mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-05 19:21:05 +00:00
1d9cbb9608
The previous definition of THREAD_SELF did not tell the compiler that %fs (or %gs) usage is invalid for the !DL_LOOKUP_GSCOPE_LOCK case in _dl_lookup_symbol_x. As a result, ld.so could try to use the TCB before it was initialized. As the comment in tls.h explains, asm volatile is undesirable here. Using the __seg_fs (or __seg_gs) namespace does not interfere with optimization, and expresses that THREAD_SELF is potentially trapping.
344 lines
12 KiB
C
344 lines
12 KiB
C
/* Definition for thread-local data handling. nptl/x86_64 version.
|
|
Copyright (C) 2002-2020 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _TLS_H
|
|
#define _TLS_H 1
|
|
|
|
#ifndef __ASSEMBLER__
|
|
# include <asm/prctl.h> /* For ARCH_SET_FS. */
|
|
# include <stdbool.h>
|
|
# include <stddef.h>
|
|
# include <stdint.h>
|
|
# include <stdlib.h>
|
|
# include <sysdep.h>
|
|
# include <libc-pointer-arith.h> /* For cast_to_integer. */
|
|
# include <kernel-features.h>
|
|
# include <dl-dtv.h>
|
|
|
|
/* Replacement type for __m128 since this file is included by ld.so,
|
|
which is compiled with -mno-sse. It must not change the alignment
|
|
of rtld_savespace_sse. */
|
|
typedef struct
|
|
{
|
|
int i[4];
|
|
} __128bits;
|
|
|
|
|
|
typedef struct
|
|
{
|
|
void *tcb; /* Pointer to the TCB. Not necessarily the
|
|
thread descriptor used by libpthread. */
|
|
dtv_t *dtv;
|
|
void *self; /* Pointer to the thread descriptor. */
|
|
int multiple_threads;
|
|
int gscope_flag;
|
|
uintptr_t sysinfo;
|
|
uintptr_t stack_guard;
|
|
uintptr_t pointer_guard;
|
|
unsigned long int unused_vgetcpu_cache[2];
|
|
/* Bit 0: X86_FEATURE_1_IBT.
|
|
Bit 1: X86_FEATURE_1_SHSTK.
|
|
*/
|
|
unsigned int feature_1;
|
|
int __glibc_unused1;
|
|
/* Reservation of some values for the TM ABI. */
|
|
void *__private_tm[4];
|
|
/* GCC split stack support. */
|
|
void *__private_ss;
|
|
/* The lowest address of shadow stack, */
|
|
unsigned long long int ssp_base;
|
|
/* Must be kept even if it is no longer used by glibc since programs,
|
|
like AddressSanitizer, depend on the size of tcbhead_t. */
|
|
__128bits __glibc_unused2[8][4] __attribute__ ((aligned (32)));
|
|
|
|
void *__padding[8];
|
|
} tcbhead_t;
|
|
|
|
# ifdef __ILP32__
|
|
/* morestack.S in libgcc uses offset 0x40 to access __private_ss, */
|
|
_Static_assert (offsetof (tcbhead_t, __private_ss) == 0x40,
|
|
"offset of __private_ss != 0x40");
|
|
/* NB: ssp_base used to be "long int __glibc_reserved2", which was
|
|
changed from 32 bits to 64 bits. Make sure that the offset of the
|
|
next field, __glibc_unused2, is unchanged. */
|
|
_Static_assert (offsetof (tcbhead_t, __glibc_unused2) == 0x60,
|
|
"offset of __glibc_unused2 != 0x60");
|
|
# else
|
|
/* morestack.S in libgcc uses offset 0x70 to access __private_ss, */
|
|
_Static_assert (offsetof (tcbhead_t, __private_ss) == 0x70,
|
|
"offset of __private_ss != 0x70");
|
|
_Static_assert (offsetof (tcbhead_t, __glibc_unused2) == 0x80,
|
|
"offset of __glibc_unused2 != 0x80");
|
|
# endif
|
|
|
|
#else /* __ASSEMBLER__ */
|
|
# include <tcb-offsets.h>
|
|
#endif
|
|
|
|
|
|
/* Alignment requirement for the stack. */
|
|
#define STACK_ALIGN 16
|
|
|
|
|
|
#ifndef __ASSEMBLER__
|
|
/* Get system call information. */
|
|
# include <sysdep.h>
|
|
|
|
#define LOCK_PREFIX "lock;"
|
|
|
|
/* This is the size of the initial TCB. Can't be just sizeof (tcbhead_t),
|
|
because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
|
|
struct pthread even when not linked with -lpthread. */
|
|
# define TLS_INIT_TCB_SIZE sizeof (struct pthread)
|
|
|
|
/* Alignment requirements for the initial TCB. */
|
|
# define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
|
|
|
|
/* This is the size of the TCB. */
|
|
# define TLS_TCB_SIZE sizeof (struct pthread)
|
|
|
|
/* Alignment requirements for the TCB. */
|
|
# define TLS_TCB_ALIGN __alignof__ (struct pthread)
|
|
|
|
/* 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_DTV_AT_TP 0
|
|
|
|
/* Get the thread descriptor definition. */
|
|
# include <nptl/descr.h>
|
|
|
|
|
|
/* Install the dtv pointer. The pointer passed is to the element with
|
|
index -1 which contain the length. */
|
|
# define INSTALL_DTV(descr, dtvp) \
|
|
((tcbhead_t *) (descr))->dtv = (dtvp) + 1
|
|
|
|
/* Install new dtv for current thread. */
|
|
# define INSTALL_NEW_DTV(dtvp) \
|
|
({ struct pthread *__pd; \
|
|
THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
|
|
|
|
/* Return dtv of given thread descriptor. */
|
|
# define GET_DTV(descr) \
|
|
(((tcbhead_t *) (descr))->dtv)
|
|
|
|
|
|
/* 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.
|
|
|
|
We have to make the syscall for both uses of the macro since the
|
|
address might be (and probably is) different. */
|
|
# define TLS_INIT_TP(thrdescr) \
|
|
({ void *_thrdescr = (thrdescr); \
|
|
tcbhead_t *_head = _thrdescr; \
|
|
int _result; \
|
|
\
|
|
_head->tcb = _thrdescr; \
|
|
/* For now the thread descriptor is at the same address. */ \
|
|
_head->self = _thrdescr; \
|
|
\
|
|
/* It is a simple syscall to set the %fs value for the thread. */ \
|
|
asm volatile ("syscall" \
|
|
: "=a" (_result) \
|
|
: "0" ((unsigned long int) __NR_arch_prctl), \
|
|
"D" ((unsigned long int) ARCH_SET_FS), \
|
|
"S" (_thrdescr) \
|
|
: "memory", "cc", "r11", "cx"); \
|
|
\
|
|
_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() \
|
|
({ struct pthread *__pd; \
|
|
THREAD_GETMEM (__pd, header.dtv); })
|
|
|
|
|
|
/* Return the thread descriptor for the current thread.
|
|
|
|
The contained asm must *not* be marked volatile since otherwise
|
|
assignments like
|
|
pthread_descr self = thread_self();
|
|
do not get optimized away. */
|
|
# if __GNUC_PREREQ (6, 0)
|
|
# define THREAD_SELF \
|
|
(*(struct pthread *__seg_fs *) offsetof (struct pthread, header.self))
|
|
# else
|
|
# define THREAD_SELF \
|
|
({ struct pthread *__self; \
|
|
asm ("mov %%fs:%c1,%0" : "=r" (__self) \
|
|
: "i" (offsetof (struct pthread, header.self))); \
|
|
__self;})
|
|
# endif
|
|
|
|
/* Magic for libthread_db to know how to do THREAD_SELF. */
|
|
# define DB_THREAD_SELF_INCLUDE <sys/reg.h> /* For the FS constant. */
|
|
# define DB_THREAD_SELF CONST_THREAD_AREA (64, FS)
|
|
|
|
/* Read member of the thread descriptor directly. */
|
|
# define THREAD_GETMEM(descr, member) \
|
|
({ __typeof (descr->member) __value; \
|
|
_Static_assert (sizeof (__value) == 1 \
|
|
|| sizeof (__value) == 4 \
|
|
|| sizeof (__value) == 8, \
|
|
"size of per-thread data"); \
|
|
if (sizeof (__value) == 1) \
|
|
asm volatile ("movb %%fs:%P2,%b0" \
|
|
: "=q" (__value) \
|
|
: "0" (0), "i" (offsetof (struct pthread, member))); \
|
|
else if (sizeof (__value) == 4) \
|
|
asm volatile ("movl %%fs:%P1,%0" \
|
|
: "=r" (__value) \
|
|
: "i" (offsetof (struct pthread, member))); \
|
|
else /* 8 */ \
|
|
{ \
|
|
asm volatile ("movq %%fs:%P1,%q0" \
|
|
: "=r" (__value) \
|
|
: "i" (offsetof (struct pthread, member))); \
|
|
} \
|
|
__value; })
|
|
|
|
|
|
/* Same as THREAD_GETMEM, but the member offset can be non-constant. */
|
|
# define THREAD_GETMEM_NC(descr, member, idx) \
|
|
({ __typeof (descr->member[0]) __value; \
|
|
_Static_assert (sizeof (__value) == 1 \
|
|
|| sizeof (__value) == 4 \
|
|
|| sizeof (__value) == 8, \
|
|
"size of per-thread data"); \
|
|
if (sizeof (__value) == 1) \
|
|
asm volatile ("movb %%fs:%P2(%q3),%b0" \
|
|
: "=q" (__value) \
|
|
: "0" (0), "i" (offsetof (struct pthread, member[0])), \
|
|
"r" (idx)); \
|
|
else if (sizeof (__value) == 4) \
|
|
asm volatile ("movl %%fs:%P1(,%q2,4),%0" \
|
|
: "=r" (__value) \
|
|
: "i" (offsetof (struct pthread, member[0])), "r" (idx));\
|
|
else /* 8 */ \
|
|
{ \
|
|
asm volatile ("movq %%fs:%P1(,%q2,8),%q0" \
|
|
: "=r" (__value) \
|
|
: "i" (offsetof (struct pthread, member[0])), \
|
|
"r" (idx)); \
|
|
} \
|
|
__value; })
|
|
|
|
|
|
/* Loading addresses of objects on x86-64 needs to be treated special
|
|
when generating PIC code. */
|
|
#ifdef __pic__
|
|
# define IMM_MODE "nr"
|
|
#else
|
|
# define IMM_MODE "ir"
|
|
#endif
|
|
|
|
|
|
/* Set member of the thread descriptor directly. */
|
|
# define THREAD_SETMEM(descr, member, value) \
|
|
({ \
|
|
_Static_assert (sizeof (descr->member) == 1 \
|
|
|| sizeof (descr->member) == 4 \
|
|
|| sizeof (descr->member) == 8, \
|
|
"size of per-thread data"); \
|
|
if (sizeof (descr->member) == 1) \
|
|
asm volatile ("movb %b0,%%fs:%P1" : \
|
|
: "iq" (value), \
|
|
"i" (offsetof (struct pthread, member))); \
|
|
else if (sizeof (descr->member) == 4) \
|
|
asm volatile ("movl %0,%%fs:%P1" : \
|
|
: IMM_MODE (value), \
|
|
"i" (offsetof (struct pthread, member))); \
|
|
else /* 8 */ \
|
|
{ \
|
|
asm volatile ("movq %q0,%%fs:%P1" : \
|
|
: IMM_MODE ((uint64_t) cast_to_integer (value)), \
|
|
"i" (offsetof (struct pthread, member))); \
|
|
}})
|
|
|
|
|
|
/* Same as THREAD_SETMEM, but the member offset can be non-constant. */
|
|
# define THREAD_SETMEM_NC(descr, member, idx, value) \
|
|
({ \
|
|
_Static_assert (sizeof (descr->member[0]) == 1 \
|
|
|| sizeof (descr->member[0]) == 4 \
|
|
|| sizeof (descr->member[0]) == 8, \
|
|
"size of per-thread data"); \
|
|
if (sizeof (descr->member[0]) == 1) \
|
|
asm volatile ("movb %b0,%%fs:%P1(%q2)" : \
|
|
: "iq" (value), \
|
|
"i" (offsetof (struct pthread, member[0])), \
|
|
"r" (idx)); \
|
|
else if (sizeof (descr->member[0]) == 4) \
|
|
asm volatile ("movl %0,%%fs:%P1(,%q2,4)" : \
|
|
: IMM_MODE (value), \
|
|
"i" (offsetof (struct pthread, member[0])), \
|
|
"r" (idx)); \
|
|
else /* 8 */ \
|
|
{ \
|
|
asm volatile ("movq %q0,%%fs:%P1(,%q2,8)" : \
|
|
: IMM_MODE ((uint64_t) cast_to_integer (value)), \
|
|
"i" (offsetof (struct pthread, member[0])), \
|
|
"r" (idx)); \
|
|
}})
|
|
|
|
|
|
/* Set the stack guard field in TCB head. */
|
|
# define THREAD_SET_STACK_GUARD(value) \
|
|
THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
|
|
# define THREAD_COPY_STACK_GUARD(descr) \
|
|
((descr)->header.stack_guard \
|
|
= THREAD_GETMEM (THREAD_SELF, header.stack_guard))
|
|
|
|
|
|
/* Set the pointer guard field in the TCB head. */
|
|
# define THREAD_SET_POINTER_GUARD(value) \
|
|
THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
|
|
# define THREAD_COPY_POINTER_GUARD(descr) \
|
|
((descr)->header.pointer_guard \
|
|
= THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
|
|
|
|
|
|
/* Get and set the global scope generation counter in the TCB head. */
|
|
# define THREAD_GSCOPE_IN_TCB 1
|
|
# define THREAD_GSCOPE_FLAG_UNUSED 0
|
|
# define THREAD_GSCOPE_FLAG_USED 1
|
|
# define THREAD_GSCOPE_FLAG_WAIT 2
|
|
# define THREAD_GSCOPE_RESET_FLAG() \
|
|
do \
|
|
{ int __res; \
|
|
asm volatile ("xchgl %0, %%fs:%P1" \
|
|
: "=r" (__res) \
|
|
: "i" (offsetof (struct pthread, header.gscope_flag)), \
|
|
"0" (THREAD_GSCOPE_FLAG_UNUSED)); \
|
|
if (__res == THREAD_GSCOPE_FLAG_WAIT) \
|
|
lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); \
|
|
} \
|
|
while (0)
|
|
# define THREAD_GSCOPE_SET_FLAG() \
|
|
THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
|
|
|
|
#endif /* __ASSEMBLER__ */
|
|
|
|
#endif /* tls.h */
|