--- /dev/null
+// Support for enabling/disabling BIOS ram shadowing.
+//
+// Copyright (C) 2008-2010 Kevin O'Connor <kevin@koconnor.net>
+// Copyright (C) 2006 Fabrice Bellard
+//
+// This file may be distributed under the terms of the GNU LGPLv3 license.
+
+#include "util.h" // memcpy
+#include "pci.h" // pci_config_writeb
+#include "config.h" // CONFIG_*
+#include "pci_ids.h" // PCI_VENDOR_ID_INTEL
+#include "pci_regs.h" // PCI_VENDOR_ID
+#include "xen.h" // usingXen
+
+// On the emulators, the bios at 0xf0000 is also at 0xffff0000
+#define BIOS_SRC_OFFSET 0xfff00000
+
+#define I440FX_PAM0 0x59
+
+// Enable shadowing and copy bios.
+static void
+__make_bios_writable_intel(u16 bdf, u32 pam0)
+{
+ // Make ram from 0xc0000-0xf0000 writable
+ int clear = 0;
+ int i;
+ for (i=0; i<6; i++) {
+ u32 pam = pam0 + 1 + i;
+ int reg = pci_config_readb(bdf, pam);
+ if (CONFIG_OPTIONROMS_DEPLOYED && (reg & 0x11) != 0x11) {
+ // Need to copy optionroms to work around qemu implementation
+ void *mem = (void*)(BUILD_ROM_START + i * 32*1024);
+ memcpy((void*)BUILD_BIOS_TMP_ADDR, mem, 32*1024);
+ pci_config_writeb(bdf, pam, 0x33);
+ memcpy(mem, (void*)BUILD_BIOS_TMP_ADDR, 32*1024);
+ clear = 1;
+ } else {
+ pci_config_writeb(bdf, pam, 0x33);
+ }
+ }
+ if (clear)
+ memset((void*)BUILD_BIOS_TMP_ADDR, 0, 32*1024);
+
+ // Make ram from 0xf0000-0x100000 writable
+ int reg = pci_config_readb(bdf, pam0);
+ pci_config_writeb(bdf, pam0, 0x30);
+ if (reg & 0x10)
+ // Ram already present.
+ return;
+
+ // Copy bios.
+ extern u8 code32flat_start[], code32flat_end[];
+ memcpy(code32flat_start, code32flat_start + BIOS_SRC_OFFSET
+ , code32flat_end - code32flat_start);
+}
+
+static void
+make_bios_writable_intel(u16 bdf, u32 pam0)
+{
+ int reg = pci_config_readb(bdf, pam0);
+ if (!(reg & 0x10)) {
+ // QEMU doesn't fully implement the piix shadow capabilities -
+ // if ram isn't backing the bios segment when shadowing is
+ // disabled, the code itself wont be in memory. So, run the
+ // code from the high-memory flash location.
+ u32 pos = (u32)__make_bios_writable_intel + BIOS_SRC_OFFSET;
+ void (*func)(u16 bdf, u32 pam0) = (void*)pos;
+ func(bdf, pam0);
+ return;
+ }
+ // Ram already present - just enable writes
+ __make_bios_writable_intel(bdf, pam0);
+}
+
+static void
+make_bios_readonly_intel(u16 bdf, u32 pam0)
+{
+ // Flush any pending writes before locking memory.
+ wbinvd();
+
+ // Write protect roms from 0xc0000-0xf0000
+ int i;
+ for (i=0; i<6; i++) {
+ u32 mem = BUILD_ROM_START + i * 32*1024;
+ u32 pam = pam0 + 1 + i;
+ if (RomEnd <= mem + 16*1024) {
+ if (RomEnd > mem)
+ pci_config_writeb(bdf, pam, 0x31);
+ break;
+ }
+ pci_config_writeb(bdf, pam, 0x11);
+ }
+
+ // Write protect 0xf0000-0x100000
+ pci_config_writeb(bdf, pam0, 0x10);
+}
+
+static void i440fx_bios_make_readonly(struct pci_device *pci, void *arg)
+{
+ make_bios_readonly_intel(pci->bdf, I440FX_PAM0);
+}
+
+static const struct pci_device_id dram_controller_make_readonly_tbl[] = {
+ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82441,
+ i440fx_bios_make_readonly),
+ PCI_DEVICE_END
+};
+
+// Make the 0xc0000-0x100000 area read/writable.
+void
+make_bios_writable(void)
+{
+ if (CONFIG_COREBOOT || usingXen())
+ return;
+
+ dprintf(3, "enabling shadow ram\n");
+
+ // At this point, statically allocated variables can't be written,
+ // so do this search manually.
+ int bdf;
+ foreachbdf(bdf, 0) {
+ u32 vendev = pci_config_readl(bdf, PCI_VENDOR_ID);
+ u16 vendor = vendev & 0xffff, device = vendev >> 16;
+ if (vendor == PCI_VENDOR_ID_INTEL
+ && device == PCI_DEVICE_ID_INTEL_82441) {
+ make_bios_writable_intel(bdf, I440FX_PAM0);
+ return;
+ }
+ }
+ dprintf(1, "Unable to unlock ram - bridge not found\n");
+}
+
+// Make the BIOS code segment area (0xf0000) read-only.
+void
+make_bios_readonly(void)
+{
+ if (CONFIG_COREBOOT || usingXen())
+ return;
+
+ dprintf(3, "locking shadow ram\n");
+ struct pci_device *pci = pci_find_init_device(
+ dram_controller_make_readonly_tbl, NULL);
+ if (!pci)
+ dprintf(1, "Unable to lock ram - bridge not found\n");
+}
+
+void
+qemu_prep_reset(void)
+{
+ if (CONFIG_COREBOOT)
+ return;
+ // QEMU doesn't map 0xc0000-0xfffff back to the original rom on a
+ // reset, so do that manually before invoking a hard reset.
+ make_bios_writable();
+ extern u8 code32flat_start[], code32flat_end[];
+ memcpy(code32flat_start, code32flat_start + BIOS_SRC_OFFSET
+ , code32flat_end - code32flat_start);
+}
