diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/mach/hurd/x86/init-first.c | 14 | ||||
| -rw-r--r-- | sysdeps/mach/hurd/x86_64/tls.h | 215 |
2 files changed, 228 insertions, 1 deletions
diff --git a/sysdeps/mach/hurd/x86/init-first.c b/sysdeps/mach/hurd/x86/init-first.c index 2fccaef..75a5c84 100644 --- a/sysdeps/mach/hurd/x86/init-first.c +++ b/sysdeps/mach/hurd/x86/init-first.c @@ -42,8 +42,14 @@ extern char **__libc_argv attribute_hidden; extern char **_dl_argv; #ifndef SHARED -unsigned short __init1_desc; static tcbhead_t __init1_tcbhead; +# ifndef __x86_64__ +unsigned short __init1_desc; +# endif +#endif + +#ifdef __x86_64__ +unsigned char __libc_tls_initialized; #endif /* Things that want to be run before _hurd_init or much anything else. @@ -161,7 +167,13 @@ first_init (void) /* In the static case, we need to set up TLS early so that the stack protection guard can be read at gs:0x14 by the gcc-generated snippets. */ _hurd_tls_init (&__init1_tcbhead); + + /* Make sure __LIBC_NO_TLS () keeps evaluating to 1. */ +# ifdef __x86_64__ + __libc_tls_initialized = 0; +# else asm ("movw %%gs,%w0" : "=m" (__init1_desc)); +# endif #endif RUN_RELHOOK (_hurd_preinit_hook, ()); diff --git a/sysdeps/mach/hurd/x86_64/tls.h b/sysdeps/mach/hurd/x86_64/tls.h new file mode 100644 index 0000000..cf74e1f --- /dev/null +++ b/sysdeps/mach/hurd/x86_64/tls.h @@ -0,0 +1,215 @@ +/* Definitions for thread-local data handling. Hurd/x86_64 version. + Copyright (C) 2003-2023 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 _X86_64_TLS_H +#define _X86_64_TLS_H + + +/* Some things really need not be machine-dependent. */ +#include <sysdeps/mach/hurd/tls.h> + + +#ifndef __ASSEMBLER__ +# include <dl-dtv.h> +# include <mach/machine/thread_status.h> +# include <errno.h> +# include <assert.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 __glibc_padding1; + int multiple_threads; + int gscope_flag; + uintptr_t sysinfo; + uintptr_t stack_guard; + uintptr_t pointer_guard; + long __glibc_padding2[2]; + int private_futex; + int __glibc_padding3; + /* 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; + + /* Keep these fields last, so offsets of fields above can continue being + compatible with the x86_64 NPTL version. */ + mach_port_t reply_port; /* This thread's reply port. */ + struct hurd_sigstate *_hurd_sigstate; + + /* Used by the exception handling implementation in the dynamic loader. */ + struct rtld_catch *rtld_catch; +} tcbhead_t; + +/* GCC generates %fs:0x28 to access the stack guard. */ +_Static_assert (offsetof (tcbhead_t, stack_guard) == 0x28, + "stack guard offset"); +/* libgcc uses %fs:0x70 to access the split stack pointer. */ +_Static_assert (offsetof (tcbhead_t, __private_ss) == 0x70, + "split stack pointer offset"); + +extern unsigned char __libc_tls_initialized; + +# define __LIBC_NO_TLS() __builtin_expect (!__libc_tls_initialized, 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_DTV_AT_TP 0 + +/* 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 + + +# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr)) + +# define THREAD_SELF \ + (*(tcbhead_t * __seg_fs *) offsetof (tcbhead_t, tcb)) +/* Read member of the thread descriptor directly. */ +# define THREAD_GETMEM(descr, member) \ + (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member)) +/* Write member of the thread descriptor directly. */ +# define THREAD_SETMEM(descr, member, value) \ + (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member) = value) + + +/* Return the TCB address of a thread given its state. + Note: this is expensive. */ +static inline tcbhead_t * __attribute__ ((unused)) +THREAD_TCB (thread_t thread, + const void *all_state __attribute__ ((unused))) +{ + error_t err; + /* Fetch the target thread's state. */ + struct i386_fsgs_base_state state; + mach_msg_type_number_t state_count = i386_FSGS_BASE_STATE_COUNT; + err = __thread_get_state (thread, i386_FSGS_BASE_STATE, + (thread_state_t) &state, + &state_count); + assert_perror (err); + assert (state_count == i386_FSGS_BASE_STATE_COUNT); + return (tcbhead_t *) state.fs_base; +} + +/* Install new dtv for current thread. */ +# define INSTALL_NEW_DTV(dtvp) THREAD_SETMEM (THREAD_SELF, dtv, dtvp) + +/* Return the address of the dtv for the current thread. */ +# define THREAD_DTV() THREAD_GETMEM (THREAD_SELF, dtv) + + +/* Set the stack guard field in TCB head. */ +# define THREAD_SET_STACK_GUARD(value) \ + THREAD_SETMEM (THREAD_SELF, stack_guard, value) +# define THREAD_COPY_STACK_GUARD(descr) \ + ((descr)->stack_guard \ + = THREAD_GETMEM (THREAD_SELF, stack_guard)) + +/* Set the pointer guard field in the TCB head. */ +# define THREAD_SET_POINTER_GUARD(value) \ + THREAD_SETMEM (THREAD_SELF, pointer_guard, value) +# define THREAD_COPY_POINTER_GUARD(descr) \ + ((descr)->pointer_guard \ + = THREAD_GETMEM (THREAD_SELF, pointer_guard)) + +/* 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, + void *machine_state __attribute__ ((unused))) +{ + error_t err; + struct i386_fsgs_base_state state; + mach_msg_type_number_t state_count = i386_FSGS_BASE_STATE_COUNT; + err = __thread_get_state (orig, i386_FSGS_BASE_STATE, + (thread_state_t) &state, + &state_count); + if (err) + return err; + assert (state_count == i386_FSGS_BASE_STATE_COUNT); + + return __thread_set_state (child, i386_FSGS_BASE_STATE, + (thread_state_t) &state, + state_count); +} + +static inline kern_return_t __attribute__ ((unused)) +_hurd_tls_new (thread_t child, tcbhead_t *tcb) +{ + struct i386_fsgs_base_state state; + + tcb->tcb = tcb; + tcb->self = child; + + /* Install the TCB address into FS base. */ + state.fs_base = (uintptr_t) tcb; + state.gs_base = 0; + return __thread_set_state (child, i386_FSGS_BASE_STATE, + (thread_state_t) &state, + i386_FSGS_BASE_STATE_COUNT); +} + +static inline bool __attribute__ ((unused)) +_hurd_tls_init (tcbhead_t *tcb) +{ + error_t err; + thread_t self = __mach_thread_self (); + + /* We always at least start the sigthread anyway. */ + tcb->multiple_threads = 1; + + err = _hurd_tls_new (self, tcb); + __mach_port_deallocate (__mach_task_self (), self); + __libc_tls_initialized = 1; + return err == 0; +} + + +/* Global scope switch support. */ +# define THREAD_GSCOPE_FLAG_UNUSED 0 +# define THREAD_GSCOPE_FLAG_USED 1 +# define THREAD_GSCOPE_FLAG_WAIT 2 + +# define THREAD_GSCOPE_SET_FLAG() \ + THREAD_SETMEM (THREAD_SELF, gscope_flag, THREAD_GSCOPE_FLAG_USED) + +# define THREAD_GSCOPE_RESET_FLAG() \ + ({ \ + int __flag; \ + asm volatile ("xchgl %0, %%fs:%P1" \ + : "=r" (__flag) \ + : "i" (offsetof (tcbhead_t, gscope_flag)), \ + "0" (THREAD_GSCOPE_FLAG_UNUSED)); \ + if (__flag == THREAD_GSCOPE_FLAG_WAIT) \ + lll_wake (THREAD_SELF->gscope_flag, LLL_PRIVATE); \ + }) + + + +#endif /* __ASSEMBLER__ */ +#endif /* x86_64/tls.h */ |