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author | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2013-07-19 17:48:08 +0100 |
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committer | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2013-12-16 17:17:32 +0000 |
commit | fb1ab1ab3889fc23ed90e452502662311ebdf229 (patch) | |
tree | e75540da487021a89a933c0451635529d98c2915 | |
parent | 95322526ef62b84adb469c27535ab0252a369a85 (diff) | |
download | linux-stable-fb1ab1ab3889fc23ed90e452502662311ebdf229.tar.gz linux-stable-fb1ab1ab3889fc23ed90e452502662311ebdf229.tar.bz2 linux-stable-fb1ab1ab3889fc23ed90e452502662311ebdf229.zip |
arm64: kernel: implement fpsimd CPU PM notifier
When a CPU enters a low power state, its FP register content is lost.
This patch adds a notifier to save the FP context on CPU shutdown
and restore it on CPU resume. The context is saved and restored only
if the suspending thread is not a kernel thread, mirroring the current
context switch behaviour.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
-rw-r--r-- | arch/arm64/kernel/fpsimd.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index bb785d23dbde..4aef42a04bdc 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -17,6 +17,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/cpu_pm.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/sched.h> @@ -113,6 +114,39 @@ EXPORT_SYMBOL(kernel_neon_end); #endif /* CONFIG_KERNEL_MODE_NEON */ +#ifdef CONFIG_CPU_PM +static int fpsimd_cpu_pm_notifier(struct notifier_block *self, + unsigned long cmd, void *v) +{ + switch (cmd) { + case CPU_PM_ENTER: + if (current->mm) + fpsimd_save_state(¤t->thread.fpsimd_state); + break; + case CPU_PM_EXIT: + if (current->mm) + fpsimd_load_state(¤t->thread.fpsimd_state); + break; + case CPU_PM_ENTER_FAILED: + default: + return NOTIFY_DONE; + } + return NOTIFY_OK; +} + +static struct notifier_block fpsimd_cpu_pm_notifier_block = { + .notifier_call = fpsimd_cpu_pm_notifier, +}; + +static void fpsimd_pm_init(void) +{ + cpu_pm_register_notifier(&fpsimd_cpu_pm_notifier_block); +} + +#else +static inline void fpsimd_pm_init(void) { } +#endif /* CONFIG_CPU_PM */ + /* * FP/SIMD support code initialisation. */ @@ -131,6 +165,8 @@ static int __init fpsimd_init(void) else elf_hwcap |= HWCAP_ASIMD; + fpsimd_pm_init(); + return 0; } late_initcall(fpsimd_init); |