[PATCH] HT & MTRRs, 2.5.31-BK-curr

This patch simply ensures that 'setting the MTRR' is atomic.  This is
important since HT CPU's may share some MTRR state.

diff --git a/arch/i386/kernel/cpu/mtrr/generic.c b/arch/i386/kernel/cpu/mtrr/generic.c
index 05f2d807a9154a677d822cb9ae7e1f3684921b6f..e338318351192930c0cd4097feee3f727c910feb 100644 (file)
--- a/arch/i386/kernel/cpu/mtrr/generic.c
+++ b/arch/i386/kernel/cpu/mtrr/generic.c
@@ -69,7 +69,9 @@ void generic_set_mtrr(unsigned int reg, unsigned long base,
 {
        u32 cr0, cr4 = 0;
        u32 deftype_lo, deftype_hi;
+       static spinlock_t set_atomicity_lock = SPIN_LOCK_UNLOCKED;
 
+       spin_lock(&set_atomicity_lock);
        /*  Save value of CR4 and clear Page Global Enable (bit 7)  */
        if ( cpu_has_pge ) {
                cr4 = read_cr4();
@@ -112,6 +114,7 @@ void generic_set_mtrr(unsigned int reg, unsigned long base,
        /*  Restore value of CR4  */
        if ( cpu_has_pge )
                write_cr4(cr4);
+       spin_unlock(&set_atomicity_lock);
 }
 
 int generic_validate_add_page(unsigned long base, unsigned long size, unsigned int type)