| /* Definitions for thread-local data handling. Hurd/i386 version. |
| Copyright (C) 2003-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| 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; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #ifndef _I386_TLS_H |
| #define _I386_TLS_H |
| |
| |
| /* Some things really need not be machine-dependent. */ |
| #include <sysdeps/mach/hurd/tls.h> |
| |
| /* The TCB can have any size and the memory following the address the |
| thread pointer points to is unspecified. Allocate the TCB there. */ |
| #define TLS_TCB_AT_TP 1 |
| |
| #ifndef __ASSEMBLER__ |
| |
| /* Use i386-specific RPCs to arrange that %gs segment register prefix |
| addresses the TCB in each thread. */ |
| # include <mach/i386/mach_i386.h> |
| |
| # ifndef HAVE_I386_SET_GDT |
| # define __i386_set_gdt(thr, sel, desc) ((void) (thr), (void) (sel), (void) (desc), MIG_BAD_ID) |
| # endif |
| |
| # include <errno.h> |
| # include <assert.h> |
| |
| # define HURD_TLS_DESC_DECL(desc, tcb) \ |
| struct descriptor desc = \ |
| { /* low word: */ \ |
| 0xffff /* limit 0..15 */ \ |
| | (((unsigned int) (tcb)) << 16) /* base 0..15 */ \ |
| , /* high word: */ \ |
| ((((unsigned int) (tcb)) >> 16) & 0xff) /* base 16..23 */ \ |
| | ((0x12 | 0x60 | 0x80) << 8) /* access = ACC_DATA_W|ACC_PL_U|ACC_P */ \ |
| | (0xf << 16) /* limit 16..19 */ \ |
| | ((4 | 8) << 20) /* granularity = SZ_32|SZ_G */ \ |
| | (((unsigned int) (tcb)) & 0xff000000) /* base 24..31 */ \ |
| } |
| |
| |
| static inline const char * __attribute__ ((unused)) |
| _hurd_tls_init (tcbhead_t *tcb, int secondcall) |
| { |
| HURD_TLS_DESC_DECL (desc, tcb); |
| |
| if (!secondcall) |
| { |
| /* This field is used by TLS accesses to get our "thread pointer" |
| from the TLS point of view. */ |
| tcb->tcb = tcb; |
| |
| /* Cache our thread port. */ |
| tcb->self = __mach_thread_self (); |
| |
| /* Get the first available selector. */ |
| int sel = -1; |
| error_t err = __i386_set_gdt (tcb->self, &sel, desc); |
| if (err == MIG_BAD_ID) |
| { |
| /* Old kernel, use a per-thread LDT. */ |
| sel = 0x27; |
| err = __i386_set_ldt (tcb->self, sel, &desc, 1); |
| assert_perror (err); |
| if (err) |
| return "i386_set_ldt failed"; |
| } |
| else if (err) |
| { |
| assert_perror (err); /* Separate from above with different line #. */ |
| return "i386_set_gdt failed"; |
| } |
| |
| /* Now install the new selector. */ |
| asm volatile ("mov %w0, %%gs" :: "q" (sel)); |
| } |
| else |
| { |
| /* Fetch the selector set by the first call. */ |
| int sel; |
| asm ("mov %%gs, %w0" : "=q" (sel) : "0" (0)); |
| if (__builtin_expect (sel, 0x50) & 4) /* LDT selector */ |
| { |
| error_t err = __i386_set_ldt (tcb->self, sel, &desc, 1); |
| assert_perror (err); |
| if (err) |
| return "i386_set_ldt failed"; |
| } |
| else |
| { |
| error_t err = __i386_set_gdt (tcb->self, &sel, desc); |
| assert_perror (err); |
| if (err) |
| return "i386_set_gdt failed"; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* Code to initially initialize the thread pointer. This might need |
| special attention since 'errno' is not yet available and if the |
| operation can cause a failure 'errno' must not be touched. */ |
| # define TLS_INIT_TP(descr, secondcall) \ |
| _hurd_tls_init ((tcbhead_t *) (descr), (secondcall)) |
| |
| /* Return the TCB address of the current thread. */ |
| # define THREAD_SELF \ |
| ({ tcbhead_t *__tcb; \ |
| __asm__ ("movl %%gs:%c1,%0" : "=r" (__tcb) \ |
| : "i" (offsetof (tcbhead_t, tcb))); \ |
| __tcb;}) |
| |
| /* Install new dtv for current thread. */ |
| # define INSTALL_NEW_DTV(dtvp) \ |
| ({ asm volatile ("movl %0,%%gs:%P1" \ |
| : : "ir" (dtvp), "i" (offsetof (tcbhead_t, dtv))); }) |
| |
| /* Return the address of the dtv for the current thread. */ |
| # define THREAD_DTV() \ |
| ({ dtv_t *_dtv; \ |
| asm ("movl %%gs:%P1,%0" : "=q" (_dtv) : "i" (offsetof (tcbhead_t, dtv)));\ |
| _dtv; }) |
| |
| # include <mach/machine/thread_status.h> |
| |
| /* Set up TLS in the new thread of a fork child, copying from our own. */ |
| static inline error_t __attribute__ ((unused)) |
| _hurd_tls_fork (thread_t child, struct i386_thread_state *state) |
| { |
| /* Fetch the selector set by _hurd_tls_init. */ |
| int sel; |
| asm ("mov %%gs, %w0" : "=q" (sel) : "0" (0)); |
| if (sel == state->ds) /* _hurd_tls_init was never called. */ |
| return 0; |
| |
| tcbhead_t *const tcb = THREAD_SELF; |
| HURD_TLS_DESC_DECL (desc, tcb); |
| error_t err; |
| |
| if (__builtin_expect (sel, 0x50) & 4) /* LDT selector */ |
| err = __i386_set_ldt (child, sel, &desc, 1); |
| else |
| err = __i386_set_gdt (child, &sel, desc); |
| |
| state->gs = sel; |
| return err; |
| } |
| |
| #endif /* !__ASSEMBLER__ */ |
| |
| #endif /* i386/tls.h */ |