Re: Fix up mmap of /dev/kmem

Re: Fix up mmap of /dev/kmem

[Olaf Hering]

 On Sat, Aug 13, Linux Kernel Mailing List wrote:

> tree e52389322e063c5b784ead6ec314503f7646c765
> parent 2da5bf80f754e28cc153362e5ed1edaa9740897a
> author Linus Torvalds <torvalds@g5.osdl.org> Sun, 14 Aug 2005 04:22:59 -0700
> committer Linus Torvalds <torvalds@g5.osdl.org> Sun, 14 Aug 2005 04:22:59 -0700
> 
> Fix up mmap of /dev/kmem
> 
> This leaves the issue of whether we should deprecate the whole thing (or
> if we should check the whole mmap range, for that matter) open. Just do
> the minimal fix for now.
> 
>  drivers/char/mem.c |   12 ++++++++----
>  1 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/char/mem.c b/drivers/char/mem.c
> --- a/drivers/char/mem.c
> +++ b/drivers/char/mem.c
> @@ -261,7 +261,11 @@ static int mmap_mem(struct file * file, 
>  
>  static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
>  {
> -        unsigned long long val;
> +	unsigned long pfn;
> +
> +	/* Turn a kernel-virtual address into a physical page frame */
> +	pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
> +
>  	/*
>  	 * RED-PEN: on some architectures there is more mapped memory
>  	 * than available in mem_map which pfn_valid checks

make all ARCH=um SUBARCH=i386 V=1

This gives 

drivers/char/mem.c: In function 'mmap_kmem':
drivers/char/mem.c:267: error: invalid operands to binary <<



static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
{
 unsigned long pfn;


 pfn = to_phys((void *) (unsigned long) (u64)vma->vm_pgoff << 12) >> 12;
# 276 "drivers/char/mem.c"
 if (!((pfn) < max_mapnr))
  return -5;

2.6.13-rc7 compile failures (was: Re: Fix up mmap of /dev/kmem)

[Geert Uytterhoeven]

On Sat, 13 Aug 2005, Linux Kernel Mailing List wrote:
> Fix up mmap of /dev/kmem
> 
> This leaves the issue of whether we should deprecate the whole thing (or
> if we should check the whole mmap range, for that matter) open. Just do
> the minimal fix for now.
> 
>  drivers/char/mem.c |   12 ++++++++----
>  1 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/char/mem.c b/drivers/char/mem.c
> --- a/drivers/char/mem.c
> +++ b/drivers/char/mem.c
> @@ -261,7 +261,11 @@ static int mmap_mem(struct file * file, 
>  
>  static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
>  {
> -        unsigned long long val;
> +	unsigned long pfn;
> +
> +	/* Turn a kernel-virtual address into a physical page frame */
> +	pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
> +
>  	/*
>  	 * RED-PEN: on some architectures there is more mapped memory
>  	 * than available in mem_map which pfn_valid checks

Some (not all!) of my m68k test builds are now failing with:

| linux-m68k-2.6.13-rc7/drivers/char/mem.c: In function `mmap_kmem':
| linux-m68k-2.6.13-rc7/drivers/char/mem.c:267: warning: cast to pointer from integer of different size
| linux-m68k-2.6.13-rc7/drivers/char/mem.c:267: invalid operands to binary <<

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: 2.6.13-rc7 compile failures (was: Re: Fix up mmap of /dev/kmem)

[Andreas Schwab]

Geert Uytterhoeven <geert@linux-m68k.org> writes:

> Some (not all!) of my m68k test builds are now failing with:
>
> | linux-m68k-2.6.13-rc7/drivers/char/mem.c: In function `mmap_kmem':
> | linux-m68k-2.6.13-rc7/drivers/char/mem.c:267: warning: cast to pointer from integer of different size
> | linux-m68k-2.6.13-rc7/drivers/char/mem.c:267: invalid operands to binary <<

Try this:

Add parens around macro parameters.

Signed-off-by: Andreas Schwab <schwab@suse.de>

--- include/asm-m68k/page.h.~1.14.~	2004-05-26 20:10:15.000000000 +0200
+++ include/asm-m68k/page.h	2005-08-24 17:29:55.000000000 +0200
@@ -138,13 +138,13 @@ extern unsigned long m68k_memoffset;
 #define __pa(vaddr)		((unsigned long)(vaddr)+m68k_memoffset)
 #define __va(paddr)		((void *)((unsigned long)(paddr)-m68k_memoffset))
 #else
-#define __pa(vaddr)		virt_to_phys((void *)vaddr)
-#define __va(paddr)		phys_to_virt((unsigned long)paddr)
+#define __pa(vaddr)		virt_to_phys((void *)(vaddr))
+#define __va(paddr)		phys_to_virt((unsigned long)(paddr))
 #endif
 
 #else	/* !CONFIG_SUN3 */
 /* This #define is a horrible hack to suppress lots of warnings. --m */
-#define __pa(x) ___pa((unsigned long)x)
+#define __pa(x) ___pa((unsigned long)(x))
 static inline unsigned long ___pa(unsigned long x)
 {
      if(x == 0)

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."