linux.git/arch/powerpc/kernel/process.c, branch v2.6.23

[POWERPC] Ensure FULL_REGS on exec

2007-09-25T10:40:41+00:00

When PTRACE_O_TRACEEXEC is used, a ptrace call to fetch the registers at
the PTRACE_EVENT_EXEC stop (PTRACE_PEEKUSR) will oops in CHECK_FULL_REGS.
With recent versions, "gdb --args /bin/sh -c 'exec /bin/true'" and "run" at
the (gdb) prompt is sufficient to produce this.  I also have written an
isolated test case, see https://bugzilla.redhat.com/show_bug.cgi?id=301791#c15.

This change fixes the problem by clearing the low bit of pt_regs.trap in
start_thread so that FULL_REGS is true again.  This is correct since all of
the GPRs that "full" refers to are cleared in start_thread.

Signed-off-by: Roland McGrath 
Signed-off-by: Paul Mackerras

[POWERPC] Flush registers to proper task context

2007-08-29T02:15:53+00:00

When we flush register state for FP, Altivec, or SPE in flush_*_to_thread
we need to respect the task_struct that the caller has passed to us.

Most cases we are called with current, however sometimes (ptrace) we may
be passed a different task_struct.

This showed up when using gdbserver debugging a simple program that used
floating point. When gdb tried to show the FP regs they all showed up as
0, because the child's FP registers were never properly flushed to memory.

Signed-off-by: Kumar Gala

[POWERPC] Fix register labels on show_regs() message for 4xx/Book-E

2007-07-26T05:46:15+00:00

In a show_regs()  message The DEAR and ESR were reported as
DAR and DSISR which only exist on classic parts.

Signed-off-by: Kumar Gala

[POWERPC] Always apply DABR changes on context switches

2007-06-14T12:29:57+00:00

This patch removes the #ifdef CONFIG_PPC64 around setting the DABR.

The actual setting of the SPR inside of the set_dabr() function is dependent
on CONFIG_PPC64 || CONFIG_6xx but you can always provide a ppc_md hook to
override that.  We should improve support for different HW breakpoints
facilities but this is a first step.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras

header cleaning: don't include smp_lock.h when not used

2007-05-08T18:15:07+00:00

Remove includes of  where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).

Signed-off-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[POWERPC] Make tlb flush batch use lazy MMU mode

2007-04-12T18:09:38+00:00

The current tlb flush code on powerpc 64 bits has a subtle race since we
lost the page table lock due to the possible faulting in of new PTEs
after a previous one has been removed but before the corresponding hash
entry has been evicted, which can leads to all sort of fatal problems.

This patch reworks the batch code completely. It doesn't use the mmu_gather
stuff anymore. Instead, we use the lazy mmu hooks that were added by the
paravirt code. They have the nice property that the enter/leave lazy mmu
mode pair is always fully contained by the PTE lock for a given range
of PTEs. Thus we can guarantee that all batches are flushed on a given
CPU before it drops that lock.

We also generalize batching for any PTE update that require a flush.

Batching is now enabled on a CPU by arch_enter_lazy_mmu_mode() and
disabled by arch_leave_lazy_mmu_mode(). The code epects that this is
always contained within a PTE lock section so no preemption can happen
and no PTE insertion in that range from another CPU. When batching
is enabled on a CPU, every PTE updates that need a hash flush will
use the batch for that flush.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras

Merge branch 'linux-2.6' into for-2.6.22

2007-04-12T17:50:03+00:00

[POWERPC] Use lowercase for hex printouts in oops messages.

2007-03-26T02:35:03+00:00

Use lowercase for hex printouts in oops messages. The number of times I have
tried to copy and paste from an oops into an objdump search...

Signed-off-by: Anton Blanchard 
Acked-by: Olof Johansson 
Signed-off-by: Paul Mackerras

[POWERPC] Remove last_syscall

2007-03-22T11:52:58+00:00

Remove last_syscall from 32bit powerpc, its been gone in 64bit for years.

Signed-off-by: Anton Blanchard 
Signed-off-by: Paul Mackerras

[POWERPC] Fix atomicity of TIF update in flush_thread()

2007-03-16T05:37:28+00:00

Fix atomicity of TIF update in flush_thread() for powerpc

Fixes it correctly with *_ti_thread_flag.

Race :

parent process executing :
sys_ptrace()
 (lock_kernel())
 (ptrace_get_task_struct(pid))
 arch_ptrace()
   ptrace_detach()
     ptrace_disable(child);
       clear_singlestep(child);
         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
         (which clears the TIF_SINGLESTEP flag atomically from a different
          process)
 (put_task_struct(child))
 (unlock_kernel())

And at the same time, in the child process :
sys_execve()
 do_execve()
   search_binary_handler()
     load_elf_binary()
       flush_old_exec()
         flush_thread()
           doing a non-atomic thread flag update

Applies on 2.6.20.

Signed-off-by: Mathieu Desnoyers 
Signed-off-by: Paul Mackerras