[PATCH stable 3.10, 3.12, 3.14] MIPS: Export FP functions used by lose_fpu(1) for KVM

[James Hogan]

[ Upstream commit 3ce465e04bfd8de9956d515d6e9587faac3375dc ]

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
f798217dfd03 ("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@xxxxxxxxxx>
Fixes: f798217dfd03 (KVM: MIPS: Don't leak FPU/DSP to guest)
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # 3.10...3.15
Patchwork: https://patchwork.linux-mips.org/patch/9260/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
[james.hogan@xxxxxxxxxx: 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@xxxxxxxxxx>
---
Appologies for the previous cavium_octeon_defconfig link breakage.
Octeon has the symbol since 3.16, but not before. This backport should
do the trick for stable 3.10, 3.12, and 3.14. Build tested with
cavium_octeon_defconfig and malta_kvm_defconfig on those stable
branches.
---
 arch/mips/kernel/mips_ksyms.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/mips/kernel/mips_ksyms.c b/arch/mips/kernel/mips_ksyms.c
index 6e58e97fcd39..cedeb5686eb5 100644
--- a/arch/mips/kernel/mips_ksyms.c
+++ b/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,
@@ -26,6 +27,13 @@ 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
  */
 EXPORT_SYMBOL(memset);
-- 
2.0.5

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