x86: PAT: make pat_x_mtrr_type() more readable
Clean up over-complications in pat_x_mtrr_type(). And if reserve_memtype() ignores stray req_type bits when pat_enabled, it's better to mask them off when not also. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
parent
faeca31d06
commit
6cf514fce1
1 changed files with 12 additions and 35 deletions
|
@ -159,47 +159,31 @@ static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */
|
|||
* The intersection is based on "Effective Memory Type" tables in IA-32
|
||||
* SDM vol 3a
|
||||
*/
|
||||
static int pat_x_mtrr_type(u64 start, u64 end, unsigned long prot,
|
||||
unsigned long *ret_prot)
|
||||
static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
|
||||
{
|
||||
unsigned long pat_type;
|
||||
u8 mtrr_type;
|
||||
|
||||
pat_type = prot & _PAGE_CACHE_MASK;
|
||||
prot &= (~_PAGE_CACHE_MASK);
|
||||
|
||||
/*
|
||||
* We return the PAT request directly for types where PAT takes
|
||||
* precedence with respect to MTRR and for UC_MINUS.
|
||||
* Consistency checks with other PAT requests is done later
|
||||
* while going through memtype list.
|
||||
*/
|
||||
if (pat_type == _PAGE_CACHE_WC) {
|
||||
*ret_prot = prot | _PAGE_CACHE_WC;
|
||||
return 0;
|
||||
} else if (pat_type == _PAGE_CACHE_UC_MINUS) {
|
||||
*ret_prot = prot | _PAGE_CACHE_UC_MINUS;
|
||||
return 0;
|
||||
} else if (pat_type == _PAGE_CACHE_UC) {
|
||||
*ret_prot = prot | _PAGE_CACHE_UC;
|
||||
return 0;
|
||||
}
|
||||
if (req_type == _PAGE_CACHE_WC ||
|
||||
req_type == _PAGE_CACHE_UC_MINUS ||
|
||||
req_type == _PAGE_CACHE_UC)
|
||||
return req_type;
|
||||
|
||||
/*
|
||||
* Look for MTRR hint to get the effective type in case where PAT
|
||||
* request is for WB.
|
||||
*/
|
||||
mtrr_type = mtrr_type_lookup(start, end);
|
||||
|
||||
if (mtrr_type == MTRR_TYPE_UNCACHABLE) {
|
||||
*ret_prot = prot | _PAGE_CACHE_UC;
|
||||
} else if (mtrr_type == MTRR_TYPE_WRCOMB) {
|
||||
*ret_prot = prot | _PAGE_CACHE_WC;
|
||||
} else {
|
||||
*ret_prot = prot | _PAGE_CACHE_WB;
|
||||
}
|
||||
|
||||
return 0;
|
||||
if (mtrr_type == MTRR_TYPE_UNCACHABLE)
|
||||
return _PAGE_CACHE_UC;
|
||||
if (mtrr_type == MTRR_TYPE_WRCOMB)
|
||||
return _PAGE_CACHE_WC;
|
||||
return _PAGE_CACHE_WB;
|
||||
}
|
||||
|
||||
/*
|
||||
|
@ -232,7 +216,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
|
|||
if (req_type == -1) {
|
||||
*ret_type = _PAGE_CACHE_WB;
|
||||
} else {
|
||||
*ret_type = req_type;
|
||||
*ret_type = req_type & _PAGE_CACHE_MASK;
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
|
@ -264,14 +248,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
|
|||
}
|
||||
} else {
|
||||
req_type &= _PAGE_CACHE_MASK;
|
||||
err = pat_x_mtrr_type(start, end, req_type, &actual_type);
|
||||
}
|
||||
|
||||
if (err) {
|
||||
if (ret_type)
|
||||
*ret_type = actual_type;
|
||||
|
||||
return -EINVAL;
|
||||
actual_type = pat_x_mtrr_type(start, end, req_type);
|
||||
}
|
||||
|
||||
new_entry = kmalloc(sizeof(struct memtype), GFP_KERNEL);
|
||||
|
|
Loading…
Reference in a new issue