vserver 1.9.3

[linux-2.6.git] / arch / ppc / kernel / traps.c

diff --git a/arch/ppc/kernel/traps.c b/arch/ppc/kernel/traps.c
index 544ea9f..7870bb6 100644 (file)
--- a/arch/ppc/kernel/traps.c
+++ b/arch/ppc/kernel/traps.c
@@ -357,7 +357,7 @@ void RunModeException(struct pt_regs *regs)
 
 /* Illegal instruction emulation support.  Originally written to
  * provide the PVR to user applications using the mfspr rd, PVR.
- * Return non-zero if we can't emulate, or EFAULT if the associated
+ * Return non-zero if we can't emulate, or -EFAULT if the associated
  * memory access caused an access fault.  Return zero on success.
  *
  * There are a couple of ways to do this, either "decode" the instruction
@@ -368,16 +368,19 @@ void RunModeException(struct pt_regs *regs)
 #define INST_MFSPR_PVR         0x7c1f42a6
 #define INST_MFSPR_PVR_MASK    0xfc1fffff
 
+#define INST_DCBA              0x7c0005ec
+#define INST_DCBA_MASK         0x7c0007fe
+
+#define INST_MCRXR             0x7c000400
+#define INST_MCRXR_MASK                0x7c0007fe
+
 static int emulate_instruction(struct pt_regs *regs)
 {
        u32 instword;
        u32 rd;
-       int retval;
-
-       retval = -EINVAL;
 
        if (!user_mode(regs))
-               return retval;
+               return -EINVAL;
        CHECK_FULL_REGS(regs);
 
        if (get_user(instword, (u32 __user *)(regs->nip)))
@@ -388,10 +391,24 @@ static int emulate_instruction(struct pt_regs *regs)
        if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
                rd = (instword >> 21) & 0x1f;
                regs->gpr[rd] = mfspr(PVR);
-               retval = 0;
-               regs->nip += 4;
+               return 0;
        }
-       return retval;
+
+       /* Emulating the dcba insn is just a no-op.  */
+       if ((instword & INST_DCBA_MASK) == INST_DCBA)
+               return 0;
+
+       /* Emulate the mcrxr insn.  */
+       if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
+               int shift = (instword >> 21) & 0x1c;
+               unsigned long msk = 0xf0000000UL >> shift;
+
+               regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
+               regs->xer &= ~0xf0000000UL;
+               return 0;
+       }
+
+       return -EINVAL;
 }
 
 /*
@@ -528,17 +545,23 @@ void ProgramCheckException(struct pt_regs *regs)
                return;
        }
 
-       if (reason & REASON_PRIVILEGED) {
-               /* Try to emulate it if we should. */
-               if (emulate_instruction(regs) == 0) {
+       /* Try to emulate it if we should. */
+       if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
+               switch (emulate_instruction(regs)) {
+               case 0:
+                       regs->nip += 4;
                        emulate_single_step(regs);
                        return;
+               case -EFAULT:
+                       _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
+                       return;
                }
-               _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
-               return;
        }
 
-       _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
+       if (reason & REASON_PRIVILEGED)
+               _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
+       else
+               _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 }
 
 void SingleStepException(struct pt_regs *regs)