Commit 25525bea authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 mm updates from Ingo Molnar:
 "The dominant change in this cycle was the continued work to isolate
  kernel drivers from MTRR legacies: this tree gets rid of all kernel
  internal driver interfaces to MTRRs (mostly by rewriting it to proper
  PAT interfaces), the only access left is the /proc/mtrr ABI.

  This work was done by Luis R Rodriguez.

  There's also some related PCI interface additions for which I've
  Cc:-ed Bjorn"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86/mm/mtrr: Remove kernel internal MTRR interfaces: unexport mtrr_add() and mtrr_del()
  s390/io: Add pci_iomap_wc() and pci_iomap_wc_range()
  drivers/dma/iop-adma: Use dma_alloc_writecombine() kernel-style
  drivers/video/fbdev/vt8623fb: Use arch_phys_wc_add() and pci_iomap_wc()
  drivers/video/fbdev/s3fb: Use arch_phys_wc_add() and pci_iomap_wc()
  drivers/video/fbdev/arkfb.c: Use arch_phys_wc_add() and pci_iomap_wc()
  PCI: Add pci_iomap_wc() variants
  drivers/video/fbdev/gxt4500: Use pci_ioremap_wc_bar() to map framebuffer
  drivers/video/fbdev/kyrofb: Use arch_phys_wc_add() and pci_ioremap_wc_bar()
  drivers/video/fbdev/i740fb: Use arch_phys_wc_add() and pci_ioremap_wc_bar()
  PCI: Add pci_ioremap_wc_bar()
  x86/mm: Make kernel/check.c explicitly non-modular
  x86/mm/pat: Make mm/pageattr[-test].c explicitly non-modular
  x86/mm/pat: Add comments to cachemode translation tables
  arch/*/io.h: Add ioremap_uc() to all architectures
  drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()
  drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC
  drivers/video/fbdev/atyfb: Clarify ioremap() base and length used
  drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a helper
  x86/mm, asm-generic: Add IOMMU ioremap_uc() variant default
  ...
parents 2962156d 2baa891e

Documentation/x86/mtrr.txt

+16 −4
Original line number Diff line number Diff line
@@ -6,10 +6,22 @@ Luis R. Rodriguez <mcgrof@do-not-panic.com> - April 9, 2015 
===============================================================================

Phasing out MTRR use



MTRR use is replaced on modern x86 hardware with PAT. Over time the only type

of effective MTRR that is expected to be supported will be for write-combining.

As MTRR use is phased out device drivers should use arch_phys_wc_add() to make

MTRR effective on non-PAT systems while a no-op on PAT enabled systems.

MTRR use is replaced on modern x86 hardware with PAT. Direct MTRR use by

drivers on Linux is now completely phased out, device drivers should use

arch_phys_wc_add() in combination with ioremap_wc() to make MTRR effective on

non-PAT systems while a no-op but equally effective on PAT enabled systems.



Even if Linux does not use MTRRs directly, some x86 platform firmware may still

set up MTRRs early before booting the OS. They do this as some platform

firmware may still have implemented access to MTRRs which would be controlled

and handled by the platform firmware directly. An example of platform use of

MTRRs is through the use of SMI handlers, one case could be for fan control,

the platform code would need uncachable access to some of its fan control

registers. Such platform access does not need any Operating System MTRR code in

place other than mtrr_type_lookup() to ensure any OS specific mapping requests

are aligned with platform MTRR setup. If MTRRs are only set up by the platform

firmware code though and the OS does not make any specific MTRR mapping

requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID.



For details refer to Documentation/x86/pat.txt.

arch/avr32/include/asm/io.h

+1 −0
Original line number Diff line number Diff line
@@ -297,6 +297,7 @@ extern void __iounmap(void __iomem *addr); 


#define ioremap_wc ioremap_nocache

#define ioremap_wt ioremap_nocache

#define ioremap_uc ioremap_nocache



#define cached(addr) P1SEGADDR(addr)

#define uncached(addr) P2SEGADDR(addr)

arch/frv/include/asm/io.h

+1 −0
Original line number Diff line number Diff line
@@ -278,6 +278,7 @@ static inline void __iomem *ioremap_fullcache(unsigned long physaddr, unsigned l 
}



#define ioremap_wc ioremap_nocache

#define ioremap_uc ioremap_nocache



extern void iounmap(void volatile __iomem *addr);

arch/m32r/include/asm/io.h

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ extern void iounmap(volatile void __iomem *addr); 
#define ioremap_nocache(off,size) ioremap(off,size)

#define ioremap_wc ioremap_nocache

#define ioremap_wt ioremap_nocache

#define ioremap_uc ioremap_nocache



/*

 * IO bus memory addresses are also 1:1 with the physical address

arch/m68k/include/asm/io_mm.h

+1 −0
Original line number Diff line number Diff line
@@ -468,6 +468,7 @@ static inline void __iomem *ioremap_nocache(unsigned long physaddr, unsigned lon 
{

	return __ioremap(physaddr, size, IOMAP_NOCACHE_SER);

}

#define ioremap_uc ioremap_nocache

static inline void __iomem *ioremap_wt(unsigned long physaddr,

					 unsigned long size)

{

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