From: Aditya Kamath1 <Aditya.Kamath1@ibm.com>
To: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>,
"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>,
"simon.marchi@efficios.com" <simon.marchi@efficios.com>
Cc: Sangamesh Mallayya <sangamesh.swamy@in.ibm.com>,
Sanket Rathi <sanrathi@in.ibm.com>
Subject: Re: [PATCH] Fix call functions command bug in 64-bit programs for AIX
Date: Wed, 16 Nov 2022 11:27:32 +0000 [thread overview]
Message-ID: <BY5PR15MB3540852D087513326BA57169D6079@BY5PR15MB3540.namprd15.prod.outlook.com> (raw)
In-Reply-To: <ab76d46b82949cc347ca8d08b2f1bb6661aa78ec.camel@de.ibm.com>
[-- Attachment #1.1: Type: text/plain, Size: 5362 bytes --]
Hi Ulrich,
>This indicates that value is already placed incorrectly
>into the register cache, before store_register was even
>called.
You were right about this. Thank you so much for your guidance.
Please find attached the new patch. See 0001-Fix-call-functions-command-bug-in-64-bit-programs.patch.
In AIX for 64-bit programs, we need to zero extend variables of integer data type.
Otherwise, a zero will get dumped in the register as we memset our word to 0 and integer is not extended.
In this patch I changed the same. I have pasted the output and code below..
Let me know what you think.
Thanks and regards,
Aditya.
----------------------------------
Program:
int num2print(long num, float num2, int num3, double num4) {
if (num == 0) {
printf("R0\n");
return 0;
}
if (num == 1) {
printf("R1\n");
return 1;
}
printf("R%ld\n",num);
printf("R%f\n",num2);
printf("R%d\n",num3);
printf("R%lf\n",num4);
return num;
}
int main(int argc, char** argv)
{
printf("Hi Bangalore %x\n",num2print(27, 16, 13, 9.9));
return 0;
}
--------------------------------------
Output before patch in 64 bit mode
Reading symbols from /home/XYZ/gdb_tests...
(gdb) b main
Breakpoint 1 at 0x100007dc: file /home/XYZ/gdb_tests.c, line 22.
(gdb) r
Starting program: /home/XYZ/gdb_tests
BFD: /usr/lib/libc.a(/usr/lib/libc.a(shr_64.o)): wrong auxtype 0xff for storage class 0x2
BFD: /usr/lib/libc.a(/usr/lib/libc.a(shr_64.o)): wrong auxtype 0xff for storage class 0x6b
Breakpoint 1, main (argc=1, argv=0xffffffffffffad0)
at /home/XYZ/gdb_tests.c:22
22 printf("Hi Bangalore %x\n",num2print(27, 16, 13, 9.9));
(gdb) call num2print
$1 = {int (long, float, int, double)} 0x1000006a0 <num2print>
(gdb) call num2print (2, 3, 4, 5)
R2
R3.000000
R0
R5.000000
$2 = 2
(gdb)
--------------------------------------------
Output after patch in 32-bit mode
Reading symbols from /home/XYZ/gdb_tests...
(gdb) b main
Breakpoint 1 at 0x10000664: file /home/XYZ/gdb_tests.c, line 22.
(gdb) r
Starting program: /home/XYZ/gdb_tests
Breakpoint 1, main (argc=1, argv=0x2ff22bf0)
at /home/XYZ/gdb_tests.c:22
22 printf("Hi Bangalore %x\n",num2print(27, 16, 13, 9.9));
(gdb) call num2print
$1 = {int (long, float, int, double)} 0x10000518 <num2print>
(gdb) call num2print (2, 3, 4, 5.43)
R2
R3.000000
R4
R5.430000
$2 = 2
(gdb)
------------------------------------
output after patch in 64-bit mode
Reading symbols from /home/XYZ/gdb_tests...
(gdb) b main
Breakpoint 1 at 0x100007dc: file /home/XYZ/gdb_tests.c, line 22.
(gdb) r
Starting program: /home/XYZ/gdb_tests
BFD: /usr/lib/libc.a(/usr/lib/libc.a(shr_64.o)): wrong auxtype 0xff for storage class 0x2
BFD: /usr/lib/libc.a(/usr/lib/libc.a(shr_64.o)): wrong auxtype 0xff for storage class 0x6b
Breakpoint 1, main (argc=1, argv=0xffffffffffffad0)
at /home/XYZ/gdb_tests.c:22
22 printf("Hi Bangalore %x\n",num2print(27, 16, 13, 9.9));
(gdb) call num2print
$1 = {int (long, float, int, double)} 0x1000006a0 <num2print>
(gdb) call num2print (2, 3.5, 43, 56.2)
R2
R3.500000
R43
R56.200000
$2 = 2
(gdb)
________________________________
From: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Sent: 15 November 2022 00:40
To: gdb-patches@sourceware.org <gdb-patches@sourceware.org>; Aditya Kamath1 <Aditya.Kamath1@ibm.com>; simon.marchi@efficios.com <simon.marchi@efficios.com>
Cc: Sangamesh Mallayya <sangamesh.swamy@in.ibm.com>; Sanket Rathi <sanrathi@in.ibm.com>
Subject: Re: [PATCH] Fix call functions command bug in 64-bit programs for AIX
Aditya Kamath1 <Aditya.Kamath1@ibm.com> wrote:
>(gdb) call num2print (2, 3, 4, 6)
>val in regno = 3 via buf is 2 and *addr is 0, regsize = 8
>val in regno = 4 via buf is 4629700416936869888 and *addr is 1077936128, regsize = 8
>val in regno = 5 via buf is 17179869184 and *addr is 4, regsize = 8
>val in regno = 6 via buf is 25769803776 and *addr is 6, regsize = 8....
Thanks!
This indicates that value is already placed incorrectly
into the register cache, before store_register was even
called.
Looking at rs6000_push_dummy_call in rs6000-aix-tdep.c, I see:
> /* Argument can fit in one register. No problem. */
> gdb_byte word[PPC_MAX_REGISTER_SIZE];
>
> memset (word, 0, reg_size);
> memcpy (word, value_contents (arg).data (), len);
> regcache->cooked_write (tdep->ppc_gp0_regnum + 3 +ii, word);
which places an "int" argument in the *high* bytes of a register
on a 64-bit system. This seems clearly wrong, and would be the
root cause of the problem you're seeing.
I think you'll need to have a closer look at this function and
make sure it implements the AIX ABI correctly, in particular
also on 64-bit systems. (You might want to have a look at the
ppc64_sysv_abi_push_dummy_call routine for comparison, which
implements the Linux 64-bit ABI; I understand this is similar
to the AIX ABI.)
I assume that once you've fixed the push_dummy_call implementation,
no changes to the store_register / fetch_register routines will
be needed at all.
Bye,
Ulrich
[-- Attachment #2: 0001-Fix-call-functions-command-bug-in-64-bit-programs.patch --]
[-- Type: application/octet-stream, Size: 1378 bytes --]
From 44c45c050bfc017e3fffc2d0bb762d2fa9affa7e Mon Sep 17 00:00:00 2001
From: Aditya Vidyadhar Kamath <Aditya.Kamath1@ibm.com>
Date: Wed, 16 Nov 2022 04:30:59 -0600
Subject: [PATCH] Fix call functions command bug in 64 bits programs for AIX
In AIX for 64 bit programs we need to zero extend variables of integer data type.
Otherwise a zero will get dumped in the register as we memset our word to 0 and integer is not extended.
This patch is a fix for the same.
---
gdb/rs6000-aix-tdep.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/gdb/rs6000-aix-tdep.c b/gdb/rs6000-aix-tdep.c
index d47974b51d1..a7d174d8be8 100644
--- a/gdb/rs6000-aix-tdep.c
+++ b/gdb/rs6000-aix-tdep.c
@@ -400,7 +400,12 @@ rs6000_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
gdb_byte word[PPC_MAX_REGISTER_SIZE];
memset (word, 0, reg_size);
- memcpy (word, value_contents (arg).data (), len);
+ if (type->code () == TYPE_CODE_INT)
+ /* Sign or zero extend the "int" into a "word". */
+ store_unsigned_integer (word, tdep->wordsize, byte_order,
+ unpack_long (type, value_contents (arg).data ()));
+ else
+ memcpy (word, value_contents (arg).data (), len);
regcache->cooked_write (tdep->ppc_gp0_regnum + 3 +ii, word);
}
++argno;
--
2.31.1
next prev parent reply other threads:[~2022-11-16 11:28 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-07 11:00 Aditya Kamath1
2022-11-08 13:30 ` Ulrich Weigand
2022-11-11 17:53 ` Aditya Kamath1
2022-11-14 15:54 ` Ulrich Weigand
2022-11-14 17:32 ` Aditya Kamath1
2022-11-14 18:19 ` Ulrich Weigand
2022-11-14 18:28 ` Aditya Kamath1
2022-11-14 18:43 ` Ulrich Weigand
2022-11-14 18:52 ` Aditya Kamath1
2022-11-14 19:10 ` Ulrich Weigand
2022-11-16 11:27 ` Aditya Kamath1 [this message]
2022-11-16 15:15 ` Ulrich Weigand
2022-11-16 18:07 ` Aditya Kamath1
2022-11-16 18:30 ` Tom Tromey
2022-11-17 12:54 ` Ulrich Weigand
2022-11-24 17:56 ` Aditya Kamath1
2022-11-24 18:15 ` Tom Tromey
2023-04-14 7:38 ` [PATCH] Fix call functions command bug in 64-bit programs for AIX and PC read in psymtab-symtab warning Aditya Kamath1
2023-04-14 14:45 ` Tom Tromey
2023-04-17 13:08 ` Aditya Kamath1
2023-04-17 13:16 ` Aditya Kamath1
2023-04-18 10:12 ` Ulrich Weigand
2023-04-21 13:00 ` Aditya Kamath1
2023-04-24 15:44 ` Ulrich Weigand
2023-04-27 10:13 ` Aditya Kamath1
2023-04-27 12:23 ` Ulrich Weigand
2023-04-27 10:14 ` Aditya Kamath1
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