linux-stable.git/arch/powerpc/kernel/process.c, branch linux-3.13.y

powerpc/tm: Fix crash when forking inside a transaction

2014-03-24T04:44:07+00:00

commit 621b5060e823301d0cba4cb52a7ee3491922d291 upstream.

When we fork/clone we currently don't copy any of the TM state to the new
thread.  This results in a TM bad thing (program check) when the new process is
switched in as the kernel does a tmrechkpt with TEXASR FS not set.  Also, since
R1 is from userspace, we trigger the bad kernel stack pointer detection.  So we
end up with something like this:

   Bad kernel stack pointer 0 at c0000000000404fc
   cpu 0x2: Vector: 700 (Program Check) at [c00000003ffefd40]
       pc: c0000000000404fc: restore_gprs+0xc0/0x148
       lr: 0000000000000000
       sp: 0
      msr: 9000000100201030
     current = 0xc000001dd1417c30
     paca    = 0xc00000000fe00800   softe: 0        irq_happened: 0x01
       pid   = 0, comm = swapper/2
   WARNING: exception is not recoverable, can't continue

The below fixes this by flushing the TM state before we copy the task_struct to
the clone.  To do this we go through the tmreclaim patch, which removes the
checkpointed registers from the CPU and transitions the CPU out of TM suspend
mode.  Hence we need to call tmrechkpt after to restore the checkpointed state
and the TM mode for the current task.

To make this fail from userspace is simply:
	tbegin
	li	r0, 2
	sc
	

Kudos to Adhemerval Zanella Neto for finding this.

Signed-off-by: Michael Neuling 
cc: Adhemerval Zanella Neto 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'signed-for-3.13' of git://github.com/agraf/linux-2.6 into kvm-master

2013-12-20T18:13:58+00:00

Patch queue for 3.13 - 2013-12-18

This fixes some grave issues we've only found after 3.13-rc1:

  - Make the modularized HV/PR book3s kvm work well as modules
  - Fix some race conditions
  - Fix compilation with certain compilers (booke)
  - Fix THP for book3s_hv
  - Fix preemption for book3s_pr

Alexander Graf (4):
      KVM: PPC: Book3S: PR: Don't clobber our exit handler id
      KVM: PPC: Book3S: PR: Export kvmppc_copy_to|from_svcpu
      KVM: PPC: Book3S: PR: Make svcpu -> vcpu store preempt savvy
      KVM: PPC: Book3S: PR: Enable interrupts earlier

Aneesh Kumar K.V (1):
      powerpc: book3s: kvm: Don't abuse host r2 in exit path

Paul Mackerras (5):
      KVM: PPC: Book3S HV: Fix physical address calculations
      KVM: PPC: Book3S HV: Refine barriers in guest entry/exit
      KVM: PPC: Book3S HV: Make tbacct_lock irq-safe
      KVM: PPC: Book3S HV: Take SRCU read lock around kvm_read_guest() call
      KVM: PPC: Book3S HV: Don't drop low-order page address bits

Scott Wood (1):
      powerpc/kvm/booke: Fix build break due to stack frame size warning

pingfan liu (1):
      powerpc: kvm: fix rare but potential deadlock scene

powerpc/kvm/booke: Fix build break due to stack frame size warning

2013-12-10T23:12:44+00:00

Commit ce11e48b7fdd256ec68b932a89b397a790566031 ("KVM: PPC: E500: Add
userspace debug stub support") added "struct thread_struct" to the
stack of kvmppc_vcpu_run().  thread_struct is 1152 bytes on my build,
compared to 48 bytes for the recently-introduced "struct debug_reg".
Use the latter instead.

This fixes the following error:

cc1: warnings being treated as errors
arch/powerpc/kvm/booke.c: In function 'kvmppc_vcpu_run':
arch/powerpc/kvm/booke.c:760:1: error: the frame size of 1424 bytes is larger than 1024 bytes
make[2]: *** [arch/powerpc/kvm/booke.o] Error 1
make[1]: *** [arch/powerpc/kvm] Error 2
make[1]: *** Waiting for unfinished jobs....

Signed-off-by: Scott Wood 
Signed-off-by: Alexander Graf

Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

2013-11-22T16:07:11+00:00

Pull third set of powerpc updates from Benjamin Herrenschmidt:
 "This is a small collection of random bug fixes and a few improvements
  of Oops output which I deemed valuable enough to include as well.

  The fixes are essentially recent build breakage and regressions, and a
  couple of older bugs such as the DTL log duplication, the EEH issue
  with PCI_COMMAND_MASTER and the problem with small contexts passed to
  get/set_context with VSX enabled"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/signals: Mark VSX not saved with small contexts
  powerpc/pseries: Fix SMP=n build of rng.c
  powerpc: Make cpu_to_chip_id() available when SMP=n
  powerpc/vio: Fix a dma_mask issue of vio
  powerpc: booke: Fix build failures
  powerpc: ppc64 address space capped at 32TB, mmap randomisation disabled
  powerpc: Only print PACATMSCRATCH in oops when TM is active
  powerpc/pseries: Duplicate dtl entries sometimes sent to userspace
  powerpc: Remove a few lines of oops output
  powerpc: Print DAR and DSISR on machine check oopses
  powerpc: Fix __get_user_pages_fast() irq handling
  powerpc/eeh: More accurate log
  powerpc/eeh: Enable PCI_COMMAND_MASTER for PCI bridges

powerpc: Only print PACATMSCRATCH in oops when TM is active

2013-11-20T23:33:40+00:00

If TM is not active there is no need to print PACATMSCRATCH
so we can save ourselves a line.

Signed-off-by: Anton Blanchard 
Acked-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Remove a few lines of oops output

2013-11-20T23:33:39+00:00

We waste quite a few lines in our oops output:

...
MSR: 8000000000009032   CR: 28044024  XER: 00000000
SOFTE: 0
CFAR: 0000000000009088
DAR: 000000000000001c, DSISR: 40000000

GPR00: c0000000000c74f0 c00000037cc1b010 c000000000d2bb30 0000000000000000
...

We can do a better job here and remove 3 lines:

MSR: 8000000000009032   CR: 28044024  XER: 00000000
CFAR: 0000000000009088 DAR: 0000000000000010, DSISR: 40000000 SOFTE: 1
GPR00: c0000000000e3d10 c00000037cc2fda0 c000000000d2c3a8 0000000000000001

Also move PACATMSCRATCH up, it doesn't really belong in the stack
trace section.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Print DAR and DSISR on machine check oopses

2013-11-20T23:33:38+00:00

Machine check exceptions set DAR and DSISR, so print them in our
oops output.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: ELF2 binaries launched directly.

2013-11-20T22:19:19+00:00

No function descriptor, but we set r12 up and set TIF_RESTOREALL as it
normally isn't restored on return from syscall.

Signed-off-by: Rusty Russell 
Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc/tm: Remove interrupt disable in __switch_to()

2013-10-31T05:19:17+00:00

We currently turn IRQs off in __switch_to(0 but this is unnecessary as it's
already disabled in the caller.

This removes the IRQ disable but adds a check to make sure it is really off
in case this changes in future.

Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt

powerpc: export debug registers save function for KVM

2013-10-18T23:46:18+00:00

KVM need this function when switching from vcpu to user-space
thread. My subsequent patch will use this function.

Signed-off-by: Bharat Bhushan 
Acked-by: Michael Neuling 
Signed-off-by: Scott Wood