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ACPI / extlog: Check for RDMSR failure

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extlog_init() uses rdmsrl() to read an MSR, which on older CPUs
provokes a error message at boot:

    unchecked MSR access error: RDMSR from 0x179 at rIP: 0xcd047307 (native_read_msr+0x7/0x40)

Use rdmsrl_safe() instead, and return -ENODEV if it fails.

Reported-by: jim@photojim.ca
References: https://bugs.debian.org/971058
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Ben Hutchings 2020-09-27 22:50:42 +01:00 committed by Rafael J. Wysocki
parent a1b8638ba1
commit 7cecb47f55
1 changed files with 3 additions and 3 deletions
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6
drivers/acpi/acpi_extlog.c
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@ -222,9 +222,9 @@ static int __init extlog_init(void)
u64 cap;
int rc;
rdmsrl(MSR_IA32_MCG_CAP, cap);
if (!(cap & MCG_ELOG_P) || !extlog_get_l1addr())
if (rdmsrl_safe(MSR_IA32_MCG_CAP, &cap) ||
!(cap & MCG_ELOG_P) ||
!extlog_get_l1addr())
return -ENODEV;
rc = -EINVAL;