[MIPS] Retry {save,restore}_fp_context if failed in atomic context.
The save_fp_context()/restore_fp_context() might sleep on accessing
user stack and therefore might lose FPU ownership in middle of them.
If these function failed due to "in_atomic" test in do_page_fault,
touch the sigcontext area in non-atomic context and retry these
save/restore operation.
This is a replacement of a (broken) fix which was titled "Allow CpU
exception in kernel partially".
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/fpu.h b/include/asm-mips/fpu.h
index 71436f9..b414a7d 100644
--- a/include/asm-mips/fpu.h
+++ b/include/asm-mips/fpu.h
@@ -100,14 +100,19 @@
set_thread_flag(TIF_USEDFPU);
}
-static inline void own_fpu(int restore)
+static inline void own_fpu_inatomic(int restore)
{
- preempt_disable();
if (cpu_has_fpu && !__is_fpu_owner()) {
__own_fpu();
if (restore)
_restore_fp(current);
}
+}
+
+static inline void own_fpu(int restore)
+{
+ preempt_disable();
+ own_fpu_inatomic(restore);
preempt_enable();
}