arch/x86/kernel/cpu/mtrr/state.c

   1 #include <linux/init.h>
   2 #include <linux/io.h>
   3 #include <linux/mm.h>
   4
   5 #include <asm/processor-cyrix.h>
   6 #include <asm/processor-flags.h>
   7 #include <asm/mtrr.h>
   8 #include <asm/msr.h>
   9
  10 #include "mtrr.h"
  11
  12 /* Put the processor into a state where MTRRs can be safely set */
  13 void set_mtrr_prepare_save(struct set_mtrr_context *ctxt)
  14 {
  15         unsigned int cr0;
  16
  17         /* Disable interrupts locally */
  18         local_irq_save(ctxt->flags);
  19
  20         if (use_intel() || is_cpu(CYRIX)) {
  21
  22                 /* Save value of CR4 and clear Page Global Enable (bit 7) */
  23                 if (cpu_has_pge) {
  24                         ctxt->cr4val = read_cr4();
  25                         write_cr4(ctxt->cr4val & ~X86_CR4_PGE);
  26                 }
  27
  28                 /*
  29                  * Disable and flush caches. Note that wbinvd flushes the TLBs
  30                  * as a side-effect
  31                  */
  32                 cr0 = read_cr0() | X86_CR0_CD;
  33                 wbinvd();
  34                 write_cr0(cr0);
  35                 wbinvd();
  36
  37                 if (use_intel()) {
  38                         /* Save MTRR state */
  39                         rdmsr(MSR_MTRRdefType, ctxt->deftype_lo, ctxt->deftype_hi);
  40                 } else {
  41                         /*
  42                          * Cyrix ARRs -
  43                          * everything else were excluded at the top
  44                          */
  45                         ctxt->ccr3 = getCx86(CX86_CCR3);
  46                 }
  47         }
  48 }
  49
  50 void set_mtrr_cache_disable(struct set_mtrr_context *ctxt)
  51 {
  52         if (use_intel()) {
  53                 /* Disable MTRRs, and set the default type to uncached */
  54                 mtrr_wrmsr(MSR_MTRRdefType, ctxt->deftype_lo & 0xf300UL,
  55                       ctxt->deftype_hi);
  56         } else {
  57                 if (is_cpu(CYRIX)) {
  58                         /* Cyrix ARRs - everything else were excluded at the top */
  59                         setCx86(CX86_CCR3, (ctxt->ccr3 & 0x0f) | 0x10);
  60                 }
  61         }
  62 }
  63
  64 /* Restore the processor after a set_mtrr_prepare */
  65 void set_mtrr_done(struct set_mtrr_context *ctxt)
  66 {
  67         if (use_intel() || is_cpu(CYRIX)) {
  68
  69                 /* Flush caches and TLBs */
  70                 wbinvd();
  71
  72                 /* Restore MTRRdefType */
  73                 if (use_intel()) {
  74                         /* Intel (P6) standard MTRRs */
  75                         mtrr_wrmsr(MSR_MTRRdefType, ctxt->deftype_lo,
  76                                    ctxt->deftype_hi);
  77                 } else {
  78                         /*
  79                          * Cyrix ARRs -
  80                          * everything else was excluded at the top
  81                          */
  82                         setCx86(CX86_CCR3, ctxt->ccr3);
  83                 }
  84
  85                 /* Enable caches */
  86                 write_cr0(read_cr0() & 0xbfffffff);
  87
  88                 /* Restore value of CR4 */
  89                 if (cpu_has_pge)
  90                         write_cr4(ctxt->cr4val);
  91         }
  92         /* Re-enable interrupts locally (if enabled previously) */
  93         local_irq_restore(ctxt->flags);
  94 }