEIGHT + 8, col = 0;
+
+    for (unsigned int i = 0; i < len; i++) {
+        char c = buf[i];
+
+        if ((col + 8) > width || c == '\n') {
+            row += sizeof(fonts[0]);
+            col = 0;
+        }
+
+        if ((row + 8) > height) {
+            clear_screen(fb_addr);
+            row = LOGO_HEIGHT + 8;
+            col = 0;
+        }
+
+        if (c == '\n')
+            continue;
+
+        put_char(c, col, row, color);
+        col += sizeof(fonts[0]);
+    }
+}