diff options
Diffstat (limited to 'sys/uvm/uvm_addr.c')
| -rw-r--r-- | sys/uvm/uvm_addr.c | 73 |
1 files changed, 26 insertions, 47 deletions
diff --git a/sys/uvm/uvm_addr.c b/sys/uvm/uvm_addr.c index aa2f2e27459..9dd0b22ad91 100644 --- a/sys/uvm/uvm_addr.c +++ b/sys/uvm/uvm_addr.c @@ -1,4 +1,4 @@ -/* $OpenBSD: uvm_addr.c,v 1.25 2018/04/10 12:27:01 otto Exp $ */ +/* $OpenBSD: uvm_addr.c,v 1.26 2018/04/17 15:50:05 otto Exp $ */ /* * Copyright (c) 2011 Ariane van der Steldt <ariane@stack.nl> @@ -1322,15 +1322,6 @@ uaddr_pivot_print(struct uvm_addr_state *uaddr_p, boolean_t full, #ifndef SMALL_KERNEL /* - * Strategy for uaddr_stack_brk_select. - */ -struct uaddr_bs_strat { - vaddr_t start; /* Start of area. */ - vaddr_t end; /* End of area. */ - int dir; /* Search direction. */ -}; - -/* * Stack/break allocator. * * Stack area is grown into in the opposite direction of the stack growth, @@ -1355,53 +1346,41 @@ uaddr_stack_brk_select(struct vm_map *map, struct uvm_addr_state *uaddr, vsize_t sz, vaddr_t align, vaddr_t offset, vm_prot_t prot, vaddr_t hint) { - vsize_t before_gap, after_gap; - int stack_idx, brk_idx; - struct uaddr_bs_strat strat[2], *s; - vsize_t sb_size; + vaddr_t start; + vaddr_t end; + vsize_t before_gap; + vsize_t after_gap; + int dir; - /* - * Choose gap size and if the stack is searched before or after the - * brk area. - */ - before_gap = ((arc4random() & 0x3) + 1) << PAGE_SHIFT; - after_gap = ((arc4random() & 0x3) + 1) << PAGE_SHIFT; + /* Set up brk search strategy. */ + start = MAX(map->b_start, uaddr->uaddr_minaddr); + end = MIN(map->b_end, uaddr->uaddr_maxaddr); + before_gap = 0; + after_gap = 0; + dir = -1; /* Opposite of brk() growth. */ - sb_size = (map->s_end - map->s_start) + (map->b_end - map->b_start); - sb_size >>= PAGE_SHIFT; - if (arc4random_uniform(MAX(sb_size, 0xffffffff)) > - map->b_end - map->b_start) { - brk_idx = 1; - stack_idx = 0; - } else { - brk_idx = 0; - stack_idx = 1; + if (end - start >= sz) { + if (uvm_addr_linsearch(map, uaddr, entry_out, addr_out, + 0, sz, align, offset, dir, start, end - sz, + before_gap, after_gap) == 0) + return 0; } /* Set up stack search strategy. */ - s = &strat[stack_idx]; - s->start = MAX(map->s_start, uaddr->uaddr_minaddr); - s->end = MIN(map->s_end, uaddr->uaddr_maxaddr); + start = MAX(map->s_start, uaddr->uaddr_minaddr); + end = MIN(map->s_end, uaddr->uaddr_maxaddr); + before_gap = ((arc4random() & 0x3) + 1) << PAGE_SHIFT; + after_gap = ((arc4random() & 0x3) + 1) << PAGE_SHIFT; #ifdef MACHINE_STACK_GROWS_UP - s->dir = -1; + dir = -1; #else - s->dir = 1; + dir = 1; #endif - - /* Set up brk search strategy. */ - s = &strat[brk_idx]; - s->start = MAX(map->b_start, uaddr->uaddr_minaddr); - s->end = MIN(map->b_end, uaddr->uaddr_maxaddr); - s->dir = -1; /* Opposite of brk() growth. */ - - /* Linear search for space. */ - for (s = &strat[0]; s < &strat[nitems(strat)]; s++) { - if (s->end - s->start < sz) - continue; + if (end - start >= sz + before_gap + after_gap) { if (uvm_addr_linsearch(map, uaddr, entry_out, addr_out, - 0, sz, align, offset, s->dir, s->start, s->end - sz, + 0, sz, align, offset, dir, start, end - sz, before_gap, after_gap) == 0) - return 0; + return 0; } return ENOMEM; |