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Re: [RFC PATCH 02/10] C-SKY: TLS support
On 03/16/2018 03:58 AM, Mao Han wrote:
> This patch implements TLS support for C-SKY. We support all four
> standard TLS addressing modes (LE, IE, LD, and GD) when running on
> Linux via NPTL.
>
> *sysdeps/csky/dl-tls.h: New file
> *sysdeps/csky/libc-tls.c: New file
> *sysdeps/csky/nptl/tcb-offsets.sym: New file
> *sysdeps/csky/nptl/tls.h: New file
> *sysdeps/csky/stackinfo.h: New file
>
OK, fairly clean, was curious about stack guard and pointer guard support.
Others may have more to comment on this in libc-alpha.
> Signed-off-by: Mao Han <han_mao@c-sky.com>
> ---
> sysdeps/csky/dl-tls.h | 26 ++++++
> sysdeps/csky/libc-tls.c | 32 ++++++++
> sysdeps/csky/nptl/tcb-offsets.sym | 10 +++
> sysdeps/csky/nptl/tls.h | 169 ++++++++++++++++++++++++++++++++++++++
> sysdeps/csky/stackinfo.h | 32 ++++++++
> 5 files changed, 269 insertions(+)
> create mode 100644 sysdeps/csky/dl-tls.h
> create mode 100644 sysdeps/csky/libc-tls.c
> create mode 100644 sysdeps/csky/nptl/tcb-offsets.sym
> create mode 100644 sysdeps/csky/nptl/tls.h
> create mode 100644 sysdeps/csky/stackinfo.h
>
> diff --git a/sysdeps/csky/dl-tls.h b/sysdeps/csky/dl-tls.h
> new file mode 100644
> index 0000000..d44fc18
> --- /dev/null
> +++ b/sysdeps/csky/dl-tls.h
> @@ -0,0 +1,26 @@
> +/* Thread-local storage handling in the ELF dynamic linker. C-SKY version.
> + Copyright (C) 2018 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
> + <http://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;
> +
> +extern void *__tls_get_addr (tls_index *ti);
> diff --git a/sysdeps/csky/libc-tls.c b/sysdeps/csky/libc-tls.c
> new file mode 100644
> index 0000000..30baf62
> --- /dev/null
> +++ b/sysdeps/csky/libc-tls.c
> @@ -0,0 +1,32 @@
> +/* Thread-local storage handling in the ELF dynamic linker. C-SKY version.
> + Copyright (C) 2018 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
> + <http://www.gnu.org/licenses/>. */
> +
> +#include <csu/libc-tls.c>
> +#include <dl-tls.h>
> +
> +/* On C-SKY, 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 + ti->ti_offset;
> +}
> diff --git a/sysdeps/csky/nptl/tcb-offsets.sym b/sysdeps/csky/nptl/tcb-offsets.sym
> new file mode 100644
> index 0000000..bf9c0a1
> --- /dev/null
> +++ b/sysdeps/csky/nptl/tcb-offsets.sym
> @@ -0,0 +1,10 @@
> +#include <sysdep.h>
> +#include <tls.h>
> +
> +--
> +
> +-- Derive offsets relative to the thread register.
> +#define thread_offsetof(mem) (long)(offsetof(struct pthread, mem) - sizeof(struct pthread))
> +
> +MULTIPLE_THREADS_OFFSET thread_offsetof (header.multiple_threads)
> +TID_OFFSET thread_offsetof (tid)
> diff --git a/sysdeps/csky/nptl/tls.h b/sysdeps/csky/nptl/tls.h
> new file mode 100644
> index 0000000..69fadad
> --- /dev/null
> +++ b/sysdeps/csky/nptl/tls.h
> @@ -0,0 +1,169 @@
> +/* Definitions for thread-local data handling. NPTL/csky version.
> + Copyright (C) 2018 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
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef _TLS_H
> +#define _TLS_H 1
> +
> +#ifndef __ASSEMBLER__
> +
> +#include <stdbool.h>
> +#include <stddef.h>
> +#include <stdint.h>
> +#include <dl-dtv.h>
> +
> +#ifdef __CSKYABIV2__
> +/* define r31 as thread pointer register. */
> +#define READ_THREAD_POINTER() \
> + ({ void *__result; \
> + __asm__ __volatile__ ("mov %0, r31" \
> + : "=r" (__result)); \
> + __result; })
> +#else
> +#define READ_THREAD_POINTER() \
> + ({ register unsigned int __result __asm__("a0"); \
> + __asm__ __volatile__ ("trap 3;" \
> + : "=r" (__result) : : ); \
> + __result; })
> +#endif
> +
> +#else /* __ASSEMBLER__ */
> +#include <tcb-offsets.h>
> +#ifdef __CSKYABIV2__
> +/* define r31 as thread pointer register. */
> +#define READ_THREAD_POINTER() \
> + mov r0, r31;
> +#else
> +#define READ_THREAD_POINTER() \
> + trap 3;
> +#endif
> +#endif /* __ASSEMBLER__ */
> +
> +#ifndef __ASSEMBLER__
> +
> +/* 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;
Stack guard or pointer guard support?
> +} tcbhead_t;
> +
> +/* This is the size of the initial TCB. */
> +#define TLS_INIT_TCB_SIZE sizeof (tcbhead_t)
> +
> +/* Alignment requirements for the initial TCB. */
> +#define TLS_INIT_TCB_ALIGN 8
> +
> +/* This is the size of the TCB. */
> +#define TLS_TCB_SIZE sizeof (tcbhead_t)
> +
> +/* Alignment requirements for the TCB. */
> +#define TLS_TCB_ALIGN 8
> +
> +/* This is the size we need before TCB. */
> +#define TLS_PRE_TCB_SIZE sizeof (struct pthread)
> +
> +/* 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))->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))->dtv)
> +
> +#define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd) + 1
> +
> +/* 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(tcbp) \
> + ({ INTERNAL_SYSCALL_DECL (err); \
> + long result_var; \
> + result_var = INTERNAL_SYSCALL (set_thread_area, err, 1, \
> + (char *) (tcbp) + TLS_TCB_OFFSET); \
> + INTERNAL_SYSCALL_ERROR_P (result_var, err) \
> + ? "unknown error" : NULL; })
> +
> +/* Return the address of the dtv for the current thread. */
> +#define THREAD_DTV() \
> + (((tcbhead_t *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET))->dtv)
> +
> +/* Return the thread descriptor for the current thread. */
> +#undef THREAD_SELF
> +#define THREAD_SELF \
> + ((struct pthread *) (READ_THREAD_POINTER () \
> + - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
> +
> +/* Magic for libthread_db to know how to do THREAD_SELF. */
> +#define DB_THREAD_SELF \
> + CONST_THREAD_AREA (32, sizeof (struct pthread))
> +
> +/* Access to data in the thread descriptor is easy. */
> +#define THREAD_GETMEM(descr, member) \
> + descr->member
> +#define THREAD_GETMEM_NC(descr, member, idx) \
> + descr->member[idx]
> +#define THREAD_SETMEM(descr, member, value) \
> + descr->member = (value)
> +#define THREAD_SETMEM_NC(descr, member, idx, value) \
> + descr->member[idx] = (value)
> +
> +/* 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)
> +#define THREAD_GSCOPE_WAIT() \
> + GL(dl_wait_lookup_done) ()
> +
> +#endif /* __ASSEMBLER__ */
> +
> +#endif /* tls.h */
> diff --git a/sysdeps/csky/stackinfo.h b/sysdeps/csky/stackinfo.h
> new file mode 100644
> index 0000000..7b5eb65
> --- /dev/null
> +++ b/sysdeps/csky/stackinfo.h
> @@ -0,0 +1,32 @@
> +/* This file contains a bit of information about the stack allocation
> + of the processor. C-SKY version.
> + Copyright (C) 2018 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
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef _STACKINFO_H
> +#define _STACKINFO_H 1
> +
> +#include <elf.h>
> +
> +/* On C-SKY the stack grows down. */
> +#define _STACK_GROWS_DOWN 1
> +
> +/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> + * present, but it is presumed absent. */
> +#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +
> +#endif /* stackinfo.h */
>