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x86/mtrr: Add get_effective_type() service function

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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>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230502120931.20719-11-jgross@suse.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
This commit is contained in:
Juergen Gross
2023-05-02 14:09:25 +02:00
committed by Borislav Petkov (AMD)
parent 961c6a4326
commit 1ca1209904
1 changed files with 19 additions and 20 deletions
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39
arch/x86/kernel/cpu/mtrr/generic.c
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@@ -80,31 +80,30 @@ 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;
}
*prev = *curr = get_effective_type(*curr, *prev);
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;
}
if (*prev != *curr) {
*prev = MTRR_TYPE_UNCACHABLE;
*curr = MTRR_TYPE_UNCACHABLE;
return 1;
}
return 0;
return *prev == MTRR_TYPE_UNCACHABLE;
}
/**