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  1. Jun 03, 2008
  3. May 20, 2008
  5. May 16, 2008
  7. May 12, 2008
  9. May 11, 2008
    • David S. Miller's avatar
      sparc: Fix debugger syscall restart interactions. · 28e61036
      David S. Miller authored 
      

So, forever, we've had this ptrace_signal_deliver implementation
which tries to handle all of the nasties that can occur when the
debugger looks at a process about to take a signal.  It's meant
to address all of these issues inside of the kernel so that the
debugger need not be mindful of such things.

Problem is, this doesn't work.

The idea was that we should do the syscall restart business first, so
that the debugger captures that state.  Otherwise, if the debugger for
example saves the child's state, makes the child execute something
else, then restores the saved state, we won't handle the syscall
restart properly because we lose the "we're in a syscall" state.

The code here worked for most cases, but if the debugger actually
passes the signal through to the child unaltered, it's possible that
we would do a syscall restart when we shouldn't have.

In particular this breaks the case of debugging a process under a gdb
which is being debugged by yet another gdb.  gdb uses sigsuspend
to wait for SIGCHLD of the inferior, but if gdb itself is being
debugged by a top-level gdb we get a ptrace_stop().  The top-level gdb
does a PTRACE_CONT with SIGCHLD to let the inferior gdb see the
signal.  But ptrace_signal_deliver() assumed the debugger would cancel
out the signal and therefore did a syscall restart, because the return
error was ERESTARTNOHAND.

Fix this by simply making ptrace_signal_deliver() a nop, and providing
a way for the debugger to control system call restarting properly:

1) Report a "in syscall" software bit in regs->{tstate,psr}.
   It is set early on in trap entry to a system call and is fully
   visible to the debugger via ptrace() and regsets.

2) Test this bit right before doing a syscall restart.  We have
   to do a final recheck right after get_signal_to_deliver() in
   case the debugger cleared the bit during ptrace_stop().

3) Clear the bit in trap return so we don't accidently try to set
   that bit in the real register.

As a result we also get a ptrace_{is,clear}_syscall() for sparc32 just
like sparc64 has.

M68K has this same exact bug, and is now the only other user of the
ptrace_signal_deliver hook.  It needs to be fixed in the same exact
way as sparc.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      28e61036
    • David S. Miller's avatar
      sparc: Fix ptrace() detach. · 986bef85
      David S. Miller authored 
      

Forever we had a PTRACE_SUNOS_DETACH which was unconditionally
recognized, regardless of the personality of the process.

Unfortunately, this value is what ended up in the GLIBC sys/ptrace.h
header file on sparc as PTRACE_DETACH and PT_DETACH.

So continue to recognize this old value.  Luckily, it doesn't conflict
with anything we actually care about.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      986bef85
  11. May 10, 2008
  13. May 08, 2008
    • David S. Miller's avatar
      sparc: Fix SA_ONSTACK signal handling. · dc5dc7e6
      David S. Miller authored 
      

We need to be more liberal about the alignment of the buffer given to
us by sigaltstack().  The user should not need to be mindful of all of
the alignment constraints we have for the stack frame.

This mirrors how we handle this situation in clone() as well.

Also, we align the stack even in non-SA_ONSTACK cases so that signals
due to bad stack alignment can be delivered properly.  This makes such
errors easier to debug and recover from.

Finally, add the sanity check x86 has to make sure we won't overflow
the signal stack.

This fixes glibc testcases nptl/tst-cancel20.c and
nptl/tst-cancelx20.c

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      dc5dc7e6
  15. May 07, 2008
  17. May 02, 2008
  19. Apr 29, 2008
  21. Apr 27, 2008
    • David S. Miller's avatar
      sparc: Remove old style signal frame support. · 5526b7e4
      David S. Miller authored 
      

Back around the same time we were bootstrapping the first 32-bit sparc
Linux kernel with a SunOS userland, we made the signal frame match
that of SunOS.

By the time we even started putting together a native Linux userland
for 32-bit Sparc we realized this layout wasn't sufficient for Linux's
needs.

Therefore we changed the layout, yet kept support for the old style
signal frame layout in there.  The detection mechanism is that we had
sys_sigaction() start passing in a negative signal number to indicate
"new style signal frames please".

Anyways, no binaries exist in the world that use the old stuff.  In
fact, I bet Jakub Jelinek and myself are the only two people who ever
had such binaries to be honest.

So let's get rid of this stuff.

I added an assertion using WARN_ON_ONCE() that makes sure 32-bit
applications are passing in that negative signal number still.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5526b7e4
  23. Apr 24, 2008
  25. Apr 21, 2008
  27. Apr 20, 2008
  29. Apr 17, 2008
  31. Apr 29, 2008
  33. Apr 10, 2008
    • David S. Miller's avatar
      [SPARC]: Fix several regset and ptrace bugs. · d786a4a6
      David S. Miller authored 
      

1) ptrace should pass 'current' to task_user_regset_view()

2) When fetching general registers using a 64-bit view, and
   the target is 32-bit, we have to convert.

3) Skip the whole register window get/set code block if
   the user isn't asking to access anything in there.

   Otherwise we have problems if the user doesn't have
   an address space setup.  Fetching ptrace register is
   still valid at such a time, and ptrace does not try
   to access the register window area of the regset.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d786a4a6
  35. Mar 18, 2008
  37. Mar 03, 2008
  39. Feb 29, 2008
  41. Feb 25, 2008
    • David S. Miller's avatar
      [SPARC]: Fix build in arch/sparc/kernel/led.c · b80a7186
      David S. Miller authored 
      

  CC [M]  arch/sparc/kernel/led.o
arch/sparc/kernel/led.c: In function 'led_blink':
arch/sparc/kernel/led.c:35: error: invalid use of undefined type 'struct
timer_list'
arch/sparc/kernel/led.c:35: error: 'jiffies' undeclared (first use in
this function)
arch/sparc/kernel/led.c:35: error: (Each undeclared identifier is
reported only once
arch/sparc/kernel/led.c:35: error: for each function it appears in.)
arch/sparc/kernel/led.c:36: error: 'avenrun' undeclared (first use in
this function)
arch/sparc/kernel/led.c:36: error: 'FSHIFT' undeclared (first use in
this function)
arch/sparc/kernel/led.c:36: error: 'HZ' undeclared (first use in this
function)
arch/sparc/kernel/led.c:37: error: invalid use of undefined type 'struct
timer_list'
arch/sparc/kernel/led.c:39: error: invalid use of undefined type 'struct
timer_list'
arch/sparc/kernel/led.c:40: error: invalid use of undefined type 'struct
timer_list'
arch/sparc/kernel/led.c:42: error: implicit declaration of function
'add_timer'
arch/sparc/kernel/led.c: In function 'led_write_proc':
arch/sparc/kernel/led.c:70: error: implicit declaration of function
'copy_from_user'
arch/sparc/kernel/led.c:84: error: implicit declaration of function
'del_timer_sync'
arch/sparc/kernel/led.c: In function 'led_init':
arch/sparc/kernel/led.c:109: error: implicit declaration of function
'init_timer'
arch/sparc/kernel/led.c:110: error: invalid use of undefined type
'struct timer_list'
make[1]: *** [arch/sparc/kernel/led.o] Error 1

Based upon original patch by Robert Reif.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b80a7186
  43. Feb 18, 2008
  45. Feb 13, 2008
  47. Feb 09, 2008
  49. Feb 08, 2008
    • Martin Schwidefsky's avatar
      CONFIG_HIGHPTE vs. sub-page page tables. · 2f569afd
      Martin Schwidefsky authored 
      

Background: I've implemented 1K/2K page tables for s390.  These sub-page
page tables are required to properly support the s390 virtualization
instruction with KVM.  The SIE instruction requires that the page tables
have 256 page table entries (pte) followed by 256 page status table entries
(pgste).  The pgstes are only required if the process is using the SIE
instruction.  The pgstes are updated by the hardware and by the hypervisor
for a number of reasons, one of them is dirty and reference bit tracking.
To avoid wasting memory the standard pte table allocation should return
1K/2K (31/64 bit) and 2K/4K if the process is using SIE.

Problem: Page size on s390 is 4K, page table size is 1K or 2K.  That means
the s390 version for pte_alloc_one cannot return a pointer to a struct
page.  Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one
cannot return a pointer to a pte either, since that would require more than
32 bit for the return value of pte_alloc_one (and the pte * would not be
accessible since its not kmapped).

Solution: The only solution I found to this dilemma is a new typedef: a
pgtable_t.  For s390 pgtable_t will be a (pte *) - to be introduced with a
later patch.  For everybody else it will be a (struct page *).  The
additional problem with the initialization of the ptl lock and the
NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and
a destructor pgtable_page_dtor.  The page table allocation and free
functions need to call these two whenever a page table page is allocated or
freed.  pmd_populate will get a pgtable_t instead of a struct page pointer.
 To get the pgtable_t back from a pmd entry that has been installed with
pmd_populate a new function pmd_pgtable is added.  It replaces the pmd_page
call in free_pte_range and apply_to_pte_range.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2f569afd