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  1. 04 2月, 2019 1 次提交
  3. 03 2月, 2019 2 次提交
  5. 01 2月, 2019 1 次提交
  7. 31 1月, 2019 6 次提交
    • J
      powerpc/livepatch: return -ERRNO values in save_stack_trace_tsk_reliable() · 3de27dcf
      由 Joe Lawrence 提交于 
      To match its x86 counterpart, save_stack_trace_tsk_reliable() should
return -EINVAL in cases that it is currently returning 1.  No caller is
currently differentiating non-zero error codes, but let's keep the
arch-specific implementations consistent.
Signed-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      3de27dcf
    • J
      powerpc/livepatch: small cleanups in save_stack_trace_tsk_reliable() · 29a77bbb
      由 Joe Lawrence 提交于 
      Mostly cosmetic changes:

- Group common stack pointer code at the top
- Simplify the first frame logic
- Code stackframe iteration into for...loop construct
- Check for trace->nr_entries overflow before adding any into the array
Suggested-by: NNicolai Stange <nstange@suse.de>
Signed-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      29a77bbb
    • J
      powerpc/livepatch: relax reliable stack tracer checks for first-frame · 18be3760
      由 Joe Lawrence 提交于 
      The bottom-most stack frame (the first to be unwound) may be largely
uninitialized, for the "Power Architecture 64-Bit ELF V2 ABI" only
requires its backchain pointer to be set.

The reliable stack tracer should be careful when verifying this frame:
skip checks on STACK_FRAME_LR_SAVE and STACK_FRAME_MARKER offsets that
may contain uninitialized residual data.

Fixes: df78d3f6 ("powerpc/livepatch: Implement reliable stack tracing for the consistency model")
Signed-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      18be3760
    • N
      powerpc/64s: Make reliable stacktrace dependency clearer · a50d3250
      由 Nicolai Stange 提交于 
      Make the HAVE_RELIABLE_STACKTRACE Kconfig option depend on
PPC_BOOK3S_64 for documentation purposes. Before this patch, it
depended on PPC64 && CPU_LITTLE_ENDIAN and because CPU_LITTLE_ENDIAN
implies PPC_BOOK3S_64, there's no functional change here.
Signed-off-by: NNicolai Stange <nstange@suse.de>
Signed-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
[mpe: Split out of larger patch]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      a50d3250
    • N
      powerpc/64s: Clear on-stack exception marker upon exception return · eddd0b33
      由 Nicolai Stange 提交于 
      The ppc64 specific implementation of the reliable stacktracer,
save_stack_trace_tsk_reliable(), bails out and reports an "unreliable
trace" whenever it finds an exception frame on the stack. Stack frames
are classified as exception frames if the STACK_FRAME_REGS_MARKER
magic, as written by exception prologues, is found at a particular
location.

However, as observed by Joe Lawrence, it is possible in practice that
non-exception stack frames can alias with prior exception frames and
thus, that the reliable stacktracer can find a stale
STACK_FRAME_REGS_MARKER on the stack. It in turn falsely reports an
unreliable stacktrace and blocks any live patching transition to
finish. Said condition lasts until the stack frame is
overwritten/initialized by function call or other means.

In principle, we could mitigate this by making the exception frame
classification condition in save_stack_trace_tsk_reliable() stronger:
in addition to testing for STACK_FRAME_REGS_MARKER, we could also take
into account that for all exceptions executing on the kernel stack
  - their stack frames's backlink pointers always match what is saved
    in their pt_regs instance's ->gpr[1] slot and that
  - their exception frame size equals STACK_INT_FRAME_SIZE, a value
    uncommonly large for non-exception frames.

However, while these are currently true, relying on them would make
the reliable stacktrace implementation more sensitive towards future
changes in the exception entry code. Note that false negatives, i.e.
not detecting exception frames, would silently break the live patching
consistency model.

Furthermore, certain other places (diagnostic stacktraces, perf, xmon)
rely on STACK_FRAME_REGS_MARKER as well.

Make the exception exit code clear the on-stack
STACK_FRAME_REGS_MARKER for those exceptions running on the "normal"
kernel stack and returning to kernelspace: because the topmost frame
is ignored by the reliable stack tracer anyway, returns to userspace
don't need to take care of clearing the marker.

Furthermore, as I don't have the ability to test this on Book 3E or 32
bits, limit the change to Book 3S and 64 bits.

Fixes: df78d3f6 ("powerpc/livepatch: Implement reliable stack tracing for the consistency model")
Reported-by: NJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: NNicolai Stange <nstange@suse.de>
Signed-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      eddd0b33
    • M
      powerpc/perf: Add mem access events to sysfs · ab4510e9
      由 Madhavan Srinivasan 提交于 
      Add mem-loads/mem-stores events to sysfs.
The event is formed based on raw event encoding.
Primary PMU event used here is PM_MRK_INST_CMPL
along with MMCRA[SM] modes and Thresholding bit
Signed-off-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      ab4510e9
  9. 30 1月, 2019 6 次提交
  11. 15 1月, 2019 11 次提交
  13. 14 1月, 2019 11 次提交
  15. 08 1月, 2019 1 次提交
  17. 06 1月, 2019 1 次提交