[PATCH] SPU use current stack pointer to limit sbrk() heap allocation

[Jeff Johnston]

Patch applied.

-- Jeff J.

Patrick Mansfield wrote:
> libgloss ChangeLog:
> 
> 2007-09-17 Patrick Mansfield <patmans@us.ibm.com>
> 
> 	* spu/sbrk.c: Use the current stack pointer value rather than the
> 	maximum available memory to determine the amount of heap space
> 	left. Without this change calling sbrk() can allocate space that
> 	is currently in use on the stack.
> 
> Index: src/libgloss/spu/sbrk.c
> ===================================================================
> --- src.orig/libgloss/spu/sbrk.c
> +++ src/libgloss/spu/sbrk.c
> @@ -37,7 +37,6 @@ Author: Andreas Neukoetter (ti95neuk@de.
>  extern int errno;
>  
>  extern caddr_t  _end;
> -#define RAMSIZE 262144
>  #define STACKSIZE 4096
>  
>  void *
> @@ -47,6 +46,7 @@ sbrk (ptrdiff_t increment)
>  	caddr_t base;
>  	vector unsigned int sp_reg, sp_delta;
>  	vector unsigned int *sp_ptr;
> +	caddr_t sps;
>  
>  	/* The stack pointer register.  */
>  	volatile register vector unsigned int sp_r1 __asm__("1");
> @@ -54,7 +54,8 @@ sbrk (ptrdiff_t increment)
>  	if (heap_ptr == NULL)
>  	  heap_ptr = (caddr_t) & _end;
>  	
> -	if (((RAMSIZE - STACKSIZE) - (int) heap_ptr) >= increment)
> +	sps = (caddr_t) spu_extract (sp_r1, 0);
> +	if (((int) sps - STACKSIZE - (int) heap_ptr) >= increment)
>  	  {
>  	    base = heap_ptr;
>  	    heap_ptr += increment;