1/* $NetBSD: i386func.S,v 1.22 2020/05/19 21:40:55 ad Exp $ */ 2 3/*- 4 * Copyright (c) 1998, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Charles M. Hannum, and by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32/* 33 * Functions to provide access to i386-specific instructions. 34 * 35 * These are _not_ shared with NetBSD/xen. 36 */ 37 38#include <machine/asm.h> 39__KERNEL_RCSID(0, "$NetBSD: i386func.S,v 1.22 2020/05/19 21:40:55 ad Exp $"); 40 41#include <machine/specialreg.h> 42#include <machine/segments.h> 43 44#include "assym.h" 45 46ENTRY(invlpg) 47 movl 4(%esp), %eax 48 invlpg (%eax) 49 ret 50END(invlpg) 51 52ENTRY(lldt) 53 movl 4(%esp), %eax 54 cmpl %eax, CPUVAR(CURLDT) 55 jne 1f 56 ret 571: 58 movl %eax, CPUVAR(CURLDT) 59 lldt %ax 60 ret 61END(lldt) 62 63ENTRY(ltr) 64 movl 4(%esp), %eax 65 ltr %ax 66 ret 67END(ltr) 68 69/* 70 * Big hammer: flush all TLB entries, including ones from PTE's 71 * with the G bit set. This should only be necessary if TLB 72 * shootdown falls far behind. 73 * 74 * Intel Architecture Software Developer's Manual, Volume 3, 75 * System Programming, section 9.10, "Invalidating the 76 * Translation Lookaside Buffers (TLBS)": 77 * "The following operations invalidate all TLB entries, irrespective 78 * of the setting of the G flag: 79 * ... 80 * "(P6 family processors only): Writing to control register CR4 to 81 * modify the PSE, PGE, or PAE flag." 82 * 83 * (the alternatives not quoted above are not an option here.) 84 * 85 * If PGE is not in use, we reload CR3. Check for the PGE feature 86 * first since i486 does not have CR4. Note: the feature flag may 87 * be present while the actual PGE functionality not yet enabled. 88 */ 89ENTRY(tlbflushg) 90 testl $CPUID_PGE, _C_LABEL(cpu_feature) 91 jz 1f 92 movl %cr4, %eax 93 testl $CR4_PGE, %eax 94 jz 1f 95 movl %eax, %edx 96 andl $~CR4_PGE, %edx 97 movl %edx, %cr4 98 movl %eax, %cr4 99 ret 100END(tlbflushg) 101 102ENTRY(tlbflush) 1031: 104 movl %cr3, %eax 105 movl %eax, %cr3 106 ret 107END(tlbflush) 108 109ENTRY(wbinvd) 110 wbinvd 111 ret 112END(wbinvd) 113 114/* 115 * void lgdt(struct region_descriptor *rdp); 116 * 117 * Load a new GDT pointer (and do any necessary cleanup). 118 * XXX It's somewhat questionable whether reloading all the segment registers 119 * is necessary, since the actual descriptor data is not changed except by 120 * process creation and exit, both of which clean up via task switches. OTOH, 121 * this only happens at run time when the GDT is resized. 122 */ 123ENTRY(lgdt) 124 /* Reload the descriptor table. */ 125 movl 4(%esp), %eax 126 lgdt (%eax) 127 /* Flush the prefetch queue. */ 128 jmp 1f 129 nop 1301: /* Reload "stale" selectors. */ 131 movl $GSEL(GDATA_SEL, SEL_KPL), %eax 132 movl %eax, %ds 133 movl %eax, %es 134 movl %eax, %gs 135 movl %eax, %ss 136 movl $GSEL(GCPU_SEL, SEL_KPL), %eax 137 movl %eax, %fs 138 jmp _C_LABEL(x86_flush) 139END(lgdt) 140