Storing DAR (and maybe DSISR and ES) in uc_mcontext

[Richard M Kreuter <kreuter%progn.net@localhost>]

Hello,

I'm trying to port an application from Darwin and Linux whose segfault
handler wants to examine the contents of the DAR, but the DAR doesn't
get stored in the native ucontext on NetBSD (it looks as though it does
get stored in the Darwin ucontext for emulation, though).  I thought the
patch below would do this, but it doesn't seem to work (or perhaps my
test programs are incorrect).  In any case this patch doesn't seem to
destabilize anything: I've been running with a kernel and userland built
with these patches for a couple weeks.  Can anybody help me get this
working?

Thank you,
Richard M Kreuter

--- ./sys/arch/powerpc/include/mcontext.h.~1.7~ 2005-12-12 21:55:35.000000000 
-0500
+++ ./sys/arch/powerpc/include/mcontext.h       2005-12-12 21:54:49.000000000 
-0500
@@ -47,7 +47,7 @@
  * an ucontext_t is different from System V.
  */
 
-#define        _NGREG  39              /* GR0-31, CR, LR, SRR0, SRR1, CTR, 
XER, MQ */
+#define        _NGREG  42              /* GR0-31, CR, LR, SRR0, SRR1, CTR, 
XER, MQ, DAR, DSISR, EXC */
 
 typedef        long            __greg_t;
 typedef        __greg_t        __gregset_t[_NGREG];
@@ -91,6 +91,9 @@ typedef       __greg_t        __gregset_t[_NGREG];
 #define        _REG_CTR        36              /* Count Register */
 #define        _REG_XER        37              /* Integet Exception Reigster */
 #define        _REG_MQ         38              /* MQ Register (POWER only) */
+#define        _REG_DAR        39              /* Data Address register */
+#define        _REG_DSISR      40              /* DSISR */
+#define        _REG_EXC        41              /* EXC */
 
 typedef struct {
        double          __fpu_regs[32]; /* FP0-31 */
--- ./sys/arch/powerpc/powerpc/sig_machdep.c.~1.24~     2005-12-12 
21:56:18.000000000 -0500
+++ ./sys/arch/powerpc/powerpc/sig_machdep.c    2005-12-12 21:54:51.000000000 
-0500
@@ -175,6 +175,9 @@ cpu_getmcontext(struct lwp *l, mcontext_
 #else
        gr[_REG_MQ]  = 0;
 #endif
+       gr[_REG_DAR] = tf->dar;
+       gr[_REG_DSISR] = tf->dsisr;
+       gr[_REG_EXC] = tf->exc;
        *flagp |= _UC_CPU;
 
 #ifdef PPC_HAVE_FPU
@@ -244,6 +247,9 @@ cpu_setmcontext(struct lwp *l, const mco
 #ifdef PPC_OEA
                tf->tf_xtra[TF_MQ] = gr[_REG_MQ];
 #endif
+               tf->dar = gr[_REG_DAR]; 
+               tf->dsisr = gr[_REG_DSISR];
+               tf->exc = gr[_REG_EXC];
        }
 
 #ifdef PPC_HAVE_FPU /* Restore FPR context, if any. */