PAGE_ALIGN + PAGE_SHIFT from userspace

PAGE_ALIGN + PAGE_SHIFT from userspace

[Daniel Laird]

Hi All,

I was using linux 2.6.17.13 on my MIPS and it was all going well.  I am just
porting to 2.6.19 and am having a couple of issues.

My first issue is that i used to mmap a buffer from user space.  I used to
use a PAGE_ALIGN macro when doing this:
/** to align the pointer to the (next) page boundary */
#define PAGE_ALIGN(addr)	(((addr) + PAGE_SIZE - 1) & PAGE_MASK)

this worked as PAGE_SIZE and PAGE_MASK were available in page.h.

This have now been moved inside the #ifdef KERNEL guard in the header file. 
Meaning these are no longer available.

Are these available somewhere else?
Should I be doing something different to mmap?

Any help appreciated
Daniel Laird
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Re: PAGE_ALIGN + PAGE_SHIFT from userspace

[Thiemo Seufer]

Daniel Laird wrote:
> 
> Hi All,
> 
> I was using linux 2.6.17.13 on my MIPS and it was all going well.  I am just
> porting to 2.6.19 and am having a couple of issues.
> 
> My first issue is that i used to mmap a buffer from user space.  I used to
> use a PAGE_ALIGN macro when doing this:
> /** to align the pointer to the (next) page boundary */
> #define PAGE_ALIGN(addr)	(((addr) + PAGE_SIZE - 1) & PAGE_MASK)
> 
> this worked as PAGE_SIZE and PAGE_MASK were available in page.h.

It didn't work reliably since the pagesize is a kernel configuration option.

> This have now been moved inside the #ifdef KERNEL guard in the header file. 
> Meaning these are no longer available.
> 
> Are these available somewhere else?
> Should I be doing something different to mmap?

Use the libc's sysconf(_SC_PAGESIZE) function.


Thiemo

Re: PAGE_ALIGN + PAGE_SHIFT from userspace

[Daniel Laird]

Works a treat thankyou!
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