/* 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). */ #include #include #include #include #include #include #include #include #include #include "mtrr.h" #define MTRR_VERSION "2.0 (20020519)" u32 num_var_ranges = 0; unsigned int *usage_table; static DECLARE_MUTEX(main_lock); u32 size_or_mask, size_and_mask; static struct mtrr_ops * mtrr_ops[X86_VENDOR_NUM] = {}; struct mtrr_ops * mtrr_if = NULL; static void set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type); extern int arr3_protected; void set_mtrr_ops(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; u8 rev; if ((dev = pci_get_class(PCI_CLASS_BRIDGE_HOST << 8, NULL)) != 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) { pci_read_config_byte(dev, PCI_CLASS_REVISION, &rev); if (rev <= 5) { printk(KERN_INFO "mtrr: 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) { printk(KERN_INFO "mtrr: 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(MTRRcap_MSR, config, dummy); } else if (is_cpu(AMD)) 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; if ((usage_table = kmalloc(max * sizeof *usage_table, GFP_KERNEL)) == NULL) { printk(KERN_ERR "mtrr: could not allocate\n"); return; } for (i = 0; i < max; i++) usage_table[i] = 1; } struct set_mtrr_data { atomic_t count; atomic_t gate; unsigned long smp_base; unsigned long smp_size; unsigned int smp_reg; mtrr_type smp_type; }; #ifdef CONFIG_SMP static void ipi_handler(void *info) /* [SUMMARY] Synchronisation handler. Executed by "other" CPUs. [RETURNS] Nothing. */ { struct set_mtrr_data *data = info; unsigned long flags; local_irq_save(flags); atomic_dec(&data->count); while(!atomic_read(&data->gate)) cpu_relax(); /* The master has cleared me to execute */ if (data->smp_reg != ~0U) mtrr_if->set(data->smp_reg, data->smp_base, data->smp_size, data->smp_type); else mtrr_if->set_all(); atomic_dec(&data->count); while(atomic_read(&data->gate)) cpu_relax(); atomic_dec(&data->count); local_irq_restore(flags); } #endif /** * 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. Send IPI to do the following: * 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, first we set data.count to the number * of CPUs. As each CPU disables interrupts, it'll decrement it once. We wait * until it hits 0 and proceed. We set the data.gate flag and reset data.count. * Meanwhile, they are waiting for that flag to be set. Once it's set, each * CPU goes through the transition of updating MTRRs. The CPU vendors may each do it * differently, so we call mtrr_if->set() callback and let them take care of it. * When they're done, they again decrement data->count and wait for data.gate to * be reset. * When we finish, we wait for data.count to hit 0 and toggle the data.gate flag. * Everyone then enables interrupts and we all continue on. * * 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; unsigned long flags; data.smp_reg = reg; data.smp_base = base; data.smp_size = size; data.smp_type = type; atomic_set(&data.count, num_booting_cpus() - 1); atomic_set(&data.gate,0); /* Start the ball rolling on other CPUs */ if (smp_call_function(ipi_handler, &data, 1, 0) != 0) panic("mtrr: timed out waiting for other CPUs\n"); local_irq_save(flags); while(atomic_read(&data.count)) cpu_relax(); /* ok, reset count and toggle gate */ atomic_set(&data.count, num_booting_cpus() - 1); atomic_set(&data.gate,1); /* do our MTRR business */ /* HACK! * We use this same function to initialize the mtrrs on boot. * The state of the boot cpu's mtrrs has been saved, and we want * to replicate across all the APs. * If we're doing that @reg is set to something special... */ if (reg != ~0U) mtrr_if->set(reg,base,size,type); /* wait for the others */ while(atomic_read(&data.count)) cpu_relax(); atomic_set(&data.count, num_booting_cpus() - 1); atomic_set(&data.gate,0); /* * Wait here for everyone to have seen the gate change * So we're the last ones to touch 'data' */ while(atomic_read(&data.count)) cpu_relax(); local_irq_restore(flags); } /** * mtrr_add_page - Add a memory type region * @base: Physical base address of region in pages (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, char increment) { int i; mtrr_type ltype; unsigned long lbase; unsigned int lsize; int error; if (!mtrr_if) return -ENXIO; if ((error = mtrr_if->validate_add_page(base,size,type))) return error; if (type >= MTRR_NUM_TYPES) { printk(KERN_WARNING "mtrr: 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()) { printk(KERN_WARNING "mtrr: your processor doesn't support write-combining\n"); return -ENOSYS; } if (base & size_or_mask || size & size_or_mask) { printk(KERN_WARNING "mtrr: base or size exceeds the MTRR width\n"); return -EINVAL; } error = -EINVAL; /* No CPU hotplug when we change MTRR entries */ lock_cpu_hotplug(); /* Search for existing MTRR */ down(&main_lock); for (i = 0; i < num_var_ranges; ++i) { mtrr_if->get(i, &lbase, &lsize, <ype); if (base >= lbase + lsize) continue; if ((base < lbase) && (base + size <= lbase)) continue; /* At this point we know there is some kind of overlap/enclosure */ if ((base < lbase) || (base + size > lbase + lsize)) { printk(KERN_WARNING "mtrr: 0x%lx000,0x%lx000 overlaps existing" " 0x%lx000,0x%x000\n", base, size, lbase, lsize); goto out; } /* New region is enclosed by an existing region */ if (ltype != type) { if (type == MTRR_TYPE_UNCACHABLE) continue; printk (KERN_WARNING "mtrr: 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) ++usage_table[i]; error = i; goto out; } /* Search for an empty MTRR */ i = mtrr_if->get_free_region(base, size); if (i >= 0) { set_mtrr(i, base, size, type); usage_table[i] = 1; } else printk(KERN_INFO "mtrr: no more MTRRs available\n"); error = i; out: up(&main_lock); unlock_cpu_hotplug(); return error; } static int mtrr_check(unsigned long base, unsigned long size) { if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1))) { printk(KERN_WARNING "mtrr: size and base must be multiples of 4 kiB\n"); printk(KERN_DEBUG "mtrr: 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, char increment) { 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; unsigned int lsize; int error = -EINVAL; if (!mtrr_if) return -ENXIO; max = num_var_ranges; /* No CPU hotplug when we change MTRR entries */ lock_cpu_hotplug(); down(&main_lock); 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) { printk(KERN_DEBUG "mtrr: no MTRR for %lx000,%lx000 found\n", base, size); goto out; } } if (reg >= max) { printk(KERN_WARNING "mtrr: register: %d too big\n", reg); goto out; } if (is_cpu(CYRIX) && !use_intel()) { if ((reg == 3) && arr3_protected) { printk(KERN_WARNING "mtrr: ARR3 cannot be changed\n"); goto out; } } mtrr_if->get(reg, &lbase, &lsize, <ype); if (lsize < 1) { printk(KERN_WARNING "mtrr: MTRR %d not used\n", reg); goto out; } if (usage_table[reg] < 1) { printk(KERN_WARNING "mtrr: reg: %d has count=0\n", reg); goto out; } if (--usage_table[reg] < 1) set_mtrr(reg, 0, 0, 0); error = reg; out: up(&main_lock); unlock_cpu_hotplug(); 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_check(base, size)) return -EINVAL; return mtrr_del_page(reg, base >> PAGE_SHIFT, size >> PAGE_SHIFT); } EXPORT_SYMBOL(mtrr_add); EXPORT_SYMBOL(mtrr_del); /* HACK ALERT! * These should be called implicitly, but we can't yet until all the initcall * stuff is done... */ extern void amd_init_mtrr(void); extern void cyrix_init_mtrr(void); extern void centaur_init_mtrr(void); static void __init init_ifs(void) { amd_init_mtrr(); cyrix_init_mtrr(); centaur_init_mtrr(); } /* 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 int lsize; }; static struct mtrr_value * mtrr_state; static int mtrr_save(struct sys_device * sysdev, u32 state) { int i; int size = num_var_ranges * sizeof(struct mtrr_value); mtrr_state = kmalloc(size,GFP_ATOMIC); if (mtrr_state) memset(mtrr_state,0,size); else return -ENOMEM; for (i = 0; i < num_var_ranges; i++) { mtrr_if->get(i, &mtrr_state[i].lbase, &mtrr_state[i].lsize, &mtrr_state[i].ltype); } return 0; } static int mtrr_restore(struct sys_device * sysdev) { int i; for (i = 0; i < num_var_ranges; i++) { if (mtrr_state[i].lsize) set_mtrr(i, mtrr_state[i].lbase, mtrr_state[i].lsize, mtrr_state[i].ltype); } kfree(mtrr_state); return 0; } static struct sysdev_driver mtrr_sysdev_driver = { .suspend = mtrr_save, .resume = mtrr_restore, }; /** * 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) { init_ifs(); if (cpu_has_mtrr) { mtrr_if = &generic_mtrr_ops; size_or_mask = 0xff000000; /* 36 bits */ size_and_mask = 0x00f00000; /* This is an AMD specific MSR, but we assume(hope?) that Intel will implement it to when they extend the address bus of the Xeon. */ if (cpuid_eax(0x80000000) >= 0x80000008) { u32 phys_addr; phys_addr = cpuid_eax(0x80000008) & 0xff; size_or_mask = ~((1 << (phys_addr - PAGE_SHIFT)) - 1); size_and_mask = ~size_or_mask & 0xfff00000; } 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 = 0xfff00000; /* 32 bits */ size_and_mask = 0; } } else { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: if (cpu_has_k6_mtrr) { /* Pre-Athlon (K6) AMD CPU MTRRs */ mtrr_if = mtrr_ops[X86_VENDOR_AMD]; size_or_mask = 0xfff00000; /* 32 bits */ size_and_mask = 0; } break; case X86_VENDOR_CENTAUR: if (cpu_has_centaur_mcr) { mtrr_if = mtrr_ops[X86_VENDOR_CENTAUR]; size_or_mask = 0xfff00000; /* 32 bits */ size_and_mask = 0; } break; case X86_VENDOR_CYRIX: if (cpu_has_cyrix_arr) { mtrr_if = mtrr_ops[X86_VENDOR_CYRIX]; size_or_mask = 0xfff00000; /* 32 bits */ size_and_mask = 0; } break; default: break; } } printk(KERN_INFO "mtrr: v%s\n",MTRR_VERSION); if (mtrr_if) { set_num_var_ranges(); init_table(); if (use_intel()) get_mtrr_state(); } } void mtrr_ap_init(void) { unsigned long flags; if (!mtrr_if || !use_intel()) return; /* * Ideally we should hold main_lock 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 */ local_irq_save(flags); mtrr_if->set_all(); local_irq_restore(flags); } static int __init mtrr_init_finialize(void) { if (!mtrr_if) return 0; if (use_intel()) mtrr_state_warn(); else { /* The CPUs haven't MTRR and seemes 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. */ sysdev_driver_register(&cpu_sysdev_class, &mtrr_sysdev_driver); } return 0; } subsys_initcall(mtrr_init_finialize);