summaryrefslogtreecommitdiff
path: root/src/cpu/x86/mtrr/mtrr.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/cpu/x86/mtrr/mtrr.c')
-rw-r--r--src/cpu/x86/mtrr/mtrr.c184
1 files changed, 55 insertions, 129 deletions
diff --git a/src/cpu/x86/mtrr/mtrr.c b/src/cpu/x86/mtrr/mtrr.c
index 7b1b659097..13fe85f5a6 100644
--- a/src/cpu/x86/mtrr/mtrr.c
+++ b/src/cpu/x86/mtrr/mtrr.c
@@ -133,20 +133,8 @@ static void enable_var_mtrr(unsigned char deftype)
#define RANGE_1MB PHYS_TO_RANGE_ADDR(1 << 20)
#define RANGE_4GB (1 << (ADDR_SHIFT_TO_RANGE_SHIFT(32)))
-/*
- * The default MTRR type selection uses 3 approaches for selecting the
- * optimal number of variable MTRRs. For each range do 3 calculations:
- * 1. UC as default type with no holes at top of range.
- * 2. UC as default using holes at top of range.
- * 3. WB as default.
- * If using holes is optimal for a range when UC is the default type the
- * tag is updated to direct the commit routine to use a hole at the top
- * of a range.
- */
#define MTRR_ALGO_SHIFT (8)
#define MTRR_TAG_MASK ((1 << MTRR_ALGO_SHIFT) - 1)
-/* If the default type is UC use the hole carving algorithm for a range. */
-#define MTRR_RANGE_UC_USE_HOLE (1 << MTRR_ALGO_SHIFT)
static inline uint32_t range_entry_base_mtrr_addr(struct range_entry *r)
{
@@ -557,9 +545,7 @@ static void calc_var_mtrrs_with_hole(struct var_mtrr_state *var_state,
struct range_entry *r)
{
uint32_t a1, a2, b1, b2;
- uint64_t b2_limit;
int mtrr_type, carve_hole;
- struct range_entry *next;
/*
* Determine MTRRs based on the following algorithm for the given entry:
@@ -597,42 +583,50 @@ static void calc_var_mtrrs_with_hole(struct var_mtrr_state *var_state,
a2 = RANGE_4GB;
b1 = a2;
-
- /*
- * Depending on the type of the next range, there are three
- * different situations to handle:
- *
- * 1. WB range is last in address space:
- * Aligning up, up to the next power of 2, may gain us
- * something.
- *
- * 2. The next range is of type UC:
- * We may align up, up to the _end_ of the next range. If
- * there is a gap between the current and the next range,
- * it would have been covered by the default type UC anyway.
- *
- * 3. The next range is not of type UC:
- * We may align up, up to the _base_ of the next range. This
- * may either be the end of the current range (if the next
- * range follows immediately) or the end of the gap between
- * the ranges.
- */
- next = memranges_next_entry(var_state->addr_space, r);
- if (next == NULL) {
- b2_limit = ALIGN_UP((uint64_t)b1, 1 << fms(b1));
- /* If it's the last range above 4GiB, we won't carve
- the hole out. If an OS wanted to move MMIO there,
- it would have to override the MTRR setting using
- PAT just like it would with WB as default type. */
- carve_hole = a1 < RANGE_4GB;
- } else if (range_entry_mtrr_type(next) == MTRR_TYPE_UNCACHEABLE) {
- b2_limit = range_entry_end_mtrr_addr(next);
- carve_hole = 1;
- } else {
- b2_limit = range_entry_base_mtrr_addr(next);
- carve_hole = 1;
+ b2 = a2;
+ carve_hole = 0;
+
+ /* We only consider WB type ranges for hole-carving. */
+ if (mtrr_type == MTRR_TYPE_WRBACK) {
+ struct range_entry *next;
+ uint64_t b2_limit;
+ /*
+ * Depending on the type of the next range, there are three
+ * different situations to handle:
+ *
+ * 1. WB range is last in address space:
+ * Aligning up, up to the next power of 2, may gain us
+ * something.
+ *
+ * 2. The next range is of type UC:
+ * We may align up, up to the _end_ of the next range. If
+ * there is a gap between the current and the next range,
+ * it would have been covered by the default type UC anyway.
+ *
+ * 3. The next range is not of type UC:
+ * We may align up, up to the _base_ of the next range. This
+ * may either be the end of the current range (if the next
+ * range follows immediately) or the end of the gap between
+ * the ranges.
+ */
+ next = memranges_next_entry(var_state->addr_space, r);
+ if (next == NULL) {
+ b2_limit = ALIGN_UP((uint64_t)b1, 1 << fms(b1));
+ /* If it's the last range above 4GiB, we won't carve
+ the hole out. If an OS wanted to move MMIO there,
+ it would have to override the MTRR setting using
+ PAT just like it would with WB as default type. */
+ carve_hole = a1 < RANGE_4GB;
+ } else if (range_entry_mtrr_type(next)
+ == MTRR_TYPE_UNCACHEABLE) {
+ b2_limit = range_entry_end_mtrr_addr(next);
+ carve_hole = 1;
+ } else {
+ b2_limit = range_entry_base_mtrr_addr(next);
+ carve_hole = 1;
+ }
+ b2 = optimize_var_mtrr_hole(a1, b1, b2_limit, carve_hole);
}
- b2 = optimize_var_mtrr_hole(a1, b1, b2_limit, carve_hole);
calc_var_mtrr_range(var_state, a1, b2 - a1, mtrr_type);
if (carve_hole && b2 != b1) {
@@ -641,37 +635,6 @@ static void calc_var_mtrrs_with_hole(struct var_mtrr_state *var_state,
}
}
-static void calc_var_mtrrs_without_hole(struct var_mtrr_state *var_state,
- struct range_entry *r)
-{
- const int mtrr_type = range_entry_mtrr_type(r);
-
- uint32_t base = range_entry_base_mtrr_addr(r);
- uint32_t end = range_entry_end_mtrr_addr(r);
-
- /* The end address is within the first 1MiB. The fixed MTRRs take
- * precedence over the variable ones. Therefore this range
- * can be ignored. */
- if (end <= RANGE_1MB)
- return;
-
- /* Again, the fixed MTRRs take precedence so the beginning
- * of the range can be set to 0 if it starts at or below 1MiB. */
- if (base <= RANGE_1MB)
- base = 0;
-
- /* If the range starts above 4GiB the processing is done. */
- if (!var_state->above4gb && base >= RANGE_4GB)
- return;
-
- /* Clip the upper address to 4GiB if addresses above 4GiB
- * are not being processed. */
- if (!var_state->above4gb && end > RANGE_4GB)
- end = RANGE_4GB;
-
- calc_var_mtrr_range(var_state, base, end - base, mtrr_type);
-}
-
static void __calc_var_mtrrs(struct memranges *addr_space,
int above4gb, int address_bits,
int *num_def_wb_mtrrs, int *num_def_uc_mtrrs)
@@ -693,16 +656,14 @@ static void __calc_var_mtrrs(struct memranges *addr_space,
uc_deftype_count = 0;
/*
- * For each range do 3 calculations:
- * 1. UC as default type with no holes at top of range.
- * 2. UC as default using holes at top of range.
- * 3. WB as default.
+ * For each range do 2 calculations:
+ * 1. UC as default type with possible holes at top of range.
+ * 2. WB as default.
* The lowest count is then used as default after totaling all
- * MTRRs. Note that the optimal algorithm for UC default is marked in
- * the tag of each range regardless of final decision. UC takes
- * precedence in the MTRR architecture. Therefore, only holes can be
- * used when the type of the region is MTRR_TYPE_WRBACK with
- * MTRR_TYPE_UNCACHEABLE as the default type.
+ * MTRRs. UC takes precedence in the MTRR architecture. There-
+ * fore, only holes can be used when the type of the region is
+ * MTRR_TYPE_WRBACK with MTRR_TYPE_UNCACHEABLE as the default
+ * type.
*/
memranges_each_entry(r, var_state.addr_space) {
int mtrr_type;
@@ -710,43 +671,16 @@ static void __calc_var_mtrrs(struct memranges *addr_space,
mtrr_type = range_entry_mtrr_type(r);
if (mtrr_type != MTRR_TYPE_UNCACHEABLE) {
- int uc_hole_count;
- int uc_no_hole_count;
-
- var_state.def_mtrr_type = MTRR_TYPE_UNCACHEABLE;
var_state.mtrr_index = 0;
-
- /* No hole calculation. */
- calc_var_mtrrs_without_hole(&var_state, r);
- uc_no_hole_count = var_state.mtrr_index;
-
- /* Hole calculation only if type is WB. The 64 number
- * is a count that is unachievable, thus making it
- * a default large number in the case of not doing
- * the hole calculation. */
- uc_hole_count = 64;
- if (mtrr_type == MTRR_TYPE_WRBACK) {
- var_state.mtrr_index = 0;
- calc_var_mtrrs_with_hole(&var_state, r);
- uc_hole_count = var_state.mtrr_index;
- }
-
- /* Mark the entry with the optimal algorithm. */
- if (uc_no_hole_count < uc_hole_count) {
- uc_deftype_count += uc_no_hole_count;
- } else {
- unsigned long new_tag;
-
- new_tag = mtrr_type | MTRR_RANGE_UC_USE_HOLE;
- range_entry_update_tag(r, new_tag);
- uc_deftype_count += uc_hole_count;
- }
+ var_state.def_mtrr_type = MTRR_TYPE_UNCACHEABLE;
+ calc_var_mtrrs_with_hole(&var_state, r);
+ uc_deftype_count += var_state.mtrr_index;
}
if (mtrr_type != MTRR_TYPE_WRBACK) {
var_state.mtrr_index = 0;
var_state.def_mtrr_type = MTRR_TYPE_WRBACK;
- calc_var_mtrrs_without_hole(&var_state, r);
+ calc_var_mtrrs_with_hole(&var_state, r);
wb_deftype_count += var_state.mtrr_index;
}
}
@@ -803,12 +737,7 @@ static void prepare_var_mtrrs(struct memranges *addr_space, int def_type,
memranges_each_entry(r, var_state.addr_space) {
if (range_entry_mtrr_type(r) == def_type)
continue;
-
- if (def_type == MTRR_TYPE_UNCACHEABLE &&
- (range_entry_tag(r) & MTRR_RANGE_UC_USE_HOLE))
- calc_var_mtrrs_with_hole(&var_state, r);
- else
- calc_var_mtrrs_without_hole(&var_state, r);
+ calc_var_mtrrs_with_hole(&var_state, r);
}
/* Update the solution. */
@@ -919,9 +848,6 @@ void mtrr_use_temp_range(uintptr_t begin, size_t size, int type)
memranges_each_entry(r, orig) {
unsigned long tag = range_entry_tag(r);
- /* Remove any special tags from original solution. */
- tag &= ~MTRR_RANGE_UC_USE_HOLE;
-
/* Remove any write combining MTRRs from the temporary
* solution as it just fragments the address space. */
if (tag == MTRR_TYPE_WRCOMB)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 19:07:34 +0000