diff options
| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-12-14 12:33:51 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-12-30 11:51:47 +0100 |
| commit | 6001db0272dad842c151151f5a9b89a53a7f7520 (patch) | |
| tree | 7093b73ae280487ef4a0e877436d4257a974c8d2 /kernel/trace | |
| parent | 33afcf723a0e655d35a60afe451bba47c9045ed3 (diff) | |
Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"
commit adab66b71abfe206a020f11e561f4df41f0b2aba upstream.
It was believed that metag was the only architecture that required the ring
buffer to keep 8 byte words aligned on 8 byte architectures, and with its
removal, it was assumed that the ring buffer code did not need to handle
this case. It appears that sparc64 also requires this.
The following was reported on a sparc64 boot up:
kernel: futex hash table entries: 65536 (order: 9, 4194304 bytes, linear)
kernel: Running postponed tracer tests:
kernel: Testing tracer function:
kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
kernel: PASSED
Need to put back the 64BIT aligned code for the ring buffer.
Link: https://lore.kernel.org/r/CADxRZqzXQRYgKc=y-KV=S_yHL+Y8Ay2mh5ezeZUnpRvg+syWKw@mail.gmail.com
Cc: stable@vger.kernel.org
Fixes: 86b3de60a0b6 ("ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS")
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 6e5c6b023dc3..077877ed54f7 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -129,7 +129,16 @@ int ring_buffer_print_entry_header(struct trace_seq *s) #define RB_ALIGNMENT 4U #define RB_MAX_SMALL_DATA (RB_ALIGNMENT * RINGBUF_TYPE_DATA_TYPE_LEN_MAX) #define RB_EVNT_MIN_SIZE 8U /* two 32bit words */ -#define RB_ALIGN_DATA __aligned(RB_ALIGNMENT) + +#ifndef CONFIG_HAVE_64BIT_ALIGNED_ACCESS +# define RB_FORCE_8BYTE_ALIGNMENT 0 +# define RB_ARCH_ALIGNMENT RB_ALIGNMENT +#else +# define RB_FORCE_8BYTE_ALIGNMENT 1 +# define RB_ARCH_ALIGNMENT 8U +#endif + +#define RB_ALIGN_DATA __aligned(RB_ARCH_ALIGNMENT) /* define RINGBUF_TYPE_DATA for 'case RINGBUF_TYPE_DATA:' */ #define RINGBUF_TYPE_DATA 0 ... RINGBUF_TYPE_DATA_TYPE_LEN_MAX @@ -2367,7 +2376,7 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer, event->time_delta = delta; length -= RB_EVNT_HDR_SIZE; - if (length > RB_MAX_SMALL_DATA) { + if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT) { event->type_len = 0; event->array[0] = length; } else @@ -2382,11 +2391,11 @@ static unsigned rb_calculate_event_length(unsigned length) if (!length) length++; - if (length > RB_MAX_SMALL_DATA) + if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT) length += sizeof(event.array[0]); length += RB_EVNT_HDR_SIZE; - length = ALIGN(length, RB_ALIGNMENT); + length = ALIGN(length, RB_ARCH_ALIGNMENT); /* * In case the time delta is larger than the 27 bits for it |