Re: [PATCH v6 05/13] LoongArch: Thread-Local Storage Support

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


On 08/07/22 03:52, caiyinyu wrote:
> ---
>   sysdeps/loongarch/dl-tls.h             |  46 +++++++++
>   sysdeps/loongarch/libc-tls.c           |  32 ++++++
>   sysdeps/loongarch/nptl/tcb-offsets.sym |   6 ++
>   sysdeps/loongarch/nptl/tls.h           | 138 +++++++++++++++++++++++++
>   sysdeps/loongarch/stackinfo.h          |  33 ++++++
>   5 files changed, 255 insertions(+)
>   create mode 100644 sysdeps/loongarch/dl-tls.h
>   create mode 100644 sysdeps/loongarch/libc-tls.c
>   create mode 100644 sysdeps/loongarch/nptl/tcb-offsets.sym
>   create mode 100644 sysdeps/loongarch/nptl/tls.h
>   create mode 100644 sysdeps/loongarch/stackinfo.h
> 
> diff --git a/sysdeps/loongarch/dl-tls.h b/sysdeps/loongarch/dl-tls.h
> new file mode 100644
> index 0000000000..f82edcae76
> --- /dev/null
> +++ b/sysdeps/loongarch/dl-tls.h
> @@ -0,0 +1,46 @@
> +/* Thread-local storage handling in the ELF dynamic linker.
> +   Copyright (C) 2022 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/>.  */
> +
> +/* Type used for the representation of TLS information in the GOT.  */
> +typedef struct
> +{
> +  unsigned long int ti_module;
> +  unsigned long int ti_offset;
> +} tls_index;
> +
> +/* The thread pointer points to the first static TLS block.  */
> +#define TLS_TP_OFFSET 0
> +
> +/* Dynamic thread vector pointers point to the start of each
> +   TLS block.  */
> +#define TLS_DTV_OFFSET 0
> +
> +/* Compute the value for a GOTTPREL reloc.  */
> +#define TLS_TPREL_VALUE(sym_map, sym) \
> +  ((sym_map)->l_tls_offset + (sym)->st_value - TLS_TP_OFFSET)
> +
> +/* Compute the value for a DTPREL reloc.  */
> +#define TLS_DTPREL_VALUE(sym) ((sym)->st_value - TLS_DTV_OFFSET)
> +
> +extern void *__tls_get_addr (tls_index *ti);
> +
> +#define GET_ADDR_OFFSET (ti->ti_offset + TLS_DTV_OFFSET)
> +#define __TLS_GET_ADDR(__ti) (__tls_get_addr (__ti) - TLS_DTV_OFFSET)
> +
> +/* Value used for dtv entries for which the allocation is delayed.  */
> +#define TLS_DTV_UNALLOCATED ((void *) -1l)
> diff --git a/sysdeps/loongarch/libc-tls.c b/sysdeps/loongarch/libc-tls.c
> new file mode 100644
> index 0000000000..9285d11a7b
> --- /dev/null
> +++ b/sysdeps/loongarch/libc-tls.c
> @@ -0,0 +1,32 @@
> +/* Thread-local storage handling in the ELF dynamic linker.
> +   Copyright (C) 2022 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/>.  */
> +
> +#include <csu/libc-tls.c>
> +#include <dl-tls.h>
> +
> +/* On LoongArch, linker optimizations are not required, so __tls_get_addr
> +   can be called even in statically linked binaries.  In this case module
> +   must be always 1 and PT_TLS segment exist in the binary, otherwise it
> +   would not link.  */
> +
> +void *
> +__tls_get_addr (tls_index *ti)
> +{
> +  dtv_t *dtv = THREAD_DTV ();
> +  return (char *) dtv[1].pointer.val + GET_ADDR_OFFSET;
> +}
> diff --git a/sysdeps/loongarch/nptl/tcb-offsets.sym b/sysdeps/loongarch/nptl/tcb-offsets.sym
> new file mode 100644
> index 0000000000..7d0c7596e8
> --- /dev/null
> +++ b/sysdeps/loongarch/nptl/tcb-offsets.sym
> @@ -0,0 +1,6 @@
> +#include <sysdep.h>
> +#include <tls.h>
> +
> +#define thread_offsetof(mem)  (long)(offsetof (struct pthread, mem) - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE)
> +
> +MULTIPLE_THREADS_OFFSET		thread_offsetof (header.multiple_threads)
> diff --git a/sysdeps/loongarch/nptl/tls.h b/sysdeps/loongarch/nptl/tls.h
> new file mode 100644
> index 0000000000..f77265ae52
> --- /dev/null
> +++ b/sysdeps/loongarch/nptl/tls.h
> @@ -0,0 +1,138 @@
> +/* Definition for thread-local data handling.
> +   Copyright (C) 2022 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 _LOONGARCH_TLS_H
> +#define _LOONGARCH_TLS_H 1
> +
> +#include <dl-sysdep.h>
> +
> +#ifndef __ASSEMBLER__
> +#include <stdbool.h>
> +#include <stddef.h>
> +#include <stdint.h>
> +#include <dl-dtv.h>
> +
> +register void *__thread_self asm("$tp");
> +#define READ_THREAD_POINTER() ({ __thread_self; })
> +
> +/* Get system call information.  */
> +#include <sysdep.h>
> +
> +/* The TP points to the start of the thread blocks.  */
> +#define TLS_DTV_AT_TP 1
> +#define TLS_TCB_AT_TP 0
> +
> +/* Get the thread descriptor definition.  */
> +#include <nptl/descr.h>
> +
> +typedef struct
> +{
> +  dtv_t *dtv;
> +  void *private;
> +} tcbhead_t;
> +
> +/* This is the size of the initial TCB.  Because our TCB is before the thread
> +   pointer, we don't need this.  */
> +#define TLS_INIT_TCB_SIZE 0
> +
> +/* Alignment requirements for the initial TCB.  */
> +#define TLS_INIT_TCB_ALIGN __alignof__(struct pthread)
> +
> +/* This is the size of the TCB.  Because our TCB is before the thread
> +   pointer, we don't need this.  */
> +#define TLS_TCB_SIZE 0
> +
> +/* Alignment requirements for the TCB.  */
> +#define TLS_TCB_ALIGN __alignof__(struct pthread)
> +
> +/* This is the size we need before TCB - actually, it includes the TCB.  */
> +#define TLS_PRE_TCB_SIZE \
> +  (sizeof (struct pthread) \
> +   + ((sizeof (tcbhead_t) + TLS_TCB_ALIGN - 1) & ~(TLS_TCB_ALIGN - 1)))
> +
> +/* The thread pointer tp points to the end of the TCB.
> +   The pthread_descr structure is immediately in front of the TCB.  */
> +#define TLS_TCB_OFFSET 0
> +
> +/* Install the dtv pointer.  The pointer passed is to the element with
> +   index -1 which contain the length.  */
> +#define INSTALL_DTV(tcbp, dtvp) (((tcbhead_t *) (tcbp))[-1].dtv = (dtvp) + 1)
> +
> +/* Install new dtv for current thread.  */
> +#define INSTALL_NEW_DTV(dtv) (THREAD_DTV () = (dtv))
> +
> +/* Return dtv of given thread descriptor.  */
> +#define GET_DTV(tcbp) (((tcbhead_t *) (tcbp))[-1].dtv)
> +
> +/* Code to initially initialize the thread pointer.  */
> +#define TLS_INIT_TP(tcbp) \
> +  ({ \
> +    __thread_self = (char *) tcbp + TLS_TCB_OFFSET; \
> +    NULL; \
> +  })
> +
> +/* Return the address of the dtv for the current thread.  */
> +#define THREAD_DTV() \
> +  (((tcbhead_t *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET))[-1].dtv)
> +
> +/* Return the thread descriptor for the current thread.  */
> +#define THREAD_SELF \
> +  ((struct pthread *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET \
> +		       - TLS_PRE_TCB_SIZE))
> +
> +/* Value passed to 'clone' for initialization of the thread register.  */
> +#define TLS_DEFINE_INIT_TP(tp, pd) \
> +  void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE
> +
> +/* Informs libthread_db that the thread pointer is register 2, which is used
> + * to know how to do THREAD_SELF.  */
> +#define DB_THREAD_SELF \
> +  REGISTER (64, 64, 2 * 8, -TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE)
> +
> +/* Access to data in the thread descriptor is easy.  */
> +# include <tcb-access.h>
> +
> +/* l_tls_offset == 0 is perfectly valid, so we have to use some different
> +   value to mean unset l_tls_offset.  */
> +#define NO_TLS_OFFSET -1
> +
> +/* Get and set the global scope generation counter in struct pthread.  */
> +#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 = atomic_exchange_rel (&THREAD_SELF->header.gscope_flag, \
> +				       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() \
> +  do \
> +    { \
> +      THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED; \
> +      atomic_write_barrier (); \
> +    } \
> +  while (0)
> +
> +#endif /* __ASSEMBLER__ */
> +
> +#endif /* tls.h */
> diff --git a/sysdeps/loongarch/stackinfo.h b/sysdeps/loongarch/stackinfo.h
> new file mode 100644
> index 0000000000..ff8b9b7bf2
> --- /dev/null
> +++ b/sysdeps/loongarch/stackinfo.h
> @@ -0,0 +1,33 @@
> +/* Stack environment definitions for LoongArch.
> +   Copyright (C) 2022 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/>.  */
> +
> +/* This file contains a bit of information about the stack allocation
> +   of the processor.  */
> +
> +#ifndef _STACKINFO_H
> +#define _STACKINFO_H 1
> +
> +#include <elf.h>
> +
> +/* On LoongArch the stack grows down.  */
> +#define _STACK_GROWS_DOWN 1
> +
> +/* Default to a non-executable stack.  */
> +#define DEFAULT_STACK_PERMS (PF_R | PF_W)
> +
> +#endif /* stackinfo.h */