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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/kernel/amd_nb.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kernel/amd_nb.c')
-rw-r--r--arch/x86/kernel/amd_nb.c524
1 files changed, 524 insertions, 0 deletions
diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
new file mode 100644
index 000000000..8ea24df3c
--- /dev/null
+++ b/arch/x86/kernel/amd_nb.c
@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Shared support code for AMD K8 northbridges and derivatives.
+ * Copyright 2006 Andi Kleen, SUSE Labs.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <linux/pci_ids.h>
+#include <asm/amd_nb.h>
+
+#define PCI_DEVICE_ID_AMD_17H_ROOT 0x1450
+#define PCI_DEVICE_ID_AMD_17H_M10H_ROOT 0x15d0
+#define PCI_DEVICE_ID_AMD_17H_M30H_ROOT 0x1480
+#define PCI_DEVICE_ID_AMD_17H_M60H_ROOT 0x1630
+#define PCI_DEVICE_ID_AMD_17H_MA0H_ROOT 0x14b5
+#define PCI_DEVICE_ID_AMD_19H_M10H_ROOT 0x14a4
+#define PCI_DEVICE_ID_AMD_19H_M60H_ROOT 0x14d8
+#define PCI_DEVICE_ID_AMD_19H_M70H_ROOT 0x14e8
+#define PCI_DEVICE_ID_AMD_17H_DF_F4 0x1464
+#define PCI_DEVICE_ID_AMD_17H_M10H_DF_F4 0x15ec
+#define PCI_DEVICE_ID_AMD_17H_M30H_DF_F4 0x1494
+#define PCI_DEVICE_ID_AMD_17H_M60H_DF_F4 0x144c
+#define PCI_DEVICE_ID_AMD_17H_M70H_DF_F4 0x1444
+#define PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4 0x1728
+#define PCI_DEVICE_ID_AMD_19H_DF_F4 0x1654
+#define PCI_DEVICE_ID_AMD_19H_M10H_DF_F4 0x14b1
+#define PCI_DEVICE_ID_AMD_19H_M40H_ROOT 0x14b5
+#define PCI_DEVICE_ID_AMD_19H_M40H_DF_F4 0x167d
+#define PCI_DEVICE_ID_AMD_19H_M50H_DF_F4 0x166e
+#define PCI_DEVICE_ID_AMD_19H_M60H_DF_F4 0x14e4
+#define PCI_DEVICE_ID_AMD_19H_M70H_DF_F4 0x14f4
+#define PCI_DEVICE_ID_AMD_19H_M78H_DF_F4 0x12fc
+
+/* Protect the PCI config register pairs used for SMN. */
+static DEFINE_MUTEX(smn_mutex);
+
+static u32 *flush_words;
+
+static const struct pci_device_id amd_root_ids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_ROOT) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_ROOT) },
+ {}
+};
+
+#define PCI_DEVICE_ID_AMD_CNB17H_F4 0x1704
+
+static const struct pci_device_id amd_nb_misc_ids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M10H_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F3) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F3) },
+ {}
+};
+
+static const struct pci_device_id amd_nb_link_ids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F4) },
+ { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F4) },
+ {}
+};
+
+static const struct pci_device_id hygon_root_ids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_ROOT) },
+ {}
+};
+
+static const struct pci_device_id hygon_nb_misc_ids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F3) },
+ {}
+};
+
+static const struct pci_device_id hygon_nb_link_ids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F4) },
+ {}
+};
+
+const struct amd_nb_bus_dev_range amd_nb_bus_dev_ranges[] __initconst = {
+ { 0x00, 0x18, 0x20 },
+ { 0xff, 0x00, 0x20 },
+ { 0xfe, 0x00, 0x20 },
+ { }
+};
+
+static struct amd_northbridge_info amd_northbridges;
+
+u16 amd_nb_num(void)
+{
+ return amd_northbridges.num;
+}
+EXPORT_SYMBOL_GPL(amd_nb_num);
+
+bool amd_nb_has_feature(unsigned int feature)
+{
+ return ((amd_northbridges.flags & feature) == feature);
+}
+EXPORT_SYMBOL_GPL(amd_nb_has_feature);
+
+struct amd_northbridge *node_to_amd_nb(int node)
+{
+ return (node < amd_northbridges.num) ? &amd_northbridges.nb[node] : NULL;
+}
+EXPORT_SYMBOL_GPL(node_to_amd_nb);
+
+static struct pci_dev *next_northbridge(struct pci_dev *dev,
+ const struct pci_device_id *ids)
+{
+ do {
+ dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
+ if (!dev)
+ break;
+ } while (!pci_match_id(ids, dev));
+ return dev;
+}
+
+static int __amd_smn_rw(u16 node, u32 address, u32 *value, bool write)
+{
+ struct pci_dev *root;
+ int err = -ENODEV;
+
+ if (node >= amd_northbridges.num)
+ goto out;
+
+ root = node_to_amd_nb(node)->root;
+ if (!root)
+ goto out;
+
+ mutex_lock(&smn_mutex);
+
+ err = pci_write_config_dword(root, 0x60, address);
+ if (err) {
+ pr_warn("Error programming SMN address 0x%x.\n", address);
+ goto out_unlock;
+ }
+
+ err = (write ? pci_write_config_dword(root, 0x64, *value)
+ : pci_read_config_dword(root, 0x64, value));
+ if (err)
+ pr_warn("Error %s SMN address 0x%x.\n",
+ (write ? "writing to" : "reading from"), address);
+
+out_unlock:
+ mutex_unlock(&smn_mutex);
+
+out:
+ return err;
+}
+
+int amd_smn_read(u16 node, u32 address, u32 *value)
+{
+ return __amd_smn_rw(node, address, value, false);
+}
+EXPORT_SYMBOL_GPL(amd_smn_read);
+
+int amd_smn_write(u16 node, u32 address, u32 value)
+{
+ return __amd_smn_rw(node, address, &value, true);
+}
+EXPORT_SYMBOL_GPL(amd_smn_write);
+
+
+static int amd_cache_northbridges(void)
+{
+ const struct pci_device_id *misc_ids = amd_nb_misc_ids;
+ const struct pci_device_id *link_ids = amd_nb_link_ids;
+ const struct pci_device_id *root_ids = amd_root_ids;
+ struct pci_dev *root, *misc, *link;
+ struct amd_northbridge *nb;
+ u16 roots_per_misc = 0;
+ u16 misc_count = 0;
+ u16 root_count = 0;
+ u16 i, j;
+
+ if (amd_northbridges.num)
+ return 0;
+
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
+ root_ids = hygon_root_ids;
+ misc_ids = hygon_nb_misc_ids;
+ link_ids = hygon_nb_link_ids;
+ }
+
+ misc = NULL;
+ while ((misc = next_northbridge(misc, misc_ids)))
+ misc_count++;
+
+ if (!misc_count)
+ return -ENODEV;
+
+ root = NULL;
+ while ((root = next_northbridge(root, root_ids)))
+ root_count++;
+
+ if (root_count) {
+ roots_per_misc = root_count / misc_count;
+
+ /*
+ * There should be _exactly_ N roots for each DF/SMN
+ * interface.
+ */
+ if (!roots_per_misc || (root_count % roots_per_misc)) {
+ pr_info("Unsupported AMD DF/PCI configuration found\n");
+ return -ENODEV;
+ }
+ }
+
+ nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL);
+ if (!nb)
+ return -ENOMEM;
+
+ amd_northbridges.nb = nb;
+ amd_northbridges.num = misc_count;
+
+ link = misc = root = NULL;
+ for (i = 0; i < amd_northbridges.num; i++) {
+ node_to_amd_nb(i)->root = root =
+ next_northbridge(root, root_ids);
+ node_to_amd_nb(i)->misc = misc =
+ next_northbridge(misc, misc_ids);
+ node_to_amd_nb(i)->link = link =
+ next_northbridge(link, link_ids);
+
+ /*
+ * If there are more PCI root devices than data fabric/
+ * system management network interfaces, then the (N)
+ * PCI roots per DF/SMN interface are functionally the
+ * same (for DF/SMN access) and N-1 are redundant. N-1
+ * PCI roots should be skipped per DF/SMN interface so
+ * the following DF/SMN interfaces get mapped to
+ * correct PCI roots.
+ */
+ for (j = 1; j < roots_per_misc; j++)
+ root = next_northbridge(root, root_ids);
+ }
+
+ if (amd_gart_present())
+ amd_northbridges.flags |= AMD_NB_GART;
+
+ /*
+ * Check for L3 cache presence.
+ */
+ if (!cpuid_edx(0x80000006))
+ return 0;
+
+ /*
+ * Some CPU families support L3 Cache Index Disable. There are some
+ * limitations because of E382 and E388 on family 0x10.
+ */
+ if (boot_cpu_data.x86 == 0x10 &&
+ boot_cpu_data.x86_model >= 0x8 &&
+ (boot_cpu_data.x86_model > 0x9 ||
+ boot_cpu_data.x86_stepping >= 0x1))
+ amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
+
+ if (boot_cpu_data.x86 == 0x15)
+ amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
+
+ /* L3 cache partitioning is supported on family 0x15 */
+ if (boot_cpu_data.x86 == 0x15)
+ amd_northbridges.flags |= AMD_NB_L3_PARTITIONING;
+
+ return 0;
+}
+
+/*
+ * Ignores subdevice/subvendor but as far as I can figure out
+ * they're useless anyways
+ */
+bool __init early_is_amd_nb(u32 device)
+{
+ const struct pci_device_id *misc_ids = amd_nb_misc_ids;
+ const struct pci_device_id *id;
+ u32 vendor = device & 0xffff;
+
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
+ boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
+ return false;
+
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
+ misc_ids = hygon_nb_misc_ids;
+
+ device >>= 16;
+ for (id = misc_ids; id->vendor; id++)
+ if (vendor == id->vendor && device == id->device)
+ return true;
+ return false;
+}
+
+struct resource *amd_get_mmconfig_range(struct resource *res)
+{
+ u32 address;
+ u64 base, msr;
+ unsigned int segn_busn_bits;
+
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
+ boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
+ return NULL;
+
+ /* assume all cpus from fam10h have mmconfig */
+ if (boot_cpu_data.x86 < 0x10)
+ return NULL;
+
+ address = MSR_FAM10H_MMIO_CONF_BASE;
+ rdmsrl(address, msr);
+
+ /* mmconfig is not enabled */
+ if (!(msr & FAM10H_MMIO_CONF_ENABLE))
+ return NULL;
+
+ base = msr & (FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT);
+
+ segn_busn_bits = (msr >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
+ FAM10H_MMIO_CONF_BUSRANGE_MASK;
+
+ res->flags = IORESOURCE_MEM;
+ res->start = base;
+ res->end = base + (1ULL<<(segn_busn_bits + 20)) - 1;
+ return res;
+}
+
+int amd_get_subcaches(int cpu)
+{
+ struct pci_dev *link = node_to_amd_nb(topology_die_id(cpu))->link;
+ unsigned int mask;
+
+ if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
+ return 0;
+
+ pci_read_config_dword(link, 0x1d4, &mask);
+
+ return (mask >> (4 * cpu_data(cpu).cpu_core_id)) & 0xf;
+}
+
+int amd_set_subcaches(int cpu, unsigned long mask)
+{
+ static unsigned int reset, ban;
+ struct amd_northbridge *nb = node_to_amd_nb(topology_die_id(cpu));
+ unsigned int reg;
+ int cuid;
+
+ if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING) || mask > 0xf)
+ return -EINVAL;
+
+ /* if necessary, collect reset state of L3 partitioning and BAN mode */
+ if (reset == 0) {
+ pci_read_config_dword(nb->link, 0x1d4, &reset);
+ pci_read_config_dword(nb->misc, 0x1b8, &ban);
+ ban &= 0x180000;
+ }
+
+ /* deactivate BAN mode if any subcaches are to be disabled */
+ if (mask != 0xf) {
+ pci_read_config_dword(nb->misc, 0x1b8, &reg);
+ pci_write_config_dword(nb->misc, 0x1b8, reg & ~0x180000);
+ }
+
+ cuid = cpu_data(cpu).cpu_core_id;
+ mask <<= 4 * cuid;
+ mask |= (0xf ^ (1 << cuid)) << 26;
+
+ pci_write_config_dword(nb->link, 0x1d4, mask);
+
+ /* reset BAN mode if L3 partitioning returned to reset state */
+ pci_read_config_dword(nb->link, 0x1d4, &reg);
+ if (reg == reset) {
+ pci_read_config_dword(nb->misc, 0x1b8, &reg);
+ reg &= ~0x180000;
+ pci_write_config_dword(nb->misc, 0x1b8, reg | ban);
+ }
+
+ return 0;
+}
+
+static void amd_cache_gart(void)
+{
+ u16 i;
+
+ if (!amd_nb_has_feature(AMD_NB_GART))
+ return;
+
+ flush_words = kmalloc_array(amd_northbridges.num, sizeof(u32), GFP_KERNEL);
+ if (!flush_words) {
+ amd_northbridges.flags &= ~AMD_NB_GART;
+ pr_notice("Cannot initialize GART flush words, GART support disabled\n");
+ return;
+ }
+
+ for (i = 0; i != amd_northbridges.num; i++)
+ pci_read_config_dword(node_to_amd_nb(i)->misc, 0x9c, &flush_words[i]);
+}
+
+void amd_flush_garts(void)
+{
+ int flushed, i;
+ unsigned long flags;
+ static DEFINE_SPINLOCK(gart_lock);
+
+ if (!amd_nb_has_feature(AMD_NB_GART))
+ return;
+
+ /*
+ * Avoid races between AGP and IOMMU. In theory it's not needed
+ * but I'm not sure if the hardware won't lose flush requests
+ * when another is pending. This whole thing is so expensive anyways
+ * that it doesn't matter to serialize more. -AK
+ */
+ spin_lock_irqsave(&gart_lock, flags);
+ flushed = 0;
+ for (i = 0; i < amd_northbridges.num; i++) {
+ pci_write_config_dword(node_to_amd_nb(i)->misc, 0x9c,
+ flush_words[i] | 1);
+ flushed++;
+ }
+ for (i = 0; i < amd_northbridges.num; i++) {
+ u32 w;
+ /* Make sure the hardware actually executed the flush*/
+ for (;;) {
+ pci_read_config_dword(node_to_amd_nb(i)->misc,
+ 0x9c, &w);
+ if (!(w & 1))
+ break;
+ cpu_relax();
+ }
+ }
+ spin_unlock_irqrestore(&gart_lock, flags);
+ if (!flushed)
+ pr_notice("nothing to flush?\n");
+}
+EXPORT_SYMBOL_GPL(amd_flush_garts);
+
+static void __fix_erratum_688(void *info)
+{
+#define MSR_AMD64_IC_CFG 0xC0011021
+
+ msr_set_bit(MSR_AMD64_IC_CFG, 3);
+ msr_set_bit(MSR_AMD64_IC_CFG, 14);
+}
+
+/* Apply erratum 688 fix so machines without a BIOS fix work. */
+static __init void fix_erratum_688(void)
+{
+ struct pci_dev *F4;
+ u32 val;
+
+ if (boot_cpu_data.x86 != 0x14)
+ return;
+
+ if (!amd_northbridges.num)
+ return;
+
+ F4 = node_to_amd_nb(0)->link;
+ if (!F4)
+ return;
+
+ if (pci_read_config_dword(F4, 0x164, &val))
+ return;
+
+ if (val & BIT(2))
+ return;
+
+ on_each_cpu(__fix_erratum_688, NULL, 0);
+
+ pr_info("x86/cpu/AMD: CPU erratum 688 worked around\n");
+}
+
+static __init int init_amd_nbs(void)
+{
+ amd_cache_northbridges();
+ amd_cache_gart();
+
+ fix_erratum_688();
+
+ return 0;
+}
+
+/* This has to go after the PCI subsystem */
+fs_initcall(init_amd_nbs);