mips/signal: In force_fcr31_sig return in the impossible case

In a recent discussion Maciej Rozycki reported that this case is
impossible.

Handle the impossible case by just returning instead of trying to
handle it.  This makes static analysis simpler as it means nothing
needs to consider the impossible case after the return statement.

As the code no longer has to deal with this case remove FPE_FIXME from
the mips siginfo.h

Cc: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: http://lkml.kernel.org/r/20170718140651.15973-4-ebiederm@xmission.com
Ref: ea1b75cf9138 ("signal/mips: Document a conflict with SI_USER with SIGFPE")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

diff --git a/arch/mips/include/uapi/asm/siginfo.h b/arch/mips/include/uapi/asm/siginfo.h
index 22a86d84a5048f93569049e6352ef0ae0e65794e..cf6113bbcb98cfb4edeeb4e052a6452580d9f018 100644 (file)
--- a/arch/mips/include/uapi/asm/siginfo.h
+++ b/arch/mips/include/uapi/asm/siginfo.h
@@ -123,11 +123,4 @@ typedef struct siginfo {
 #define SI_TIMER       -3      /* sent by timer expiration */
 #define SI_MESGQ       -4      /* sent by real time mesq state change */
 
-/*
- * SIGFPE si_codes
- */
-#ifdef __KERNEL__
-#define FPE_FIXME      0       /* Broken dup of SI_USER */
-#endif /* __KERNEL__ */
-
 #endif /* _UAPI_ASM_SIGINFO_H */

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 6c9cca9c53419bcdef5b1fe3926fba26c5c26656..2bf41499334777e7a8682453222427dd084765ee 100644 (file)
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -735,7 +735,7 @@ void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
        else if (fcr31 & FPU_CSR_INE_X)
                si.si_code = FPE_FLTRES;
        else
-               si.si_code = FPE_FIXME;
+               return; /* Broken hardware? */
        force_sig_info(SIGFPE, &si, tsk);
 }