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Subject[PATCH 4/4] x86/pat: Remove pat_enabled() checks
Date
From: Borislav Petkov <bp@suse.de>

Now that we emulate a PAT table when PAT is disabled, there's no need
for those checks anymore as the PAT abstraction will handle those cases
too.

Based on a conglomerate patch from Toshi Kani.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: arnd@arndb.de
Cc: Elliott@hp.com
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: stefan.bader@canonical.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: x86-ml <x86@kernel.org>
Cc: yigal@plexistor.com
---
arch/x86/mm/iomap_32.c | 12 ++++++------
arch/x86/mm/ioremap.c | 5 +----
arch/x86/mm/pageattr.c | 3 ---
arch/x86/mm/pat.c | 13 +++----------
4 files changed, 10 insertions(+), 23 deletions(-)

diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index 3a2ec8790ca7..a9dc7a37e6a2 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -77,13 +77,13 @@ void __iomem *
iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
{
/*
- * For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS.
- * PAGE_KERNEL_WC maps to PWT, which translates to uncached if the
- * MTRR is UC or WC. UC_MINUS gets the real intention, of the
- * user, which is "WC if the MTRR is WC, UC if you can't do that."
+ * For non-PAT systems, translate non-WB request to UC- just in
+ * case the caller set the PWT bit to prot directly without using
+ * pgprot_writecombine(). UC- translates to uncached if the MTRR
+ * is UC or WC. UC- gets the real intention, of the user, which is
+ * "WC if the MTRR is WC, UC if you can't do that."
*/
- if (!pat_enabled() && pgprot_val(prot) ==
- (__PAGE_KERNEL | cachemode2protval(_PAGE_CACHE_MODE_WC)))
+ if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB)
prot = __pgprot(__PAGE_KERNEL |
cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS));

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index b0da3588b452..cc0f17c5ad9f 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -292,11 +292,8 @@ EXPORT_SYMBOL_GPL(ioremap_uc);
*/
void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size)
{
- if (pat_enabled())
- return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC,
+ return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC,
__builtin_return_address(0));
- else
- return ioremap_nocache(phys_addr, size);
}
EXPORT_SYMBOL(ioremap_wc);

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 70d221fe2eb4..94aae76a5e06 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1571,9 +1571,6 @@ int set_memory_wc(unsigned long addr, int numpages)
{
int ret;

- if (!pat_enabled())
- return set_memory_uc(addr, numpages);
-
ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
_PAGE_CACHE_MODE_WC, NULL);
if (ret)
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 62171cb2b0cb..e65555e0fe3d 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -432,12 +432,8 @@ int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type,

if (!pat_enabled()) {
/* This is identical to page table setting without PAT */
- if (new_type) {
- if (req_type == _PAGE_CACHE_MODE_WC)
- *new_type = _PAGE_CACHE_MODE_UC_MINUS;
- else
- *new_type = req_type;
- }
+ if (new_type)
+ *new_type = req_type;
return 0;
}

@@ -941,11 +937,8 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,

pgprot_t pgprot_writecombine(pgprot_t prot)
{
- if (pat_enabled())
- return __pgprot(pgprot_val(prot) |
+ return __pgprot(pgprot_val(prot) |
cachemode2protval(_PAGE_CACHE_MODE_WC));
- else
- return pgprot_noncached(prot);
}
EXPORT_SYMBOL_GPL(pgprot_writecombine);

--
2.3.5


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