[MIPS] Maintain si_code field properly for FP exceptions

The appended patch adds code to update siginfo_t's si_code field. It
fixes e.g. a floating point overflow regression in the SBCL testsuite.

Signed-off-By: Thiemo Seufer <ths@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 18 insertions, 3 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index d6103e510899..6379003f9d8d 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -606,6 +606,8 @@ asmlinkage void do_ov(struct pt_regs *regs)
  */
 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 {
+        siginfo_t info;
+
         die_if_kernel("FP exception in kernel code", regs);
 
         if (fcr31 & FPU_CSR_UNI_X) {
@@ -641,9 +643,22 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
                         force_sig(sig, current);
 
                 return;
-        }
-
-        force_sig(SIGFPE, current);
+        } else if (fcr31 & FPU_CSR_INV_X)
+                info.si_code = FPE_FLTINV;
+        else if (fcr31 & FPU_CSR_DIV_X)
+                info.si_code = FPE_FLTDIV;
+        else if (fcr31 & FPU_CSR_OVF_X)
+                info.si_code = FPE_FLTOVF;
+        else if (fcr31 & FPU_CSR_UDF_X)
+                info.si_code = FPE_FLTUND;
+        else if (fcr31 & FPU_CSR_INE_X)
+                info.si_code = FPE_FLTRES;
+        else
+                info.si_code = __SI_FAULT;
+        info.si_signo = SIGFPE;
+        info.si_errno = 0;
+        info.si_addr = (void __user *) regs->cp0_epc;
+        force_sig_info(SIGFPE, &info, current);
 }
 
 asmlinkage void do_bp(struct pt_regs *regs)