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 */