svn commit: r338930 - head/libexec/rtld-elf/powerpc

[Michael Tuexen]

> On 25. Sep 2018, at 21:29, Andreas Tobler <andreast at FreeBSD.org> wrote:
> 
> Author: andreast
> Date: Tue Sep 25 19:29:35 2018
> New Revision: 338930
> URL: https://svnweb.freebsd.org/changeset/base/338930
> 
> Log:
>  Bring the 32-bit powerpc (PowerMac) back to live. The commit 338486 reworked
>  some TLS bits. This broke operation on the PowerMac. Namely one could not login.
>  At login the screen/shell was giving back lots of backslashes and the login
>  shell dumped core.
> 
>  The fix to this issue is to revert the powerpc commit from 338486 and to
>  increase the TLS_TCB_SIZE to 16.
>  Reverting only did not help, login was possible but userland applications
>  aborted with strange messages.
> 
>  I tested this patch with world/kernel builds and with port upgrades.
>  Additionally a full gcc8 bootstrap was successfully completed.
> 
>  Reviewed by: jhibbits@
>  Approved by: re (Glen)
> 
> Modified:
>  head/libexec/rtld-elf/powerpc/rtld_machdep.h
> 
> Modified: head/libexec/rtld-elf/powerpc/rtld_machdep.h
> ==============================================================================
> --- head/libexec/rtld-elf/powerpc/rtld_machdep.h	Tue Sep 25 18:54:18 2018	(r338929)
> +++ head/libexec/rtld-elf/powerpc/rtld_machdep.h	Tue Sep 25 19:29:35 2018	(r338930)
> @@ -69,12 +69,12 @@ void _rtld_powerpc_pltcall(void);
> 
> #define TLS_TP_OFFSET	0x7000
> #define TLS_DTV_OFFSET	0x8000
> -#define TLS_TCB_SIZE	8
> +#define TLS_TCB_SIZE	16
> 
> #define round(size, align) \
>     (((size) + (align) - 1) & ~((align) - 1))
> #define calculate_first_tls_offset(size, align) \
> -    TLS_TCB_SIZE
> +    round(8, align)
> #define calculate_tls_offset(prev_offset, prev_size, size, align) \
>     round(prev_offset + prev_size, align)
> #define calculate_tls_end(off, size)    ((off) + (size))
> 
After performing a buildworld/buildkernel and running r338956 on a 32-bit powerpc machine (G4 Mac Mini),
the following program:

#include <pthread.h>
#include <stdio.h>
#include <string.h>

void *
f(void * arg)
{
	return (arg);
}

int
main(void)
{
	void *res;
	pthread_t tid;
	int err;

	if ((err = pthread_create(&tid, NULL, f, NULL)) != 0) {
		fprintf(stderr, "pthread_create: %s\n", strerror(err));
	}
	if ((err = pthread_join(tid, &res)) != 0) {
		fprintf(stderr, "pthread_join: %s\n", strerror(err));
	}
	return (0);
}

is killed:

tuexen at bsd5:~ % ./test
ld-elf.so.1: assert failed: /usr/home/tuexen/head/libexec/rtld-elf/rtld.c:4753
Abort (core dumped)

gdb shows:

tuexen at bsd5:~ % gdb -c test.core test
GNU gdb (GDB) 8.1 [GDB v8.1 for FreeBSD]
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "powerpc-portbld-freebsd12.0".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from test...done.
[New LWP 100112]
Core was generated by `./test'.
Program terminated with signal SIGABRT, Aborted.
#0  0x41829a58 in thr_kill () at thr_kill.S:3
3	RSYSCALL(thr_kill)
(gdb) bt
#0  0x41829a58 in thr_kill () at thr_kill.S:3
#1  0x41829378 in __raise (s=6)
    at /usr/home/tuexen/head/lib/libc/gen/raise.c:52
#2  0x41823b84 in abort () at /usr/home/tuexen/head/lib/libc/stdlib/abort.c:67
#3  0x41813f58 in allocate_tls (objs=0x41843000, oldtcb=<optimized out>, 
    tcbsize=8, tcbalign=<optimized out>)
    at /usr/home/tuexen/head/libexec/rtld-elf/rtld.c:4753
#4  0x41813fc0 in _rtld_allocate_tls (oldtls=0x0, tcbsize=8, tcbalign=16)
    at /usr/home/tuexen/head/libexec/rtld-elf/rtld.c:5030
#5  0x41877438 in _tcb_ctor (thread=0x41a8d300, initial=<optimized out>)
    at /usr/home/tuexen/head/lib/libthr/thread/thr_ctrdtr.c:45
#6  0x41876ebc in _thr_alloc (curthread=0x41a8d000)
    at /usr/home/tuexen/head/lib/libthr/thread/thr_list.c:172
#7  0x41867118 in _pthread_create (thread=0xffffdc10, attr=0x0, 
    start_routine=0x180073c <f>, arg=0x0)
    at /usr/home/tuexen/head/lib/libthr/thread/thr_create.c:81
#8  0x01800798 in main ()
(gdb) quit

Any idea what is wrong?

Best regards
Michael