On Wed, Apr 18, 2012 at 11:10 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 04/18/2012 11:01 AM, H.J. Lu wrote:
>> On Wed, Apr 18, 2012 at 10:47 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>>> On 04/18/2012 10:38 AM, H.J. Lu wrote:
>>>>
>>>> It doesn't match struct siginfo in include/asm-generic/siginfo.h for
>>>> x32.
>>>>
>>>
>>> What is missing (from either)?
>>>
>>
>> include/asm-generic/siginfo.h has
>>
>> /* SIGCHLD */
>> struct {
>> __kernel_pid_t _pid; /* which child */
>> __ARCH_SI_UID_T _uid; /* sender's uid */
>> int _status; /* exit code */
>> __kernel_clock_t _utime;
>> __kernel_clock_t _stime;
>> } _sigchld;
>>
>>
>> Although x32 __kernel_clock_t is s64 with 64bit alignment, in
>> _sigchld, it must be compat_s64 with 32bit alignment.
>>
>
> What would you suggest? Change __kernel_clock_t? It would somewhat
> stink to have to muck with things here.
>
> The problem here of course is that this is a phony misalignment...
>
> -hpa
>
In x32 glibc, I have
# if compile for X32
/* si_utime and si_stime must be 4 byte aligned for x32 to match the
kernel. We align siginfo_t to 8 bytes so that si_utime and si_stime
are actually aligned to 8 bytes since their offsets are multiple of
8 bytes. */
typedef __clock_t __attribute__ ((__aligned__ (4))) __sigchld_clock_t;
# define __SI_ALIGNMENT __attribute__ ((__aligned__ (8)))
# else
typedef __clock_t __sigchld_clock_t;
# define __SI_ALIGNMENT
# endif
typedef struct siginfo
{
...
/* SIGCHLD. */
struct
{
__pid_t si_pid; /* Which child. */
__uid_t si_uid; /* Real user ID of sending process. */
int si_status; /* Exit value or signal. */
__sigchld_clock_t si_utime;
__sigchld_clock_t si_stime;
} _sigchld;
...
} siginfo_t __SI_ALIGNMENT;
--
H.J.
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