MIPS: Dumb MSA FP exception handler

This patch adds a simple handler for MSA FP exceptions which delivers a
SIGFPE to the running task. In the future it should probably be extended
to re-execute the instruction with the MSACSR.NX bit set in order to
generate results for any elements which did not cause an exception
before delivering the SIGFPE signal.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6432/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 278a49b..7365cd6 100644 (file)
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -475,6 +475,7 @@ NESTED(nmi_handler, PT_SIZE, sp)
        BUILD_HANDLER cpu cpu sti silent                /* #11 */
        BUILD_HANDLER ov ov sti silent                  /* #12 */
        BUILD_HANDLER tr tr sti silent                  /* #13 */
+       BUILD_HANDLER msa_fpe msa_fpe sti silent        /* #14 */
        BUILD_HANDLER fpe fpe fpe silent                /* #15 */
        BUILD_HANDLER ftlb ftlb none silent             /* #16 */
        BUILD_HANDLER msa msa sti silent                /* #21 */

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 4f27cbf..7ac4d8f 100644 (file)
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -78,6 +78,7 @@ extern asmlinkage void handle_ri_rdhwr(void);
 extern asmlinkage void handle_cpu(void);
 extern asmlinkage void handle_ov(void);
 extern asmlinkage void handle_tr(void);
+extern asmlinkage void handle_msa_fpe(void);
 extern asmlinkage void handle_fpe(void);
 extern asmlinkage void handle_ftlb(void);
 extern asmlinkage void handle_msa(void);
@@ -1250,6 +1251,16 @@ out:
        exception_exit(prev_state);
 }
 
+asmlinkage void do_msa_fpe(struct pt_regs *regs)
+{
+       enum ctx_state prev_state;
+
+       prev_state = exception_enter();
+       die_if_kernel("do_msa_fpe invoked from kernel context!", regs);
+       force_sig(SIGFPE, current);
+       exception_exit(prev_state);
+}
+
 asmlinkage void do_msa(struct pt_regs *regs)
 {
        enum ctx_state prev_state;
@@ -2106,6 +2117,7 @@ void __init trap_init(void)
        set_except_vector(11, handle_cpu);
        set_except_vector(12, handle_ov);
        set_except_vector(13, handle_tr);
+       set_except_vector(14, handle_msa_fpe);
 
        if (current_cpu_type() == CPU_R6000 ||
            current_cpu_type() == CPU_R6000A) {