Re: [PATCH 04/10] mach: Add __mach_setup_thread_call ()

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev via Libc-alpha, le mer. 17 mai 2023 22:14:30 +0300, a ecrit:
> This is just like mach_setup_thread (), but it's suitable for making the
> thread call a function correctly, as opposed to explicitly setting the
> thread's stack and instruction pointers to the given values. Internally,
> it uses MACHINE_THREAD_STATE_SETUP_CALL.
> 
> Unlike mach_setup_thread (), which is exported via mach.h for the
> benefit of the Hurd exec server, __mach_setup_thread_call () is private
> to glibc for the time being.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  mach/mach.h         |  6 +++++-
>  mach/setup-thread.c | 52 ++++++++++++++++++++++++++++++++-------------
>  mach/setup-thread.h | 32 ++++++++++++++++++++++++++++
>  3 files changed, 74 insertions(+), 16 deletions(-)
>  create mode 100644 mach/setup-thread.h
> 
> diff --git a/mach/mach.h b/mach/mach.h
> index d115f5a1..348f0196 100644
> --- a/mach/mach.h
> +++ b/mach/mach.h
> @@ -88,7 +88,11 @@ extern FILE *mach_open_devstream (mach_port_t device_port, 
> const char *mode);
>     If STACK_BASE is not null it is filled in with the chosen stack base.
>     If STACK_SIZE is not null it is filled in with the chosen stack size.
>     Regardless, an extra page of red zone is allocated off the end; this
> -   is not included in *STACK_SIZE.  */
> +   is not included in *STACK_SIZE.
> +
> +   Mote: this function is unsuitable for setting up the thread to call a
> +   function at PC, since the architecture ABI may impose additional
> +   requirements beyond setting PC and stack.  */
>  kern_return_t __mach_setup_thread (task_t task, thread_t thread, void *pc,
>                                  vm_address_t *stack_base,
>                                  vm_size_t *stack_size);
> diff --git a/mach/setup-thread.c b/mach/setup-thread.c
> index ae24a149..0e149787 100644
> --- a/mach/setup-thread.c
> +++ b/mach/setup-thread.c
> @@ -16,6 +16,7 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <mach.h>
> +#include <mach/setup-thread.h>
>  #include <thread_state.h>
>  #include <string.h>
>  #include <mach/machine/vm_param.h>
> @@ -24,17 +25,10 @@
>  
>  #define      STACK_SIZE      (16 * 1024 * 1024) /* 16MB, arbitrary.  */
>  
> -/* Give THREAD a stack and set it to run at PC when resumed.
> -   If *STACK_SIZE is nonzero, that size of stack is allocated.
> -   If *STACK_BASE is nonzero, that stack location is used.
> -   If STACK_BASE is not null it is filled in with the chosen stack base.
> -   If STACK_SIZE is not null it is filled in with the chosen stack size.
> -   Regardless, an extra page of red zone is allocated off the end; this
> -   is not included in *STACK_SIZE.  */
> -
> -kern_return_t
> -__mach_setup_thread (task_t task, thread_t thread, void *pc,
> -                  vm_address_t *stack_base, vm_size_t *stack_size)
> +static kern_return_t
> +mach_setup_thread_impl (task_t task, thread_t thread, int is_call,
> +                     void *pc, vm_address_t *stack_base,
> +                     vm_size_t *stack_size)
>  {
>    kern_return_t error;
>    struct machine_thread_state ts;
> @@ -43,6 +37,8 @@ __mach_setup_thread (task_t task, thread_t thread, void *pc,
>    vm_size_t size;
>    int anywhere;
>  
> +  memset (&ts, 0, sizeof (ts));
> +
>    size = stack_size ? *stack_size ? : STACK_SIZE : STACK_SIZE;
>    stack = stack_base ? *stack_base ? : 0 : 0;
>    anywhere = !stack_base || !*stack_base;
> @@ -54,21 +50,25 @@ __mach_setup_thread (task_t task, thread_t thread, void 
> *pc,
>    if (stack_size)
>      *stack_size = size;
>  
> -  memset (&ts, 0, sizeof (ts));
> -  MACHINE_THREAD_STATE_SET_PC (&ts, pc);
>  #ifdef STACK_GROWTH_DOWN
>    if (stack_base)
>      *stack_base = stack + __vm_page_size;
> -  ts.SP = stack + __vm_page_size + size;
>  #elif defined (STACK_GROWTH_UP)
>    if (stack_base)
>      *stack_base = stack;
> -  ts.SP = stack;
>    stack += size;
>  #else
>    #error stack direction unknown
>  #endif
>  
> +  if (is_call)
> +    MACHINE_THREAD_STATE_SETUP_CALL (&ts, *stack_base, size, pc);
> +  else
> +    {
> +      MACHINE_THREAD_STATE_SET_PC (&ts, pc);
> +      MACHINE_THREAD_STATE_SET_SP (&ts, *stack_base, size);
> +    }
> +
>    /* Create the red zone.  */
>    if (error = __vm_protect (task, stack, __vm_page_size, 0, VM_PROT_NONE))
>      return error;
> @@ -77,8 +77,30 @@ __mach_setup_thread (task_t task, thread_t thread, void 
> *pc,
>                            (natural_t *) &ts, tssize);
>  }
>  
> +/* Give THREAD a stack and set it to run at PC when resumed.
> +   If *STACK_SIZE is nonzero, that size of stack is allocated.
> +   If *STACK_BASE is nonzero, that stack location is used.
> +   If STACK_BASE is not null it is filled in with the chosen stack base.
> +   If STACK_SIZE is not null it is filled in with the chosen stack size.
> +   Regardless, an extra page of red zone is allocated off the end; this
> +   is not included in *STACK_SIZE.  */
> +
> +kern_return_t
> +__mach_setup_thread (task_t task, thread_t thread, void *pc,
> +                  vm_address_t *stack_base, vm_size_t *stack_size)
> +{
> +  return mach_setup_thread_impl (task, thread, 0, pc, stack_base, 
> stack_size);
> +}
> +
>  weak_alias (__mach_setup_thread, mach_setup_thread)
>  
> +kern_return_t
> +__mach_setup_thread_call (task_t task, thread_t thread, void *pc,
> +                       vm_address_t *stack_base, vm_size_t *stack_size)
> +{
> +  return mach_setup_thread_impl (task, thread, 1, pc, stack_base, 
> stack_size);
> +}
> +
>  /* Give THREAD a TLS area.  */
>  kern_return_t
>  __mach_setup_tls (thread_t thread)
> diff --git a/mach/setup-thread.h b/mach/setup-thread.h
> new file mode 100644
> index 00000000..b4c94d1d
> --- /dev/null
> +++ b/mach/setup-thread.h
> @@ -0,0 +1,32 @@
> +/* Setup a Mach thread.
> +   Copyright (C) 1993-2023 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      _MACH_SETUP_THREAD_H
> +
> +#define      _MACH_SETUP_THREAD_H    1
> +
> +#include <mach.h>
> +
> +/* Like mach_setup_thread (), but suitable for setting up function
> +   calls.  */
> +kern_return_t __mach_setup_thread_call (task_t task, thread_t thread,
> +                                     void *function,
> +                                     vm_address_t *stack_base,
> +                                     vm_size_t *stack_size);
> +
> +#endif       /* mach/setup-thread.h */
> -- 
> 2.40.1
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.