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Commit 5c4c8075 authored by Lino Sanfilippo's avatar Lino Sanfilippo Committed by Greg Kroah-Hartman
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tpm, tpm_tis: Avoid cache incoherency in test for interrupts

[ Upstream commit 858e8b79

 ]

The interrupt handler that sets the boolean variable irq_tested may run on
another CPU as the thread that checks irq_tested as part of the irq test in
tpm_tis_send().

Since nothing guarantees cache coherency between CPUs for unsynchronized
accesses to boolean variables the testing thread might not perceive the
value change done in the interrupt handler.

Avoid this issue by setting the bit TPM_TIS_IRQ_TESTED in the flags field
of the tpm_tis_data struct and by accessing this field with the bit
manipulating functions that provide cache coherency.

Also convert all other existing sites to use the proper macros when
accessing this bitfield.

Signed-off-by: default avatarLino Sanfilippo <l.sanfilippo@kunbus.com>
Tested-by: default avatarMichael Niewöhner <linux@mniewoehner.de>
Tested-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Stable-dep-of: 1398aa80

 ("tpm_tis: Use tpm_chip_{start,stop} decoration inside tpm_tis_resume")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 1ec14527
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