path: root/tools/testing/selftests/powerpc/vphn
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authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2019-07-03 22:33:57 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2019-07-04 22:23:38 +1000
commit06220d78f24a20549757be1014e57c382406cc92 (patch)
tree361c14510bdc0baa3ad92b3429d3df548dcbef34 /tools/testing/selftests/powerpc/vphn
parentpowerpc/pseries: Factor out DTL buffer allocation and registration routines (diff)
powerpc/pseries: Introduce rwlock to gatekeep DTLB usage
Since we would be introducing a new user of the DTL buffer in a subsequent patch, we need a way to gatekeep use of the DTL buffer. The current debugfs interface for DTL allows registering and opening cpu-specific DTL buffers. Cpu specific files are exposed under debugfs 'powerpc/dtl/' node, and changing 'dtl_event_mask' in the same directory enables controlling the event mask used when registering DTL buffer for a particular cpu. Subsequently, we will be introducing a user of the DTL buffers that registers access to the DTL buffers across all cpus with the same event mask. To ensure these two users do not step on each other, we introduce a rwlock to gatekeep DTL buffer access. This fits the requirement of the current debugfs interface wanting to allow multiple independent cpu-specific users (read lock), and the subsequent user wanting exclusive access (write lock). Suggested-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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