arm64 SIGBUS/SIGSEGV fixes

[Mark Kettenis]

This brings arm64 in line with amd64/i386.  Makes the siginfo-fault
regress test pass.

ok?


Index: arch/arm64/arm64/trap.c
===================================================================
RCS file: /cvs/src/sys/arch/arm64/arm64/trap.c,v
retrieving revision 1.7
diff -u -p -r1.7 trap.c
--- arch/arm64/arm64/trap.c     29 Apr 2017 17:10:43 -0000      1.7
+++ arch/arm64/arm64/trap.c     20 Jul 2017 19:24:45 -0000
@@ -136,7 +136,7 @@ data_abort(struct trapframe *frame, uint
        vaddr_t va;
        union sigval sv;
        uint64_t far;
-       int error = 0, sig;
+       int error = 0, sig, code;
 
        pcb = curcpu()->ci_curpcb;
        p = curcpu()->ci_curproc;
@@ -191,13 +191,22 @@ data_abort(struct trapframe *frame, uint
 
        if (error != 0) {
                if (lower) {
-                       if (error == ENOMEM)
+                       if (error == ENOMEM) {
                                sig = SIGKILL;
-                       else
+                               code = 0;
+                       } else if (error == EIO) {
+                               sig = SIGBUS;
+                               code = BUS_OBJERR;
+                       } else if (error == EACCES) {
                                sig = SIGSEGV;
+                               code = SEGV_ACCERR;
+                       } else {
+                               sig = SIGSEGV;
+                               code = SEGV_MAPERR;
+                       }
                        sv.sival_ptr = (u_int64_t *)far;
 
-                       trapsignal(p, sig, 0, SEGV_ACCERR, sv);
+                       trapsignal(p, sig, 0, code, sv);
                } else {
                        if (curcpu()->ci_idepth == 0 &&
                            pcb->pcb_onfault != 0) {