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