librdbg fix for PowerPC

[Joel Sherrill]

This is merged.  Between holidays, my personal situation and
replacing the main RTEMS development machine, things have
been backed up a little.  I expect a snapshot today or
over the weekend.

Thanks.

-joel

Till Straumann wrote:
> 
> Hi.
> 
> Today was RDBG day for me. I started using the debugger
> for EPICS applications on PowerPC / SVGM5.
> 
> However, librdbg needed to be fixed - the out of the box
> version didn't work (see comments in the patch file)
> 
> -- Till.
> 
>   ------------------------------------------------------------------------
> RTEMS librdbg patch (against rtems-ss-20011210)
> 
> Author: Till Straumann <strauman at slac.stanford.edu>
> 
> This patch addresses the following issues:
>  - exception handler needs to enable MSR_FP if the
>    interrupted thread is FP enabled.
>  - printk message for MSR fixed and
>    added stacktrace
>    NOTE: this requires the stacktrace
>    patch to lib/libbsp/powerpc/shared/vectors/vector_init.c
>    (#ifdef DDEBUG only, however)
> 
> Index: c/src/librdbg//src/powerpc/excep_f.c
> ===================================================================
> RCS file: /afs/slac/g/spear/cvsrep/rtems/src/c/src/librdbg/src/powerpc/excep_f.c,v
> retrieving revision 1.1.1.1
> retrieving revision 1.2
> diff -c -r1.1.1.1 -r1.2
> *** c/src/librdbg//src/powerpc/excep_f.c        2001/12/14 22:54:21     1.1.1.1
> --- c/src/librdbg//src/powerpc/excep_f.c        2002/01/18 05:25:44     1.2
> ***************
> *** 56,61 ****
> --- 56,73 ----
>     rtems_status_code status;
>     rtems_id continueSemId;
> 
> +   /* T. Straumann, 1/16/2002: we must re-enable the floating point engine
> +    *                          if the interrupted thread is FP. Otherwise,
> +    *                          the semaphore primitives may crash when they
> +    *                          try to save FP context while switching this
> +    *                          thread...
> +    */
> +   if (ctx->EXC_SRR1 & 0x2000) {
> +       register unsigned long msr;
> +       __asm__ __volatile__("mfmsr %0":"=r"(msr));
> +       __asm__ __volatile__("mtmsr %0"::"r"(msr|MSR_FP));
> +   }
> +
>     if ( (justSaveContext) && (ctx->_EXC_number == ASM_SYS_VECTOR) ) {
>       PushSavedExceptCtx (_Thread_Executing->Object.id, ctx);
>       justSaveContext = 0;
> ***************
> *** 114,120 ****
>       printk("\t CTR = %x\n", ctx->EXC_CTR);
>       printk("\t XER = %x\n", ctx->EXC_XER);
>       printk("\t LR = %x\n", ctx->EXC_LR);
> !     printk("\t MSR = %x\n", ctx->EXC_MSR);
>   #endif
> 
>       status = rtems_semaphore_create (rtems_build_name('D', 'B', 'G', 'c'),
> --- 126,132 ----
>       printk("\t CTR = %x\n", ctx->EXC_CTR);
>       printk("\t XER = %x\n", ctx->EXC_XER);
>       printk("\t LR = %x\n", ctx->EXC_LR);
> !     printk("\t MSR = %x\n", ctx->EXC_SRR1);
>   #endif
> 
>       status = rtems_semaphore_create (rtems_build_name('D', 'B', 'G', 'c'),
> ***************
> *** 151,156 ****
> --- 163,173 ----
> 
>       default:
>         DPRINTF((" OTHER EXCEPTION !!!\n"));
> + #ifdef DDEBUG
> +       { extern void BSP_printStackTrace();
> +               BSP_printStackTrace(ctx);
> +       }
> + #endif
>         rtems_semaphore_release( wakeupEventSemId );
>         break;
>       }

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel at OARcorp.com                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
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