Re: [parisc-linux] 720 - some progress

[Jurij Smakov <jurij@lokmail.net>]

Hi!

I hope I've got it right. It only emulates MFCTL and only when the
source control register is 27. It turns out, that pt_regs does not
have a member for cr26 and adding one does not look like an easy
task. 

Jurij.

--- linux-2.4.9-pa24/arch/parisc/kernel/traps.c Wed Sep 19 12:02:30 2001
+++ linux/arch/parisc/kernel/traps.c    Thu Sep 27 16:16:54 2001
@@ -273,6 +273,7 @@
 {
        unsigned long fault_address = 0;
        unsigned long fault_space = 0;
+       int fromcr,togr;
        struct siginfo si;
 #ifdef CONFIG_KWDB
        struct save_state ssp;
@@ -363,6 +364,17 @@
                si.si_code = ILL_PRVOPC;
                goto give_sigill;
        case 11:
+               if(!(regs->iir & 0xfc000000) && (((regs->iir & 0x1fe0)>>5) == 0x45)) {
+                 /* This is MFCTL instruction */
+                 fromcr = (regs->iir & 0x03e00000)>>21;
+                 togr = (regs->iir & 0x1f);
+                 /* Emulate the instruction if the read is from cr27 */
+                 if(fromcr == 27) {
+                   regs->gr[togr] = regs->cr27;
+                   return;
+                 }
+               }
+               /* Something else is wrong */
                die_if_kernel("Privileged register - shouldn't happen!", regs, code);
                si.si_code = ILL_PRVREG;
        give_sigill: