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Commit 87eae076 authored by Ben Hutchings's avatar Ben Hutchings Committed by Greg Kroah-Hartman
Browse files

ACPI / extlog: Check for RDMSR failure 



commit 7cecb47f55e00282f972a1e0b09136c8cd938221 upstream.

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: default avatar <jim@photojim.ca>
References: https://bugs.debian.org/971058


Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 02e92557

drivers/acpi/acpi_extlog.c

+3 −3
Original line number Diff line number Diff line
@@ -224,9 +224,9 @@ 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;



	if (edac_get_report_status() == EDAC_REPORTING_FORCE) {