xref: /freebsd/sys/amd64/amd64/initcpu.c (revision 15c433351f54e7cd5bec8d36c8e89e6a7fa55b26)
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  Unpublished rights reserved under the copyright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("$FreeBSD$");
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 
62 	/*
63 	 * Work around Erratum 721 for Family 10h and 12h processors.
64 	 * These processors may incorrectly update the stack pointer
65 	 * after a long series of push and/or near-call instructions,
66 	 * or a long series of pop and/or near-return instructions.
67 	 *
68 	 * http://support.amd.com/us/Processor_TechDocs/41322_10h_Rev_Gd.pdf
69 	 * http://support.amd.com/us/Processor_TechDocs/44739_12h_Rev_Gd.pdf
70 	 *
71 	 * Hypervisors do not provide access to the errata MSR,
72 	 * causing #GP exception on attempt to apply the errata.  The
73 	 * MSR write shall be done on host and persist globally
74 	 * anyway, so do not try to do it when under virtualization.
75 	 */
76 	switch (CPUID_TO_FAMILY(cpu_id)) {
77 	case 0x10:
78 	case 0x12:
79 		if ((cpu_feature2 & CPUID2_HV) == 0)
80 			wrmsr(0xc0011029, rdmsr(0xc0011029) | 1);
81 		break;
82 	}
83 }
84 
85 /*
86  * Initialize special VIA features
87  */
88 static void
89 init_via(void)
90 {
91 	u_int regs[4], val;
92 
93 	/*
94 	 * Check extended CPUID for PadLock features.
95 	 *
96 	 * http://www.via.com.tw/en/downloads/whitepapers/initiatives/padlock/programming_guide.pdf
97 	 */
98 	do_cpuid(0xc0000000, regs);
99 	if (regs[0] >= 0xc0000001) {
100 		do_cpuid(0xc0000001, regs);
101 		val = regs[3];
102 	} else
103 		return;
104 
105 	/* Enable RNG if present. */
106 	if ((val & VIA_CPUID_HAS_RNG) != 0) {
107 		via_feature_rng = VIA_HAS_RNG;
108 		wrmsr(0x110B, rdmsr(0x110B) | VIA_CPUID_DO_RNG);
109 	}
110 
111 	/* Enable PadLock if present. */
112 	if ((val & VIA_CPUID_HAS_ACE) != 0)
113 		via_feature_xcrypt |= VIA_HAS_AES;
114 	if ((val & VIA_CPUID_HAS_ACE2) != 0)
115 		via_feature_xcrypt |= VIA_HAS_AESCTR;
116 	if ((val & VIA_CPUID_HAS_PHE) != 0)
117 		via_feature_xcrypt |= VIA_HAS_SHA;
118 	if ((val & VIA_CPUID_HAS_PMM) != 0)
119 		via_feature_xcrypt |= VIA_HAS_MM;
120 	if (via_feature_xcrypt != 0)
121 		wrmsr(0x1107, rdmsr(0x1107) | (1 << 28));
122 }
123 
124 /*
125  * Initialize CPU control registers
126  */
127 void
128 initializecpu(void)
129 {
130 	uint64_t msr;
131 	uint32_t cr4;
132 
133 	cr4 = rcr4();
134 	if ((cpu_feature & CPUID_XMM) && (cpu_feature & CPUID_FXSR)) {
135 		cr4 |= CR4_FXSR | CR4_XMM;
136 		cpu_fxsr = hw_instruction_sse = 1;
137 	}
138 	if (cpu_stdext_feature & CPUID_STDEXT_FSGSBASE)
139 		cr4 |= CR4_FSGSBASE;
140 
141 	/*
142 	 * Postpone enabling the SMEP on the boot CPU until the page
143 	 * tables are switched from the boot loader identity mapping
144 	 * to the kernel tables.  The boot loader enables the U bit in
145 	 * its tables.
146 	 */
147 	if (!IS_BSP() && (cpu_stdext_feature & CPUID_STDEXT_SMEP))
148 		cr4 |= CR4_SMEP;
149 	load_cr4(cr4);
150 	if ((amd_feature & AMDID_NX) != 0) {
151 		msr = rdmsr(MSR_EFER) | EFER_NXE;
152 		wrmsr(MSR_EFER, msr);
153 		pg_nx = PG_NX;
154 	}
155 	switch (cpu_vendor_id) {
156 	case CPU_VENDOR_AMD:
157 		init_amd();
158 		break;
159 	case CPU_VENDOR_CENTAUR:
160 		init_via();
161 		break;
162 	}
163 }
164 
165 void
166 initializecpucache(void)
167 {
168 
169 	/*
170 	 * CPUID with %eax = 1, %ebx returns
171 	 * Bits 15-8: CLFLUSH line size
172 	 * 	(Value * 8 = cache line size in bytes)
173 	 */
174 	if ((cpu_feature & CPUID_CLFSH) != 0)
175 		cpu_clflush_line_size = ((cpu_procinfo >> 8) & 0xff) * 8;
176 	/*
177 	 * XXXKIB: (temporary) hack to work around traps generated
178 	 * when CLFLUSHing APIC register window under virtualization
179 	 * environments.  These environments tend to disable the
180 	 * CPUID_SS feature even though the native CPU supports it.
181 	 */
182 	TUNABLE_INT_FETCH("hw.clflush_disable", &hw_clflush_disable);
183 	if (vm_guest != VM_GUEST_NO && hw_clflush_disable == -1) {
184 		cpu_feature &= ~CPUID_CLFSH;
185 		cpu_stdext_feature &= ~CPUID_STDEXT_CLFLUSHOPT;
186 	}
187 
188 	/*
189 	 * The kernel's use of CLFLUSH{,OPT} can be disabled manually
190 	 * by setting the hw.clflush_disable tunable.
191 	 */
192 	if (hw_clflush_disable == 1) {
193 		cpu_feature &= ~CPUID_CLFSH;
194 		cpu_stdext_feature &= ~CPUID_STDEXT_CLFLUSHOPT;
195 	}
196 }
197