diff options
Diffstat (limited to 'lib/libthr/arch/i386/i386/_setcurthread.c')
| -rw-r--r-- | lib/libthr/arch/i386/i386/_setcurthread.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/lib/libthr/arch/i386/i386/_setcurthread.c b/lib/libthr/arch/i386/i386/_setcurthread.c new file mode 100644 index 0000000..2e8150f --- /dev/null +++ b/lib/libthr/arch/i386/i386/_setcurthread.c @@ -0,0 +1,122 @@ +/* + * Copyright (c) 2003, Jeffrey Roberson <jeff@freebsd.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice unmodified, this list of conditions, and the following + * disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + */ + +#include <sys/types.h> + +#include <stdio.h> + +#include <machine/sysarch.h> +#include <machine/segments.h> + +#define MAXTHR 128 + +#define LDT_INDEX(x) (((long)(x) - (long)ldt_entries) / sizeof(ldt_entries[0])) + +void **ldt_free = NULL; +static int ldt_inited = 0; +void *ldt_entries[MAXTHR]; + +static void ldt_init(void); + +static void +ldt_init(void) +{ + int i; + + ldt_free = &ldt_entries[NLDT]; + + for (i = 0; i < MAXTHR; i++) + ldt_entries[i] = (void *)&ldt_entries[i + 1]; + + ldt_entries[MAXTHR] = NULL; + + ldt_inited = 1; +} + +void +_retire_thread(void *entry) +{ + *(void **)entry = *ldt_free; + ldt_free = entry; +} + +void * +_set_curthread(void *thr) +{ + union descriptor desc; + void **ldt_entry; + int ldt_index; + int error; + + if (ldt_inited == NULL) + ldt_init(); + + if (ldt_free == NULL) + abort(); + + /* + * Pull one off of the free list and update the free list pointer. + */ + ldt_entry = ldt_free; + ldt_free = (void **)*ldt_entry; + + /* + * Cache the address of the thread structure here. This is + * what the gs register will point to. + */ + *ldt_entry = thr; + ldt_index = LDT_INDEX(ldt_entry); + + bzero(&desc, sizeof(desc)); + + /* + * Set up the descriptor to point into the ldt table which contains + * only a pointer to the thread. + */ + desc.sd.sd_lolimit = sizeof(*ldt_entry); + desc.sd.sd_lobase = (unsigned int)ldt_entry & 0xFFFFFF; + desc.sd.sd_type = SDT_MEMRO; + desc.sd.sd_dpl = SEL_UPL; + desc.sd.sd_p = 1; + desc.sd.sd_hilimit = 0; + desc.sd.sd_xx = 0; + desc.sd.sd_def32 = 1; + desc.sd.sd_gran = 0; + desc.sd.sd_hibase = (unsigned int)ldt_entry >> 24; + + error = i386_set_ldt(ldt_index, &desc, 1); + if (error == -1) + abort(); + + /* + * Set up our gs with the index into the ldt for this entry. + */ + _set_gs(LSEL(ldt_index, SEL_UPL)); + + return (ldt_entry); +} |
