diff options
| -rw-r--r-- | src/cpu/x86/mtrr/mtrr.c | 236 |
1 files changed, 188 insertions, 48 deletions
diff --git a/src/cpu/x86/mtrr/mtrr.c b/src/cpu/x86/mtrr/mtrr.c index 9c8f8c7647..005ea81063 100644 --- a/src/cpu/x86/mtrr/mtrr.c +++ b/src/cpu/x86/mtrr/mtrr.c @@ -122,6 +122,21 @@ static inline unsigned int fls(unsigned int x) #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) { return PHYS_TO_RANGE_ADDR(range_entry_base(r)); @@ -132,6 +147,11 @@ static inline uint32_t range_entry_end_mtrr_addr(struct range_entry *r) return PHYS_TO_RANGE_ADDR(range_entry_end(r)); } +static inline int range_entry_mtrr_type(struct range_entry *r) +{ + return range_entry_tag(r) & MTRR_TAG_MASK; +} + static struct memranges *get_physical_address_space(void) { static struct memranges *addr_space; @@ -491,9 +511,72 @@ static void calc_var_mtrr_range(struct var_mtrr_state *var_state, } } -static void setup_var_mtrrs_by_state(struct var_mtrr_state *var_state) +static void calc_var_mtrrs_with_hole(struct var_mtrr_state *var_state, + struct range_entry *r) { - struct range_entry *r; + uint32_t a1, a2, b1, b2; + int mtrr_type; + struct range_entry *next; + + /* + * Determine MTRRs based on the following algoirthm for the given entry: + * +------------------+ b2 = ALIGN_UP(end) + * | 0 or more bytes | <-- hole is carved out between b1 and b2 + * +------------------+ a2 = b1 = end + * | | + * +------------------+ a1 = begin + * + * Thus, there are 3 sub-ranges to configure variable MTRRs for. + */ + mtrr_type = range_entry_mtrr_type(r); + + a1 = range_entry_base_mtrr_addr(r); + a2 = range_entry_end_mtrr_addr(r); + + /* The end address is under 1MiB. The fixed MTRRs take + * precedence over the variable ones. Therefore this range + * can be ignored. */ + if (a2 < RANGE_1MB) + return; + + /* Again, the fixed MTRRs take precedence so the beginning + * of the range can be set to 0 if it starts below 1MiB. */ + if (a1 < RANGE_1MB) + a1 = 0; + + /* If the range starts above 4GiB the processing is done. */ + if (!var_state->above4gb && a1 >= RANGE_4GB) + return; + + /* Clip the upper address to 4GiB if addresses above 4GiB + * are not being processed. */ + if (!var_state->above4gb && a2 > RANGE_4GB) + a2 = RANGE_4GB; + + b1 = a2; + b2 = ALIGN_UP(a2, MTRR_MIN_ALIGN); + + /* Check against the next range. If the current range_entry is the + * last entry then carving a hole is no problem. If the current entry + * isn't the last entry then check that the last entry covers the + * entire hole range with the default mtrr type. */ + next = memranges_next_entry(var_state->addr_space, r); + if (next != NULL && + (range_entry_mtrr_type(next) != var_state->def_mtrr_type || + range_entry_end_mtrr_addr(next) < b2)) { + calc_var_mtrr_range(var_state, a1, a2 - a1, mtrr_type); + return; + } + + calc_var_mtrr_range(var_state, a1, b2 - a1, mtrr_type); + calc_var_mtrr_range(var_state, b1, b2 - b1, var_state->def_mtrr_type); +} + +static void calc_var_mtrrs_without_hole(struct var_mtrr_state *var_state, + struct range_entry *r) +{ + uint32_t a1, a2, b1, b2, c1, c2; + int mtrr_type; /* * For each range that meets the non-default type process it in the @@ -508,51 +591,44 @@ static void setup_var_mtrrs_by_state(struct var_mtrr_state *var_state) * * Thus, there are 3 sub-ranges to configure variable MTRRs for. */ - memranges_each_entry(r, var_state->addr_space) { - uint32_t a1, a2, b1, b2, c1, c2; - int mtrr_type = range_entry_tag(r); + mtrr_type = range_entry_mtrr_type(r); - /* Skip default type. */ - if (var_state->def_mtrr_type == mtrr_type) - continue; - - a1 = range_entry_base_mtrr_addr(r); - c2 = range_entry_end_mtrr_addr(r); + a1 = range_entry_base_mtrr_addr(r); + c2 = range_entry_end_mtrr_addr(r); - /* The end address is under 1MiB. The fixed MTRRs take - * precedence over the variable ones. Therefore this range - * can be ignored. */ - if (c2 < RANGE_1MB) - continue; + /* The end address is under 1MiB. The fixed MTRRs take + * precedence over the variable ones. Therefore this range + * can be ignored. */ + if (c2 < RANGE_1MB) + return; - /* Again, the fixed MTRRs take precedence so the beginning - * of the range can be set to 0 if it starts below 1MiB. */ - if (a1 < RANGE_1MB) - a1 = 0; + /* Again, the fixed MTRRs take precedence so the beginning + * of the range can be set to 0 if it starts below 1MiB. */ + if (a1 < RANGE_1MB) + a1 = 0; - /* If the range starts above 4GiB the processing is done. */ - if (!var_state->above4gb && a1 >= RANGE_4GB) - break; + /* If the range starts above 4GiB the processing is done. */ + if (!var_state->above4gb && a1 >= RANGE_4GB) + return; - /* Clip the upper address to 4GiB if addresses above 4GiB - * are not being processed. */ - if (!var_state->above4gb && c2 > RANGE_4GB) - c2 = RANGE_4GB; + /* Clip the upper address to 4GiB if addresses above 4GiB + * are not being processed. */ + if (!var_state->above4gb && c2 > RANGE_4GB) + c2 = RANGE_4GB; - /* Don't align up or down on the range if it is smaller - * than the minimum granularity. */ - if ((c2 - a1) < MTRR_MIN_ALIGN) { - calc_var_mtrr_range(var_state, a1, c2 - a1, mtrr_type); - continue; - } + /* Don't align up or down on the range if it is smaller + * than the minimum granularity. */ + if ((c2 - a1) < MTRR_MIN_ALIGN) { + calc_var_mtrr_range(var_state, a1, c2 - a1, mtrr_type); + return; + } - b1 = a2 = ALIGN_UP(a1, MTRR_MIN_ALIGN); - b2 = c1 = ALIGN_DOWN(c2, MTRR_MIN_ALIGN); + b1 = a2 = ALIGN_UP(a1, MTRR_MIN_ALIGN); + b2 = c1 = ALIGN_DOWN(c2, MTRR_MIN_ALIGN); - calc_var_mtrr_range(var_state, a1, a2 - a1, mtrr_type); - calc_var_mtrr_range(var_state, b1, b2 - b1, mtrr_type); - calc_var_mtrr_range(var_state, c1, c2 - c1, mtrr_type); - } + calc_var_mtrr_range(var_state, a1, a2 - a1, mtrr_type); + calc_var_mtrr_range(var_state, b1, b2 - b1, mtrr_type); + calc_var_mtrr_range(var_state, c1, c2 - c1, mtrr_type); } static int calc_var_mtrrs(struct memranges *addr_space, @@ -560,6 +636,7 @@ static int calc_var_mtrrs(struct memranges *addr_space, { int wb_deftype_count; int uc_deftype_count; + struct range_entry *r; struct var_mtrr_state var_state; /* The default MTRR cacheability type is determined by calculating @@ -570,15 +647,67 @@ static int calc_var_mtrrs(struct memranges *addr_space, var_state.address_bits = address_bits; var_state.commit_mtrrs = 0; - var_state.mtrr_index = 0; - var_state.def_mtrr_type = MTRR_TYPE_WRBACK; - setup_var_mtrrs_by_state(&var_state); - wb_deftype_count = var_state.mtrr_index; + wb_deftype_count = 0; + uc_deftype_count = 0; - var_state.mtrr_index = 0; - var_state.def_mtrr_type = MTRR_TYPE_UNCACHEABLE; - setup_var_mtrrs_by_state(&var_state); - uc_deftype_count = var_state.mtrr_index; + /* + * 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. + * The lowest count is then used as default after totalling all + * MTRRs. Note that the optimal algoirthm for UC default is marked in + * the tag of each range regardless of final decision. UC takes + * precedence in the MTRR archiecture. Therefore, 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; + + 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; + } + } + + 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); + wb_deftype_count += var_state.mtrr_index; + } + } printk(BIOS_DEBUG, "MTRR: default type WB/UC MTRR counts: %d/%d.\n", wb_deftype_count, uc_deftype_count); @@ -594,6 +723,7 @@ static int calc_var_mtrrs(struct memranges *addr_space, static void commit_var_mtrrs(struct memranges *addr_space, int def_type, int above4gb, int address_bits) { + struct range_entry *r; struct var_mtrr_state var_state; int i; @@ -604,7 +734,17 @@ static void commit_var_mtrrs(struct memranges *addr_space, int def_type, var_state.commit_mtrrs = 1; var_state.mtrr_index = 0; var_state.def_mtrr_type = def_type; - setup_var_mtrrs_by_state(&var_state); + + 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); + } /* Clear all remaining variable MTTRs. */ for (i = var_state.mtrr_index; i < total_mtrrs; i++) |