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Commit 03d72aa1 authored by venkatesh.pallipadi@intel.com's avatar venkatesh.pallipadi@intel.com Committed by Ingo Molnar
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x86: PAT use reserve free memtype in pci_mmap_page_range 



Add reserve_memtype and free_memtype wrapper for pci_mmap_page_range. Free
is called on unmap, but identity map continues to be mapped as per
pci_mmap_page_range request, until next request for the same region calls
ioremap_change_attr(), which will go through without conflict. This way of
mapping is identical to one used in ioremap/iounmap.

Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1219333d

arch/x86/pci/i386.c

+60 −8
Original line number Diff line number Diff line
@@ -30,6 +30,9 @@ 
#include <linux/init.h>

#include <linux/ioport.h>

#include <linux/errno.h>

#include <linux/bootmem.h>



#include <asm/pat.h>



#include "pci.h"
@@ -297,10 +300,34 @@ void pcibios_set_master(struct pci_dev *dev) 
	pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);

}



static void pci_unmap_page_range(struct vm_area_struct *vma)

{

	u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;

	free_memtype(addr, addr + vma->vm_end - vma->vm_start);

}



static void pci_track_mmap_page_range(struct vm_area_struct *vma)

{

	u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;

	unsigned long flags = pgprot_val(vma->vm_page_prot)

						& _PAGE_CACHE_MASK;



	reserve_memtype(addr, addr + vma->vm_end - vma->vm_start, flags, NULL);

}



static struct vm_operations_struct pci_mmap_ops = {

	.open  = pci_track_mmap_page_range,

	.close = pci_unmap_page_range,

};



int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,

			enum pci_mmap_state mmap_state, int write_combine)

{

	unsigned long prot;

	u64 addr = vma->vm_pgoff << PAGE_SHIFT;

	unsigned long len = vma->vm_end - vma->vm_start;

	unsigned long flags;

	unsigned long new_flags;



	/* I/O space cannot be accessed via normal processor loads and

	 * stores on this platform.
@@ -308,21 +335,46 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, 
	if (mmap_state == pci_mmap_io)

		return -EINVAL;



	/* Leave vm_pgoff as-is, the PCI space address is the physical

	 * address on this platform.

	 */

	prot = pgprot_val(vma->vm_page_prot);

	if (boot_cpu_data.x86 > 3)

		prot |= _PAGE_PCD | _PAGE_PWT;

	if (pat_wc_enabled && write_combine)

		prot |= _PAGE_CACHE_WC;

	else if (boot_cpu_data.x86 > 3)

		prot |= _PAGE_CACHE_UC;



	vma->vm_page_prot = __pgprot(prot);



	/* Write-combine setting is ignored, it is changed via the mtrr

	 * interfaces on this platform.

	flags = pgprot_val(vma->vm_page_prot) & _PAGE_CACHE_MASK;

	if (reserve_memtype(addr, addr + len, flags, &new_flags)) {

		/*

		 * Do not fallback to certain memory types with certain

		 * requested type:

		 * - request is uncached, return cannot be write-back

		 * - request is uncached, return cannot be write-combine

		 * - request is write-combine, return cannot be write-back

		 */

		if ((flags == _PAGE_CACHE_UC &&

		     (new_flags == _PAGE_CACHE_WB ||

		      new_flags == _PAGE_CACHE_WC)) ||

		    (flags == _PAGE_CACHE_WC &&

		     new_flags == _PAGE_CACHE_WB)) {

			free_memtype(addr, addr+len);

			return -EINVAL;

		}

		flags = new_flags;

	}



	if (vma->vm_pgoff <= max_pfn_mapped &&

	    ioremap_change_attr((unsigned long)__va(addr), len, flags)) {

		free_memtype(addr, addr + len);

		return -EINVAL;

	}



	if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,

			       vma->vm_end - vma->vm_start,

			       vma->vm_page_prot))

		return -EAGAIN;



	vma->vm_ops = &pci_mmap_ops;



	return 0;

}