kernel: mips_disable_fpu: initialize fault_addr in fpu_emulator_cop1Handler

Code calling fpu_emulator_cop1Handler will pass on fault_addr, making gcc
complain about it not being initialized when the FPU emulator is disabled.

Fixes:

arch/mips/kernel/traps.c: In function 'do_fpe':
arch/mips/kernel/traps.c:864:22: error: 'fault_addr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  process_fpemu_return(sig, fault_addr, fcr31);
                      ^
arch/mips/kernel/traps.c: In function 'do_ri':
arch/mips/kernel/traps.c:806:22: error: 'fault_addr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  process_fpemu_return(sig, fault_addr, fcr31);
                      ^
arch/mips/kernel/traps.c:763:15: note: 'fault_addr' was declared here
  void __user *fault_addr;
               ^
arch/mips/kernel/traps.c: In function 'do_cpu':
arch/mips/kernel/traps.c:1421:28: error: 'fault_addr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   if (!process_fpemu_return(sig, fault_addr, fcr31) && !err)
                            ^
cc1: all warnings being treated as errors
make[7]: *** [arch/mips/kernel/traps.o] Error 1

Signed-off-by: Jonas Gorski <jogo@openwrt.org>

SVN-Revision: 46184

target/linux/generic/patches-4.1/304-mips_disable_fpu.patch

@@ -82,7 +82,7 @@ v2: incorporated changes suggested by Jonas Gorski
  #ifdef CONFIG_DEBUG_FS
  
  struct mips_fpu_emulator_stats {
-@@ -66,6 +67,20 @@ extern int do_dsemulret(struct pt_regs *
+@@ -66,6 +67,21 @@ extern int do_dsemulret(struct pt_regs *
  extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
  				    struct mips_fpu_struct *ctx, int has_fpu,
  				    void *__user *fault_addr);
@@ -96,6 +96,7 @@ v2: incorporated changes suggested by Jonas Gorski
 +				struct mips_fpu_struct *ctx, int has_fpu,
 +				void *__user *fault_addr)
 +{
++	*fault_addr = NULL;
 +	return SIGILL;	/* we don't speak MIPS FPU */
 +}
 +#endif	/* CONFIG_MIPS_FPU_EMULATOR */