Messages in this thread Patch in this message | | | From | Juergen Gross <> | Subject | [PATCH v6 10/16] x86/mtrr: add get_effective_type() service function | Date | Tue, 2 May 2023 14:09:25 +0200 |
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Add a service function for obtaining the effective cache mode of overlapping MTRR registers.
Make use of that function in check_type_overlap().
Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Michael Kelley <mikelley@microsoft.com> --- V3: - new patch --- arch/x86/kernel/cpu/mtrr/generic.c | 39 +++++++++++++++--------------- 1 file changed, 19 insertions(+), 20 deletions(-)
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index cd887327ba3a..44e035a8e9fb 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -86,31 +86,30 @@ static u64 get_mtrr_size(u64 mask) return size; } +static u8 get_effective_type(u8 type1, u8 type2) +{ + if (type1 == MTRR_TYPE_UNCACHABLE || type2 == MTRR_TYPE_UNCACHABLE) + return MTRR_TYPE_UNCACHABLE; + + if ((type1 == MTRR_TYPE_WRBACK && type2 == MTRR_TYPE_WRTHROUGH) || + (type1 == MTRR_TYPE_WRTHROUGH && type2 == MTRR_TYPE_WRBACK)) + return MTRR_TYPE_WRTHROUGH; + + if (type1 != type2) + return MTRR_TYPE_UNCACHABLE; + + return type1; +} + /* * Check and return the effective type for MTRR-MTRR type overlap. - * Returns 1 if the effective type is UNCACHEABLE, else returns 0 + * Returns true if the effective type is UNCACHEABLE, else returns false */ -static int check_type_overlap(u8 *prev, u8 *curr) +static bool check_type_overlap(u8 *prev, u8 *curr) { - if (*prev == MTRR_TYPE_UNCACHABLE || *curr == MTRR_TYPE_UNCACHABLE) { - *prev = MTRR_TYPE_UNCACHABLE; - *curr = MTRR_TYPE_UNCACHABLE; - return 1; - } - - if ((*prev == MTRR_TYPE_WRBACK && *curr == MTRR_TYPE_WRTHROUGH) || - (*prev == MTRR_TYPE_WRTHROUGH && *curr == MTRR_TYPE_WRBACK)) { - *prev = MTRR_TYPE_WRTHROUGH; - *curr = MTRR_TYPE_WRTHROUGH; - } + *prev = *curr = get_effective_type(*curr, *prev); - if (*prev != *curr) { - *prev = MTRR_TYPE_UNCACHABLE; - *curr = MTRR_TYPE_UNCACHABLE; - return 1; - } - - return 0; + return *prev == MTRR_TYPE_UNCACHABLE; } /** -- 2.35.3
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