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x86, mtrr: Refactor MTRR type overlap check code 

Move the MTRR type overlap check into a new function. No functional change in
this patch. Just making it easier to add multiple region overlap check in
the following patch.

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
LKML-Reference: <1284159350-19841-2-git-send-email-venki@google.com>
Reviewed-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Venkatesh Pallipadi 2010-09-10 15:55:49 -07:00 committed by H. Peter Anvin
parent 2bfc96a127
commit a7f07cfbaa
1 changed files with 29 additions and 15 deletions
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44
arch/x86/kernel/cpu/mtrr/generic.c
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@ -64,6 +64,33 @@ static inline void k8_check_syscfg_dram_mod_en(void)
} }
} }
/*
* Check and return the effective type for MTRR-MTRR type overlap.
* Returns 1 if the effective type is UNCACHEABLE, else returns 0
*/
static int 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;
}
if (*prev != *curr) {
*prev = MTRR_TYPE_UNCACHABLE;
*curr = MTRR_TYPE_UNCACHABLE;
return 1;
}
return 0;
}
/* /*
* Returns the effective MTRR type for the region * Returns the effective MTRR type for the region
* Error returns: * Error returns:
@ -138,21 +165,8 @@ u8 mtrr_type_lookup(u64 start, u64 end)
continue; continue;
} }
if (prev_match == MTRR_TYPE_UNCACHABLE || if (check_type_overlap(&prev_match, &curr_match))
curr_match == MTRR_TYPE_UNCACHABLE) { return curr_match;
return MTRR_TYPE_UNCACHABLE;
}
if ((prev_match == MTRR_TYPE_WRBACK &&
curr_match == MTRR_TYPE_WRTHROUGH) ||
(prev_match == MTRR_TYPE_WRTHROUGH &&
curr_match == MTRR_TYPE_WRBACK)) {
prev_match = MTRR_TYPE_WRTHROUGH;
curr_match = MTRR_TYPE_WRTHROUGH;
}
if (prev_match != curr_match)
return MTRR_TYPE_UNCACHABLE;
} }
if (mtrr_tom2) { if (mtrr_tom2) {