[RFA] x86-64-linux-nat.c cleanup

[RFA] x86-64-linux-nat.c cleanup

[Michal Ludvig]

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Hi all,
because x86-64 ptrace() now conforms to standards, I removed our 
versions of child_resume and child_xfer_memory from x86-64-linux.nat.c 
and started to use those from infptrace.c. This is an obvious change, 
but quite large, so I'm sending it for approval first.
So, can I commit?

Michal Ludvig
-- 
* SuSE CR, s.r.o     * mludvig@suse.cz
* +420 2 9654 5373   * http://www.suse.cz

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Index: x86-64-linux-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/x86-64-linux-nat.c,v
retrieving revision 1.8
diff -c -3 -p -r1.8 x86-64-linux-nat.c
*** x86-64-linux-nat.c	4 Apr 2002 13:18:59 -0000	1.8
--- x86-64-linux-nat.c	9 Apr 2002 19:52:17 -0000
*************** x86_64_linux_dr_get_status (void)
*** 128,135 ****
    (0 <= (regno) && (regno) < x86_64_num_gregs)
  #define GETFPREGS_SUPPLIES(regno) \
    (FP0_REGNUM <= (regno) && (regno) <= MXCSR_REGNUM)
- 
- #define PTRACE_XFER_TYPE unsigned long
  \f
  
  /* Transfering the general-purpose registers between GDB, inferiors
--- 128,133 ----
*************** static const unsigned char linux_syscall
*** 344,507 ****
  /* Offset to saved processor registers from <asm/ucontext.h> */
  #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36)
  
- /* Resume execution of the inferior process.
-    If STEP is nonzero, single-step it.
-    If SIGNAL is nonzero, give it that signal.  */
- 
- void
- child_resume (ptid_t ptid, int step, enum target_signal signal)
- {
-   int pid = PIDGET (ptid);
-   int request = PTRACE_CONT;
- 
-   if (pid == -1)
-     /* Resume all threads.  */
-     /* I think this only gets used in the non-threaded case, where "resume
-        all threads" and "resume inferior_ptid" are the same.  */
-     pid = PIDGET (inferior_ptid);
- 
-   if (step)
-     {
-       CORE_ADDR pc = read_pc_pid (pid_to_ptid (pid));
-       unsigned char buf[LINUX_SYSCALL_LEN];
- 
-       request = PTRACE_SINGLESTEP;
- 
-       /* Returning from a signal trampoline is done by calling a
-          special system call (sigreturn or rt_sigreturn, see
-          i386-linux-tdep.c for more information).  This system call
-          restores the registers that were saved when the signal was
-          raised, including %eflags.  That means that single-stepping
-          won't work.  Instead, we'll have to modify the signal context
-          that's about to be restored, and set the trace flag there.  */
- 
-       /* First check if PC is at a system call.  */
-       if (read_memory_nobpt (pc, (char *) buf, LINUX_SYSCALL_LEN) == 0
- 	  && memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0)
- 	{
- 	  int syscall =
- 	    read_register_pid (LINUX_SYSCALL_REGNUM, pid_to_ptid (pid));
- 
- 	  /* Then check the system call number.  */
- 	  if (syscall == SYS_rt_sigreturn)
- 	    {
- 	      CORE_ADDR sp = read_register (SP_REGNUM);
- 	      CORE_ADDR addr = sp;
- 	      unsigned long int eflags;
- 
- 	      addr +=
- 		sizeof (struct siginfo) + LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
- 
- 	      /* Set the trace flag in the context that's about to be
- 	         restored.  */
- 	      addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET;
- 	      read_memory (addr, (char *) &eflags, 8);
- 	      eflags |= 0x0100;
- 	      write_memory (addr, (char *) &eflags, 8);
- 	    }
- 	}
-     }
- 
-   if (ptrace (request, pid, 0, target_signal_to_host (signal)) == -1)
-     perror_with_name ("ptrace");
- }
- \f
- 
- /* Copy LEN bytes to or from inferior's memory starting at MEMADDR
-    to debugger memory starting at MYADDR.   Copy to inferior if
-    WRITE is nonzero.  TARGET is ignored.
- 
-    Returns the length copied, which is either the LEN argument or zero.
-    This xfer function does not do partial moves, since child_ops
-    doesn't allow memory operations to cross below us in the target stack
-    anyway.  */
- 
- int
- child_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
- 		   struct mem_attrib *attrib, struct target_ops *target)
- {
-   register int i;
-   /* Round starting address down to longword boundary.  */
-   register CORE_ADDR addr = memaddr & -sizeof (PTRACE_XFER_TYPE);
-   /* Round ending address up; get number of longwords that makes.  */
-   register int count
-     = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
-     / sizeof (PTRACE_XFER_TYPE);
-   /* Allocate buffer of that many longwords.  */
-   /* FIXME (alloca): This code, cloned from infptrace.c, is unsafe
-      because it uses alloca to allocate a buffer of arbitrary size.
-      For very large xfers, this could crash GDB's stack.  */
-   register PTRACE_XFER_TYPE *buffer
-     = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
- 
-   if (write)
-     {
-       /* Fill start and end extra bytes of buffer with existing memory data.  */
-       if (addr != memaddr || len < (int) sizeof (PTRACE_XFER_TYPE))
- 	{
- 	  /* Need part of initial word -- fetch it.  */
- 	  buffer[0] = ptrace (PT_READ_I, PIDGET (inferior_ptid),
- 			      (PTRACE_ARG3_TYPE) addr, 0);
- 	}
- 
-       if (count > 1)		/* FIXME, avoid if even boundary */
- 	{
- 	  buffer[count - 1] = ptrace (PT_READ_I, PIDGET (inferior_ptid),
- 				      ((PTRACE_ARG3_TYPE)
- 				       (addr +
- 					(count -
- 					 1) * sizeof (PTRACE_XFER_TYPE))), 0);
- 	}
- 
-       /* Copy data to be written over corresponding part of buffer */
- 
-       memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
- 	      myaddr, len);
- 
-       /* Write the entire buffer.  */
- 
-       for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
- 	{
- 	  errno = 0;
- 	  ptrace (PT_WRITE_D, PIDGET (inferior_ptid),
- 		  (PTRACE_ARG3_TYPE) addr, buffer[i]);
- 	  if (errno)
- 	    {
- 	      /* Using the appropriate one (I or D) is necessary for
- 	         Gould NP1, at least.  */
- 	      errno = 0;
- 	      ptrace (PT_WRITE_I, PIDGET (inferior_ptid),
- 		      (PTRACE_ARG3_TYPE) addr, buffer[i]);
- 	    }
- 	  if (errno)
- 	    return 0;
- 	}
- #ifdef CLEAR_INSN_CACHE
-       CLEAR_INSN_CACHE ();
- #endif
-     }
-   else
-     {
-       /* Read all the longwords */
-       for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
- 	{
- 	  errno = 0;
- 	  buffer[i] = ptrace (PT_READ_I, PIDGET (inferior_ptid),
- 			      (PTRACE_ARG3_TYPE) addr, 0);
- 	  if (errno)
- 	    return 0;
- 	}
- 
-       /* Copy appropriate bytes out of the buffer.  */
-       memcpy (myaddr,
- 	      (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
- 	      len);
-     }
-   return len;
- }
- 
  /* Interpreting register set info found in core files.  */
- 
  /* Provide registers to GDB from a core file.
  
     CORE_REG_SECT points to an array of bytes, which are the contents
--- 342,348 ----
Index: config/i386/nm-x86-64.h
===================================================================
RCS file: /cvs/src/src/gdb/config/i386/nm-x86-64.h,v
retrieving revision 1.3
diff -c -3 -p -r1.3 nm-x86-64.h
*** config/i386/nm-x86-64.h	24 Feb 2002 22:56:05 -0000	1.3
--- config/i386/nm-x86-64.h	9 Apr 2002 19:52:17 -0000
*************** extern int kernel_u_size (void);
*** 65,74 ****
     to get the offset in the core file of the register values.  */
  #define KERNEL_U_ADDR 0x0
  
- /* FIXME use special child_xfer_memory.  */
- #define CHILD_XFER_MEMORY
- 
  #define PTRACE_ARG3_TYPE void*
  \f
  
  /* We define this if link.h is available, because with ELF we use SVR4 style
--- 65,72 ----
     to get the offset in the core file of the register values.  */
  #define KERNEL_U_ADDR 0x0
  
  #define PTRACE_ARG3_TYPE void*
+ #define PTRACE_XFER_TYPE unsigned long
  \f
  
  /* We define this if link.h is available, because with ELF we use SVR4 style
*************** extern int kernel_u_size (void);
*** 81,89 ****
  
  /* Override copies of {fetch,store}_inferior_registers in `infptrace.c'.  */
  #define FETCH_INFERIOR_REGISTERS
- 
- /* Override child_resume in `infptrace.c'.  */
- #define CHILD_RESUME
  
  #undef PREPARE_TO_PROCEED
  
--- 79,84 ----

Re: [RFA] x86-64-linux-nat.c cleanup

[Michal Ludvig]

Oops, sorry, I forgot to include the ChangeLog (it's too late :-)

2002-04-09  Michal Ludvig  <mludvig@suse.cz>

         * x86-64-linux-nat.c (child_resume, child_xfer_memory): Delete.
         (PTRACE_XFER_TYPE): Moved to config/i386/nm-x86-64.h.
         * config/i386/nm-x86-64.h (CHILD_XFER_MEMORY, CHILD_RESUME):
	Delete.
         (PTRACE_XFER_TYPE): Moved here from config/i386/nm-x86-64.h.

-- ML

Michal Ludvig wrote:
> Hi all,
> because x86-64 ptrace() now conforms to standards, I removed our 
> versions of child_resume and child_xfer_memory from x86-64-linux.nat.c 
> and started to use those from infptrace.c. This is an obvious change, 
> but quite large, so I'm sending it for approval first.
> So, can I commit?
> 
> Michal Ludvig
> 
> 
> ------------------------------------------------------------------------
> 
> Index: x86-64-linux-nat.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/x86-64-linux-nat.c,v
> retrieving revision 1.8
> diff -c -3 -p -r1.8 x86-64-linux-nat.c
> *** x86-64-linux-nat.c	4 Apr 2002 13:18:59 -0000	1.8
> --- x86-64-linux-nat.c	9 Apr 2002 19:52:17 -0000
> *************** x86_64_linux_dr_get_status (void)
> *** 128,135 ****
>     (0 <= (regno) && (regno) < x86_64_num_gregs)
>   #define GETFPREGS_SUPPLIES(regno) \
>     (FP0_REGNUM <= (regno) && (regno) <= MXCSR_REGNUM)
> - 
> - #define PTRACE_XFER_TYPE unsigned long
>   \f
>   
>   /* Transfering the general-purpose registers between GDB, inferiors
> --- 128,133 ----
> *************** static const unsigned char linux_syscall
> *** 344,507 ****
>   /* Offset to saved processor registers from <asm/ucontext.h> */
>   #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36)
>   
> - /* Resume execution of the inferior process.
> -    If STEP is nonzero, single-step it.
> -    If SIGNAL is nonzero, give it that signal.  */
> - 
> - void
> - child_resume (ptid_t ptid, int step, enum target_signal signal)
> - {
> -   int pid = PIDGET (ptid);
> -   int request = PTRACE_CONT;
> - 
> -   if (pid == -1)
> -     /* Resume all threads.  */
> -     /* I think this only gets used in the non-threaded case, where "resume
> -        all threads" and "resume inferior_ptid" are the same.  */
> -     pid = PIDGET (inferior_ptid);
> - 
> -   if (step)
> -     {
> -       CORE_ADDR pc = read_pc_pid (pid_to_ptid (pid));
> -       unsigned char buf[LINUX_SYSCALL_LEN];
> - 
> -       request = PTRACE_SINGLESTEP;
> - 
> -       /* Returning from a signal trampoline is done by calling a
> -          special system call (sigreturn or rt_sigreturn, see
> -          i386-linux-tdep.c for more information).  This system call
> -          restores the registers that were saved when the signal was
> -          raised, including %eflags.  That means that single-stepping
> -          won't work.  Instead, we'll have to modify the signal context
> -          that's about to be restored, and set the trace flag there.  */
> - 
> -       /* First check if PC is at a system call.  */
> -       if (read_memory_nobpt (pc, (char *) buf, LINUX_SYSCALL_LEN) == 0
> - 	  && memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0)
> - 	{
> - 	  int syscall =
> - 	    read_register_pid (LINUX_SYSCALL_REGNUM, pid_to_ptid (pid));
> - 
> - 	  /* Then check the system call number.  */
> - 	  if (syscall == SYS_rt_sigreturn)
> - 	    {
> - 	      CORE_ADDR sp = read_register (SP_REGNUM);
> - 	      CORE_ADDR addr = sp;
> - 	      unsigned long int eflags;
> - 
> - 	      addr +=
> - 		sizeof (struct siginfo) + LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
> - 
> - 	      /* Set the trace flag in the context that's about to be
> - 	         restored.  */
> - 	      addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET;
> - 	      read_memory (addr, (char *) &eflags, 8);
> - 	      eflags |= 0x0100;
> - 	      write_memory (addr, (char *) &eflags, 8);
> - 	    }
> - 	}
> -     }
> - 
> -   if (ptrace (request, pid, 0, target_signal_to_host (signal)) == -1)
> -     perror_with_name ("ptrace");
> - }
> - \f
> - 
> - /* Copy LEN bytes to or from inferior's memory starting at MEMADDR
> -    to debugger memory starting at MYADDR.   Copy to inferior if
> -    WRITE is nonzero.  TARGET is ignored.
> - 
> -    Returns the length copied, which is either the LEN argument or zero.
> -    This xfer function does not do partial moves, since child_ops
> -    doesn't allow memory operations to cross below us in the target stack
> -    anyway.  */
> - 
> - int
> - child_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
> - 		   struct mem_attrib *attrib, struct target_ops *target)
> - {
> -   register int i;
> -   /* Round starting address down to longword boundary.  */
> -   register CORE_ADDR addr = memaddr & -sizeof (PTRACE_XFER_TYPE);
> -   /* Round ending address up; get number of longwords that makes.  */
> -   register int count
> -     = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
> -     / sizeof (PTRACE_XFER_TYPE);
> -   /* Allocate buffer of that many longwords.  */
> -   /* FIXME (alloca): This code, cloned from infptrace.c, is unsafe
> -      because it uses alloca to allocate a buffer of arbitrary size.
> -      For very large xfers, this could crash GDB's stack.  */
> -   register PTRACE_XFER_TYPE *buffer
> -     = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
> - 
> -   if (write)
> -     {
> -       /* Fill start and end extra bytes of buffer with existing memory data.  */
> -       if (addr != memaddr || len < (int) sizeof (PTRACE_XFER_TYPE))
> - 	{
> - 	  /* Need part of initial word -- fetch it.  */
> - 	  buffer[0] = ptrace (PT_READ_I, PIDGET (inferior_ptid),
> - 			      (PTRACE_ARG3_TYPE) addr, 0);
> - 	}
> - 
> -       if (count > 1)		/* FIXME, avoid if even boundary */
> - 	{
> - 	  buffer[count - 1] = ptrace (PT_READ_I, PIDGET (inferior_ptid),
> - 				      ((PTRACE_ARG3_TYPE)
> - 				       (addr +
> - 					(count -
> - 					 1) * sizeof (PTRACE_XFER_TYPE))), 0);
> - 	}
> - 
> -       /* Copy data to be written over corresponding part of buffer */
> - 
> -       memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
> - 	      myaddr, len);
> - 
> -       /* Write the entire buffer.  */
> - 
> -       for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
> - 	{
> - 	  errno = 0;
> - 	  ptrace (PT_WRITE_D, PIDGET (inferior_ptid),
> - 		  (PTRACE_ARG3_TYPE) addr, buffer[i]);
> - 	  if (errno)
> - 	    {
> - 	      /* Using the appropriate one (I or D) is necessary for
> - 	         Gould NP1, at least.  */
> - 	      errno = 0;
> - 	      ptrace (PT_WRITE_I, PIDGET (inferior_ptid),
> - 		      (PTRACE_ARG3_TYPE) addr, buffer[i]);
> - 	    }
> - 	  if (errno)
> - 	    return 0;
> - 	}
> - #ifdef CLEAR_INSN_CACHE
> -       CLEAR_INSN_CACHE ();
> - #endif
> -     }
> -   else
> -     {
> -       /* Read all the longwords */
> -       for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
> - 	{
> - 	  errno = 0;
> - 	  buffer[i] = ptrace (PT_READ_I, PIDGET (inferior_ptid),
> - 			      (PTRACE_ARG3_TYPE) addr, 0);
> - 	  if (errno)
> - 	    return 0;
> - 	}
> - 
> -       /* Copy appropriate bytes out of the buffer.  */
> -       memcpy (myaddr,
> - 	      (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
> - 	      len);
> -     }
> -   return len;
> - }
> - 
>   /* Interpreting register set info found in core files.  */
> - 
>   /* Provide registers to GDB from a core file.
>   
>      CORE_REG_SECT points to an array of bytes, which are the contents
> --- 342,348 ----
> Index: config/i386/nm-x86-64.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/config/i386/nm-x86-64.h,v
> retrieving revision 1.3
> diff -c -3 -p -r1.3 nm-x86-64.h
> *** config/i386/nm-x86-64.h	24 Feb 2002 22:56:05 -0000	1.3
> --- config/i386/nm-x86-64.h	9 Apr 2002 19:52:17 -0000
> *************** extern int kernel_u_size (void);
> *** 65,74 ****
>      to get the offset in the core file of the register values.  */
>   #define KERNEL_U_ADDR 0x0
>   
> - /* FIXME use special child_xfer_memory.  */
> - #define CHILD_XFER_MEMORY
> - 
>   #define PTRACE_ARG3_TYPE void*
>   \f
>   
>   /* We define this if link.h is available, because with ELF we use SVR4 style
> --- 65,72 ----
>      to get the offset in the core file of the register values.  */
>   #define KERNEL_U_ADDR 0x0
>   
>   #define PTRACE_ARG3_TYPE void*
> + #define PTRACE_XFER_TYPE unsigned long
>   \f
>   
>   /* We define this if link.h is available, because with ELF we use SVR4 style
> *************** extern int kernel_u_size (void);
> *** 81,89 ****
>   
>   /* Override copies of {fetch,store}_inferior_registers in `infptrace.c'.  */
>   #define FETCH_INFERIOR_REGISTERS
> - 
> - /* Override child_resume in `infptrace.c'.  */
> - #define CHILD_RESUME
>   
>   #undef PREPARE_TO_PROCEED
>   
> --- 79,84 ----

Re: [RFA] x86-64-linux-nat.c cleanup

[Andrew Cagney]

> Hi all,
> because x86-64 ptrace() now conforms to standards, I removed our versions of child_resume and child_xfer_memory from x86-64-linux.nat.c and started to use those from infptrace.c. This is an obvious change, but quite large, so I'm sending it for approval first.
> So, can I commit?
> 
> Michal Ludvig 

Yes, 5.2 branch if you think it helps as well.

Andrew