The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/initcpu.c

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    1 /*-
    2  * Copyright (c) KATO Takenori, 1997, 1998.
    3  * 
    4  * All rights reserved.  Unpublished rights reserved under the copyright
    5  * laws of Japan.
    6  * 
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer as
   13  *    the first lines of this file unmodified.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  * 
   18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/11.1/sys/amd64/amd64/initcpu.c 330908 2018-03-14 04:00:00Z gordon $");
   32 
   33 #include "opt_cpu.h"
   34 
   35 #include <sys/param.h>
   36 #include <sys/kernel.h>
   37 #include <sys/pcpu.h>
   38 #include <sys/systm.h>
   39 #include <sys/sysctl.h>
   40 
   41 #include <machine/cputypes.h>
   42 #include <machine/md_var.h>
   43 #include <machine/specialreg.h>
   44 
   45 #include <vm/vm.h>
   46 #include <vm/pmap.h>
   47 
   48 static int      hw_instruction_sse;
   49 SYSCTL_INT(_hw, OID_AUTO, instruction_sse, CTLFLAG_RD,
   50     &hw_instruction_sse, 0, "SIMD/MMX2 instructions available in CPU");
   51 /*
   52  * -1: automatic (default)
   53  *  0: keep enable CLFLUSH
   54  *  1: force disable CLFLUSH
   55  */
   56 static int      hw_clflush_disable = -1;
   57 
   58 static void
   59 init_amd(void)
   60 {
   61         uint64_t msr;
   62 
   63         /*
   64          * Work around Erratum 721 for Family 10h and 12h processors.
   65          * These processors may incorrectly update the stack pointer
   66          * after a long series of push and/or near-call instructions,
   67          * or a long series of pop and/or near-return instructions.
   68          *
   69          * http://support.amd.com/us/Processor_TechDocs/41322_10h_Rev_Gd.pdf
   70          * http://support.amd.com/us/Processor_TechDocs/44739_12h_Rev_Gd.pdf
   71          *
   72          * Hypervisors do not provide access to the errata MSR,
   73          * causing #GP exception on attempt to apply the errata.  The
   74          * MSR write shall be done on host and persist globally
   75          * anyway, so do not try to do it when under virtualization.
   76          */
   77         switch (CPUID_TO_FAMILY(cpu_id)) {
   78         case 0x10:
   79         case 0x12:
   80                 if ((cpu_feature2 & CPUID2_HV) == 0)
   81                         wrmsr(0xc0011029, rdmsr(0xc0011029) | 1);
   82                 break;
   83         }
   84 
   85         /*
   86          * BIOS may fail to set InitApicIdCpuIdLo to 1 as it should per BKDG.
   87          * So, do it here or otherwise some tools could be confused by
   88          * Initial Local APIC ID reported with CPUID Function 1 in EBX.
   89          */
   90         if (CPUID_TO_FAMILY(cpu_id) == 0x10) {
   91                 if ((cpu_feature2 & CPUID2_HV) == 0) {
   92                         msr = rdmsr(MSR_NB_CFG1);
   93                         msr |= (uint64_t)1 << 54;
   94                         wrmsr(MSR_NB_CFG1, msr);
   95                 }
   96         }
   97 
   98         /*
   99          * BIOS may configure Family 10h processors to convert WC+ cache type
  100          * to CD.  That can hurt performance of guest VMs using nested paging.
  101          * The relevant MSR bit is not documented in the BKDG,
  102          * the fix is borrowed from Linux.
  103          */
  104         if (CPUID_TO_FAMILY(cpu_id) == 0x10) {
  105                 if ((cpu_feature2 & CPUID2_HV) == 0) {
  106                         msr = rdmsr(0xc001102a);
  107                         msr &= ~((uint64_t)1 << 24);
  108                         wrmsr(0xc001102a, msr);
  109                 }
  110         }
  111 
  112         /*
  113          * Work around Erratum 793: Specific Combination of Writes to Write
  114          * Combined Memory Types and Locked Instructions May Cause Core Hang.
  115          * See Revision Guide for AMD Family 16h Models 00h-0Fh Processors,
  116          * revision 3.04 or later, publication 51810.
  117          */
  118         if (CPUID_TO_FAMILY(cpu_id) == 0x16 && CPUID_TO_MODEL(cpu_id) <= 0xf) {
  119                 if ((cpu_feature2 & CPUID2_HV) == 0) {
  120                         msr = rdmsr(0xc0011020);
  121                         msr |= (uint64_t)1 << 15;
  122                         wrmsr(0xc0011020, msr);
  123                 }
  124         }
  125 }
  126 
  127 /*
  128  * Initialize special VIA features
  129  */
  130 static void
  131 init_via(void)
  132 {
  133         u_int regs[4], val;
  134 
  135         /*
  136          * Check extended CPUID for PadLock features.
  137          *
  138          * http://www.via.com.tw/en/downloads/whitepapers/initiatives/padlock/programming_guide.pdf
  139          */
  140         do_cpuid(0xc0000000, regs);
  141         if (regs[0] >= 0xc0000001) {
  142                 do_cpuid(0xc0000001, regs);
  143                 val = regs[3];
  144         } else
  145                 return;
  146 
  147         /* Enable RNG if present. */
  148         if ((val & VIA_CPUID_HAS_RNG) != 0) {
  149                 via_feature_rng = VIA_HAS_RNG;
  150                 wrmsr(0x110B, rdmsr(0x110B) | VIA_CPUID_DO_RNG);
  151         }
  152 
  153         /* Enable PadLock if present. */
  154         if ((val & VIA_CPUID_HAS_ACE) != 0)
  155                 via_feature_xcrypt |= VIA_HAS_AES;
  156         if ((val & VIA_CPUID_HAS_ACE2) != 0)
  157                 via_feature_xcrypt |= VIA_HAS_AESCTR;
  158         if ((val & VIA_CPUID_HAS_PHE) != 0)
  159                 via_feature_xcrypt |= VIA_HAS_SHA;
  160         if ((val & VIA_CPUID_HAS_PMM) != 0)
  161                 via_feature_xcrypt |= VIA_HAS_MM;
  162         if (via_feature_xcrypt != 0)
  163                 wrmsr(0x1107, rdmsr(0x1107) | (1 << 28));
  164 }
  165 
  166 /*
  167  * Initialize CPU control registers
  168  */
  169 void
  170 initializecpu(void)
  171 {
  172         uint64_t msr;
  173         uint32_t cr4;
  174 
  175         cr4 = rcr4();
  176         if ((cpu_feature & CPUID_XMM) && (cpu_feature & CPUID_FXSR)) {
  177                 cr4 |= CR4_FXSR | CR4_XMM;
  178                 cpu_fxsr = hw_instruction_sse = 1;
  179         }
  180         if (cpu_stdext_feature & CPUID_STDEXT_FSGSBASE)
  181                 cr4 |= CR4_FSGSBASE;
  182 
  183         /*
  184          * Postpone enabling the SMEP on the boot CPU until the page
  185          * tables are switched from the boot loader identity mapping
  186          * to the kernel tables.  The boot loader enables the U bit in
  187          * its tables.
  188          */
  189         if (!IS_BSP() && (cpu_stdext_feature & CPUID_STDEXT_SMEP))
  190                 cr4 |= CR4_SMEP;
  191         load_cr4(cr4);
  192         if ((amd_feature & AMDID_NX) != 0) {
  193                 msr = rdmsr(MSR_EFER) | EFER_NXE;
  194                 wrmsr(MSR_EFER, msr);
  195                 pg_nx = PG_NX;
  196         }
  197         hw_ibrs_recalculate();
  198         switch (cpu_vendor_id) {
  199         case CPU_VENDOR_AMD:
  200                 init_amd();
  201                 break;
  202         case CPU_VENDOR_CENTAUR:
  203                 init_via();
  204                 break;
  205         }
  206 }
  207 
  208 void
  209 initializecpucache(void)
  210 {
  211 
  212         /*
  213          * CPUID with %eax = 1, %ebx returns
  214          * Bits 15-8: CLFLUSH line size
  215          *      (Value * 8 = cache line size in bytes)
  216          */
  217         if ((cpu_feature & CPUID_CLFSH) != 0)
  218                 cpu_clflush_line_size = ((cpu_procinfo >> 8) & 0xff) * 8;
  219         /*
  220          * XXXKIB: (temporary) hack to work around traps generated
  221          * when CLFLUSHing APIC register window under virtualization
  222          * environments.  These environments tend to disable the
  223          * CPUID_SS feature even though the native CPU supports it.
  224          */
  225         TUNABLE_INT_FETCH("hw.clflush_disable", &hw_clflush_disable);
  226         if (vm_guest != VM_GUEST_NO && hw_clflush_disable == -1) {
  227                 cpu_feature &= ~CPUID_CLFSH;
  228                 cpu_stdext_feature &= ~CPUID_STDEXT_CLFLUSHOPT;
  229         }
  230 
  231         /*
  232          * The kernel's use of CLFLUSH{,OPT} can be disabled manually
  233          * by setting the hw.clflush_disable tunable.
  234          */
  235         if (hw_clflush_disable == 1) {
  236                 cpu_feature &= ~CPUID_CLFSH;
  237                 cpu_stdext_feature &= ~CPUID_STDEXT_CLFLUSHOPT;
  238         }
  239 }

Cache object: 7631ea1ab8ab0c6ff4116186ead9ecb2


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