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authorShaohua Li <shaohua.li@intel.com>2008-07-23 21:28:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:24 -0700
commitbdfe6b7c681669148dae4db27eb24ee5408ba371 (patch)
tree644b84a7e4a329a635d9a9bc02102424cfb616e2
parent2f15fc4bdf91eb399da3f47a09c55831d9f22826 (diff)
pm: acpi hibernation: utilize hardware signature
ACPI defines a hardware signature. BIOS calculates the signature according to hardware configure and if hardware changes while hibernated, the signature will change. In that case, S4 resume should fail. Still, there may be systems on which this mechanism does not work correctly, so it is better to provide a workaround for them. For this reason, add a new switch to the acpi_sleep= command line argument allowing one to disable hardware signature checking. [shaohua.li@intel.com: build fix] Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Andi Kleen <andi@firstfloor.org> Cc: Len Brown <lenb@kernel.org> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: <Valdis.Kletnieks@vt.edu> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Documentation/kernel-parameters.txt4
-rw-r--r--arch/x86/kernel/acpi/sleep.c4
-rw-r--r--drivers/acpi/sleep/main.c22
-rw-r--r--include/linux/acpi.h1
4 files changed, 30 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4d705713cab..497a98dafda 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -148,10 +148,12 @@ and is between 256 and 4096 characters. It is defined in the file
default: 0
acpi_sleep= [HW,ACPI] Sleep options
- Format: { s3_bios, s3_mode, s3_beep, old_ordering }
+ Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
See Documentation/power/video.txt for s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
+ s4_nohwsig prevents ACPI hardware signature from being
+ used during resume from hibernation.
old_ordering causes the ACPI 1.0 ordering of the _PTS
control method, wrt putting devices into low power
states, to be enforced (the ACPI 2.0 ordering of _PTS is
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index a3ddad18aaa..fa2161d5003 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -150,6 +150,10 @@ static int __init acpi_sleep_setup(char *str)
acpi_realmode_flags |= 2;
if (strncmp(str, "s3_beep", 7) == 0)
acpi_realmode_flags |= 4;
+#ifdef CONFIG_HIBERNATION
+ if (strncmp(str, "s4_nohwsig", 10) == 0)
+ acpi_no_s4_hw_signature();
+#endif
if (strncmp(str, "old_ordering", 12) == 0)
acpi_old_suspend_ordering();
str = strchr(str, ',');
diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c
index 0489a7d1d42..313507accf1 100644
--- a/drivers/acpi/sleep/main.c
+++ b/drivers/acpi/sleep/main.c
@@ -283,6 +283,15 @@ static struct platform_suspend_ops acpi_suspend_ops_old = {
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATION
+static unsigned long s4_hardware_signature;
+static struct acpi_table_facs *facs;
+static bool nosigcheck;
+
+void __init acpi_no_s4_hw_signature(void)
+{
+ nosigcheck = true;
+}
+
static int acpi_hibernation_begin(void)
{
acpi_target_sleep_state = ACPI_STATE_S4;
@@ -316,6 +325,12 @@ static void acpi_hibernation_leave(void)
acpi_enable();
/* Reprogram control registers and execute _BFS */
acpi_leave_sleep_state_prep(ACPI_STATE_S4);
+ /* Check the hardware signature */
+ if (facs && s4_hardware_signature != facs->hardware_signature) {
+ printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
+ "cannot resume!\n");
+ panic("ACPI S4 hardware signature mismatch");
+ }
}
static void acpi_pm_enable_gpes(void)
@@ -544,6 +559,13 @@ int __init acpi_sleep_init(void)
&acpi_hibernation_ops_old : &acpi_hibernation_ops);
sleep_states[ACPI_STATE_S4] = 1;
printk(" S4");
+ if (!nosigcheck) {
+ acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
+ (struct acpi_table_header **)&facs);
+ if (facs)
+ s4_hardware_signature =
+ facs->hardware_signature;
+ }
}
#endif
status = acpi_get_sleep_type_data(ACPI_STATE_S5, &type_a, &type_b);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index a1717763937..702f79dad16 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -236,6 +236,7 @@ int acpi_check_mem_region(resource_size_t start, resource_size_t n,
const char *name);
#ifdef CONFIG_PM_SLEEP
+void __init acpi_no_s4_hw_signature(void);
void __init acpi_old_suspend_ordering(void);
#endif /* CONFIG_PM_SLEEP */
#else /* CONFIG_ACPI */