diff options
| -rw-r--r-- | arch/x86/Kconfig | 15 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/generic.c | 120 | ||||
| -rw-r--r-- | arch/x86/mm/Makefile | 3 | ||||
| -rw-r--r-- | arch/x86/mm/pageattr.c | 4 | ||||
| -rw-r--r-- | arch/x86/mm/pat.c | 402 | ||||
| -rw-r--r-- | include/asm-x86/cpufeature.h | 1 | ||||
| -rw-r--r-- | include/asm-x86/msr-index.h | 2 | ||||
| -rw-r--r-- | include/asm-x86/mtrr.h | 2 | ||||
| -rw-r--r-- | include/asm-x86/pat.h | 16 | ||||
| -rw-r--r-- | include/asm-x86/pgtable.h | 6 |
10 files changed, 568 insertions, 3 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index fd27048..5b46756 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1009,6 +1009,21 @@ config MTRR See <file:Documentation/mtrr.txt> for more information. +config X86_PAT + def_bool y + prompt "x86 PAT support" + depends on MTRR && NONPROMISC_DEVMEM + help + Use PAT attributes to setup page level cache control. + ---help--- + PATs are the modern equivalents of MTRRs and are much more + flexible than MTRRs. + + Say N here if you see bootup problems (boot crash, boot hang, + spontaneous reboots) or a non-working Xorg. + + If unsure, say Y. + config EFI def_bool n prompt "EFI runtime service support" diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index 3e18db4..011e07e 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -11,6 +11,7 @@ #include <asm/cpufeature.h> #include <asm/processor-flags.h> #include <asm/tlbflush.h> +#include <asm/pat.h> #include "mtrr.h" struct mtrr_state { @@ -35,6 +36,7 @@ static struct fixed_range_block fixed_range_blocks[] = { static unsigned long smp_changes_mask; static struct mtrr_state mtrr_state = {}; +static int mtrr_state_set; #undef MODULE_PARAM_PREFIX #define MODULE_PARAM_PREFIX "mtrr." @@ -42,6 +44,106 @@ static struct mtrr_state mtrr_state = {}; static int mtrr_show; module_param_named(show, mtrr_show, bool, 0); +/* + * Returns the effective MTRR type for the region + * Error returns: + * - 0xFE - when the range is "not entirely covered" by _any_ var range MTRR + * - 0xFF - when MTRR is not enabled + */ +u8 mtrr_type_lookup(u64 start, u64 end) +{ + int i; + u64 base, mask; + u8 prev_match, curr_match; + + if (!mtrr_state_set) + return 0xFF; + + if (!mtrr_state.enabled) + return 0xFF; + + /* Make end inclusive end, instead of exclusive */ + end--; + + /* Look in fixed ranges. Just return the type as per start */ + if (mtrr_state.have_fixed && (start < 0x100000)) { + int idx; + + if (start < 0x80000) { + idx = 0; + idx += (start >> 16); + return mtrr_state.fixed_ranges[idx]; + } else if (start < 0xC0000) { + idx = 1 * 8; + idx += ((start - 0x80000) >> 14); + return mtrr_state.fixed_ranges[idx]; + } else if (start < 0x1000000) { + idx = 3 * 8; + idx += ((start - 0xC0000) >> 12); + return mtrr_state.fixed_ranges[idx]; + } + } + + /* + * Look in variable ranges + * Look of multiple ranges matching this address and pick type + * as per MTRR precedence + */ + if (!mtrr_state.enabled & 2) { + return mtrr_state.def_type; + } + + prev_match = 0xFF; + for (i = 0; i < num_var_ranges; ++i) { + unsigned short start_state, end_state; + + if (!(mtrr_state.var_ranges[i].mask_lo & (1 << 11))) + continue; + + base = (((u64)mtrr_state.var_ranges[i].base_hi) << 32) + + (mtrr_state.var_ranges[i].base_lo & PAGE_MASK); + mask = (((u64)mtrr_state.var_ranges[i].mask_hi) << 32) + + (mtrr_state.var_ranges[i].mask_lo & PAGE_MASK); + + start_state = ((start & mask) == (base & mask)); + end_state = ((end & mask) == (base & mask)); + if (start_state != end_state) + return 0xFE; + + if ((start & mask) != (base & mask)) { + continue; + } + + curr_match = mtrr_state.var_ranges[i].base_lo & 0xff; + if (prev_match == 0xFF) { + prev_match = curr_match; + continue; + } + + if (prev_match == MTRR_TYPE_UNCACHABLE || + curr_match == MTRR_TYPE_UNCACHABLE) { + return MTRR_TYPE_UNCACHABLE; + } + + if ((prev_match == MTRR_TYPE_WRBACK && + curr_match == MTRR_TYPE_WRTHROUGH) || + (prev_match == MTRR_TYPE_WRTHROUGH && + curr_match == MTRR_TYPE_WRBACK)) { + prev_match = MTRR_TYPE_WRTHROUGH; + curr_match = MTRR_TYPE_WRTHROUGH; + } + + if (prev_match != curr_match) { + return MTRR_TYPE_UNCACHABLE; + } + } + + if (prev_match != 0xFF) + return prev_match; + + return mtrr_state.def_type; +} + /* Get the MSR pair relating to a var range */ static void get_mtrr_var_range(unsigned int index, struct mtrr_var_range *vr) @@ -79,12 +181,16 @@ static void print_fixed(unsigned base, unsigned step, const mtrr_type*types) base, base + step - 1, mtrr_attrib_to_str(*types)); } +static void prepare_set(void); +static void post_set(void); + /* Grab all of the MTRR state for this CPU into *state */ void __init get_mtrr_state(void) { unsigned int i; struct mtrr_var_range *vrs; unsigned lo, dummy; + unsigned long flags; vrs = mtrr_state.var_ranges; @@ -131,6 +237,17 @@ void __init get_mtrr_state(void) printk(KERN_INFO "MTRR %u disabled\n", i); } } + mtrr_state_set = 1; + + /* PAT setup for BP. We need to go through sync steps here */ + local_irq_save(flags); + prepare_set(); + + pat_init(); + + post_set(); + local_irq_restore(flags); + } /* Some BIOS's are fucked and don't set all MTRRs the same! */ @@ -397,6 +514,9 @@ static void generic_set_all(void) /* Actually set the state */ mask = set_mtrr_state(); + /* also set PAT */ + pat_init(); + post_set(); local_irq_restore(flags); diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index 9ab9889..20941d2 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -1,4 +1,5 @@ -obj-y := init_$(BITS).o fault.o ioremap.o extable.o pageattr.o mmap.o +obj-y := init_$(BITS).o fault.o ioremap.o extable.o pageattr.o mmap.o \ + pat.o obj-$(CONFIG_X86_32) += pgtable_32.o diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 6cdfc0f..f7d5ca1 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -773,14 +773,14 @@ static inline int change_page_attr_clear(unsigned long addr, int numpages, int set_memory_uc(unsigned long addr, int numpages) { return change_page_attr_set(addr, numpages, - __pgprot(_PAGE_PCD)); + __pgprot(_PAGE_CACHE_UC)); } EXPORT_SYMBOL(set_memory_uc); int set_memory_wb(unsigned long addr, int numpages) { return change_page_attr_clear(addr, numpages, - __pgprot(_PAGE_PCD | _PAGE_PWT)); + __pgprot(_PAGE_CACHE_MASK)); } EXPORT_SYMBOL(set_memory_wb); diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c new file mode 100644 index 0000000..7cc71d8 --- /dev/null +++ b/arch/x86/mm/pat.c @@ -0,0 +1,402 @@ +/* + * Handle caching attributes in page tables (PAT) + * + * Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> + * Suresh B Siddha <suresh.b.siddha@intel.com> + * + * Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen. + */ + +#include <linux/mm.h> +#include <linux/kernel.h> +#include <linux/gfp.h> +#include <linux/fs.h> + +#include <asm/msr.h> +#include <asm/tlbflush.h> +#include <asm/processor.h> +#include <asm/pgtable.h> +#include <asm/pat.h> +#include <asm/e820.h> +#include <asm/cacheflush.h> +#include <asm/fcntl.h> +#include <asm/mtrr.h> + +int pat_wc_enabled = 1; + +static u64 __read_mostly boot_pat_state; + +static int nopat(char *str) +{ + pat_wc_enabled = 0; + printk(KERN_INFO "x86: PAT support disabled.\n"); + + return 0; +} +early_param("nopat", nopat); + +static int pat_known_cpu(void) +{ + if (!pat_wc_enabled) + return 0; + + if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && + (boot_cpu_data.x86 == 0xF || + (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model >= 15))) { + if (cpu_has_pat) { + return 1; + } + } + + pat_wc_enabled = 0; + printk(KERN_INFO "CPU and/or kernel does not support PAT.\n"); + return 0; +} + +enum { + PAT_UC = 0, /* uncached */ + PAT_WC = 1, /* Write combining */ + PAT_WT = 4, /* Write Through */ + PAT_WP = 5, /* Write Protected */ + PAT_WB = 6, /* Write Back (default) */ + PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */ +}; + +#define PAT(x,y) ((u64)PAT_ ## y << ((x)*8)) + +void pat_init(void) +{ + u64 pat; + +#ifndef CONFIG_X86_PAT + nopat(NULL); +#endif + + /* Boot CPU enables PAT based on CPU feature */ + if (!smp_processor_id() && !pat_known_cpu()) + return; + + /* APs enable PAT iff boot CPU has enabled it before */ + if (smp_processor_id() && !pat_wc_enabled) + return; + + /* Set PWT to Write-Combining. All other bits stay the same */ + /* + * PTE encoding used in Linux: + * PAT + * |PCD + * ||PWT + * ||| + * 000 WB _PAGE_CACHE_WB + * 001 WC _PAGE_CACHE_WC + * 010 UC- _PAGE_CACHE_UC_MINUS + * 011 UC _PAGE_CACHE_UC + * PAT bit unused + */ + pat = PAT(0,WB) | PAT(1,WC) | PAT(2,UC_MINUS) | PAT(3,UC) | + PAT(4,WB) | PAT(5,WC) | PAT(6,UC_MINUS) | PAT(7,UC); + + /* Boot CPU check */ + if (!smp_processor_id()) { + rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); + } + + wrmsrl(MSR_IA32_CR_PAT, pat); + printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n", + smp_processor_id(), boot_pat_state, pat); +} + +#undef PAT + +static char *cattr_name(unsigned long flags) +{ + switch (flags & _PAGE_CACHE_MASK) { + case _PAGE_CACHE_UC: return "uncached"; + case _PAGE_CACHE_UC_MINUS: return "uncached-minus"; + case _PAGE_CACHE_WB: return "write-back"; + case _PAGE_CACHE_WC: return "write-combining"; + default: return "broken"; + } +} + +/* + * The global memtype list keeps track of memory type for specific + * physical memory areas. Conflicting memory types in different + * mappings can cause CPU cache corruption. To avoid this we keep track. + * + * The list is sorted based on starting address and can contain multiple + * entries for each address (this allows reference counting for overlapping + * areas). All the aliases have the same cache attributes of course. + * Zero attributes are represented as holes. + * + * Currently the data structure is a list because the number of mappings + * are expected to be relatively small. If this should be a problem + * it could be changed to a rbtree or similar. + * + * memtype_lock protects the whole list. + */ + +struct memtype { + u64 start; + u64 end; + unsigned long type; + struct list_head nd; +}; + +static LIST_HEAD(memtype_list); +static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */ + +/* + * Does intersection of PAT memory type and MTRR memory type and returns + * the resulting memory type as PAT understands it. + * (Type in pat and mtrr will not have same value) + * The intersection is based on "Effective Memory Type" tables in IA-32 + * SDM vol 3a + */ +static int pat_x_mtrr_type(u64 start, u64 end, unsigned long prot, + unsigned long *ret_prot) +{ + unsigned long pat_type; + u8 mtrr_type; + + mtrr_type = mtrr_type_lookup(start, end); + if (mtrr_type == 0xFF) { /* MTRR not enabled */ + *ret_prot = prot; + return 0; + } + if (mtrr_type == 0xFE) { /* MTRR match error */ + *ret_prot = _PAGE_CACHE_UC; + return -1; + } + if (mtrr_type != MTRR_TYPE_UNCACHABLE && + mtrr_type != MTRR_TYPE_WRBACK && + mtrr_type != MTRR_TYPE_WRCOMB) { /* MTRR type unhandled */ + *ret_prot = _PAGE_CACHE_UC; + return -1; + } + + pat_type = prot & _PAGE_CACHE_MASK; + prot &= (~_PAGE_CACHE_MASK); + + /* Currently doing intersection by hand. Optimize it later. */ + if (pat_type == _PAGE_CACHE_WC) { + *ret_prot = prot | _PAGE_CACHE_WC; + } else if (pat_type == _PAGE_CACHE_UC_MINUS) { + *ret_prot = prot | _PAGE_CACHE_UC_MINUS; + } else if (pat_type == _PAGE_CACHE_UC || + mtrr_type == MTRR_TYPE_UNCACHABLE) { + *ret_prot = prot | _PAGE_CACHE_UC; + } else if (mtrr_type == MTRR_TYPE_WRCOMB) { + *ret_prot = prot | _PAGE_CACHE_WC; + } else { + *ret_prot = prot | _PAGE_CACHE_WB; + } + + return 0; +} + +int reserve_memtype(u64 start, u64 end, unsigned long req_type, + unsigned long *ret_type) +{ + struct memtype *new_entry = NULL; + struct memtype *parse; + unsigned long actual_type; + int err = 0; + + /* Only track when pat_wc_enabled */ + if (!pat_wc_enabled) { + if (ret_type) + *ret_type = req_type; + + return 0; + } + + /* Low ISA region is always mapped WB in page table. No need to track */ + if (start >= ISA_START_ADDRESS && (end - 1) <= ISA_END_ADDRESS) { + if (ret_type) + *ret_type = _PAGE_CACHE_WB; + + return 0; + } + + req_type &= _PAGE_CACHE_MASK; + err = pat_x_mtrr_type(start, end, req_type, &actual_type); + if (err) { + if (ret_type) + *ret_type = actual_type; + + return -EINVAL; + } + + new_entry = kmalloc(sizeof(struct memtype), GFP_KERNEL); + if (!new_entry) + return -ENOMEM; + + new_entry->start = start; + new_entry->end = end; + new_entry->type = actual_type; + + if (ret_type) + *ret_type = actual_type; + + spin_lock(&memtype_lock); + + /* Search for existing mapping that overlaps the current range */ + list_for_each_entry(parse, &memtype_list, nd) { + struct memtype *saved_ptr; + + if (parse->start >= end) { + list_add(&new_entry->nd, parse->nd.prev); + new_entry = NULL; + break; + } + + if (start <= parse->start && end >= parse->start) { + if (actual_type != parse->type && ret_type) { + actual_type = parse->type; + *ret_type = actual_type; + new_entry->type = actual_type; + } + + if (actual_type != parse->type) { + printk( + KERN_INFO "%s:%d conflicting memory types %Lx-%Lx %s<->%s\n", + current->comm, current->pid, + start, end, + cattr_name(actual_type), + cattr_name(parse->type)); + err = -EBUSY; + break; + } + + saved_ptr = parse; + /* + * Check to see whether the request overlaps more + * than one entry in the list + */ + list_for_each_entry_continue(parse, &memtype_list, nd) { + if (end <= parse->start) { + break; + } + + if (actual_type != parse->type) { + printk( + KERN_INFO "%s:%d conflicting memory types %Lx-%Lx %s<->%s\n", + current->comm, current->pid, + start, end, + cattr_name(actual_type), + cattr_name(parse->type)); + err = -EBUSY; + break; + } + } + + if (err) { + break; + } + + /* No conflict. Go ahead and add this new entry */ + list_add(&new_entry->nd, saved_ptr->nd.prev); + new_entry = NULL; + break; + } + + if (start < parse->end) { + if (actual_type != parse->type && ret_type) { + actual_type = parse->type; + *ret_type = actual_type; + new_entry->type = actual_type; + } + + if (actual_type != parse->type) { + printk( + KERN_INFO "%s:%d conflicting memory types %Lx-%Lx %s<->%s\n", + current->comm, current->pid, + start, end, + cattr_name(actual_type), + cattr_name(parse->type)); + err = -EBUSY; + break; + } + + saved_ptr = parse; + /* + * Check to see whether the request overlaps more + * than one entry in the list + */ + list_for_each_entry_continue(parse, &memtype_list, nd) { + if (end <= parse->start) { + break; + } + + if (actual_type != parse->type) { + printk( + KERN_INFO "%s:%d conflicting memory types %Lx-%Lx %s<->%s\n", + current->comm, current->pid, + start, end, + cattr_name(actual_type), + cattr_name(parse->type)); + err = -EBUSY; + break; + } + } + + if (err) { + break; + } + + /* No conflict. Go ahead and add this new entry */ + list_add(&new_entry->nd, &saved_ptr->nd); + new_entry = NULL; + break; + } + } + + if (err) { + kfree(new_entry); + spin_unlock(&memtype_lock); + return err; + } + + if (new_entry) { + /* No conflict. Not yet added to the list. Add to the tail */ + list_add_tail(&new_entry->nd, &memtype_list); + } + + spin_unlock(&memtype_lock); + return err; +} + +int free_memtype(u64 start, u64 end) +{ + struct memtype *ml; + int err = -EINVAL; + + /* Only track when pat_wc_enabled */ + if (!pat_wc_enabled) { + return 0; + } + + /* Low ISA region is always mapped WB. No need to track */ + if (start >= ISA_START_ADDRESS && end <= ISA_END_ADDRESS) { + return 0; + } + + spin_lock(&memtype_lock); + list_for_each_entry(ml, &memtype_list, nd) { + if (ml->start == start && ml->end == end) { + list_del(&ml->nd); + kfree(ml); + err = 0; + break; + } + } + spin_unlock(&memtype_lock); + + if (err) { + printk(KERN_DEBUG "%s:%d freeing invalid memtype %Lx-%Lx\n", + current->comm, current->pid, start, end); + } + return err; +} + diff --git a/include/asm-x86/cpufeature.h b/include/asm-x86/cpufeature.h index 90feb6f..0d609c8 100644 --- a/include/asm-x86/cpufeature.h +++ b/include/asm-x86/cpufeature.h @@ -186,6 +186,7 @@ extern const char * const x86_power_flags[32]; #define cpu_has_bts boot_cpu_has(X86_FEATURE_BTS) #define cpu_has_gbpages boot_cpu_has(X86_FEATURE_GBPAGES) #define cpu_has_arch_perfmon boot_cpu_has(X86_FEATURE_ARCH_PERFMON) +#define cpu_has_pat boot_cpu_has(X86_FEATURE_PAT) #if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64) # define cpu_has_invlpg 1 diff --git a/include/asm-x86/msr-index.h b/include/asm-x86/msr-index.h index 3ed9714..af4e07f 100644 --- a/include/asm-x86/msr-index.h +++ b/include/asm-x86/msr-index.h @@ -57,6 +57,8 @@ #define MSR_MTRRfix4K_F8000 0x0000026f #define MSR_MTRRdefType 0x000002ff +#define MSR_IA32_CR_PAT 0x00000277 + #define MSR_IA32_DEBUGCTLMSR 0x000001d9 #define MSR_IA32_LASTBRANCHFROMIP 0x000001db #define MSR_IA32_LASTBRANCHTOIP 0x000001dc diff --git a/include/asm-x86/mtrr.h b/include/asm-x86/mtrr.h index 319d065..968794a 100644 --- a/include/asm-x86/mtrr.h +++ b/include/asm-x86/mtrr.h @@ -84,6 +84,8 @@ struct mtrr_gentry #ifdef __KERNEL__ +extern u8 mtrr_type_lookup(u64 addr, u64 end); + /* The following functions are for use by other drivers */ # ifdef CONFIG_MTRR extern void mtrr_save_fixed_ranges(void *); diff --git a/include/asm-x86/pat.h b/include/asm-x86/pat.h new file mode 100644 index 0000000..8b822b5 --- /dev/null +++ b/include/asm-x86/pat.h @@ -0,0 +1,16 @@ + +#ifndef _ASM_PAT_H +#define _ASM_PAT_H 1 + +#include <linux/types.h> + +extern int pat_wc_enabled; + +extern void pat_init(void); + +extern int reserve_memtype(u64 start, u64 end, + unsigned long req_type, unsigned long *ret_type); +extern int free_memtype(u64 start, u64 end); + +#endif + diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h index 9cf472a..ca6deb3 100644 --- a/include/asm-x86/pgtable.h +++ b/include/asm-x86/pgtable.h @@ -57,6 +57,12 @@ #define _PAGE_CHG_MASK (PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY) +#define _PAGE_CACHE_MASK (_PAGE_PCD | _PAGE_PWT) +#define _PAGE_CACHE_WB (0) +#define _PAGE_CACHE_WC (_PAGE_PWT) +#define _PAGE_CACHE_UC_MINUS (_PAGE_PCD) +#define _PAGE_CACHE_UC (_PAGE_PCD | _PAGE_PWT) + #define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED) #define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_NX) |
