diff options
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r-- | arch/x86/kernel/cpu/mtrr/generic.c | 40 |
1 files changed, 30 insertions, 10 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index e51100c49eea..f782d9b62cb3 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -147,19 +147,24 @@ static u8 mtrr_type_lookup_fixed(u64 start, u64 end) * Return Value: * MTRR_TYPE_(type) - Matched memory type or default memory type (unmatched) * - * Output Argument: + * Output Arguments: * repeat - Set to 1 when [start:end] spanned across MTRR range and type * returned corresponds only to [start:*partial_end]. Caller has * to lookup again for [*partial_end:end]. + * + * uniform - Set to 1 when an MTRR covers the region uniformly, i.e. the + * region is fully covered by a single MTRR entry or the default + * type. */ static u8 mtrr_type_lookup_variable(u64 start, u64 end, u64 *partial_end, - int *repeat) + int *repeat, u8 *uniform) { int i; u64 base, mask; u8 prev_match, curr_match; *repeat = 0; + *uniform = 1; /* Make end inclusive instead of exclusive */ end--; @@ -214,6 +219,7 @@ static u8 mtrr_type_lookup_variable(u64 start, u64 end, u64 *partial_end, end = *partial_end - 1; /* end is inclusive */ *repeat = 1; + *uniform = 0; } if ((start & mask) != (base & mask)) @@ -225,6 +231,7 @@ static u8 mtrr_type_lookup_variable(u64 start, u64 end, u64 *partial_end, continue; } + *uniform = 0; if (check_type_overlap(&prev_match, &curr_match)) return curr_match; } @@ -241,10 +248,15 @@ static u8 mtrr_type_lookup_variable(u64 start, u64 end, u64 *partial_end, * Return Values: * MTRR_TYPE_(type) - The effective MTRR type for the region * MTRR_TYPE_INVALID - MTRR is disabled + * + * Output Argument: + * uniform - Set to 1 when an MTRR covers the region uniformly, i.e. the + * region is fully covered by a single MTRR entry or the default + * type. */ -u8 mtrr_type_lookup(u64 start, u64 end) +u8 mtrr_type_lookup(u64 start, u64 end, u8 *uniform) { - u8 type, prev_type; + u8 type, prev_type, is_uniform = 1, dummy; int repeat; u64 partial_end; @@ -260,14 +272,18 @@ u8 mtrr_type_lookup(u64 start, u64 end) */ if ((start < 0x100000) && (mtrr_state.have_fixed) && - (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) - return mtrr_type_lookup_fixed(start, end); + (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) { + is_uniform = 0; + type = mtrr_type_lookup_fixed(start, end); + goto out; + } /* * Look up the variable ranges. Look of multiple ranges matching * this address and pick type as per MTRR precedence. */ - type = mtrr_type_lookup_variable(start, end, &partial_end, &repeat); + type = mtrr_type_lookup_variable(start, end, &partial_end, + &repeat, &is_uniform); /* * Common path is with repeat = 0. @@ -278,15 +294,19 @@ u8 mtrr_type_lookup(u64 start, u64 end) while (repeat) { prev_type = type; start = partial_end; - type = mtrr_type_lookup_variable(start, end, &partial_end, &repeat); + is_uniform = 0; + type = mtrr_type_lookup_variable(start, end, &partial_end, + &repeat, &dummy); if (check_type_overlap(&prev_type, &type)) - return type; + goto out; } if (mtrr_tom2 && (start >= (1ULL<<32)) && (end < mtrr_tom2)) - return MTRR_TYPE_WRBACK; + type = MTRR_TYPE_WRBACK; +out: + *uniform = is_uniform; return type; } |