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Date: Thu, 12 Jun 2014 12:46:58 -0700
From: Kees Cook <keescook@...omium.org>
To: linux-kernel@...r.kernel.org
Cc: Kees Cook <keescook@...omium.org>,
Randy Dunlap <rdunlap@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
Wei Yongjun <yongjun_wei@...ndmicro.com.cn>,
linux-doc@...r.kernel.org, linux-pm@...r.kernel.org
Subject: [PATCH 1/2] hibernate: create one-way disable mode
To support using kernel features that are not compatible with hibernation,
this creates a "disabled" hibernation state so that hibernation selection
can be a boot-time choice instead of only a compile-time choice.
Signed-off-by: Kees Cook <keescook@...omium.org>
---
include/linux/suspend.h | 2 ++
kernel/power/hibernate.c | 55 +++++++++++++++++++++++++++++++---------------
kernel/power/main.c | 6 ++---
kernel/power/user.c | 3 +++
4 files changed, 44 insertions(+), 22 deletions(-)
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index f76994b9396c..519064e0c943 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -327,6 +327,7 @@ extern unsigned long get_safe_page(gfp_t gfp_mask);
extern void hibernation_set_ops(const struct platform_hibernation_ops *ops);
extern int hibernate(void);
extern bool system_entering_hibernation(void);
+extern bool hibernation_available(void);
asmlinkage int swsusp_save(void);
extern struct pbe *restore_pblist;
#else /* CONFIG_HIBERNATION */
@@ -339,6 +340,7 @@ static inline void swsusp_unset_page_free(struct page *p) {}
static inline void hibernation_set_ops(const struct platform_hibernation_ops *ops) {}
static inline int hibernate(void) { return -ENOSYS; }
static inline bool system_entering_hibernation(void) { return false; }
+static inline bool hibernation_available(void) { return false; }
#endif /* CONFIG_HIBERNATION */
/* Hibernation and suspend events */
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index df88d55dc436..32672da81114 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -43,6 +43,7 @@ __visible int in_suspend __nosavedata;
enum {
HIBERNATION_INVALID,
+ HIBERNATION_DISABLED,
HIBERNATION_PLATFORM,
HIBERNATION_SHUTDOWN,
HIBERNATION_REBOOT,
@@ -61,6 +62,11 @@ bool freezer_test_done;
static const struct platform_hibernation_ops *hibernation_ops;
+bool hibernation_available(void)
+{
+ return (hibernation_mode > HIBERNATION_DISABLED);
+}
+
/**
* hibernation_set_ops - Set the global hibernate operations.
* @ops: Hibernation operations to use in subsequent hibernation transitions.
@@ -75,10 +81,12 @@ void hibernation_set_ops(const struct platform_hibernation_ops *ops)
}
lock_system_sleep();
hibernation_ops = ops;
- if (ops)
- hibernation_mode = HIBERNATION_PLATFORM;
- else if (hibernation_mode == HIBERNATION_PLATFORM)
- hibernation_mode = HIBERNATION_SHUTDOWN;
+ if (hibernation_available()) {
+ if (ops)
+ hibernation_mode = HIBERNATION_PLATFORM;
+ else if (hibernation_mode == HIBERNATION_PLATFORM)
+ hibernation_mode = HIBERNATION_SHUTDOWN;
+ }
unlock_system_sleep();
}
@@ -639,6 +647,11 @@ int hibernate(void)
{
int error;
+ if (!hibernation_available()) {
+ pr_debug("PM: Hibernation not available.\n");
+ return -EINVAL;
+ }
+
lock_system_sleep();
/* The snapshot device should not be opened while we're running */
if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
@@ -731,7 +744,7 @@ static int software_resume(void)
/*
* If the user said "noresume".. bail out early.
*/
- if (noresume)
+ if (noresume || !hibernation_available())
return 0;
/*
@@ -857,6 +870,7 @@ late_initcall_sync(software_resume);
static const char * const hibernation_modes[] = {
+ [HIBERNATION_DISABLED] = "disabled",
[HIBERNATION_PLATFORM] = "platform",
[HIBERNATION_SHUTDOWN] = "shutdown",
[HIBERNATION_REBOOT] = "reboot",
@@ -931,6 +945,9 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
char *p;
int mode = HIBERNATION_INVALID;
+ if (!hibernation_available())
+ return -EINVAL;
+
p = memchr(buf, '\n', n);
len = p ? p - buf : n;
@@ -942,23 +959,25 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
break;
}
}
- if (mode != HIBERNATION_INVALID) {
- switch (mode) {
- case HIBERNATION_SHUTDOWN:
- case HIBERNATION_REBOOT:
+ switch (mode) {
+ case HIBERNATION_DISABLED:
+ case HIBERNATION_SHUTDOWN:
+ case HIBERNATION_REBOOT:
#ifdef CONFIG_SUSPEND
- case HIBERNATION_SUSPEND:
+ case HIBERNATION_SUSPEND:
#endif
+ hibernation_mode = mode;
+ break;
+ case HIBERNATION_PLATFORM:
+ if (hibernation_ops)
hibernation_mode = mode;
- break;
- case HIBERNATION_PLATFORM:
- if (hibernation_ops)
- hibernation_mode = mode;
- else
- error = -EINVAL;
- }
- } else
+ else
+ error = -EINVAL;
+ break;
+ default:
error = -EINVAL;
+ break;
+ }
if (!error)
pr_debug("PM: Hibernation mode set to '%s'\n",
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 573410d6647e..8e90f330f139 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -300,13 +300,11 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
s += sprintf(s,"%s ", pm_states[i].label);
#endif
-#ifdef CONFIG_HIBERNATION
- s += sprintf(s, "%s\n", "disk");
-#else
+ if (hibernation_available())
+ s += sprintf(s, "disk ");
if (s != buf)
/* convert the last space to a newline */
*(s-1) = '\n';
-#endif
return (s - buf);
}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 98d357584cd6..000b94419182 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -49,6 +49,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
struct snapshot_data *data;
int error;
+ if (!hibernation_available())
+ return -EINVAL;
+
lock_system_sleep();
if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
--
1.7.9.5
--
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