From: Jonathan Gray <jsg@jsg.id.au>
Subject: Re: uvm_map: kill ifdef __i386__
To: tech@openbsd.org
Date: Sun, 9 Nov 2025 21:55:31 +1100

On Sun, Nov 09, 2025 at 10:31:25AM +0000, Martin Pieuchot wrote:
> There's a specific uvm_map_setup_md() for i386 but it does exactly the
> same as other 32 bits architectures.
> 
> I386 is no longer the main architecture and I doubt anyone will
> resurrect these experiments.  But if that happens it is easy to
> reintroduce a custom uvm_map_setup_md(). 
> 
> For now I'd like to remove this #ifdef.
> 
> ok?

diff between the i386 and 32-bit versions:

@@ -14,10 +14,7 @@ uvm_map_setup_md(struct vm_map *map)
 		min = VMMAP_MIN_ADDR;
 
 #if 0	/* Cool stuff, not yet */
-	/* Executable code is special. */
-	map->uaddr_exe = uaddr_rnd_create(min, I386_MAX_EXE_ADDR);
-	/* Place normal allocations beyond executable mappings. */
-	map->uaddr_any[3] = uaddr_pivot_create(2 * I386_MAX_EXE_ADDR, max);
+	map->uaddr_any[3] = uaddr_pivot_create(min, max);
 #else	/* Crappy stuff, for now */
 	map->uaddr_any[0] = uaddr_rnd_create(min, max);
 #endif

can the pivot code also be removed?

> 
> Index: uvm/uvm_map.c
> ===================================================================
> RCS file: /cvs/src/sys/uvm/uvm_map.c,v
> diff -u -p -r1.347 uvm_map.c
> --- uvm/uvm_map.c	23 Sep 2025 08:00:48 -0000	1.347
> +++ uvm/uvm_map.c	5 Oct 2025 16:00:08 -0000
> @@ -5386,37 +5386,7 @@ RBT_GENERATE_AUGMENT(uvm_map_addr, vm_ma
>  /*
>   * MD code: vmspace allocator setup.
>   */
> -
> -#ifdef __i386__
> -void
> -uvm_map_setup_md(struct vm_map *map)
> -{
> -	vaddr_t		min, max;
> -
> -	min = map->min_offset;
> -	max = map->max_offset;
> -
> -	/*
> -	 * Ensure the selectors will not try to manage page 0;
> -	 * it's too special.
> -	 */
> -	if (min < VMMAP_MIN_ADDR)
> -		min = VMMAP_MIN_ADDR;
> -
> -#if 0	/* Cool stuff, not yet */
> -	/* Executable code is special. */
> -	map->uaddr_exe = uaddr_rnd_create(min, I386_MAX_EXE_ADDR);
> -	/* Place normal allocations beyond executable mappings. */
> -	map->uaddr_any[3] = uaddr_pivot_create(2 * I386_MAX_EXE_ADDR, max);
> -#else	/* Crappy stuff, for now */
> -	map->uaddr_any[0] = uaddr_rnd_create(min, max);
> -#endif
> -
> -#ifndef SMALL_KERNEL
> -	map->uaddr_brk_stack = uaddr_stack_brk_create(min, max);
> -#endif /* !SMALL_KERNEL */
> -}
> -#elif __LP64__
> +#if __LP64__
>  void
>  uvm_map_setup_md(struct vm_map *map)
>  {
> @@ -5442,7 +5412,7 @@ uvm_map_setup_md(struct vm_map *map)
>  	map->uaddr_brk_stack = uaddr_stack_brk_create(min, max);
>  #endif /* !SMALL_KERNEL */
>  }
> -#else	/* non-i386, 32 bit */
> +#else	/* 32 bit */
>  void
>  uvm_map_setup_md(struct vm_map *map)
>  {
> 
> 
>