initcpu.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) KATO Takenori, 1997, 1998.
    5  * 
    6  * All rights reserved.  Unpublished rights reserved under the copyright
    7  * laws of Japan.
    8  * 
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer as
   15  *    the first lines of this file unmodified.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 
   20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/12.0/sys/amd64/amd64/initcpu.c 336876 2018-07-29 20:47:00Z kib $");
   34 
   35 #include "opt_cpu.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/kernel.h>
   39 #include <sys/pcpu.h>
   40 #include <sys/systm.h>
   41 #include <sys/sysctl.h>
   42 
   43 #include <machine/cputypes.h>
   44 #include <machine/md_var.h>
   45 #include <machine/specialreg.h>
   46 
   47 #include <vm/vm.h>
   48 #include <vm/pmap.h>
   49 
   50 static int      hw_instruction_sse;
   51 SYSCTL_INT(_hw, OID_AUTO, instruction_sse, CTLFLAG_RD,
   52     &hw_instruction_sse, 0, "SIMD/MMX2 instructions available in CPU");
   53 static int      lower_sharedpage_init;
   54 int             hw_lower_amd64_sharedpage;
   55 SYSCTL_INT(_hw, OID_AUTO, lower_amd64_sharedpage, CTLFLAG_RDTUN,
   56     &hw_lower_amd64_sharedpage, 0,
   57    "Lower sharedpage to work around Ryzen issue with executing code near the top of user memory");
   58 /*
   59  * -1: automatic (default)
   60  *  0: keep enable CLFLUSH
   61  *  1: force disable CLFLUSH
   62  */
   63 static int      hw_clflush_disable = -1;
   64 
   65 static void
   66 init_amd(void)
   67 {
   68         uint64_t msr;
   69 
   70         /*
   71          * Work around Erratum 721 for Family 10h and 12h processors.
   72          * These processors may incorrectly update the stack pointer
   73          * after a long series of push and/or near-call instructions,
   74          * or a long series of pop and/or near-return instructions.
   75          *
   76          * http://support.amd.com/us/Processor_TechDocs/41322_10h_Rev_Gd.pdf
   77          * http://support.amd.com/us/Processor_TechDocs/44739_12h_Rev_Gd.pdf
   78          *
   79          * Hypervisors do not provide access to the errata MSR,
   80          * causing #GP exception on attempt to apply the errata.  The
   81          * MSR write shall be done on host and persist globally
   82          * anyway, so do not try to do it when under virtualization.
   83          */
   84         switch (CPUID_TO_FAMILY(cpu_id)) {
   85         case 0x10:
   86         case 0x12:
   87                 if ((cpu_feature2 & CPUID2_HV) == 0)
   88                         wrmsr(0xc0011029, rdmsr(0xc0011029) | 1);
   89                 break;
   90         }
   91 
   92         /*
   93          * BIOS may fail to set InitApicIdCpuIdLo to 1 as it should per BKDG.
   94          * So, do it here or otherwise some tools could be confused by
   95          * Initial Local APIC ID reported with CPUID Function 1 in EBX.
   96          */
   97         if (CPUID_TO_FAMILY(cpu_id) == 0x10) {
   98                 if ((cpu_feature2 & CPUID2_HV) == 0) {
   99                         msr = rdmsr(MSR_NB_CFG1);
  100                         msr |= (uint64_t)1 << 54;
  101                         wrmsr(MSR_NB_CFG1, msr);
  102                 }
  103         }
  104 
  105         /*
  106          * BIOS may configure Family 10h processors to convert WC+ cache type
  107          * to CD.  That can hurt performance of guest VMs using nested paging.
  108          * The relevant MSR bit is not documented in the BKDG,
  109          * the fix is borrowed from Linux.
  110          */
  111         if (CPUID_TO_FAMILY(cpu_id) == 0x10) {
  112                 if ((cpu_feature2 & CPUID2_HV) == 0) {
  113                         msr = rdmsr(0xc001102a);
  114                         msr &= ~((uint64_t)1 << 24);
  115                         wrmsr(0xc001102a, msr);
  116                 }
  117         }
  118 
  119         /*
  120          * Work around Erratum 793: Specific Combination of Writes to Write
  121          * Combined Memory Types and Locked Instructions May Cause Core Hang.
  122          * See Revision Guide for AMD Family 16h Models 00h-0Fh Processors,
  123          * revision 3.04 or later, publication 51810.
  124          */
  125         if (CPUID_TO_FAMILY(cpu_id) == 0x16 && CPUID_TO_MODEL(cpu_id) <= 0xf) {
  126                 if ((cpu_feature2 & CPUID2_HV) == 0) {
  127                         msr = rdmsr(0xc0011020);
  128                         msr |= (uint64_t)1 << 15;
  129                         wrmsr(0xc0011020, msr);
  130                 }
  131         }
  132 
  133         /* Ryzen erratas. */
  134         if (CPUID_TO_FAMILY(cpu_id) == 0x17 && CPUID_TO_MODEL(cpu_id) == 0x1 &&
  135             (cpu_feature2 & CPUID2_HV) == 0) {
  136                 /* 1021 */
  137                 msr = rdmsr(0xc0011029);
  138                 msr |= 0x2000;
  139                 wrmsr(0xc0011029, msr);
  140 
  141                 /* 1033 */
  142                 msr = rdmsr(0xc0011020);
  143                 msr |= 0x10;
  144                 wrmsr(0xc0011020, msr);
  145 
  146                 /* 1049 */
  147                 msr = rdmsr(0xc0011028);
  148                 msr |= 0x10;
  149                 wrmsr(0xc0011028, msr);
  150 
  151                 /* 1095 */
  152                 msr = rdmsr(0xc0011020);
  153                 msr |= 0x200000000000000;
  154                 wrmsr(0xc0011020, msr);
  155         }
  156 
  157         /*
  158          * Work around a problem on Ryzen that is triggered by executing
  159          * code near the top of user memory, in our case the signal
  160          * trampoline code in the shared page on amd64.
  161          *
  162          * This function is executed once for the BSP before tunables take
  163          * effect so the value determined here can be overridden by the
  164          * tunable.  This function is then executed again for each AP and
  165          * also on resume.  Set a flag the first time so that value set by
  166          * the tunable is not overwritten.
  167          *
  168          * The stepping and/or microcode versions should be checked after
  169          * this issue is fixed by AMD so that we don't use this mode if not
  170          * needed.
  171          */
  172         if (lower_sharedpage_init == 0) {
  173                 lower_sharedpage_init = 1;
  174                 if (CPUID_TO_FAMILY(cpu_id) == 0x17) {
  175                         hw_lower_amd64_sharedpage = 1;
  176                 }
  177         }
  178 }
  179 
  180 /*
  181  * Initialize special VIA features
  182  */
  183 static void
  184 init_via(void)
  185 {
  186         u_int regs[4], val;
  187 
  188         /*
  189          * Check extended CPUID for PadLock features.
  190          *
  191          * http://www.via.com.tw/en/downloads/whitepapers/initiatives/padlock/programming_guide.pdf
  192          */
  193         do_cpuid(0xc0000000, regs);
  194         if (regs[0] >= 0xc0000001) {
  195                 do_cpuid(0xc0000001, regs);
  196                 val = regs[3];
  197         } else
  198                 return;
  199 
  200         /* Enable RNG if present. */
  201         if ((val & VIA_CPUID_HAS_RNG) != 0) {
  202                 via_feature_rng = VIA_HAS_RNG;
  203                 wrmsr(0x110B, rdmsr(0x110B) | VIA_CPUID_DO_RNG);
  204         }
  205 
  206         /* Enable PadLock if present. */
  207         if ((val & VIA_CPUID_HAS_ACE) != 0)
  208                 via_feature_xcrypt |= VIA_HAS_AES;
  209         if ((val & VIA_CPUID_HAS_ACE2) != 0)
  210                 via_feature_xcrypt |= VIA_HAS_AESCTR;
  211         if ((val & VIA_CPUID_HAS_PHE) != 0)
  212                 via_feature_xcrypt |= VIA_HAS_SHA;
  213         if ((val & VIA_CPUID_HAS_PMM) != 0)
  214                 via_feature_xcrypt |= VIA_HAS_MM;
  215         if (via_feature_xcrypt != 0)
  216                 wrmsr(0x1107, rdmsr(0x1107) | (1 << 28));
  217 }
  218 
  219 /*
  220  * Initialize CPU control registers
  221  */
  222 void
  223 initializecpu(void)
  224 {
  225         uint64_t msr;
  226         uint32_t cr4;
  227 
  228         cr4 = rcr4();
  229         if ((cpu_feature & CPUID_XMM) && (cpu_feature & CPUID_FXSR)) {
  230                 cr4 |= CR4_FXSR | CR4_XMM;
  231                 cpu_fxsr = hw_instruction_sse = 1;
  232         }
  233         if (cpu_stdext_feature & CPUID_STDEXT_FSGSBASE)
  234                 cr4 |= CR4_FSGSBASE;
  235 
  236         /*
  237          * Postpone enabling the SMEP on the boot CPU until the page
  238          * tables are switched from the boot loader identity mapping
  239          * to the kernel tables.  The boot loader enables the U bit in
  240          * its tables.
  241          */
  242         if (!IS_BSP()) {
  243                 if (cpu_stdext_feature & CPUID_STDEXT_SMEP)
  244                         cr4 |= CR4_SMEP;
  245                 if (cpu_stdext_feature & CPUID_STDEXT_SMAP)
  246                         cr4 |= CR4_SMAP;
  247         }
  248         load_cr4(cr4);
  249         if (IS_BSP() && (amd_feature & AMDID_NX) != 0) {
  250                 msr = rdmsr(MSR_EFER) | EFER_NXE;
  251                 wrmsr(MSR_EFER, msr);
  252                 pg_nx = PG_NX;
  253         }
  254         hw_ibrs_recalculate();
  255         hw_ssb_recalculate(false);
  256         switch (cpu_vendor_id) {
  257         case CPU_VENDOR_AMD:
  258                 init_amd();
  259                 break;
  260         case CPU_VENDOR_CENTAUR:
  261                 init_via();
  262                 break;
  263         }
  264 }
  265 
  266 void
  267 initializecpucache(void)
  268 {
  269 
  270         /*
  271          * CPUID with %eax = 1, %ebx returns
  272          * Bits 15-8: CLFLUSH line size
  273          *      (Value * 8 = cache line size in bytes)
  274          */
  275         if ((cpu_feature & CPUID_CLFSH) != 0)
  276                 cpu_clflush_line_size = ((cpu_procinfo >> 8) & 0xff) * 8;
  277         /*
  278          * XXXKIB: (temporary) hack to work around traps generated
  279          * when CLFLUSHing APIC register window under virtualization
  280          * environments.  These environments tend to disable the
  281          * CPUID_SS feature even though the native CPU supports it.
  282          */
  283         TUNABLE_INT_FETCH("hw.clflush_disable", &hw_clflush_disable);
  284         if (vm_guest != VM_GUEST_NO && hw_clflush_disable == -1) {
  285                 cpu_feature &= ~CPUID_CLFSH;
  286                 cpu_stdext_feature &= ~CPUID_STDEXT_CLFLUSHOPT;
  287         }
  288 
  289         /*
  290          * The kernel's use of CLFLUSH{,OPT} can be disabled manually
  291          * by setting the hw.clflush_disable tunable.
  292          */
  293         if (hw_clflush_disable == 1) {
  294                 cpu_feature &= ~CPUID_CLFSH;
  295                 cpu_stdext_feature &= ~CPUID_STDEXT_CLFLUSHOPT;
  296         }
  297 }
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FreeBSD/Linux Kernel Cross Reference sys/amd64/amd64/initcpu.c

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