tile: improve illegal translation interrupt handling

First, don't re-enable interrupts blindly in the Linux trap handler.
We already handle page faults this way; synchronous interrupts like
ILL_TRANS will fire even when interrupts are disabled, and we don't
want to re-enable interrupts in that case.

For ILL_TRANS, we now pass the ILL_VA_PC reason into the trap handler
so we can report it properly; this is the address that caused the
illegal translation trap.  We print the address as part of the
pr_alert() message now if it's coming from the kernel.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 38a60f2..562886d 100644 (file)
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -492,7 +492,7 @@ intvec_\vecname:
        mfspr   r3, SPR_SYSTEM_SAVE_K_2   /* info about page fault */
        .else
        .ifc \vecnum, INT_ILL_TRANS
-       mfspr   r2, ILL_TRANS_REASON
+       mfspr   r2, ILL_VA_PC
        .else
        .ifc \vecnum, INT_DOUBLE_FAULT
        mfspr   r2, SPR_SYSTEM_SAVE_K_2   /* double fault info from HV */

diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c
index 5b19a23..a1bbc5d 100644 (file)
--- a/arch/tile/kernel/traps.c
+++ b/arch/tile/kernel/traps.c
@@ -222,8 +222,9 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
        unsigned long address = 0;
        bundle_bits instr;
 
-       /* Re-enable interrupts. */
-       local_irq_enable();
+       /* Re-enable interrupts, if they were previously enabled. */
+       if (!(regs->flags & PT_FLAGS_DISABLE_IRQ))
+               local_irq_enable();
 
        /*
         * If it hits in kernel mode and we can't fix it up, just exit the
@@ -231,7 +232,8 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
         */
        if (!user_mode(regs)) {
                const char *name;
-               if (fixup_exception(regs))  /* only UNALIGN_DATA in practice */
+               char buf[100];
+               if (fixup_exception(regs))  /* ILL_TRANS or UNALIGN_DATA */
                        return;
                if (fault_num >= 0 &&
                    fault_num < sizeof(int_name)/sizeof(int_name[0]) &&
@@ -239,10 +241,16 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
                        name = int_name[fault_num];
                else
                        name = "Unknown interrupt";
-               pr_alert("Kernel took bad trap %d (%s) at PC %#lx\n",
-                        fault_num, name, regs->pc);
                if (fault_num == INT_GPV)
-                       pr_alert("GPV_REASON is %#lx\n", reason);
+                       snprintf(buf, sizeof(buf), "; GPV_REASON %#lx", reason);
+#ifdef __tilegx__
+               else if (fault_num == INT_ILL_TRANS)
+                       snprintf(buf, sizeof(buf), "; address %#lx", reason);
+#endif
+               else
+                       buf[0] = '\0';
+               pr_alert("Kernel took bad trap %d (%s) at PC %#lx%s\n",
+                        fault_num, name, regs->pc, buf);
                show_regs(regs);
                do_exit(SIGKILL);  /* FIXME: implement i386 die() */
                return;
@@ -324,11 +332,8 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
                fill_ra_stack();
 
                signo = SIGSEGV;
+               address = reason;
                code = SEGV_MAPERR;
-               if (reason & SPR_ILL_TRANS_REASON__I_STREAM_VA_RMASK)
-                       address = regs->pc;
-               else
-                       address = 0;  /* FIXME: GX: single-step for address */
                break;
        }
 #endif