diff mbox

[v2] /dev/mem: use phys_addr_t for physical addresses

Message ID 1347473158-7219-1-git-send-email-cyril@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Cyril Chemparathy Sept. 12, 2012, 6:05 p.m. UTC 
This patch fixes the /dev/mem driver to use phys_addr_t for physical
addresses.  This is required on PAE systems, especially those that run
entirely out of >4G physical memory space.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
---
 arch/arm/include/asm/io.h  |    2 +-
 arch/arm/mm/mmap.c         |    2 +-
 arch/ia64/include/asm/io.h |    2 +-
 arch/ia64/kernel/efi.c     |    2 +-
 arch/sh/include/asm/io.h   |    2 +-
 arch/sh/mm/mmap.c          |    2 +-
 drivers/char/mem.c         |   10 +++++-----
 7 files changed, 11 insertions(+), 11 deletions(-)

Comments

Greg KH Sept. 12, 2012, 6:15 p.m. UTC | #1 
On Wed, Sep 12, 2012 at 02:05:58PM -0400, Cyril Chemparathy wrote:
> This patch fixes the /dev/mem driver to use phys_addr_t for physical
> addresses.  This is required on PAE systems, especially those that run
> entirely out of >4G physical memory space.

What is the symptom if this patch is not applied?  Does it need to be
backported to older kernels?  If so, which ones?

thanks,

greg k-h
Cyril Chemparathy Sept. 12, 2012, 10:54 p.m. UTC | #2 
Greg,

On 9/12/2012 2:15 PM, Greg KH wrote:
> On Wed, Sep 12, 2012 at 02:05:58PM -0400, Cyril Chemparathy wrote:
>> This patch fixes the /dev/mem driver to use phys_addr_t for physical
>> addresses.  This is required on PAE systems, especially those that run
>> entirely out of >4G physical memory space.
>
> What is the symptom if this patch is not applied?  Does it need to be
> backported to older kernels?  If so, which ones?
>

As far as I can tell, this change only benefits platforms where lowmem 
lies outside the 32-bit addressable range.  On the ARM based KeyStone 
platform, all of our memory is located above the 4GB limit at 
0x8:0000:0000.  On this platform, trying to read lowmem breaks as follows:

# dd if==/dev/mem of=/dev/null bs==4k count=1 skip=8388608
dd: /dev/mem: Bad address

Assuming that we are unique in this regard (i.e. lowmem outside 4GB), I 
don't see any reason to backport this to earlier kernels.
diff mbox

Patch

diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index 35c1ed8..f52a93d 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -374,7 +374,7 @@  extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr);
 
 #ifdef CONFIG_MMU
 #define ARCH_HAS_VALID_PHYS_ADDR_RANGE
-extern int valid_phys_addr_range(unsigned long addr, size_t size);
+extern int valid_phys_addr_range(phys_addr_t addr, size_t size);
 extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
 extern int devmem_is_allowed(unsigned long pfn);
 #endif
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index ce8cb19..89f2b7f 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -279,7 +279,7 @@  void arch_pick_mmap_layout(struct mm_struct *mm)
  * You really shouldn't be using read() or write() on /dev/mem.  This
  * might go away in the future.
  */
-int valid_phys_addr_range(unsigned long addr, size_t size)
+int valid_phys_addr_range(phys_addr_t addr, size_t size)
 {
 	if (addr < PHYS_OFFSET)
 		return 0;
diff --git a/arch/ia64/include/asm/io.h b/arch/ia64/include/asm/io.h
index 2c26321..74a7cc3 100644
--- a/arch/ia64/include/asm/io.h
+++ b/arch/ia64/include/asm/io.h
@@ -90,7 +90,7 @@  phys_to_virt (unsigned long address)
 
 #define ARCH_HAS_VALID_PHYS_ADDR_RANGE
 extern u64 kern_mem_attribute (unsigned long phys_addr, unsigned long size);
-extern int valid_phys_addr_range (unsigned long addr, size_t count); /* efi.c */
+extern int valid_phys_addr_range (phys_addr_t addr, size_t count); /* efi.c */
 extern int valid_mmap_phys_addr_range (unsigned long pfn, size_t count);
 
 /*
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index d37bbd4..f034563 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -870,7 +870,7 @@  kern_mem_attribute (unsigned long phys_addr, unsigned long size)
 EXPORT_SYMBOL(kern_mem_attribute);
 
 int
-valid_phys_addr_range (unsigned long phys_addr, unsigned long size)
+valid_phys_addr_range (phys_addr_t phys_addr, unsigned long size)
 {
 	u64 attr;
 
diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h
index 0cf60a6..c4302a5 100644
--- a/arch/sh/include/asm/io.h
+++ b/arch/sh/include/asm/io.h
@@ -382,7 +382,7 @@  static inline int iounmap_fixed(void __iomem *addr) { return -EINVAL; }
 #define xlate_dev_kmem_ptr(p)	p
 
 #define ARCH_HAS_VALID_PHYS_ADDR_RANGE
-int valid_phys_addr_range(unsigned long addr, size_t size);
+int valid_phys_addr_range(phys_addr_t addr, size_t size);
 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
 
 #endif /* __KERNEL__ */
diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c
index afeb710..80bf494 100644
--- a/arch/sh/mm/mmap.c
+++ b/arch/sh/mm/mmap.c
@@ -238,7 +238,7 @@  bottomup:
  * You really shouldn't be using read() or write() on /dev/mem.  This
  * might go away in the future.
  */
-int valid_phys_addr_range(unsigned long addr, size_t count)
+int valid_phys_addr_range(phys_addr_t addr, size_t count)
 {
 	if (addr < __MEMORY_START)
 		return 0;
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 0537903..c6fa3bc 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -48,7 +48,7 @@  static inline unsigned long size_inside_page(unsigned long start,
 }
 
 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
-static inline int valid_phys_addr_range(unsigned long addr, size_t count)
+static inline int valid_phys_addr_range(phys_addr_t addr, size_t count)
 {
 	return addr + count <= __pa(high_memory);
 }
@@ -96,7 +96,7 @@  void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
 static ssize_t read_mem(struct file *file, char __user *buf,
 			size_t count, loff_t *ppos)
 {
-	unsigned long p = *ppos;
+	phys_addr_t p = *ppos;
 	ssize_t read, sz;
 	char *ptr;
 
@@ -153,7 +153,7 @@  static ssize_t read_mem(struct file *file, char __user *buf,
 static ssize_t write_mem(struct file *file, const char __user *buf,
 			 size_t count, loff_t *ppos)
 {
-	unsigned long p = *ppos;
+	phys_addr_t p = *ppos;
 	ssize_t written, sz;
 	unsigned long copied;
 	void *ptr;
@@ -226,7 +226,7 @@  int __weak phys_mem_access_prot_allowed(struct file *file,
  *
  */
 #ifdef pgprot_noncached
-static int uncached_access(struct file *file, unsigned long addr)
+static int uncached_access(struct file *file, phys_addr_t addr)
 {
 #if defined(CONFIG_IA64)
 	/*
@@ -258,7 +258,7 @@  static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 				     unsigned long size, pgprot_t vma_prot)
 {
 #ifdef pgprot_noncached
-	unsigned long offset = pfn << PAGE_SHIFT;
+	phys_addr_t offset = pfn << PAGE_SHIFT;
 
 	if (uncached_access(file, offset))
 		return pgprot_noncached(vma_prot);