1 files changed, 78 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/mtrr/state.c b/arch/i386/kernel/cpu/mtrr/state.c
new file mode 100644
index 000000000000..f62ecd15811a
--- /dev/null
+++ b/arch/i386/kernel/cpu/mtrr/state.c
@@ -0,0 +1,78 @@
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <asm/io.h>
+#include <asm/mtrr.h>
+#include <asm/msr.h>
+#include "mtrr.h"
+
+
+/*  Put the processor into a state where MTRRs can be safely set  */
+void set_mtrr_prepare_save(struct set_mtrr_context *ctxt)
+{
+	unsigned int cr0;
+
+	/*  Disable interrupts locally  */
+	local_irq_save(ctxt->flags);
+
+	if (use_intel() || is_cpu(CYRIX)) {
+
+		/*  Save value of CR4 and clear Page Global Enable (bit 7)  */
+		if ( cpu_has_pge ) {
+			ctxt->cr4val = read_cr4();
+			write_cr4(ctxt->cr4val & (unsigned char) ~(1 << 7));
+		}
+
+		/*  Disable and flush caches. Note that wbinvd flushes the TLBs as
+		    a side-effect  */
+		cr0 = read_cr0() | 0x40000000;
+		wbinvd();
+		write_cr0(cr0);
+		wbinvd();
+
+		if (use_intel())
+			/*  Save MTRR state */
+			rdmsr(MTRRdefType_MSR, ctxt->deftype_lo, ctxt->deftype_hi);
+		else
+			/* Cyrix ARRs - everything else were excluded at the top */
+			ctxt->ccr3 = getCx86(CX86_CCR3);
+	}
+}
+
+void set_mtrr_cache_disable(struct set_mtrr_context *ctxt)
+{
+	if (use_intel()) 
+		/*  Disable MTRRs, and set the default type to uncached  */
+		mtrr_wrmsr(MTRRdefType_MSR, ctxt->deftype_lo & 0xf300UL,
+		      ctxt->deftype_hi);
+	else if (is_cpu(CYRIX))
+		/* Cyrix ARRs - everything else were excluded at the top */
+		setCx86(CX86_CCR3, (ctxt->ccr3 & 0x0f) | 0x10);
+}
+
+/*  Restore the processor after a set_mtrr_prepare  */
+void set_mtrr_done(struct set_mtrr_context *ctxt)
+{
+	if (use_intel() || is_cpu(CYRIX)) {
+
+		/*  Flush caches and TLBs  */
+		wbinvd();
+
+		/*  Restore MTRRdefType  */
+		if (use_intel())
+			/* Intel (P6) standard MTRRs */
+			mtrr_wrmsr(MTRRdefType_MSR, ctxt->deftype_lo, ctxt->deftype_hi);
+		else
+			/* Cyrix ARRs - everything else was excluded at the top */
+			setCx86(CX86_CCR3, ctxt->ccr3);
+		
+		/*  Enable caches  */
+		write_cr0(read_cr0() & 0xbfffffff);
+
+		/*  Restore value of CR4  */
+		if ( cpu_has_pge )
+			write_cr4(ctxt->cr4val);
+	}
+	/*  Re-enable interrupts locally (if enabled previously)  */
+	local_irq_restore(ctxt->flags);
+}
+