MIPS: Export FP functions used by lose_fpu(1) for KVM

[ Upstream commit 3ce465e0 ]

Export the _save_fp asm function used by the lose_fpu(1) macro to GPL
modules so that KVM can make use of it when it is built as a module.

This fixes the following build error when CONFIG_KVM=m due to commit
f798217d ("KVM: MIPS: Don't leak FPU/DSP to guest"):

ERROR: "_save_fp" [arch/mips/kvm/kvm.ko] undefined!
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Fixes: f798217d (KVM: MIPS: Don't leak FPU/DSP to guest)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9260/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[james.hogan@imgtec.com: Only export when CPU_R4K_FPU=y prior to v3.16,
 so as not to break the Octeon build which excludes FPU support. KVM
 depends on MIPS32r2 anyway.]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

arch/mips/kernel/mips_ksyms.c

@@ -14,6 +14,7 @@
 #include <linux/mm.h>
 #include <asm/uaccess.h>
 #include <asm/ftrace.h>
+#include <asm/fpu.h>
 
 extern void *__bzero(void *__s, size_t __count);
 extern long __strncpy_from_user_nocheck_asm(char *__to,
@@ -25,6 +26,13 @@ extern long __strlen_user_asm(const char *s);
 extern long __strnlen_user_nocheck_asm(const char *s);
 extern long __strnlen_user_asm(const char *s);
 
+/*
+ * Core architecture code
+ */
+#ifdef CONFIG_CPU_R4K_FPU
+EXPORT_SYMBOL_GPL(_save_fp);
+#endif
+
 /*
  * String functions
  */