1 files changed, 90 insertions, 21 deletions

diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index f091786187a6..07d67309451a 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -20,6 +20,7 @@
 #include <linux/ptrace.h>
 #include <linux/unistd.h>
 #include <linux/compiler.h>
+#include <linux/uaccess.h>
 
 #include <asm/abi.h>
 #include <asm/asm.h>
@@ -27,7 +28,6 @@
 #include <asm/cacheflush.h>
 #include <asm/fpu.h>
 #include <asm/sim.h>
-#include <asm/uaccess.h>
 #include <asm/ucontext.h>
 #include <asm/cpu-features.h>
 #include <asm/war.h>
@@ -78,10 +78,51 @@ struct rt_sigframe {
 /*
  * Helper routines
  */
+static int protected_save_fp_context(struct sigcontext __user *sc)
+{
+        int err;
+        while (1) {
+                lock_fpu_owner();
+                own_fpu_inatomic(1);
+                err = save_fp_context(sc); /* this might fail */
+                unlock_fpu_owner();
+                if (likely(!err))
+                        break;
+                /* touch the sigcontext and try again */
+                err = __put_user(0, &sc->sc_fpregs[0]) |
+                        __put_user(0, &sc->sc_fpregs[31]) |
+                        __put_user(0, &sc->sc_fpc_csr);
+                if (err)
+                        break;  /* really bad sigcontext */
+        }
+        return err;
+}
+
+static int protected_restore_fp_context(struct sigcontext __user *sc)
+{
+        int err, tmp;
+        while (1) {
+                lock_fpu_owner();
+                own_fpu_inatomic(0);
+                err = restore_fp_context(sc); /* this might fail */
+                unlock_fpu_owner();
+                if (likely(!err))
+                        break;
+                /* touch the sigcontext and try again */
+                err = __get_user(tmp, &sc->sc_fpregs[0]) |
+                        __get_user(tmp, &sc->sc_fpregs[31]) |
+                        __get_user(tmp, &sc->sc_fpc_csr);
+                if (err)
+                        break;  /* really bad sigcontext */
+        }
+        return err;
+}
+
 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 {
         int err = 0;
         int i;
+        unsigned int used_math;
 
         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 
@@ -104,24 +145,48 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
         }
 
-        err |= __put_user(!!used_math(), &sc->sc_used_math);
+        used_math = !!used_math();
+        err |= __put_user(used_math, &sc->sc_used_math);
 
-        if (used_math()) {
+        if (used_math) {
                 /*
                  * Save FPU state to signal context. Signal handler
                  * will "inherit" current FPU state.
                  */
-                preempt_disable();
+                err |= protected_save_fp_context(sc);
+        }
+        return err;
+}
 
-                if (!is_fpu_owner()) {
-                        own_fpu();
-                        restore_fp(current);
-                }
-                err |= save_fp_context(sc);
+int fpcsr_pending(unsigned int __user *fpcsr)
+{
+        int err, sig = 0;
+        unsigned int csr, enabled;
 
-                preempt_enable();
+        err = __get_user(csr, fpcsr);
+        enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
+        /*
+         * If the signal handler set some FPU exceptions, clear it and
+         * send SIGFPE.
+         */
+        if (csr & enabled) {
+                csr &= ~enabled;
+                err |= __put_user(csr, fpcsr);
+                sig = SIGFPE;
         }
-        return err;
+        return err ?: sig;
+}
+
+static int
+check_and_restore_fp_context(struct sigcontext __user *sc)
+{
+        int err, sig;
+
+        err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+        if (err > 0)
+                err = 0;
+        err |= protected_restore_fp_context(sc);
+        return err ?: sig;
 }
 
 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
@@ -157,19 +222,15 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
         err |= __get_user(used_math, &sc->sc_used_math);
         conditional_used_math(used_math);
 
-        preempt_disable();
-
-        if (used_math()) {
+        if (used_math) {
                 /* restore fpu context if we have used it before */
-                own_fpu();
-                err |= restore_fp_context(sc);
+                if (!err)
+                        err = check_and_restore_fp_context(sc);
         } else {
                 /* signal handler may have used FPU.  Give it up. */
-                lose_fpu();
+                lose_fpu(0);
         }
 
-        preempt_enable();
-
         return err;
 }
 
@@ -332,6 +393,7 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 {
         struct sigframe __user *frame;
         sigset_t blocked;
+        int sig;
 
         frame = (struct sigframe __user *) regs.regs[29];
         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -345,8 +407,11 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
 
-        if (restore_sigcontext(&regs, &frame->sf_sc))
+        sig = restore_sigcontext(&regs, &frame->sf_sc);
+        if (sig < 0)
                 goto badframe;
+        else if (sig)
+                force_sig(sig, current);
 
         /*
          * Don't let your children do this ...
@@ -368,6 +433,7 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
         struct rt_sigframe __user *frame;
         sigset_t set;
         stack_t st;
+        int sig;
 
         frame = (struct rt_sigframe __user *) regs.regs[29];
         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -381,8 +447,11 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
 
-        if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
+        sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
+        if (sig < 0)
                 goto badframe;
+        else if (sig)
+                force_sig(sig, current);
 
         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
                 goto badframe;