Re: PATCH: Support x32 siginfo_t conversion

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

> Date: Fri, 11 May 2012 12:21:33 -0700
> From: "H.J. Lu" <hongjiu.lu@intel.com>
> 
> Hi,
> 
> This patch implements x32 siginfo_t conversion.  Tested on Linux/x86-64.
> OK to install?
> 
> Thanks.
> 
> 
> H.J.
> --
> 	* amd64-linux-nat.c (compat_x32_clock_t): New.
> 	(compat_x32_siginfo_t): Likewise.
> 	(compat_x32_siginfo_from_siginfo): Likewise.
> 	(siginfo_from_compat_x32_siginfo): Likewise.
> 	(amd64_linux_siginfo_fixup): Call compat_x32_siginfo_from_siginfo
> 	and siginfo_from_compat_x32_siginfo for x32.
> 
> diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
> index 3be8404..97c9a49 100644
> --- a/gdb/amd64-linux-nat.c
> +++ b/gdb/amd64-linux-nat.c
> @@ -591,6 +591,67 @@ typedef struct compat_siginfo
>    } _sifields;
>  } compat_siginfo_t;
>  
> +/* For x32, clock_t in _sigchld is 64bit aligned at 4 bytes.  */
> +typedef long __attribute__ ((__aligned__ (4))) compat_x32_clock_t;

Sorry, but that isn't acceptable.

Is your X32 ABI really that broken?

> +typedef struct compat_x32_siginfo
> +{
> +  int si_signo;
> +  int si_errno;
> +  int si_code;
> +
> +  union
> +  {
> +    int _pad[((128 / sizeof (int)) - 3)];
> +
> +    /* kill() */
> +    struct
> +    {
> +      unsigned int _pid;
> +      unsigned int _uid;
> +    } _kill;
> +
> +    /* POSIX.1b timers */
> +    struct
> +    {
> +      compat_timer_t _tid;
> +      int _overrun;
> +      compat_sigval_t _sigval;
> +    } _timer;
> +
> +    /* POSIX.1b signals */
> +    struct
> +    {
> +      unsigned int _pid;
> +      unsigned int _uid;
> +      compat_sigval_t _sigval;
> +    } _rt;
> +
> +    /* SIGCHLD */
> +    struct
> +    {
> +      unsigned int _pid;
> +      unsigned int _uid;
> +      int _status;
> +      compat_x32_clock_t _utime;
> +      compat_x32_clock_t _stime;
> +    } _sigchld;
> +
> +    /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
> +    struct
> +    {
> +      unsigned int _addr;
> +    } _sigfault;
> +
> +    /* SIGPOLL */
> +    struct
> +    {
> +      int _band;
> +      int _fd;
> +    } _sigpoll;
> +  } _sifields;
> +} compat_x32_siginfo_t __attribute__ ((__aligned__ (8)));

Same here.  I don't think you need alignment here, even with the broken ABI.

If it really is too late to fix the X32 ABI, you'll have to write this
portably by splitting _utime and _stime into two 32-bit variables and
write code that correctly sets the upper and lower 32-bits.



> +
>  #define cpt_si_pid _sifields._kill._pid
>  #define cpt_si_uid _sifields._kill._uid
>  #define cpt_si_timerid _sifields._timer._tid
> @@ -724,6 +785,120 @@ siginfo_from_compat_siginfo (siginfo_t *to, compat_siginfo_t *from)
>      }
>  }
>  
> +static void
> +compat_x32_siginfo_from_siginfo (compat_x32_siginfo_t *to,
> +				 siginfo_t *from)
> +{
> +  memset (to, 0, sizeof (*to));
> +
> +  to->si_signo = from->si_signo;
> +  to->si_errno = from->si_errno;
> +  to->si_code = from->si_code;
> +
> +  if (to->si_code == SI_TIMER)
> +    {
> +      to->cpt_si_timerid = from->si_timerid;
> +      to->cpt_si_overrun = from->si_overrun;
> +      to->cpt_si_ptr = (intptr_t) from->si_ptr;
> +    }
> +  else if (to->si_code == SI_USER)
> +    {
> +      to->cpt_si_pid = from->si_pid;
> +      to->cpt_si_uid = from->si_uid;
> +    }
> +  else if (to->si_code < 0)
> +    {
> +      to->cpt_si_pid = from->si_pid;
> +      to->cpt_si_uid = from->si_uid;
> +      to->cpt_si_ptr = (intptr_t) from->si_ptr;
> +    }
> +  else
> +    {
> +      switch (to->si_signo)
> +	{
> +	case SIGCHLD:
> +	  to->cpt_si_pid = from->si_pid;
> +	  to->cpt_si_uid = from->si_uid;
> +	  to->cpt_si_status = from->si_status;
> +	  to->cpt_si_utime = from->si_utime;
> +	  to->cpt_si_stime = from->si_stime;
> +	  break;
> +	case SIGILL:
> +	case SIGFPE:
> +	case SIGSEGV:
> +	case SIGBUS:
> +	  to->cpt_si_addr = (intptr_t) from->si_addr;
> +	  break;
> +	case SIGPOLL:
> +	  to->cpt_si_band = from->si_band;
> +	  to->cpt_si_fd = from->si_fd;
> +	  break;
> +	default:
> +	  to->cpt_si_pid = from->si_pid;
> +	  to->cpt_si_uid = from->si_uid;
> +	  to->cpt_si_ptr = (intptr_t) from->si_ptr;
> +	  break;
> +	}
> +    }
> +}
> +
> +static void
> +siginfo_from_compat_x32_siginfo (siginfo_t *to,
> +				 compat_x32_siginfo_t *from)
> +{
> +  memset (to, 0, sizeof (*to));
> +
> +  to->si_signo = from->si_signo;
> +  to->si_errno = from->si_errno;
> +  to->si_code = from->si_code;
> +
> +  if (to->si_code == SI_TIMER)
> +    {
> +      to->si_timerid = from->cpt_si_timerid;
> +      to->si_overrun = from->cpt_si_overrun;
> +      to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
> +    }
> +  else if (to->si_code == SI_USER)
> +    {
> +      to->si_pid = from->cpt_si_pid;
> +      to->si_uid = from->cpt_si_uid;
> +    }
> +  if (to->si_code < 0)
> +    {
> +      to->si_pid = from->cpt_si_pid;
> +      to->si_uid = from->cpt_si_uid;
> +      to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
> +    }
> +  else
> +    {
> +      switch (to->si_signo)
> +	{
> +	case SIGCHLD:
> +	  to->si_pid = from->cpt_si_pid;
> +	  to->si_uid = from->cpt_si_uid;
> +	  to->si_status = from->cpt_si_status;
> +	  to->si_utime = from->cpt_si_utime;
> +	  to->si_stime = from->cpt_si_stime;
> +	  break;
> +	case SIGILL:
> +	case SIGFPE:
> +	case SIGSEGV:
> +	case SIGBUS:
> +	  to->si_addr = (void *) (intptr_t) from->cpt_si_addr;
> +	  break;
> +	case SIGPOLL:
> +	  to->si_band = from->cpt_si_band;
> +	  to->si_fd = from->cpt_si_fd;
> +	  break;
> +	default:
> +	  to->si_pid = from->cpt_si_pid;
> +	  to->si_uid = from->cpt_si_uid;
> +	  to->si_ptr = (void* ) (intptr_t) from->cpt_si_ptr;
> +	  break;
> +	}
> +    }
> +}
> +
>  /* Convert a native/host siginfo object, into/from the siginfo in the
>     layout of the inferiors' architecture.  Returns true if any
>     conversion was done; false otherwise.  If DIRECTION is 1, then copy
> @@ -747,6 +922,20 @@ amd64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
>  
>        return 1;
>      }
> +  /* No fixup for native x32 GDB.  */
> +  else if (gdbarch_addr_bit (gdbarch) == 32 && sizeof (void *) == 8)
> +    {
> +      gdb_assert (sizeof (siginfo_t) == sizeof (compat_x32_siginfo_t));
> +
> +      if (direction == 0)
> +	compat_x32_siginfo_from_siginfo ((struct compat_x32_siginfo *) inf,
> +					 native);
> +      else
> +	siginfo_from_compat_x32_siginfo (native,
> +					 (struct compat_x32_siginfo *) inf);
> +
> +      return 1;
> +    }
>    else
>      return 0;
>  }
>