S390: Sync ptrace.h with kernel. [BZ #21539]

Hi,

this patch removes PTRACE_GETREGS, PTRACE_SETREGS, PTRACE_GETFPREGS
and PTRACE_SETFPREGS as these requests does not exist on s390 kernel.

But the kernel has support for PTRACE_SINGLEBLOCK,
PTRACE_SECCOMP_GET_FILTER, PTRACE_PEEKUSR_AREA, PTRACE_POKEUSR_AREA,
PTRACE_GET_LAST_BREAK, PTRACE_ENABLE_TE, PTRACE_DISABLE_TE and
PTRACE_TE_ABORT_RAND.  Thus those are defined now.

The current kernel s390 specific ptrace.h file also defines
PTRACE_PEEKTEXT_AREA, PTRACE_PEEKDATA_AREA, PTRACE_POKETEXT_AREA,
PTRACE_POKEDATA_AREA, PTRACE_PEEK_SYSTEM_CALL, PTRACE_POKE_SYSTEM_CALL
and PTRACE_PROT, but those requests are not supported.
Thus those defines are skipped in glibc ptrace.h.

There were old includes of ptrace.h in sysdeps/s390/fpu/fesetenv.c.
The ptrace feature isn't used there anymore, thus I removed the includes.

Before this patch, <glibc>/sysdeps/unix/sysv/linux/s390/sys/ptrace.h
uses ptrace-request 12 for PTRACE_GETREGS,
but <kernel>/include/uapi/linux/ptrace.h uses 12 for PTRACE_SINGLEBLOCK.

The s390 kernel has never had support for PTRACE_GETREGS!
Thus glibc ptrace.h is adjusted to match kernel ptrace.h.

The new s390 specific test ensures, that PTRACE_SINGLEBLOCK defined
in glibc works as expected.  If the kernel would interpret it as
PTRACE_GETREGS, then the testcase will not make any progress
and will time out.

Bye.
Stefan

ChangeLog:

	[BZ #21539]
	* sysdeps/unix/sysv/linux/s390/sys/ptrace.h
	(PTRACE_GETREGS, PTRACE_SETREGS, PTRACE_GETFPREGS,
	PTRACE_SETFPREGS): Remove enum constant.
	(PT_GETREGS, PT_SETREGS, PT_GETFPREGS, T_SETFPREGS):
	Remove defines.
	(PTRACE_SINGLEBLOCK): New enum constant.
	(PT_STEPBLOCK): New define.
	(PTRACE_PEEKUSR_AREA, PTRACE_POKEUSR_AREA,
	PTRACE_GET_LAST_BREAK, PTRACE_ENABLE_TE, PTRACE_DISABLE_TE,
	PTRACE_TE_ABORT_RAND): New enum constant and define.
	* sysdeps/s390/fpu/fesetenv.c: Remove ptrace.h includes.
	* sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c:
	New file.
	* sysdeps/unix/sysv/linux/s390/Makefile: Add test.

On Jun 06 2017, Stefan Liebler <stli@linux.vnet.ibm.com> wrote:

> Hi,
>
> this patch removes PTRACE_GETREGS, PTRACE_SETREGS, PTRACE_GETFPREGS
> and PTRACE_SETFPREGS as these requests does not exist on s390 kernel.

Since it is an API change it should probably get a NEWS entry.

> +static void
> +tracer_func (int pid)
> +{
> +  unsigned long last_break;
> +  ptrace_area parea;
> +  gregset_t regs;
> +  int status;
> +
> +  while (1)
> +    {
> +      /* Wait for the tracee to be stopped or exited.  */
> +      wait (&status);

Doesn't that need to use WUNTRACED?

Andreas.

On Tue, Jun 06, 2017 at 12:44:04PM +0200, Andreas Schwab wrote:
> On Jun 06 2017, Stefan Liebler <stli@linux.vnet.ibm.com> wrote:
[...]
> > +static void
> > +tracer_func (int pid)
> > +{
> > +  unsigned long last_break;
> > +  ptrace_area parea;
> > +  gregset_t regs;
> > +  int status;
> > +
> > +  while (1)
> > +    {
> > +      /* Wait for the tracee to be stopped or exited.  */
> > +      wait (&status);
> 
> Doesn't that need to use WUNTRACED?

No, it doesn't: as the tracee has called PTRACE_TRACEME before raising
SIGSTOP, there is going to be a ptrace signal delivery stop.

On 06/06/2017 12:44 PM, Andreas Schwab wrote:
> On Jun 06 2017, Stefan Liebler <stli@linux.vnet.ibm.com> wrote:
> 
>> Hi,
>>
>> this patch removes PTRACE_GETREGS, PTRACE_SETREGS, PTRACE_GETFPREGS
>> and PTRACE_SETFPREGS as these requests does not exist on s390 kernel.
> 
> Since it is an API change it should probably get a NEWS entry.
> 
I've added this NEWS entry:
* The s390 specific ptrace requests are adjusted to the kernel ones.
   Request 12 is now used for PTRACE_SINGLEBLOCK instead of
   PTRACE_GETREGS.  The requests PTRACE_GETREGS, PTRACE_SETREGS,
   PTRACE_GETFPREGS and PTRACE_SETFPREGS were removed as those are not
   supported by the s390 kernel.  The requests PTRACE_SINGLEBLOCK,
   PTRACE_SECCOMP_GET_FILTER, PTRACE_PEEKUSR_AREA, PTRACE_POKEUSR_AREA,
   PTRACE_GET_LAST_BREAK, PTRACE_ENABLE_TE, PTRACE_DISABLE_TE and
   PTRACE_TE_ABORT_RAND were added as those are supported by the s390
   kernel.

On 06/06/2017 01:56 PM, Stefan Liebler wrote:
> On 06/06/2017 12:44 PM, Andreas Schwab wrote:
>> On Jun 06 2017, Stefan Liebler <stli@linux.vnet.ibm.com> wrote:
>>
>>> Hi,
>>>
>>> this patch removes PTRACE_GETREGS, PTRACE_SETREGS, PTRACE_GETFPREGS
>>> and PTRACE_SETFPREGS as these requests does not exist on s390 kernel.
>>
>> Since it is an API change it should probably get a NEWS entry.
>>
> I've added this NEWS entry:
> * The s390 specific ptrace requests are adjusted to the kernel ones.
>    Request 12 is now used for PTRACE_SINGLEBLOCK instead of
>    PTRACE_GETREGS.  The requests PTRACE_GETREGS, PTRACE_SETREGS,
>    PTRACE_GETFPREGS and PTRACE_SETFPREGS were removed as those are not
>    supported by the s390 kernel.  The requests PTRACE_SINGLEBLOCK,
>    PTRACE_SECCOMP_GET_FILTER, PTRACE_PEEKUSR_AREA, PTRACE_POKEUSR_AREA,
>    PTRACE_GET_LAST_BREAK, PTRACE_ENABLE_TE, PTRACE_DISABLE_TE and
>    PTRACE_TE_ABORT_RAND were added as those are supported by the s390
>    kernel.
> 

Any objection?
Otherwise I'll commit the patch tomorrow.

Bye
Stefan

On Tue, Jun 06, 2017 at 12:17:33PM +0200, Stefan Liebler wrote:
[...]
> diff --git a/sysdeps/unix/sysv/linux/s390/sys/ptrace.h b/sysdeps/unix/sysv/linux/s390/sys/ptrace.h
> index 7caf101..88079fc 100644
> --- a/sysdeps/unix/sysv/linux/s390/sys/ptrace.h
> +++ b/sysdeps/unix/sysv/linux/s390/sys/ptrace.h
> @@ -89,25 +89,9 @@ enum __ptrace_request
>    PTRACE_SINGLESTEP = 9,
>  #define PT_STEP PTRACE_SINGLESTEP
>  
> -  /* Get all general purpose registers used by a processes.
> -     This is not supported on all machines.  */
> -   PTRACE_GETREGS = 12,
> -#define PT_GETREGS PTRACE_GETREGS
> -
> -  /* Set all general purpose registers used by a processes.
> -     This is not supported on all machines.  */
> -   PTRACE_SETREGS = 13,
> -#define PT_SETREGS PTRACE_SETREGS
> -
> -  /* Get all floating point registers used by a processes.
> -     This is not supported on all machines.  */
> -   PTRACE_GETFPREGS = 14,
> -#define PT_GETFPREGS PTRACE_GETFPREGS
> -
> -  /* Set all floating point registers used by a processes.
> -     This is not supported on all machines.  */
> -   PTRACE_SETFPREGS = 15,
> -#define PT_SETFPREGS PTRACE_SETFPREGS
> +  /* Execute process until next taken branch.  */
> +  PTRACE_SINGLEBLOCK = 12,
> +#define PT_STEPBLOCK PTRACE_SINGLEBLOCK
>  
>    /* Attach to a process that is already running. */
>    PTRACE_ATTACH = 16,
> @@ -167,8 +151,26 @@ enum __ptrace_request
>    PTRACE_SETSIGMASK = 0x420b,
>  #define PTRACE_SETSIGMASK PTRACE_SETSIGMASK
>  
> -  PTRACE_SECCOMP_GET_FILTER = 0x420c
> +  PTRACE_SECCOMP_GET_FILTER = 0x420c,
>  #define PTRACE_SECCOMP_GET_FILTER PTRACE_SECCOMP_GET_FILTER
> +
> +  PTRACE_PEEKUSR_AREA = 0x5000,
> +#define PTRACE_PEEKUSR_AREA PTRACE_PEEKUSR_AREA
> +
> +  PTRACE_POKEUSR_AREA = 0x5001,
> +#define PTRACE_POKEUSR_AREA PTRACE_POKEUSR_AREA
> +
> +  PTRACE_GET_LAST_BREAK = 0x5006,
> +#define PTRACE_GET_LAST_BREAK PTRACE_GET_LAST_BREAK
> +
> +  PTRACE_ENABLE_TE = 0x5009,
> +#define PTRACE_ENABLE_TE PTRACE_ENABLE_TE
> +
> +  PTRACE_DISABLE_TE = 0x5010,
> +#define PTRACE_DISABLE_TE PTRACE_DISABLE_TE
> +
> +  PTRACE_TE_ABORT_RAND = 0x5011
> +#define PTRACE_TE_ABORT_RAND PTRACE_TE_ABORT_RAND
>  };

The sys/ptrace.h part of the change looks fine.

> diff --git a/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c b/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c
> new file mode 100644
> index 0000000..b384562
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c
> @@ -0,0 +1,110 @@
> +/* Testing s390x PTRACE_SINGLEBLOCK ptrace request.
> +   Copyright (C) 2017 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <sys/wait.h>
> +#include <sys/types.h>
> +#include <support/xunistd.h>
> +
> +/* Ensure that we use the PTRACE_SINGLEBLOCK definition from glibc ptrace.h
> +   in tracer_func.  We need the kernel ptrace.h for structs ptrace_area
> +   and gregset_t.  */
> +#include <sys/ptrace.h>
> +static const enum __ptrace_request req_singleblock = PTRACE_SINGLEBLOCK;
> +#include <asm/ptrace.h>
> +
> +static void
> +tracee_func (int pid)
> +{
> +  /* Dump the mapping information for manual inspection of the printed
> +     tracee addresses.  */
> +  char str[80];
> +  sprintf (str, "cat /proc/%d/maps", pid);
> +  puts (str);
> +  system (str);
> +  fflush (stdout);
> +
> +  ptrace (PTRACE_TRACEME);
> +  /* Stop tracee.  Afterwards the tracer_func can operate.  */
> +  kill (pid, SIGSTOP);
> +
> +  puts ("The PTRACE_SINGLEBLOCK of the tracer will stop after: "
> +	"brasl %r14,<puts@plt>!");
> +}
> +
> +static void
> +tracer_func (int pid)
> +{
> +  unsigned long last_break;
> +  ptrace_area parea;
> +  gregset_t regs;
> +  int status;
> +
> +  while (1)
> +    {
> +      /* Wait for the tracee to be stopped or exited.  */
> +      wait (&status);
> +      if (WIFEXITED (status))
> +	break;
> +
> +      /* Get information about tracee: gprs, last breaking address.  */
> +      parea.len = sizeof (regs);
> +      parea.process_addr = (unsigned long) &regs;
> +      parea.kernel_addr = 0;
> +      ptrace (PTRACE_PEEKUSR_AREA, pid, &parea);

Note that you can verify whether PTRACE_PEEKUSR_AREA has returned
the expected result by comparing registers with those returned
by PTRACE_GETREGSET.  The latter is implemented on s390 since
linux 2.6.27 so its use in glibc is safe.

> +      ptrace (PTRACE_GET_LAST_BREAK, pid, NULL, &last_break);

As these ptrace calls are expected to succeed,
you might want to check their return code.

> +
> +      printf ("child IA: %p last_break: %p\n",
> +	      (void *) regs[1], (void *) last_break);
> +
> +      /* Execute tracee until next taken branch.
> +
> +	 Note:
> +	 Before the commit which introduced this testcase,
> +	 <glibc>/sysdeps/unix/sysv/linux/s390/sys/ptrace.h
> +	 uses ptrace-request 12 for PTRACE_GETREGS,
> +	 but <kernel>/include/uapi/linux/ptrace.h
> +	 uses 12 for PTRACE_SINGLEBLOCK.
> +
> +	 The s390 kernel has no support for PTRACE_GETREGS!
> +	 Thus glibc ptrace.h is adjusted to match kernel ptrace.h.
> +
> +	 This test ensures, that PTRACE_SINGLEBLOCK defined in glibc
> +	 works as expected.  If the kernel would interpret it as
> +	 PTRACE_GETREGS, then the tracee will not make any progress
> +	 and this testcase will time out.  */
> +      ptrace (req_singleblock, pid, NULL, NULL);

Likewise.