Commit 8b150478 authored by Roland Dreier's avatar Roland Dreier Committed by Paul Mackerras
Browse files

[PATCH] ppc: make phys_mem_access_prot() work with pfns instead of addresses 



Change the phys_mem_access_prot() function to take a pfn instead of an
address.  This allows mmap64() to work on /dev/mem for addresses above 4G
on 32-bit architectures.  We start with a pfn in mmap_mem(), so there's no
need to convert to an address; in fact, it's actively bad, since the
conversion can overflow when the address is above 4G.

Similarly fix the ppc32 page_is_ram() function to avoid a conversion to an
address by directly comparing to max_pfn.  Working with max_pfn instead of
high_memory fixes page_is_ram() to give the right answer for highmem pages.

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent d49b3401

arch/powerpc/mm/mem.c

+3 −3
Original line number Diff line number Diff line
@@ -88,13 +88,13 @@ int page_is_ram(unsigned long pfn) 
}

EXPORT_SYMBOL(page_is_ram);



pgprot_t phys_mem_access_prot(struct file *file, unsigned long addr,

pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,

			      unsigned long size, pgprot_t vma_prot)

{

	if (ppc_md.phys_mem_access_prot)

		return ppc_md.phys_mem_access_prot(file, addr, size, vma_prot);

		return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);



	if (!page_is_ram(addr >> PAGE_SHIFT))

	if (!page_is_ram(pfn))

		vma_prot = __pgprot(pgprot_val(vma_prot)

				    | _PAGE_GUARDED | _PAGE_NO_CACHE);

	return vma_prot;

arch/ppc/kernel/pci.c

+3 −2
Original line number Diff line number Diff line
@@ -1594,16 +1594,17 @@ static pgprot_t __pci_mmap_set_pgprot(struct pci_dev *dev, struct resource *rp, 
 * above routine

 */

pgprot_t pci_phys_mem_access_prot(struct file *file,

				  unsigned long offset,

				  unsigned long pfn,

				  unsigned long size,

				  pgprot_t protection)

{

	struct pci_dev *pdev = NULL;

	struct resource *found = NULL;

	unsigned long prot = pgprot_val(protection);

	unsigned long offset = pfn << PAGE_SHIFT;

	int i;



	if (page_is_ram(offset >> PAGE_SHIFT))

	if (page_is_ram(pfn))

		return prot;



	prot |= _PAGE_NO_CACHE | _PAGE_GUARDED;

arch/ppc/mm/init.c

+4 −6
Original line number Diff line number Diff line
@@ -637,18 +637,16 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, 
 */

int page_is_ram(unsigned long pfn)

{

	unsigned long paddr = (pfn << PAGE_SHIFT);



	return paddr < __pa(high_memory);

	return pfn < max_pfn;

}



pgprot_t phys_mem_access_prot(struct file *file, unsigned long addr,

pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,

			      unsigned long size, pgprot_t vma_prot)

{

	if (ppc_md.phys_mem_access_prot)

		return ppc_md.phys_mem_access_prot(file, addr, size, vma_prot);

		return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);



	if (!page_is_ram(addr >> PAGE_SHIFT))

	if (!page_is_ram(pfn))

		vma_prot = __pgprot(pgprot_val(vma_prot)

				    | _PAGE_GUARDED | _PAGE_NO_CACHE);

	return vma_prot;

arch/ppc64/kernel/pci.c

+3 −2
Original line number Diff line number Diff line
@@ -726,16 +726,17 @@ static pgprot_t __pci_mmap_set_pgprot(struct pci_dev *dev, struct resource *rp, 
 * above routine

 */

pgprot_t pci_phys_mem_access_prot(struct file *file,

				  unsigned long offset,

				  unsigned long pfn,

				  unsigned long size,

				  pgprot_t protection)

{

	struct pci_dev *pdev = NULL;

	struct resource *found = NULL;

	unsigned long prot = pgprot_val(protection);

	unsigned long offset = pfn << PAGE_SHIFT;

	int i;



	if (page_is_ram(offset >> PAGE_SHIFT))

	if (page_is_ram(pfn))

		return __pgprot(prot);



	prot |= _PAGE_NO_CACHE | _PAGE_GUARDED;

drivers/char/mem.c

+1 −3
Original line number Diff line number Diff line
@@ -231,9 +231,7 @@ static ssize_t write_mem(struct file * file, const char __user * buf, 
static int mmap_mem(struct file * file, struct vm_area_struct * vma)

{

#if defined(__HAVE_PHYS_MEM_ACCESS_PROT)

	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;



	vma->vm_page_prot = phys_mem_access_prot(file, offset,

	vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,

						 vma->vm_end - vma->vm_start,

						 vma->vm_page_prot);

#elif defined(pgprot_noncached)

CRA Git | Maintained and supported by SUSTech CRA and CCSE