3b9cfc0a99
This is part of the ops structure constification effort started by Arjan van de Ven et al. Benefits of this constification: * prevents modification of data that is shared (referenced) by many other structure instances at runtime * detects/prevents accidental (but not intentional) modification attempts on archs that enforce read-only kernel data at runtime * potentially better optimized code as the compiler can assume that the const data cannot be changed * the compiler/linker move const data into .rodata and therefore exclude them from false sharing Signed-off-by: Emese Revfy <re.emese@gmail.com> LKML-Reference: <4B65D712.3080804@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
126 lines
3 KiB
C
126 lines
3 KiB
C
#include <linux/init.h>
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#include <linux/mm.h>
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#include <asm/mtrr.h>
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#include <asm/msr.h>
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#include "mtrr.h"
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static struct {
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unsigned long high;
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unsigned long low;
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} centaur_mcr[8];
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static u8 centaur_mcr_reserved;
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static u8 centaur_mcr_type; /* 0 for winchip, 1 for winchip2 */
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/**
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* centaur_get_free_region - Get a free MTRR.
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*
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* @base: The starting (base) address of the region.
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* @size: The size (in bytes) of the region.
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*
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* Returns: the index of the region on success, else -1 on error.
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*/
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static int
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centaur_get_free_region(unsigned long base, unsigned long size, int replace_reg)
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{
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unsigned long lbase, lsize;
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mtrr_type ltype;
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int i, max;
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max = num_var_ranges;
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if (replace_reg >= 0 && replace_reg < max)
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return replace_reg;
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for (i = 0; i < max; ++i) {
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if (centaur_mcr_reserved & (1 << i))
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continue;
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mtrr_if->get(i, &lbase, &lsize, <ype);
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if (lsize == 0)
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return i;
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}
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return -ENOSPC;
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}
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/*
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* Report boot time MCR setups
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*/
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void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
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{
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centaur_mcr[mcr].low = lo;
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centaur_mcr[mcr].high = hi;
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}
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static void
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centaur_get_mcr(unsigned int reg, unsigned long *base,
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unsigned long *size, mtrr_type * type)
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{
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*base = centaur_mcr[reg].high >> PAGE_SHIFT;
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*size = -(centaur_mcr[reg].low & 0xfffff000) >> PAGE_SHIFT;
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*type = MTRR_TYPE_WRCOMB; /* write-combining */
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if (centaur_mcr_type == 1 && ((centaur_mcr[reg].low & 31) & 2))
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*type = MTRR_TYPE_UNCACHABLE;
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if (centaur_mcr_type == 1 && (centaur_mcr[reg].low & 31) == 25)
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*type = MTRR_TYPE_WRBACK;
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if (centaur_mcr_type == 0 && (centaur_mcr[reg].low & 31) == 31)
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*type = MTRR_TYPE_WRBACK;
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}
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static void
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centaur_set_mcr(unsigned int reg, unsigned long base,
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unsigned long size, mtrr_type type)
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{
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unsigned long low, high;
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if (size == 0) {
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/* Disable */
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high = low = 0;
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} else {
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high = base << PAGE_SHIFT;
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if (centaur_mcr_type == 0) {
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/* Only support write-combining... */
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low = -size << PAGE_SHIFT | 0x1f;
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} else {
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if (type == MTRR_TYPE_UNCACHABLE)
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low = -size << PAGE_SHIFT | 0x02; /* NC */
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else
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low = -size << PAGE_SHIFT | 0x09; /* WWO, WC */
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}
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}
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centaur_mcr[reg].high = high;
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centaur_mcr[reg].low = low;
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wrmsr(MSR_IDT_MCR0 + reg, low, high);
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}
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static int
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centaur_validate_add_page(unsigned long base, unsigned long size, unsigned int type)
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{
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/*
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* FIXME: Winchip2 supports uncached
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*/
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if (type != MTRR_TYPE_WRCOMB &&
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(centaur_mcr_type == 0 || type != MTRR_TYPE_UNCACHABLE)) {
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pr_warning("mtrr: only write-combining%s supported\n",
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centaur_mcr_type ? " and uncacheable are" : " is");
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return -EINVAL;
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}
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return 0;
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}
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static const struct mtrr_ops centaur_mtrr_ops = {
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.vendor = X86_VENDOR_CENTAUR,
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.set = centaur_set_mcr,
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.get = centaur_get_mcr,
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.get_free_region = centaur_get_free_region,
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.validate_add_page = centaur_validate_add_page,
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.have_wrcomb = positive_have_wrcomb,
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};
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int __init centaur_init_mtrr(void)
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{
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set_mtrr_ops(¢aur_mtrr_ops);
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return 0;
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}
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