[MIPS] Check FCSR for pending interrupts, alternative version

Commit 6d6671066a311703bca1b91645bb1e04cc983387 is incomplete and misses
non-r4k CPUs.  This patch reverts the commit and fixes in other way.

 o Do FCSR checking in caller of restore_fp_context.
 o Send SIGFPE if the signal handler set any FPU exception bits.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 24 insertions, 3 deletions

diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
index 19bbef001959..20013b6fe725 100644
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -220,6 +220,18 @@ static int setup_sigcontext32(struct pt_regs *regs,
         return err;
 }
 
+static int
+check_and_restore_fp_context32(struct sigcontext32 __user *sc)
+{
+        int err, sig;
+
+        err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+        if (err > 0)
+                err = 0;
+        err |= restore_fp_context32(sc);
+        return err ?: sig;
+}
+
 static int restore_sigcontext32(struct pt_regs *regs,
                                 struct sigcontext32 __user *sc)
 {
@@ -255,7 +267,8 @@ static int restore_sigcontext32(struct pt_regs *regs,
         if (used_math()) {
                 /* restore fpu context if we have used it before */
                 own_fpu();
-                err |= restore_fp_context32(sc);
+                if (!err)
+                        err = check_and_restore_fp_context32(sc);
         } else {
                 /* signal handler may have used FPU.  Give it up. */
                 lose_fpu();
@@ -508,6 +521,7 @@ asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
 {
         struct sigframe32 __user *frame;
         sigset_t blocked;
+        int sig;
 
         frame = (struct sigframe32 __user *) regs.regs[29];
         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -521,8 +535,11 @@ asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
 
-        if (restore_sigcontext32(&regs, &frame->sf_sc))
+        sig = restore_sigcontext32(&regs, &frame->sf_sc);
+        if (sig < 0)
                 goto badframe;
+        else if (sig)
+                force_sig(sig, current);
 
         /*
          * Don't let your children do this ...
@@ -545,6 +562,7 @@ asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
         sigset_t set;
         stack_t st;
         s32 sp;
+        int sig;
 
         frame = (struct rt_sigframe32 __user *) regs.regs[29];
         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -558,8 +576,11 @@ asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
 
-        if (restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext))
+        sig = restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext);
+        if (sig < 0)
                 goto badframe;
+        else if (sig)
+                force_sig(sig, current);
 
         /* The ucontext contains a stack32_t, so we must convert!  */
         if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))