diff options
author | Jarkko Sakkinen <jarkko@kernel.org> | 2023-04-26 20:29:28 +0300 |
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committer | Jarkko Sakkinen <jarkko@kernel.org> | 2023-05-16 02:43:12 +0300 |
commit | 99d46450625590d410f86fe4660a5eff7d3b8343 (patch) | |
tree | 446c3d6a59c7a4a8762954ee3e527ff0b257d686 /drivers/char/tpm/tpm-interface.c | |
parent | 1398aa803f198b7a386fdd8404666043e95f4c16 (diff) | |
download | linux-99d46450625590d410f86fe4660a5eff7d3b8343.tar.xz |
tpm: Prevent hwrng from activating during resume
Set TPM_CHIP_FLAG_SUSPENDED in tpm_pm_suspend() and reset in
tpm_pm_resume(). While the flag is set, tpm_hwrng() gives back zero
bytes. This prevents hwrng from racing during resume.
Cc: stable@vger.kernel.org
Fixes: 6e592a065d51 ("tpm: Move Linux RNG connection to hwrng")
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'drivers/char/tpm/tpm-interface.c')
-rw-r--r-- | drivers/char/tpm/tpm-interface.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 4463d0018290..586ca10b0d72 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -412,6 +412,8 @@ int tpm_pm_suspend(struct device *dev) } suspended: + chip->flags |= TPM_CHIP_FLAG_SUSPENDED; + if (rc) dev_err(dev, "Ignoring error %d while suspending\n", rc); return 0; @@ -429,6 +431,14 @@ int tpm_pm_resume(struct device *dev) if (chip == NULL) return -ENODEV; + chip->flags &= ~TPM_CHIP_FLAG_SUSPENDED; + + /* + * Guarantee that SUSPENDED is written last, so that hwrng does not + * activate before the chip has been fully resumed. + */ + wmb(); + return 0; } EXPORT_SYMBOL_GPL(tpm_pm_resume); |