diff options
Diffstat (limited to 'libc/sysdeps/mach/hurd/i386/tls.h')
| -rw-r--r-- | libc/sysdeps/mach/hurd/i386/tls.h | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/libc/sysdeps/mach/hurd/i386/tls.h b/libc/sysdeps/mach/hurd/i386/tls.h new file mode 100644 index 000000000..223a47d2f --- /dev/null +++ b/libc/sysdeps/mach/hurd/i386/tls.h @@ -0,0 +1,174 @@ +/* Definitions for thread-local data handling. Hurd/i386 version. + Copyright (C) 2003, 2004 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#ifndef _I386_TLS_H +#define _I386_TLS_H + +#if defined HAVE_TLS_SUPPORT + +/* Some things really need not be machine-dependent. */ +# include <sysdeps/mach/hurd/tls.h> + +/* Indiciate that TLS support is available. */ +# define USE_TLS 1 + +/* 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)) +# define TLS_INIT_TP_EXPENSIVE 1 + +/* 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 /* HAVE_TLS_SUPPORT */ + +#endif /* i386/tls.h */ |