Commit a7c4c0d9 authored Nov 13, 2009 by H. Peter Anvin

x86, sleep: Always save the value of EFER



Always save the value of EFER, regardless of the state of NX.  Since
EFER may not actually exist, use rdmsr_safe() to do so.

v2: check the return value from rdmsr_safe() instead of relying on
    the output values being unchanged on error.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@tuxonice.net>
LKML-Reference: <1258154897-6770-3-git-send-email-hpa@zytor.com>
Acked-by: Kees Cook <kees.cook@canonical.com>

parent 8a50e513

arch/x86/kernel/acpi/sleep.c

+3 −6

Original line number	Diff line number	Diff line
		@@ -78,12 +78,9 @@ int acpi_save_state_mem(void)
		#ifndef CONFIG_64BIT
		store_gdt((struct desc_ptr *)&header->pmode_gdt);

		header->pmode_efer_low = nx_enabled;
		if (header->pmode_efer_low & 1) {
		/* This is strange, why not save efer, always? */
		rdmsr(MSR_EFER, header->pmode_efer_low,
		header->pmode_efer_high);
		}
		if (rdmsr_safe(MSR_EFER, &header->pmode_efer_low,
		&header->pmode_efer_high))
		header->pmode_efer_low = header->pmode_efer_high = 0;
		#endif /* !CONFIG_64BIT */

		header->pmode_cr0 = read_cr0();