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authorRoland McGrath <roland@hack.frob.com>2014-06-09 12:52:55 -0700
committerRoland McGrath <roland@hack.frob.com>2014-06-09 12:52:55 -0700
commit962b744d06c1df8653570f32c03da572801e4b6b (patch)
tree408556ab7597eba9480e1bd53379681c01c2a55b /nptl
parent2976feab1f37ad7b4e06b253f0a2e844505217da (diff)
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Start cleaning up TLS initial value for pthread_create.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/sysdeps/i386/tls.h45
-rw-r--r--nptl/sysdeps/pthread/createthread.c22
-rw-r--r--nptl/sysdeps/x86_64/tls.h2
3 files changed, 47 insertions, 22 deletions
diff --git a/nptl/sysdeps/i386/tls.h b/nptl/sysdeps/i386/tls.h
index 2f8d11def1..ac9c9a22f9 100644
--- a/nptl/sysdeps/i386/tls.h
+++ b/nptl/sysdeps/i386/tls.h
@@ -192,6 +192,26 @@ union user_desc_init
# endif
#endif
+static inline void __attribute__ ((unused, always_inline))
+tls_fill_user_desc (union user_desc_init *desc,
+ unsigned int entry_number,
+ void *pd)
+{
+ desc->vals[0] = entry_number;
+ /* The 'base_addr' field. Pointer to the TCB. */
+ desc->vals[1] = (unsigned long int) pd;
+ /* The 'limit' field. We use 4GB which is 0xfffff pages. */
+ desc->vals[2] = 0xfffff;
+ /* Collapsed value of the bitfield:
+ .seg_32bit = 1
+ .contents = 0
+ .read_exec_only = 0
+ .limit_in_pages = 1
+ .seg_not_present = 0
+ .useable = 1 */
+ desc->vals[3] = 0x51;
+}
+
/* 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. */
@@ -207,20 +227,8 @@ union user_desc_init
/* New syscall handling support. */ \
INIT_SYSINFO; \
\
- /* The 'entry_number' field. Let the kernel pick a value. */ \
- _segdescr.vals[0] = -1; \
- /* The 'base_addr' field. Pointer to the TCB. */ \
- _segdescr.vals[1] = (unsigned long int) _thrdescr; \
- /* The 'limit' field. We use 4GB which is 0xfffff pages. */ \
- _segdescr.vals[2] = 0xfffff; \
- /* Collapsed value of the bitfield: \
- .seg_32bit = 1 \
- .contents = 0 \
- .read_exec_only = 0 \
- .limit_in_pages = 1 \
- .seg_not_present = 0 \
- .useable = 1 */ \
- _segdescr.vals[3] = 0x51; \
+ /* Let the kernel pick a value for the 'entry_number' field. */ \
+ tls_fill_user_desc (&_segdescr, -1, _thrdescr); \
\
/* Install the TLS. */ \
asm volatile (TLS_LOAD_EBX \
@@ -244,6 +252,15 @@ union user_desc_init
_result == 0 ? NULL \
: "set_thread_area failed when setting up thread-local storage\n"; })
+# define TLS_DEFINE_INIT_TP(tp, pd) \
+ union user_desc_init _segdescr; \
+ /* Find the 'entry_number' field that the kernel selected in TLS_INIT_TP. \
+ The first three bits of the segment register value select the GDT, \
+ ignore them. We get the index from the value of the %gs register in \
+ the current thread. */ \
+ tls_fill_user_desc (&_segdescr, TLS_GET_GS () >> 3, pd); \
+ const struct user_desc *tp = &_segdescr.desc
+
/* Return the address of the dtv for the current thread. */
# define THREAD_DTV() \
diff --git a/nptl/sysdeps/pthread/createthread.c b/nptl/sysdeps/pthread/createthread.c
index e1856f7b1c..28c1ea67d3 100644
--- a/nptl/sysdeps/pthread/createthread.c
+++ b/nptl/sysdeps/pthread/createthread.c
@@ -30,10 +30,18 @@
#define CLONE_SIGNAL (CLONE_SIGHAND | CLONE_THREAD)
-/* Unless otherwise specified, the thread "register" is going to be
- initialized with a pointer to the TCB. */
-#ifndef TLS_VALUE
-# define TLS_VALUE pd
+/* The <tls.h> header should define the macro TLS_DEFINE_INIT_TP such that:
+ TLS_DEFINE_INIT_TP (VAR, PD);
+ Declares and initializes a variable VAR with the value that should
+ be passed to the OS thread creation function (e.g. clone) to initialize
+ its TLS state for the 'struct pthread *' PD. */
+#ifndef TLS_DEFINE_INIT_TP
+/* For a transitional period while all the <tls.h> implementations are
+ getting updated, we define it using the old TLS_VALUE macro. */
+# define TLS_DEFINE_INIT_TP(tp, pd) void *tp = TLS_VALUE
+# ifndef TLS_VALUE
+# define TLS_VALUE pd
+# endif
#endif
#ifndef ARCH_CLONE
@@ -52,9 +60,7 @@ do_clone (struct pthread *pd, const struct pthread_attr *attr,
int clone_flags, int (*fct) (void *), STACK_VARIABLES_PARMS,
int stopped)
{
-#ifdef PREPARE_CREATE
- PREPARE_CREATE;
-#endif
+ TLS_DEFINE_INIT_TP (tp, pd);
if (__glibc_unlikely (stopped != 0))
/* We make sure the thread does not run far by forcing it to get a
@@ -73,7 +79,7 @@ do_clone (struct pthread *pd, const struct pthread_attr *attr,
atomic_increment (&__nptl_nthreads);
int rc = ARCH_CLONE (fct, STACK_VARIABLES_ARGS, clone_flags,
- pd, &pd->tid, TLS_VALUE, &pd->tid);
+ pd, &pd->tid, tp, &pd->tid);
if (__glibc_unlikely (rc == -1))
{
diff --git a/nptl/sysdeps/x86_64/tls.h b/nptl/sysdeps/x86_64/tls.h
index fb671f4795..3e811b6aea 100644
--- a/nptl/sysdeps/x86_64/tls.h
+++ b/nptl/sysdeps/x86_64/tls.h
@@ -164,6 +164,8 @@ typedef struct
_result ? "cannot set %fs base address for thread-local storage" : 0; \
})
+# define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd)
+
/* Return the address of the dtv for the current thread. */
# define THREAD_DTV() \