/* Generic MTRR (Memory Type Range Register) driver. Copyright (C) 1997-2000 Richard Gooch Copyright (c) 2002 Patrick Mochel This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. Richard Gooch may be reached by email at rgooch@atnf.csiro.au The postal address is: Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. Source: "Pentium Pro Family Developer's Manual, Volume 3: Operating System Writer's Guide" (Intel document number 242692), section 11.11.7 This was cleaned and made readable by Patrick Mochel on 6-7 March 2002. Source: Intel Architecture Software Developers Manual, Volume 3: System Programming Guide; Section 9.11. (1997 edition - PPro). */ #define DEBUG #include /* FIXME: kvm_para.h needs this */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "mtrr.h" /* arch_phys_wc_add returns an MTRR register index plus this offset. */ #define MTRR_TO_PHYS_WC_OFFSET 1000 u32 num_var_ranges; static bool __mtrr_enabled; static bool mtrr_enabled(void) { return __mtrr_enabled; } unsigned int mtrr_usage_table[MTRR_MAX_VAR_RANGES]; static DEFINE_MUTEX(mtrr_mutex); u64 size_or_mask, size_and_mask; static bool mtrr_aps_delayed_init; static const struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM] __ro_after_init; const struct mtrr_ops *mtrr_if; static void set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type); void __init set_mtrr_ops(const struct mtrr_ops *ops) { if (ops->vendor && ops->vendor < X86_VENDOR_NUM) mtrr_ops[ops->vendor] = ops; } /* Returns non-zero if we have the write-combining memory type */ static int have_wrcomb(void) { struct pci_dev *dev; dev = pci_get_class(PCI_CLASS_BRIDGE_HOST << 8, NULL); if (dev != NULL) { /* * ServerWorks LE chipsets < rev 6 have problems with * write-combining. Don't allow it and leave room for other * chipsets to be tagged */ if (dev->vendor == PCI_VENDOR_ID_SERVERWORKS && dev->device == PCI_DEVICE_ID_SERVERWORKS_LE && dev->revision <= 5) { pr_info("Serverworks LE rev < 6 detected. Write-combining disabled.\n"); pci_dev_put(dev); return 0; } /* * Intel 450NX errata # 23. Non ascending cacheline evictions to * write combining memory may resulting in data corruption */ if (dev->vendor == PCI_VENDOR_ID_INTEL && dev->device == PCI_DEVICE_ID_INTEL_82451NX) { pr_info("Intel 450NX MMC detected. Write-combining disabled.\n"); pci_dev_put(dev); return 0; } pci_dev_put(dev); } return mtrr_if->have_wrcomb ? mtrr_if->have_wrcomb() : 0; } /* This function returns the number of variable MTRRs */ static void __init set_num_var_ranges(void) { unsigned long config = 0, dummy; if (use_intel()) rdmsr(MSR_MTRRcap, config, dummy); else if (is_cpu(AMD) || is_cpu(HYGON)) config = 2; else if (is_cpu(CYRIX) || is_cpu(CENTAUR)) config = 8; num_var_ranges = config & 0xff; } static void __init init_table(void) { int i, max; max = num_var_ranges; for (i = 0; i < max; i++) mtrr_usage_table[i] = 1; } struct set_mtrr_data { unsigned long smp_base; unsigned long smp_size; unsigned int smp_reg; mtrr_type smp_type; }; /** * mtrr_rendezvous_handler - Work done in the synchronization handler. Executed * by all the CPUs. * @info: pointer to mtrr configuration data * * Returns nothing. */ static int mtrr_rendezvous_handler(void *info) { struct set_mtrr_data *data = info; /* * We use this same function to initialize the mtrrs during boot, * resume, runtime cpu online and on an explicit request to set a * specific MTRR. * * During boot or suspend, the state of the boot cpu's mtrrs has been * saved, and we want to replicate that across all the cpus that come * online (either at the end of boot or resume or during a runtime cpu * online). If we're doing that, @reg is set to something special and on * all the cpu's we do mtrr_if->set_all() (On the logical cpu that * started the boot/resume sequence, this might be a duplicate * set_all()). */ if (data->smp_reg != ~0U) { mtrr_if->set(data->smp_reg, data->smp_base, data->smp_size, data->smp_type); } else if (mtrr_aps_delayed_init || !cpu_online(smp_processor_id())) { mtrr_if->set_all(); } return 0; } static inline int types_compatible(mtrr_type type1, mtrr_type type2) { return type1 == MTRR_TYPE_UNCACHABLE || type2 == MTRR_TYPE_UNCACHABLE || (type1 == MTRR_TYPE_WRTHROUGH && type2 == MTRR_TYPE_WRBACK) || (type1 == MTRR_TYPE_WRBACK && type2 == MTRR_TYPE_WRTHROUGH); } /** * set_mtrr - update mtrrs on all processors * @reg: mtrr in question * @base: mtrr base * @size: mtrr size * @type: mtrr type * * This is kinda tricky, but fortunately, Intel spelled it out for us cleanly: * * 1. Queue work to do the following on all processors: * 2. Disable Interrupts * 3. Wait for all procs to do so * 4. Enter no-fill cache mode * 5. Flush caches * 6. Clear PGE bit * 7. Flush all TLBs * 8. Disable all range registers * 9. Update the MTRRs * 10. Enable all range registers * 11. Flush all TLBs and caches again * 12. Enter normal cache mode and reenable caching * 13. Set PGE * 14. Wait for buddies to catch up * 15. Enable interrupts. * * What does that mean for us? Well, stop_machine() will ensure that * the rendezvous handler is started on each CPU. And in lockstep they * do the state transition of disabling interrupts, updating MTRR's * (the CPU vendors may each do it differently, so we call mtrr_if->set() * callback and let them take care of it.) and enabling interrupts. * * Note that the mechanism is the same for UP systems, too; all the SMP stuff * becomes nops. */ static void set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type) { struct set_mtrr_data data = { .smp_reg = reg, .smp_base = base, .smp_size = size, .smp_type = type }; stop_machine(mtrr_rendezvous_handler, &data, cpu_online_mask); } static void set_mtrr_cpuslocked(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type) { struct set_mtrr_data data = { .smp_reg = reg, .smp_base = base, .smp_size = size, .smp_type = type }; stop_machine_cpuslocked(mtrr_rendezvous_handler, &data, cpu_online_mask); } static void set_mtrr_from_inactive_cpu(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type) { struct set_mtrr_data data = { .smp_reg = reg, .smp_base = base, .smp_size = size, .smp_type = type }; stop_machine_from_inactive_cpu(mtrr_rendezvous_handler, &data, cpu_callout_mask); } /** * mtrr_add_page - Add a memory type region * @base: Physical base address of region in pages (in units of 4 kB!) * @size: Physical size of region in pages (4 kB) * @type: Type of MTRR desired * @increment: If this is true do usage counting on the region * * Memory type region registers control the caching on newer Intel and * non Intel processors. This function allows drivers to request an * MTRR is added. The details and hardware specifics of each processor's * implementation are hidden from the caller, but nevertheless the * caller should expect to need to provide a power of two size on an * equivalent power of two boundary. * * If the region cannot be added either because all regions are in use * or the CPU cannot support it a negative value is returned. On success * the register number for this entry is returned, but should be treated * as a cookie only. * * On a multiprocessor machine the changes are made to all processors. * This is required on x86 by the Intel processors. * * The available types are * * %MTRR_TYPE_UNCACHABLE - No caching * * %MTRR_TYPE_WRBACK - Write data back in bursts whenever * * %MTRR_TYPE_WRCOMB - Write data back soon but allow bursts * * %MTRR_TYPE_WRTHROUGH - Cache reads but not writes * * BUGS: Needs a quiet flag for the cases where drivers do not mind * failures and do not wish system log messages to be sent. */ int mtrr_add_page(unsigned long base, unsigned long size, unsigned int type, bool increment) { unsigned long lbase, lsize; int i, replace, error; mtrr_type ltype; if (!mtrr_enabled()) return -ENXIO; error = mtrr_if->validate_add_page(base, size, type); if (error) return error; if (type >= MTRR_NUM_TYPES) { pr_warn("type: %u invalid\n", type); return -EINVAL; } /* If the type is WC, check that this processor supports it */ if ((type == MTRR_TYPE_WRCOMB) && !have_wrcomb()) { pr_warn("your processor doesn't support write-combining\n"); return -ENOSYS; } if (!size) { pr_warn("zero sized request\n"); return -EINVAL; } if ((base | (base + size - 1)) >> (boot_cpu_data.x86_phys_bits - PAGE_SHIFT)) { pr_warn("base or size exceeds the MTRR width\n"); return -EINVAL; } error = -EINVAL; replace = -1; /* No CPU hotplug when we change MTRR entries */ get_online_cpus(); /* Search for existing MTRR */ mutex_lock(&mtrr_mutex); for (i = 0; i < num_var_ranges; ++i) { mtrr_if->get(i, &lbase, &lsize, <ype); if (!lsize || base > lbase + lsize - 1 || base + size - 1 < lbase) continue; /* * At this point we know there is some kind of * overlap/enclosure */ if (base < lbase || base + size - 1 > lbase + lsize - 1) { if (base <= lbase && base + size - 1 >= lbase + lsize - 1) { /* New region encloses an existing region */ if (type == ltype) { replace = replace == -1 ? i : -2; continue; } else if (types_compatible(type, ltype)) continue; } pr_warn("0x%lx000,0x%lx000 overlaps existing 0x%lx000,0x%lx000\n", base, size, lbase, lsize); goto out; } /* New region is enclosed by an existing region */ if (ltype != type) { if (types_compatible(type, ltype)) continue; pr_warn("type mismatch for %lx000,%lx000 old: %s new: %s\n", base, size, mtrr_attrib_to_str(ltype), mtrr_attrib_to_str(type)); goto out; } if (increment) ++mtrr_usage_table[i]; error = i; goto out; } /* Search for an empty MTRR */ i = mtrr_if->get_free_region(base, size, replace); if (i >= 0) { set_mtrr_cpuslocked(i, base, size, type); if (likely(replace < 0)) { mtrr_usage_table[i] = 1; } else { mtrr_usage_table[i] = mtrr_usage_table[replace]; if (increment) mtrr_usage_table[i]++; if (unlikely(replace != i)) { set_mtrr_cpuslocked(replace, 0, 0, 0); mtrr_usage_table[replace] = 0; } } } else { pr_info("no more MTRRs available\n"); } error = i; out: mutex_unlock(&mtrr_mutex); put_online_cpus(); return error; } static int mtrr_check(unsigned long base, unsigned long size) { if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1))) { pr_warn("size and base must be multiples of 4 kiB\n"); pr_debug("size: 0x%lx base: 0x%lx\n", size, base); dump_stack(); return -1; } return 0; } /** * mtrr_add - Add a memory type region * @base: Physical base address of region * @size: Physical size of region * @type: Type of MTRR desired * @increment: If this is true do usage counting on the region * * Memory type region registers control the caching on newer Intel and * non Intel processors. This function allows drivers to request an * MTRR is added. The details and hardware specifics of each processor's * implementation are hidden from the caller, but nevertheless the * caller should expect to need to provide a power of two size on an * equivalent power of two boundary. * * If the region cannot be added either because all regions are in use * or the CPU cannot support it a negative value is returned. On success * the register number for this entry is returned, but should be treated * as a cookie only. * * On a multiprocessor machine the changes are made to all processors. * This is required on x86 by the Intel processors. * * The available types are * * %MTRR_TYPE_UNCACHABLE - No caching * * %MTRR_TYPE_WRBACK - Write data back in bursts whenever * * %MTRR_TYPE_WRCOMB - Write data back soon but allow bursts * * %MTRR_TYPE_WRTHROUGH - Cache reads but not writes * * BUGS: Needs a quiet flag for the cases where drivers do not mind * failures and do not wish system log messages to be sent. */ int mtrr_add(unsigned long base, unsigned long size, unsigned int type, bool increment) { if (!mtrr_enabled()) return -ENODEV; if (mtrr_check(base, size)) return -EINVAL; return mtrr_add_page(base >> PAGE_SHIFT, size >> PAGE_SHIFT, type, increment); } /** * mtrr_del_page - delete a memory type region * @reg: Register returned by mtrr_add * @base: Physical base address * @size: Size of region * * If register is supplied then base and size are ignored. This is * how drivers should call it. * * Releases an MTRR region. If the usage count drops to zero the * register is freed and the region returns to default state. * On success the register is returned, on failure a negative error * code. */ int mtrr_del_page(int reg, unsigned long base, unsigned long size) { int i, max; mtrr_type ltype; unsigned long lbase, lsize; int error = -EINVAL; if (!mtrr_enabled()) return -ENODEV; max = num_var_ranges; /* No CPU hotplug when we change MTRR entries */ get_online_cpus(); mutex_lock(&mtrr_mutex); if (reg < 0) { /* Search for existing MTRR */ for (i = 0; i < max; ++i) { mtrr_if->get(i, &lbase, &lsize, <ype); if (lbase == base && lsize == size) { reg = i; break; } } if (reg < 0) { pr_debug("no MTRR for %lx000,%lx000 found\n", base, size); goto out; } } if (reg >= max) { pr_warn("register: %d too big\n", reg); goto out; } mtrr_if->get(reg, &lbase, &lsize, <ype); if (lsize < 1) { pr_warn("MTRR %d not used\n", reg); goto out; } if (mtrr_usage_table[reg] < 1) { pr_warn("reg: %d has count=0\n", reg); goto out; } if (--mtrr_usage_table[reg] < 1) set_mtrr_cpuslocked(reg, 0, 0, 0); error = reg; out: mutex_unlock(&mtrr_mutex); put_online_cpus(); return error; } /** * mtrr_del - delete a memory type region * @reg: Register returned by mtrr_add * @base: Physical base address * @size: Size of region * * If register is supplied then base and size are ignored. This is * how drivers should call it. * * Releases an MTRR region. If the usage count drops to zero the * register is freed and the region returns to default state. * On success the register is returned, on failure a negative error * code. */ int mtrr_del(int reg, unsigned long base, unsigned long size) { if (!mtrr_enabled()) return -ENODEV; if (mtrr_check(base, size)) return -EINVAL; return mtrr_del_page(reg, base >> PAGE_SHIFT, size >> PAGE_SHIFT); } /** * arch_phys_wc_add - add a WC MTRR and handle errors if PAT is unavailable * @base: Physical base address * @size: Size of region * * If PAT is available, this does nothing. If PAT is unavailable, it * attempts to add a WC MTRR covering size bytes starting at base and * logs an error if this fails. * * The called should provide a power of two size on an equivalent * power of two boundary. * * Drivers must store the return value to pass to mtrr_del_wc_if_needed, * but drivers should not try to interpret that return value. */ int arch_phys_wc_add(unsigned long base, unsigned long size) { int ret; if (pat_enabled() || !mtrr_enabled()) return 0; /* Success! (We don't need to do anything.) */ ret = mtrr_add(base, size, MTRR_TYPE_WRCOMB, true); if (ret < 0) { pr_warn("Failed to add WC MTRR for [%p-%p]; performance may suffer.", (void *)base, (void *)(base + size - 1)); return ret; } return ret + MTRR_TO_PHYS_WC_OFFSET; } EXPORT_SYMBOL(arch_phys_wc_add); /* * arch_phys_wc_del - undoes arch_phys_wc_add * @handle: Return value from arch_phys_wc_add * * This cleans up after mtrr_add_wc_if_needed. * * The API guarantees that mtrr_del_wc_if_needed(error code) and * mtrr_del_wc_if_needed(0) do nothing. */ void arch_phys_wc_del(int handle) { if (handle >= 1) { WARN_ON(handle < MTRR_TO_PHYS_WC_OFFSET); mtrr_del(handle - MTRR_TO_PHYS_WC_OFFSET, 0, 0); } } EXPORT_SYMBOL(arch_phys_wc_del); /* * arch_phys_wc_index - translates arch_phys_wc_add's return value * @handle: Return value from arch_phys_wc_add * * This will turn the return value from arch_phys_wc_add into an mtrr * index suitable for debugging. * * Note: There is no legitimate use for this function, except possibly * in printk line. Alas there is an illegitimate use in some ancient * drm ioctls. */ int arch_phys_wc_index(int handle) { if (handle < MTRR_TO_PHYS_WC_OFFSET) return -1; else return handle - MTRR_TO_PHYS_WC_OFFSET; } EXPORT_SYMBOL_GPL(arch_phys_wc_index); /* * HACK ALERT! * These should be called implicitly, but we can't yet until all the initcall * stuff is done... */ static void __init init_ifs(void) { #ifndef CONFIG_X86_64 amd_init_mtrr(); cyrix_init_mtrr(); centaur_init_mtrr(); #endif } /* The suspend/resume methods are only for CPU without MTRR. CPU using generic * MTRR driver doesn't require this */ struct mtrr_value { mtrr_type ltype; unsigned long lbase; unsigned long lsize; }; static struct mtrr_value mtrr_value[MTRR_MAX_VAR_RANGES]; static int mtrr_save(void) { int i; for (i = 0; i < num_var_ranges; i++) { mtrr_if->get(i, &mtrr_value[i].lbase, &mtrr_value[i].lsize, &mtrr_value[i].ltype); } return 0; } static void mtrr_restore(void) { int i; for (i = 0; i < num_var_ranges; i++) { if (mtrr_value[i].lsize) { set_mtrr(i, mtrr_value[i].lbase, mtrr_value[i].lsize, mtrr_value[i].ltype); } } } static struct syscore_ops mtrr_syscore_ops = { .suspend = mtrr_save, .resume = mtrr_restore, }; int __initdata changed_by_mtrr_cleanup; #define SIZE_OR_MASK_BITS(n) (~((1ULL << ((n) - PAGE_SHIFT)) - 1)) /** * mtrr_bp_init - initialize mtrrs on the boot CPU * * This needs to be called early; before any of the other CPUs are * initialized (i.e. before smp_init()). * */ void __init mtrr_bp_init(void) { u32 phys_addr; init_ifs(); phys_addr = 32; if (boot_cpu_has(X86_FEATURE_MTRR)) { mtrr_if = &generic_mtrr_ops; size_or_mask = SIZE_OR_MASK_BITS(36); size_and_mask = 0x00f00000; phys_addr = 36; /* * This is an AMD specific MSR, but we assume(hope?) that * Intel will implement it too when they extend the address * bus of the Xeon. */ if (cpuid_eax(0x80000000) >= 0x80000008) { phys_addr = cpuid_eax(0x80000008) & 0xff; /* CPUID workaround for Intel 0F33/0F34 CPU */ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && boot_cpu_data.x86 == 0xF && boot_cpu_data.x86_model == 0x3 && (boot_cpu_data.x86_stepping == 0x3 || boot_cpu_data.x86_stepping == 0x4)) phys_addr = 36; size_or_mask = SIZE_OR_MASK_BITS(phys_addr); size_and_mask = ~size_or_mask & 0xfffff00000ULL; } else if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR && boot_cpu_data.x86 == 6) { /* * VIA C* family have Intel style MTRRs, * but don't support PAE */ size_or_mask = SIZE_OR_MASK_BITS(32); size_and_mask = 0; phys_addr = 32; } } else { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: if (cpu_feature_enabled(X86_FEATURE_K6_MTRR)) { /* Pre-Athlon (K6) AMD CPU MTRRs */ mtrr_if = mtrr_ops[X86_VENDOR_AMD]; size_or_mask = SIZE_OR_MASK_BITS(32); size_and_mask = 0; } break; case X86_VENDOR_CENTAUR: if (cpu_feature_enabled(X86_FEATURE_CENTAUR_MCR)) { mtrr_if = mtrr_ops[X86_VENDOR_CENTAUR]; size_or_mask = SIZE_OR_MASK_BITS(32); size_and_mask = 0; } break; case X86_VENDOR_CYRIX: if (cpu_feature_enabled(X86_FEATURE_CYRIX_ARR)) { mtrr_if = mtrr_ops[X86_VENDOR_CYRIX]; size_or_mask = SIZE_OR_MASK_BITS(32); size_and_mask = 0; } break; default: break; } } if (mtrr_if) { __mtrr_enabled = true; set_num_var_ranges(); init_table(); if (use_intel()) { /* BIOS may override */ __mtrr_enabled = get_mtrr_state(); if (mtrr_enabled()) mtrr_bp_pat_init(); if (mtrr_cleanup(phys_addr)) { changed_by_mtrr_cleanup = 1; mtrr_if->set_all(); } } } if (!mtrr_enabled()) { pr_info("Disabled\n"); /* * PAT initialization relies on MTRR's rendezvous handler. * Skip PAT init until the handler can initialize both * features independently. */ pat_disable("MTRRs disabled, skipping PAT initialization too."); } } void mtrr_ap_init(void) { if (!mtrr_enabled()) return; if (!use_intel() || mtrr_aps_delayed_init) return; /* * Ideally we should hold mtrr_mutex here to avoid mtrr entries * changed, but this routine will be called in cpu boot time, * holding the lock breaks it. * * This routine is called in two cases: * * 1. very earily time of software resume, when there absolutely * isn't mtrr entry changes; * * 2. cpu hotadd time. We let mtrr_add/del_page hold cpuhotplug * lock to prevent mtrr entry changes */ set_mtrr_from_inactive_cpu(~0U, 0, 0, 0); } /** * Save current fixed-range MTRR state of the first cpu in cpu_online_mask. */ void mtrr_save_state(void) { int first_cpu; if (!mtrr_enabled()) return; first_cpu = cpumask_first(cpu_online_mask); smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1); } void set_mtrr_aps_delayed_init(void) { if (!mtrr_enabled()) return; if (!use_intel()) return; mtrr_aps_delayed_init = true; } /* * Delayed MTRR initialization for all AP's */ void mtrr_aps_init(void) { if (!use_intel() || !mtrr_enabled()) return; /* * Check if someone has requested the delay of AP MTRR initialization, * by doing set_mtrr_aps_delayed_init(), prior to this point. If not, * then we are done. */ if (!mtrr_aps_delayed_init) return; set_mtrr(~0U, 0, 0, 0); mtrr_aps_delayed_init = false; } void mtrr_bp_restore(void) { if (!use_intel() || !mtrr_enabled()) return; mtrr_if->set_all(); } static int __init mtrr_init_finialize(void) { if (!mtrr_enabled()) return 0; if (use_intel()) { if (!changed_by_mtrr_cleanup) mtrr_state_warn(); return 0; } /* * The CPU has no MTRR and seems to not support SMP. They have * specific drivers, we use a tricky method to support * suspend/resume for them. * * TBD: is there any system with such CPU which supports * suspend/resume? If no, we should remove the code. */ register_syscore_ops(&mtrr_syscore_ops); return 0; } subsys_initcall(mtrr_init_finialize);