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authorvenkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>2008-03-18 17:00:14 -0700
committerIngo Molnar <mingo@elte.hu>2008-04-17 17:41:19 +0200
commit2e5d9c857d4e6c9e7b7d8c8c86a68a7842d213d6 (patch)
tree6c90c0f9f38ff85e2f42ddc0f4ef0291cdd47d38 /arch/x86/kernel/cpu
parentd27554d874c7eeb14c8bfecdc39c3a8618cd8d32 (diff)
x86: PAT infrastructure patch
Sets up pat_init() infrastructure. PAT MSR has following setting. PAT |PCD ||PWT ||| 000 WB _PAGE_CACHE_WB 001 WC _PAGE_CACHE_WC 010 UC- _PAGE_CACHE_UC_MINUS 011 UC _PAGE_CACHE_UC We are effectively changing WT from boot time setting to WC. UC_MINUS is used to provide backward compatibility to existing /dev/mem users(X). reserve_memtype and free_memtype are new interfaces for maintaining alias-free mapping. It is currently implemented in a simple way with a linked list and not optimized. reserve and free tracks the effective memory type, as a result of PAT and MTRR setting rather than what is actually requested in PAT. pat_init piggy backs on mtrr_init as the rules for setting both pat and mtrr are same. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r--arch/x86/kernel/cpu/mtrr/generic.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 3e18db4cefe..011e07e99cd 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -11,6 +11,7 @@
#include <asm/cpufeature.h>
#include <asm/processor-flags.h>
#include <asm/tlbflush.h>
+#include <asm/pat.h>
#include "mtrr.h"
struct mtrr_state {
@@ -35,6 +36,7 @@ static struct fixed_range_block fixed_range_blocks[] = {
static unsigned long smp_changes_mask;
static struct mtrr_state mtrr_state = {};
+static int mtrr_state_set;
#undef MODULE_PARAM_PREFIX
#define MODULE_PARAM_PREFIX "mtrr."
@@ -42,6 +44,106 @@ static struct mtrr_state mtrr_state = {};
static int mtrr_show;
module_param_named(show, mtrr_show, bool, 0);
+/*
+ * Returns the effective MTRR type for the region
+ * Error returns:
+ * - 0xFE - when the range is "not entirely covered" by _any_ var range MTRR
+ * - 0xFF - when MTRR is not enabled
+ */
+u8 mtrr_type_lookup(u64 start, u64 end)
+{
+ int i;
+ u64 base, mask;
+ u8 prev_match, curr_match;
+
+ if (!mtrr_state_set)
+ return 0xFF;
+
+ if (!mtrr_state.enabled)
+ return 0xFF;
+
+ /* Make end inclusive end, instead of exclusive */
+ end--;
+
+ /* Look in fixed ranges. Just return the type as per start */
+ if (mtrr_state.have_fixed && (start < 0x100000)) {
+ int idx;
+
+ if (start < 0x80000) {
+ idx = 0;
+ idx += (start >> 16);
+ return mtrr_state.fixed_ranges[idx];
+ } else if (start < 0xC0000) {
+ idx = 1 * 8;
+ idx += ((start - 0x80000) >> 14);
+ return mtrr_state.fixed_ranges[idx];
+ } else if (start < 0x1000000) {
+ idx = 3 * 8;
+ idx += ((start - 0xC0000) >> 12);
+ return mtrr_state.fixed_ranges[idx];
+ }
+ }
+
+ /*
+ * Look in variable ranges
+ * Look of multiple ranges matching this address and pick type
+ * as per MTRR precedence
+ */
+ if (!mtrr_state.enabled & 2) {
+ return mtrr_state.def_type;
+ }
+
+ prev_match = 0xFF;
+ for (i = 0; i < num_var_ranges; ++i) {
+ unsigned short start_state, end_state;
+
+ if (!(mtrr_state.var_ranges[i].mask_lo & (1 << 11)))
+ continue;
+
+ base = (((u64)mtrr_state.var_ranges[i].base_hi) << 32) +
+ (mtrr_state.var_ranges[i].base_lo & PAGE_MASK);
+ mask = (((u64)mtrr_state.var_ranges[i].mask_hi) << 32) +
+ (mtrr_state.var_ranges[i].mask_lo & PAGE_MASK);
+
+ start_state = ((start & mask) == (base & mask));
+ end_state = ((end & mask) == (base & mask));
+ if (start_state != end_state)
+ return 0xFE;
+
+ if ((start & mask) != (base & mask)) {
+ continue;
+ }
+
+ curr_match = mtrr_state.var_ranges[i].base_lo & 0xff;
+ if (prev_match == 0xFF) {
+ prev_match = curr_match;
+ continue;
+ }
+
+ if (prev_match == MTRR_TYPE_UNCACHABLE ||
+ curr_match == MTRR_TYPE_UNCACHABLE) {
+ return MTRR_TYPE_UNCACHABLE;
+ }
+
+ if ((prev_match == MTRR_TYPE_WRBACK &&
+ curr_match == MTRR_TYPE_WRTHROUGH) ||
+ (prev_match == MTRR_TYPE_WRTHROUGH &&
+ curr_match == MTRR_TYPE_WRBACK)) {
+ prev_match = MTRR_TYPE_WRTHROUGH;
+ curr_match = MTRR_TYPE_WRTHROUGH;
+ }
+
+ if (prev_match != curr_match) {
+ return MTRR_TYPE_UNCACHABLE;
+ }
+ }
+
+ if (prev_match != 0xFF)
+ return prev_match;
+
+ return mtrr_state.def_type;
+}
+
/* Get the MSR pair relating to a var range */
static void
get_mtrr_var_range(unsigned int index, struct mtrr_var_range *vr)
@@ -79,12 +181,16 @@ static void print_fixed(unsigned base, unsigned step, const mtrr_type*types)
base, base + step - 1, mtrr_attrib_to_str(*types));
}
+static void prepare_set(void);
+static void post_set(void);
+
/* Grab all of the MTRR state for this CPU into *state */
void __init get_mtrr_state(void)
{
unsigned int i;
struct mtrr_var_range *vrs;
unsigned lo, dummy;
+ unsigned long flags;
vrs = mtrr_state.var_ranges;
@@ -131,6 +237,17 @@ void __init get_mtrr_state(void)
printk(KERN_INFO "MTRR %u disabled\n", i);
}
}
+ mtrr_state_set = 1;
+
+ /* PAT setup for BP. We need to go through sync steps here */
+ local_irq_save(flags);
+ prepare_set();
+
+ pat_init();
+
+ post_set();
+ local_irq_restore(flags);
+
}
/* Some BIOS's are fucked and don't set all MTRRs the same! */
@@ -397,6 +514,9 @@ static void generic_set_all(void)
/* Actually set the state */
mask = set_mtrr_state();
+ /* also set PAT */
+ pat_init();
+
post_set();
local_irq_restore(flags);