1. 15 Jul, 2018 1 commit
    • Hugh Dickins's avatar
      x86/events/intel/ds: Fix bts_interrupt_threshold alignment · 2c991e40
      Hugh Dickins authored
      Markus reported that BTS is sporadically missing the tail of the trace
      in the perf_event data buffer: [decode error (1): instruction overflow]
      shown in GDB; and bisected it to the conversion of debug_store to PTI.
      
      A little "optimization" crept into alloc_bts_buffer(), which mistakenly
      placed bts_interrupt_threshold away from the 24-byte record boundary.
      Intel SDM Vol 3B 17.4.9 says "This address must point to an offset from
      the BTS buffer base that is a multiple of the BTS record size."
      
      Revert "max" from a byte count to a record count, to calculate the
      bts_interrupt_threshold correctly: which turns out to fix problem seen.
      
      Fixes: c1961a46 ("x86/events/intel/ds: Map debug buffers in cpu_entry_area")
      Reported-and-tested-by: default avatarMarkus T Metzger <markus.t.metzger@intel.com>
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
      Cc: Alexander Shishkin <alexander.shishkin@intel.com>
      Cc: Andi Kleen <andi.kleen@intel.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: stable@vger.kernel.org # v4.14+
      Link: https://lkml.kernel.org/r/alpine.LSU.2.11.1807141248290.1614@eggly.anvils
      2c991e40
  2. 14 Jul, 2018 16 commits
  3. 13 Jul, 2018 15 commits
  4. 12 Jul, 2018 8 commits