/* Definitions for thread-local data handling. Hurd/i386 version.
- Copyright (C) 2003, 2004, 2006 Free Software Foundation, Inc.
+ Copyright (C) 2003-2019 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
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. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
#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>
+#include <sysdeps/mach/hurd/tls.h>
+
+
+#ifndef __ASSEMBLER__
+# include <dl-dtv.h>
+
+/* Type of the TCB. */
+typedef struct
+{
+ void *tcb; /* Points to this structure. */
+ dtv_t *dtv; /* Vector of pointers to TLS data. */
+ thread_t self; /* This thread's control port. */
+ int multiple_threads;
+ uintptr_t sysinfo;
+ uintptr_t stack_guard;
+ uintptr_t pointer_guard;
+ int gscope_flag;
+ int private_futex;
+ /* Reservation of some values for the TM ABI. */
+ void *__private_tm[4];
+ /* GCC split stack support. */
+ void *__private_ss;
+
+ /* Keep this field last, so fields above can continue being compatible with
+ the Linux version. */
+ mach_port_t reply_port; /* This thread's reply port. */
+ struct hurd_sigstate *_hurd_sigstate;
+} tcbhead_t;
+#endif
+
+/* Return tcbhead_t from a TLS segment descriptor. */
+# define HURD_DESC_TLS(desc) \
+ ({ \
+ (tcbhead_t *) ( (desc->low_word >> 16) \
+ | ((desc->high_word & 0xff) << 16) \
+ | (desc->high_word & 0xff000000)); \
+ })
+
+/* Return 1 if TLS is not initialized yet. */
+#define __LIBC_NO_TLS() \
+ ({ unsigned short ds, gs; \
+ asm ("movw %%ds,%w0; movw %%gs,%w1" : "=q" (ds), "=q" (gs)); \
+ __builtin_expect (ds == gs, 0); })
/* 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
+#define TLS_TCB_AT_TP 1
+#define TLS_DTV_AT_TP 0
-# ifndef __ASSEMBLER__
+/* Alignment requirement for TCB.
+
+ Some processors such as Intel Atom pay a big penalty on every
+ access using a segment override if that segment's base is not
+ aligned to the size of a cache line. (See Intel 64 and IA-32
+ Architectures Optimization Reference Manual, section 13.3.3.3,
+ "Segment Base".) On such machines, a cache line is 64 bytes. */
+#define TCB_ALIGNMENT 64
+
+#ifndef __ASSEMBLER__
/* Use i386-specific RPCs to arrange that %gs segment register prefix
addresses the TCB in each thread. */
# include <errno.h>
# include <assert.h>
-#define HURD_TLS_DESC_DECL(desc, tcb) \
+# define HURD_TLS_DESC_DECL(desc, tcb) \
struct descriptor desc = \
{ /* low word: */ \
0xffff /* limit 0..15 */ \
| (((unsigned int) (tcb)) & 0xff000000) /* base 24..31 */ \
}
+# define HURD_SEL_LDT(sel) (__builtin_expect ((sel) & 4, 0))
static inline const char * __attribute__ ((unused))
-_hurd_tls_init (tcbhead_t *tcb, int secondcall)
+_hurd_tls_init (tcbhead_t *tcb)
{
HURD_TLS_DESC_DECL (desc, tcb);
-
- if (!secondcall)
+ thread_t self = __mach_thread_self ();
+ const char *msg = NULL;
+
+ /* This field is used by TLS accesses to get our "thread pointer"
+ from the TLS point of view. */
+ tcb->tcb = tcb;
+ /* We always at least start the sigthread anyway. */
+ tcb->multiple_threads = 1;
+
+ /* Get the first available selector. */
+ int sel = -1;
+ error_t err = __i386_set_gdt (self, &sel, desc);
+ if (err == MIG_BAD_ID)
{
- /* 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));
+ /* Old kernel, use a per-thread LDT. */
+ sel = 0x27;
+ err = __i386_set_ldt (self, sel, &desc, 1);
+ assert_perror (err);
+ if (err)
+ {
+ msg = "i386_set_ldt failed";
+ goto out;
+ }
}
- else
+ else if (err)
{
- /* 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";
- }
+ assert_perror (err); /* Separate from above with different line #. */
+ msg = "i386_set_gdt failed";
+ goto out;
}
- return 0;
+ /* Now install the new selector. */
+ asm volatile ("mov %w0, %%gs" :: "q" (sel));
+
+out:
+ __mach_port_deallocate (__mach_task_self (), self);
+ return msg;
}
/* 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
+# define TLS_INIT_TP(descr) \
+ _hurd_tls_init ((tcbhead_t *) (descr))
/* Return the TCB address of the current thread. */
-# define THREAD_SELF \
+# define THREAD_SELF \
({ tcbhead_t *__tcb; \
__asm__ ("movl %%gs:%c1,%0" : "=r" (__tcb) \
: "i" (offsetof (tcbhead_t, tcb))); \
__tcb;})
+/* Return the TCB address of a thread given its state.
+ Note: this is expensive. */
+# define THREAD_TCB(thread, thread_state) \
+ ({ int __sel = (thread_state)->basic.gs; \
+ struct descriptor __desc, *___desc = &__desc; \
+ unsigned int __count = 1; \
+ kern_return_t __err; \
+ if (HURD_SEL_LDT (__sel)) \
+ __err = __i386_get_ldt ((thread), __sel, 1, &___desc, &__count); \
+ else \
+ __err = __i386_get_gdt ((thread), __sel, &__desc); \
+ assert_perror (__err); \
+ assert (__count == 1); \
+ HURD_DESC_TLS (___desc);})
+
/* 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() \
+# 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>
+# 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)
+/* Set up TLS in the new thread of a fork child, copying from the original. */
+static inline kern_return_t __attribute__ ((unused))
+_hurd_tls_fork (thread_t child, thread_t orig, 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;
+
+ struct descriptor desc, *_desc = &desc;
+ error_t err;
+ unsigned int count = 1;
+
+ if (HURD_SEL_LDT (sel))
+ err = __i386_get_ldt (orig, sel, 1, &_desc, &count);
+ else
+ err = __i386_get_gdt (orig, sel, &desc);
+
+ assert_perror (err);
+ if (err)
+ return err;
+
+ if (HURD_SEL_LDT (sel))
+ err = __i386_set_ldt (child, sel, &desc, 1);
+ else
+ err = __i386_set_gdt (child, &sel, desc);
+
+ state->gs = sel;
+ return err;
+}
+
+static inline kern_return_t __attribute__ ((unused))
+_hurd_tls_new (thread_t child, struct i386_thread_state *state, tcbhead_t *tcb)
{
/* Fetch the selector set by _hurd_tls_init. */
int sel;
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 */
+ tcb->tcb = tcb;
+ tcb->self = child;
+
+ if (HURD_SEL_LDT (sel))
err = __i386_set_ldt (child, sel, &desc, 1);
else
err = __i386_set_gdt (child, &sel, desc);
return err;
}
-# endif /* !__ASSEMBLER__ */
-#endif /* HAVE_TLS_SUPPORT */
+#endif /* !__ASSEMBLER__ */
#endif /* i386/tls.h */
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