1 files changed, 49 insertions, 0 deletions
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..eeb21fd
--- /dev/null
+++ b/main.c
@@ -0,0 +1,49 @@
+#include "bios.h"
+#include "pci.h"
+#include "string.h"
+
+#define PCI_VENDOR_ID_INTEL		0x8086
+#define PCI_DEVICE_ID_INTEL_82441	0x1237
+#define PCI_DEVICE_ID_INTEL_Q35_MCH     0x29c0
+
+#define I440FX_PAM0                     0x59
+#define Q35_HOST_BRIDGE_PAM0            0x90
+
+static void make_bios_writable(void)
+{
+	const int bdf = 0;
+	const uint8_t *bios_start = (uint8_t *)0xffff0000;
+	uint8_t *low_start = (uint8_t *)0xf0000;
+	int pambase;
+
+        uint32_t id = pci_config_readl(bdf, 0);
+        if (id == (PCI_VENDOR_ID_INTEL | (PCI_DEVICE_ID_INTEL_82441 << 16)))
+		pambase = I440FX_PAM0;
+        else if (id == (PCI_VENDOR_ID_INTEL | (PCI_DEVICE_ID_INTEL_Q35_MCH << 16)))
+		pambase = Q35_HOST_BRIDGE_PAM0;
+        else
+		panic();
+
+	// Make ram from 0xc0000-0xf0000 read-write
+	int i;
+	for (i=0; i<6; i++) {
+		int pam = pambase + 1 + i;
+		pci_config_writeb(bdf, pam, 0x33);
+	}
+
+	// Make ram from 0xf0000-0x100000 read-write and shadow BIOS
+	// We're still running from 0xffff0000
+	pci_config_writeb(bdf, pambase, 0x30);
+	memcpy(low_start, bios_start, 0x10000);
+}
+
+
+int main(void)
+{
+	make_bios_writable();
+	// extract_acpi();
+	// extract_smbios();
+	// extract_kernel();
+	// boot_linux();
+	panic();
+}