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6c036527a6
Add a new section called ".data.read_mostly" for data items that are read frequently and rarely written to like cpumaps etc. If these maps are placed in the .data section then these frequenly read items may end up in cachelines with data is is frequently updated. In that case all processors in an SMP system must needlessly reload the cachelines again and again containing elements of those frequently used variables. The ability to share these cachelines will allow each cpu in an SMP system to keep local copies of those shared cachelines thereby optimizing performance. Signed-off-by: Alok N Kataria <alokk@calsoftinc.com> Signed-off-by: Shobhit Dayal <shobhit@calsoftinc.com> Signed-off-by: Christoph Lameter <christoph@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
272 lines
6.2 KiB
C
272 lines
6.2 KiB
C
#include <linux/config.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/bitops.h>
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#include <linux/smp.h>
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#include <linux/thread_info.h>
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#include <asm/processor.h>
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#include <asm/msr.h>
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#include <asm/uaccess.h>
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#include "cpu.h"
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#ifdef CONFIG_X86_LOCAL_APIC
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#include <asm/mpspec.h>
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#include <asm/apic.h>
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#include <mach_apic.h>
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#endif
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extern int trap_init_f00f_bug(void);
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#ifdef CONFIG_X86_INTEL_USERCOPY
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/*
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* Alignment at which movsl is preferred for bulk memory copies.
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*/
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struct movsl_mask movsl_mask __read_mostly;
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#endif
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void __devinit early_intel_workaround(struct cpuinfo_x86 *c)
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{
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if (c->x86_vendor != X86_VENDOR_INTEL)
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return;
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/* Netburst reports 64 bytes clflush size, but does IO in 128 bytes */
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if (c->x86 == 15 && c->x86_cache_alignment == 64)
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c->x86_cache_alignment = 128;
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}
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/*
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* Early probe support logic for ppro memory erratum #50
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*
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* This is called before we do cpu ident work
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*/
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int __devinit ppro_with_ram_bug(void)
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{
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/* Uses data from early_cpu_detect now */
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if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
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boot_cpu_data.x86 == 6 &&
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boot_cpu_data.x86_model == 1 &&
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boot_cpu_data.x86_mask < 8) {
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printk(KERN_INFO "Pentium Pro with Errata#50 detected. Taking evasive action.\n");
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return 1;
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}
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return 0;
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}
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/*
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* P4 Xeon errata 037 workaround.
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* Hardware prefetcher may cause stale data to be loaded into the cache.
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*/
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static void __devinit Intel_errata_workarounds(struct cpuinfo_x86 *c)
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{
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unsigned long lo, hi;
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if ((c->x86 == 15) && (c->x86_model == 1) && (c->x86_mask == 1)) {
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rdmsr (MSR_IA32_MISC_ENABLE, lo, hi);
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if ((lo & (1<<9)) == 0) {
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printk (KERN_INFO "CPU: C0 stepping P4 Xeon detected.\n");
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printk (KERN_INFO "CPU: Disabling hardware prefetching (Errata 037)\n");
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lo |= (1<<9); /* Disable hw prefetching */
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wrmsr (MSR_IA32_MISC_ENABLE, lo, hi);
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}
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}
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}
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/*
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* find out the number of processor cores on the die
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*/
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static int __devinit num_cpu_cores(struct cpuinfo_x86 *c)
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{
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unsigned int eax;
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if (c->cpuid_level < 4)
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return 1;
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__asm__("cpuid"
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: "=a" (eax)
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: "0" (4), "c" (0)
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: "bx", "dx");
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if (eax & 0x1f)
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return ((eax >> 26) + 1);
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else
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return 1;
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}
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static void __devinit init_intel(struct cpuinfo_x86 *c)
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{
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unsigned int l2 = 0;
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char *p = NULL;
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#ifdef CONFIG_X86_F00F_BUG
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/*
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* All current models of Pentium and Pentium with MMX technology CPUs
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* have the F0 0F bug, which lets nonprivileged users lock up the system.
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* Note that the workaround only should be initialized once...
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*/
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c->f00f_bug = 0;
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if ( c->x86 == 5 ) {
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static int f00f_workaround_enabled = 0;
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c->f00f_bug = 1;
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if ( !f00f_workaround_enabled ) {
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trap_init_f00f_bug();
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printk(KERN_NOTICE "Intel Pentium with F0 0F bug - workaround enabled.\n");
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f00f_workaround_enabled = 1;
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}
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}
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#endif
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select_idle_routine(c);
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l2 = init_intel_cacheinfo(c);
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/* SEP CPUID bug: Pentium Pro reports SEP but doesn't have it until model 3 mask 3 */
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if ((c->x86<<8 | c->x86_model<<4 | c->x86_mask) < 0x633)
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clear_bit(X86_FEATURE_SEP, c->x86_capability);
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/* Names for the Pentium II/Celeron processors
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detectable only by also checking the cache size.
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Dixon is NOT a Celeron. */
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if (c->x86 == 6) {
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switch (c->x86_model) {
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case 5:
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if (c->x86_mask == 0) {
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if (l2 == 0)
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p = "Celeron (Covington)";
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else if (l2 == 256)
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p = "Mobile Pentium II (Dixon)";
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}
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break;
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case 6:
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if (l2 == 128)
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p = "Celeron (Mendocino)";
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else if (c->x86_mask == 0 || c->x86_mask == 5)
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p = "Celeron-A";
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break;
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case 8:
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if (l2 == 128)
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p = "Celeron (Coppermine)";
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break;
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}
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}
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if ( p )
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strcpy(c->x86_model_id, p);
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c->x86_num_cores = num_cpu_cores(c);
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detect_ht(c);
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/* Work around errata */
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Intel_errata_workarounds(c);
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#ifdef CONFIG_X86_INTEL_USERCOPY
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/*
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* Set up the preferred alignment for movsl bulk memory moves
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*/
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switch (c->x86) {
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case 4: /* 486: untested */
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break;
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case 5: /* Old Pentia: untested */
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break;
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case 6: /* PII/PIII only like movsl with 8-byte alignment */
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movsl_mask.mask = 7;
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break;
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case 15: /* P4 is OK down to 8-byte alignment */
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movsl_mask.mask = 7;
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break;
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}
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#endif
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if (c->x86 == 15)
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set_bit(X86_FEATURE_P4, c->x86_capability);
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if (c->x86 == 6)
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set_bit(X86_FEATURE_P3, c->x86_capability);
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}
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static unsigned int intel_size_cache(struct cpuinfo_x86 * c, unsigned int size)
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{
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/* Intel PIII Tualatin. This comes in two flavours.
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* One has 256kb of cache, the other 512. We have no way
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* to determine which, so we use a boottime override
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* for the 512kb model, and assume 256 otherwise.
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*/
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if ((c->x86 == 6) && (c->x86_model == 11) && (size == 0))
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size = 256;
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return size;
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}
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static struct cpu_dev intel_cpu_dev __devinitdata = {
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.c_vendor = "Intel",
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.c_ident = { "GenuineIntel" },
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.c_models = {
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{ .vendor = X86_VENDOR_INTEL, .family = 4, .model_names =
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{
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[0] = "486 DX-25/33",
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[1] = "486 DX-50",
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[2] = "486 SX",
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[3] = "486 DX/2",
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[4] = "486 SL",
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[5] = "486 SX/2",
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[7] = "486 DX/2-WB",
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[8] = "486 DX/4",
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[9] = "486 DX/4-WB"
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}
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},
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{ .vendor = X86_VENDOR_INTEL, .family = 5, .model_names =
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{
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[0] = "Pentium 60/66 A-step",
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[1] = "Pentium 60/66",
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[2] = "Pentium 75 - 200",
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[3] = "OverDrive PODP5V83",
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[4] = "Pentium MMX",
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[7] = "Mobile Pentium 75 - 200",
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[8] = "Mobile Pentium MMX"
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}
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},
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{ .vendor = X86_VENDOR_INTEL, .family = 6, .model_names =
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{
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[0] = "Pentium Pro A-step",
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[1] = "Pentium Pro",
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[3] = "Pentium II (Klamath)",
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[4] = "Pentium II (Deschutes)",
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[5] = "Pentium II (Deschutes)",
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[6] = "Mobile Pentium II",
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[7] = "Pentium III (Katmai)",
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[8] = "Pentium III (Coppermine)",
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[10] = "Pentium III (Cascades)",
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[11] = "Pentium III (Tualatin)",
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}
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},
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{ .vendor = X86_VENDOR_INTEL, .family = 15, .model_names =
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{
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[0] = "Pentium 4 (Unknown)",
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[1] = "Pentium 4 (Willamette)",
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[2] = "Pentium 4 (Northwood)",
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[4] = "Pentium 4 (Foster)",
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[5] = "Pentium 4 (Foster)",
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}
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},
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},
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.c_init = init_intel,
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.c_identify = generic_identify,
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.c_size_cache = intel_size_cache,
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};
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__init int intel_cpu_init(void)
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{
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cpu_devs[X86_VENDOR_INTEL] = &intel_cpu_dev;
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return 0;
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}
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// arch_initcall(intel_cpu_init);
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