glibc, linuxthreads, floating stacks
Petr Salinger
Petr.Salinger at t-systems.cz
Mon Dec 12 21:39:09 UTC 2005
Hi all!
During last search due to problems with thread signaling
I found cmd I386_SET_GSBASE for sysarch().
This is similar to linux-2.6 set_thread_area().
It is rather easy to enable FLOATING_STACKS in glibc/linuxthreads
for our current kfreebsd-5 kernel. The same syscall can be also
used later to enable __thread keyword and whole TLS.
The attached pt-machine.h should go into
glibc-2.3/linuxthreads/sysdeps/unix/bsd/bsd4.4/kfreebsd/i386/i486/pt-machine.h
It applies to both glibc 2.3.0 and 2.3.5, successfully tested with 2.3.0.
BTW, is there any progress for glibc 2.3.5 ?
Can I help with something ?
Petr
-------------- next part --------------
/* Machine-dependent pthreads configuration and inline functions.
i486 version for kfreebsd.
Copyright (C) 1996-2001, 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth at tamu.edu>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifndef _PT_MACHINE_H
#define _PT_MACHINE_H 1
#ifndef PT_EI
# define PT_EI extern inline
#endif
#ifndef ASSEMBLER
#include <stddef.h> /* For offsetof. */
#include <stdlib.h> /* For abort(). */
#include <sysarch.h>
extern long int testandset (int *spinlock);
extern int __compare_and_swap (long int *p, long int oldval, long int newval);
/* Get some notion of the current stack. Need not be exactly the top
of the stack, just something somewhere in the current frame. */
#define CURRENT_STACK_FRAME __builtin_frame_address (0)
/* Spinlock implementation; required. */
PT_EI long int
testandset (int *spinlock)
{
long int ret;
__asm__ __volatile__ (
"xchgl %0, %1"
: "=r" (ret), "=m" (*spinlock)
: "0" (1), "m" (*spinlock)
: "memory");
return ret;
}
/* Compare-and-swap for semaphores. It's always available on i486+. */
#define HAS_COMPARE_AND_SWAP
PT_EI int
__compare_and_swap (long int *p, long int oldval, long int newval)
{
char ret;
long int readval;
__asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
: "=q" (ret), "=m" (*p), "=a" (readval)
: "r" (newval), "m" (*p), "a" (oldval)
: "memory");
return ret;
}
#endif
/* The P4 and above really want some help to prevent overheating. */
#define BUSY_WAIT_NOP __asm__ ("rep; nop")
/* Return the thread descriptor for the current thread.
The contained asm must *not* be marked volatile since otherwise
assignments like
pthread_descr self = thread_self();
do not get optimized away. */
#define THREAD_SELF \
({ \
register pthread_descr __self; \
__asm__ ("movl %%gs:%c1,%0" : "=r" (__self) \
: "i" (offsetof (struct _pthread_descr_struct, \
p_header.data.self))); \
__self; \
})
/* Initialize the thread-unique value. */
#ifndef I386_SET_GSBASE
#define I386_SET_GSBASE 10
#endif
// extern int sysarch(int cmd, void * param);
#define INIT_THREAD_SELF(descr, nr) \
{ \
long tmp; \
tmp = (long) descr; \
if (sysarch(I386_SET_GSBASE, &tmp) != 0) \
{ \
abort(); \
} \
}
/* Read member of the thread descriptor directly. */
#define THREAD_GETMEM(descr, member) \
({ \
__typeof__ (descr->member) __value; \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %%gs:%P2,%b0" \
: "=q" (__value) \
: "0" (0), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %%gs:%P1,%0" \
: "=r" (__value) \
: "i" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%gs:%P1,%%eax\n\t" \
"movl %%gs:%P2,%%edx" \
: "=A" (__value) \
: "i" (offsetof (struct _pthread_descr_struct, \
member)), \
"i" (offsetof (struct _pthread_descr_struct, \
member) + 4)); \
} \
__value; \
})
/* Same as THREAD_GETMEM, but the member offset can be non-constant. */
#define THREAD_GETMEM_NC(descr, member) \
({ \
__typeof__ (descr->member) __value; \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %%gs:(%2),%b0" \
: "=q" (__value) \
: "0" (0), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %%gs:(%1),%0" \
: "=r" (__value) \
: "r" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%gs:(%1),%%eax\n\t" \
"movl %%gs:4(%1),%%edx" \
: "=&A" (__value) \
: "r" (offsetof (struct _pthread_descr_struct, \
member))); \
} \
__value; \
})
/* Same as THREAD_SETMEM, but the member offset can be non-constant. */
#define THREAD_SETMEM(descr, member, value) \
({ \
__typeof__ (descr->member) __value = (value); \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %0,%%gs:%P1" : \
: "q" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %0,%%gs:%P1" : \
: "r" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%eax,%%gs:%P1\n\n" \
"movl %%edx,%%gs:%P2" : \
: "A" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member)), \
"i" (offsetof (struct _pthread_descr_struct, \
member) + 4)); \
} \
})
/* Set member of the thread descriptor directly. */
#define THREAD_SETMEM_NC(descr, member, value) \
({ \
__typeof__ (descr->member) __value = (value); \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %0,%%gs:(%1)" : \
: "q" (__value), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %0,%%gs:(%1)" : \
: "r" (__value), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%eax,%%gs:(%1)\n\t" \
"movl %%edx,%%gs:4(%1)" : \
: "A" (__value), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
} \
})
/* We want the OS to assign stack addresses. */
#define FLOATING_STACKS 1
/* Maximum size of the stack if the rlimit is unlimited. */
#define ARCH_STACK_MAX_SIZE 8*1024*1024
#endif /* pt-machine.h */
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