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redo the fix for PR 26392 differently: instead of changing the stack bounds

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for the initial stack, just change the initial thread's pt_uc to point to
the opposite end of the stack (away from the argv, environment, etc).
This commit is contained in:
chs 2004-08-17 14:16:00 +00:00
parent f56858739a
commit c6736a59b3
1 changed files with 19 additions and 14 deletions
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33
lib/libpthread/pthread_stack.c
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@ -1,4 +1,4 @@
/* $NetBSD: pthread_stack.c,v 1.15 2004/07/25 23:22:43 chs Exp $ */
/* $NetBSD: pthread_stack.c,v 1.16 2004/08/17 14:16:00 chs Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread_stack.c,v 1.15 2004/07/25 23:22:43 chs Exp $");
__RCSID("$NetBSD: pthread_stack.c,v 1.16 2004/08/17 14:16:00 chs Exp $");
#define __EXPOSE_STACK 1
#include <sys/param.h>
@ -106,6 +106,7 @@ pthread__stackalloc(pthread_t *newt)
void
pthread__initmain(pthread_t *newt)
{
pthread_t t;
void *base;
size_t size;
@ -142,24 +143,28 @@ pthread__initmain(pthread_t *newt)
pthread_stackmask = pthread_stacksize - 1;
#endif /* PT_FIXEDSTACKSIZE_LG */
base = (void *)(pthread__sp() & ~PT_STACKMASK);
size = PT_STACKSIZE;
t = pthread__stackid_setup(base, size);
/*
* The "initial" thread stack can be smaller than requested
* The "safe" area chosen below isn't safe for the initial thread stack
* because we don't control the end of the stack.
* For example, on i386 the stack usually ends at 0xbfc00000,
* so for requested sizes >=8MB, we get a 4MB smaller stack.
* so for requested sizes >=8MB, the last 4MB of stack isn't available.
* Also, we don't want to clobber the argv, environment, etc.
* Just trim off the part of the stack that we can't use.
* Reset the initial pt_uc pointer to be safe for the initial thread.
*/
#ifdef __MACHINE_STACK_GROWS_UP
/* XXX this case isn't right */
base = (void *) (pthread__sp() & ~PT_STACKMASK);
size = PT_STACKSIZE;
#else
base = (void *) (pthread__sp() & ~PT_STACKMASK);
size = ((char *)pthread__sp() - (char *)base) & ~(pagesize - 1);
#endif
*newt = pthread__stackid_setup(base, size);
#ifdef __MACHINE_STACK_GROWS_UP
t->pt_uc = (ucontext_t *)
((char *)t->pt_stack.ss_sp + t->pt_stack.ss_size -
sizeof (ucontext_t));
#else
t->pt_uc = (ucontext_t *)t->pt_stack.ss_sp;
#endif
*newt = t;
}
static pthread_t