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authorLeo Yan <leoy@marvell.com>2014-09-01 11:09:51 +0800
committerWill Deacon <will.deacon@arm.com>2014-09-01 12:55:21 +0100
commit7c68a9cc040216c902f93f9c80305df55d9beff7 (patch)
treeecdb72890cbf45f840a2ea9e2f2b188133ca16db
parent3168a743461ecf86adf3e7dcfcd79271828fb263 (diff)
downloadtest-7c68a9cc040216c902f93f9c80305df55d9beff7.tar.gz
arm64: fix bug for reloading FPSIMD state after cpu power off
Now arm64 defers reloading FPSIMD state, but this optimization also introduces the bug after cpu resume back from low power mode. The reason is after the cpu has been powered off, s/w need set the cpu's fpsimd_last_state to NULL so that it will force to reload FPSIMD state for the thread, otherwise there has the chance to meet the condition for both the task's fpsimd_state.cpu field contains the id of the current cpu, and the cpu's fpsimd_last_state per-cpu variable points to the task's fpsimd_state, so finally kernel will skip to reload the context during it return back to userland. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Leo Yan <leoy@marvell.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--arch/arm64/kernel/fpsimd.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index ad8aebb1cdef7..3dca15634e69c 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -270,6 +270,7 @@ static int fpsimd_cpu_pm_notifier(struct notifier_block *self,
case CPU_PM_ENTER:
if (current->mm && !test_thread_flag(TIF_FOREIGN_FPSTATE))
fpsimd_save_state(&current->thread.fpsimd_state);
+ this_cpu_write(fpsimd_last_state, NULL);
break;
case CPU_PM_EXIT:
if (current->mm)