drivers/perf: arm_spe: Don't error on high-order pages for aux buf
authorWill Deacon <will.deacon@arm.com>
Mon, 13 May 2019 16:53:03 +0000 (17:53 +0100)
committerWill Deacon <will.deacon@arm.com>
Mon, 13 May 2019 17:01:56 +0000 (18:01 +0100)
commit14ae42a6f0b13130a97d94d23481128961de5d38
treec2725f3a573da711269bad4b21f286b5bf9eb99f
parenta98d9ae937d256ed679a935fc82d9deaa710d98e
drivers/perf: arm_spe: Don't error on high-order pages for aux buf

Since commit 5768402fd9c6 ("perf/ring_buffer: Use high order allocations
for AUX buffers optimistically"), the perf core tends to back aux buffer
allocations with high-order pages with the order encoded in the
PagePrivate data. The Arm SPE driver explicitly rejects such pages,
causing the perf tool to fail with:

  | failed to mmap with 12 (Cannot allocate memory)

In actual fact, we can simply treat these pages just like any other
since the perf core takes care to populate the page array appropriately.
In theory we could try to map with PMDs where possible, but for now,
let's just get things working again.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 5768402fd9c6 ("perf/ring_buffer: Use high order allocations for AUX buffers optimistically")
Reported-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
drivers/perf/arm_spe_pmu.c