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Re: PATCH: Support x32 siginfo_t conversion
On Sat, May 12, 2012 at 4:15 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Sat, May 12, 2012 at 2:16 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>>> Date: Fri, 11 May 2012 13:55:29 -0700
>>> From: "H.J. Lu" <hjl.tools@gmail.com>
>>>
>>> On Fri, May 11, 2012 at 1:11 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>>> >> 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.
>>>
>>> X32 ABI choice is done on purpose. ?X32 siginfo_t has
>>>
>>> typedef long __attribute__ ((__aligned__ (4))) compat_x32_clock_t;
>>>
>>> typedef struct compat_x32_siginfo
>>> {
>>> ? int si_signo;
>>> ? int si_errno;
>>> ? int si_code;
>>>
>>> ? union
>>> ? {
>>> ...
>>> ? ? /* SIGCHLD */
>>> ? ? struct
>>> ? ? {
>>> ? ? ? unsigned int _pid;
>>> ? ? ? unsigned int _uid;
>>> ? ? ? int _status;
>>> ? ? ? compat_x32_clock_t _utime;
>>> ? ? ? compat_x32_clock_t _stime;
>>> ? ? } _sigchld;
>>> ...
>>> } compat_x32_siginfo_t __attribute__ ((__aligned__ (8)));
>>>
>>> struct info is aligned at 8 bytes and type of _utime/_stime is aligned
>>> at 4 bytes. ?However, ?_utime offset is 3 * 4 + 3 * 4 == 24 bytes. So
>>> in reality, the addresses of _utime/_stime are 8 bytes aligned. ?There
>>> are no needs to split _utime and _stime into two 32-bit variables
>>> since their addresses are 64bits aligned.
>>
>> But there is no way you can easily express that syntax with standard C
>> syntax[1]. ?That's why you had to resort to using GCC's __attribute__
>> syntax. ?For GDB you'll have to figure out a way to do this without
>> using __attribute__ ((__aligned__ (...))).
>>
>> My recommendation would be to define a compat_x32 structure just for
>> SIGCHLD (without using a union) and use the normal 32-bit comap
>> structure for all the other conversions.
>>
>
> This is in amd64-linux-nat.c. ?All native Linux/amd64 compilers support
> __attribute__ ((__aligned__ (...))). ? ?In any case, I will use a struct with
> 2 ints.
>
> Thanks.
>
Here is the updated patch. OK to install?
Thanks.
--
H.J.
---
diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index 5ebba3a..bc28d54 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -591,6 +591,71 @@ typedef struct compat_siginfo
} _sifields;
} compat_siginfo_t;
+/* For x32, clock_t in _sigchld is 64bit aligned at 4 bytes. */
+typedef struct compat_x32_clock
+{
+ int lower;
+ int upper;
+} compat_x32_clock_t;
+
+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;
+
#define cpt_si_pid _sifields._kill._pid
#define cpt_si_uid _sifields._kill._uid
#define cpt_si_timerid _sifields._timer._tid
@@ -724,6 +789,124 @@ 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;
+ memcpy (&to->cpt_si_utime, &from->si_utime,
+ sizeof (to->cpt_si_utime));
+ memcpy (&to->cpt_si_stime, &from->si_stime,
+ sizeof (to->cpt_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;
+ memcpy (&to->si_utime, &from->cpt_si_utime,
+ sizeof (to->si_utime));
+ memcpy (&to->si_stime, &from->cpt_si_stime,
+ sizeof (to->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
@@ -733,9 +916,10 @@ siginfo_from_compat_siginfo (siginfo_t *to,
compat_siginfo_t *from)
static int
amd64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
{
+ struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
/* Is the inferior 32-bit? If so, then do fixup the siginfo
object. */
- if (gdbarch_addr_bit (get_frame_arch (get_current_frame ())) == 32)
+ if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
{
gdb_assert (sizeof (siginfo_t) == sizeof (compat_siginfo_t));
@@ -746,6 +930,20 @@ 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;
}