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// Support for enabling/disabling BIOS ram shadowing.
//
// Copyright (C) 2008 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
// Test if 'addr' is in the range from 'start'..'start+size'
#define IN_RANGE(addr, start, size) ({ \
u32 __addr = (addr); \
u32 __start = (start); \
u32 __size = (size); \
(__addr - __start < __size); \
})
// Enable shadowing and copy bios.
static void
copy_bios(u16 bdf)
{
int v = pci_config_readb(bdf, 0x59);
v |= 0x30;
pci_config_writeb(bdf, 0x59, v);
memcpy((void *)BUILD_BIOS_ADDR, (void *)BUILD_BIOS_TMP_ADDR
, BUILD_BIOS_SIZE);
}
// Make the BIOS code segment area (0xf0000) writable.
void
make_bios_writable()
{
if (CONFIG_COREBOOT)
return;
dprintf(3, "enabling shadow ram\n");
// Locate chip controlling ram shadowing.
int bdf = pci_find_device(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82441);
if (bdf < 0) {
dprintf(1, "Unable to unlock ram - bridge not found\n");
return;
}
// Copy the bios to a temporary area.
memcpy((void *)BUILD_BIOS_TMP_ADDR, (void *)BUILD_BIOS_ADDR
, BUILD_BIOS_SIZE);
// Enable shadowing and copy bios.
if (IN_RANGE((u32)copy_bios, BUILD_BIOS_ADDR, BUILD_BIOS_SIZE)) {
// Jump to shadow enable function - use the copy in the
// temporary storage area so that memory does not change under
// the executing code.
u32 pos = (u32)copy_bios - BUILD_BIOS_ADDR + BUILD_BIOS_TMP_ADDR;
void (*func)(u16 bdf) = (void*)pos;
func(bdf);
} else {
copy_bios(bdf);
}
// Clear the temporary area.
memset((void *)BUILD_BIOS_TMP_ADDR, 0, BUILD_BIOS_SIZE);
}
// Make the BIOS code segment area (0xf0000) read-only.
void
make_bios_readonly()
{
if (CONFIG_COREBOOT)
return;
dprintf(3, "locking shadow ram\n");
int bdf = pci_find_device(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82441);
if (bdf < 0) {
dprintf(1, "Unable to lock ram - bridge not found\n");
return;
}
wbinvd();
int v = pci_config_readb(bdf, 0x59);
v = (v & 0x0f) | (0x10);
pci_config_writeb(bdf, 0x59, v);
}
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