[uClinux-dev] [PATCH] : Avoid filename < TASK_SIZE test in do_getname() when no MMU

Greg Ungerer gerg at snapgear.com
Sun May 23 21:29:50 EDT 2010


David Howells wrote:
> Geert Uytterhoeven <geert at linux-m68k.org> wrote:
> 
>> Are these also problematic?
> 
> None of these are problematic for NOMMU FRV because there I set:
> 
> 	#define TASK_SIZE			__UL(0xFFFFFFFFUL)
> 
> I would set it lower, but the flash is right at the top end of the address
> space, and if I want to do XIP from it, this is required.  It's a fairly
> meaningless constant in NOMMU anyway, so it's probably better just to set it
> to this.  Actually, I should probably use ULONG_MAX instead.

This seems like a better option that all the use cases.

So something like:

--
[PATCH] m68knommu: remove size limit on non-MMU TASK_SIZE

The TASK_SIZE define is used in some places as a limit on the size
of the virtual address space of a process. On non-MMU systems those
addresses used in comparison will be physical addresses, and they
could be anywhere in the 32bit physical address space. So for
!CONFIG_MMU systems set the TASK_SIZE to the maximum physical
address.

Signed-off-by: Greg Ungerer <gerg at uclinux.org>

---
  arch/m68k/include/asm/processor.h |    4 ++++
  1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/m68k/include/asm/processor.h 
b/arch/m68k/include/asm/processor.h
index cbd3d47..7a6a759 100644
--- a/arch/m68k/include/asm/processor.h
+++ b/arch/m68k/include/asm/processor.h
@@ -44,11 +44,15 @@ static inline void wrusp(unsigned long usp)
   * User space process size: 3.75GB. This is hardcoded into a few places,
   * so don't change it unless you know what you are doing.
   */
+#ifdef CONFIG_MMU
  #ifndef CONFIG_SUN3
  #define TASK_SIZE	(0xF0000000UL)
  #else
  #define TASK_SIZE	(0x0E000000UL)
  #endif
+#else
+#define TASK_SIZE	(0xFFFFFFFFUL)
+#endif

  #ifdef __KERNEL__
  #define STACK_TOP	TASK_SIZE
-- 

------------------------------------------------------------------------
Greg Ungerer  --  Principal Engineer        EMAIL:     gerg at snapgear.com
SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
8 Gardner Close                             FAX:         +61 7 3217 5323
Milton, QLD, 4064, Australia                WEB: http://www.SnapGear.com



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