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    Subject[tip:x86/mm] x86/mm/pat: Remove pat_enabled() checks
    Commit-ID:  7202fdb1b3299ec78dc1e7702260947ec20dd9e9
    Gitweb: http://git.kernel.org/tip/7202fdb1b3299ec78dc1e7702260947ec20dd9e9
    Author: Borislav Petkov <bp@suse.de>
    AuthorDate: Thu, 4 Jun 2015 18:55:11 +0200
    Committer: Ingo Molnar <mingo@kernel.org>
    CommitDate: Sun, 7 Jun 2015 15:28:53 +0200

    x86/mm/pat: Remove pat_enabled() checks

    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>
    Reviewed-by: Toshi Kani <toshi.kani@hp.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Elliott@hp.com
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Luis R. Rodriguez <mcgrof@suse.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: arnd@arndb.de
    Cc: hch@lst.de
    Cc: hmh@hmh.eng.br
    Cc: jgross@suse.com
    Cc: konrad.wilk@oracle.com
    Cc: linux-mm <linux-mm@kvack.org>
    Cc: linux-nvdimm@lists.01.org
    Cc: stefan.bader@canonical.com
    Cc: yigal@plexistor.com
    Link: http://lkml.kernel.org/r/1433436928-31903-4-git-send-email-bp@alien8.de
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    ---
    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 3a2ec87..a9dc7a3 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 b0da358..cc0f17c 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 fae3c53..31b4f3f 100644
    --- a/arch/x86/mm/pageattr.c
    +++ b/arch/x86/mm/pageattr.c
    @@ -1572,9 +1572,6 @@ 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 6dc7826..f89e460 100644
    --- a/arch/x86/mm/pat.c
    +++ b/arch/x86/mm/pat.c
    @@ -438,12 +438,8 @@ 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;
    }

    @@ -947,11 +943,8 @@ 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);


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