powerpc/traps: factor common code from program check and emulation assist

Move the program check handling into a function called by both, rather
than have the emulation assist handler call the program check handler.

This allows each of these handlers to be implemented with "interrupt
wrappers" in a later change.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1612702475.d6qyt6qtfy.astroid@bobo.none

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index f70d3f6174c8ad4a907b2ba897b5fc701a8f4f41..2c5986109412094439133bc591053989fc9c0eef 100644 (file)
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1462,9 +1462,8 @@ static int emulate_math(struct pt_regs *regs)
 static inline int emulate_math(struct pt_regs *regs) { return -1; }
 #endif
 
-void program_check_exception(struct pt_regs *regs)
+static void do_program_check(struct pt_regs *regs)
 {
-       enum ctx_state prev_state = exception_enter();
        unsigned int reason = get_reason(regs);
 
        /* We can now get here via a FP Unavailable exception if the core
@@ -1473,22 +1472,22 @@ void program_check_exception(struct pt_regs *regs)
        if (reason & REASON_FP) {
                /* IEEE FP exception */
                parse_fpe(regs);
-               goto bail;
+               return;
        }
        if (reason & REASON_TRAP) {
                unsigned long bugaddr;
                /* Debugger is first in line to stop recursive faults in
                 * rcu_lock, notify_die, or atomic_notifier_call_chain */
                if (debugger_bpt(regs))
-                       goto bail;
+                       return;
 
                if (kprobe_handler(regs))
-                       goto bail;
+                       return;
 
                /* trap exception */
                if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
                                == NOTIFY_STOP)
-                       goto bail;
+                       return;
 
                bugaddr = regs->nip;
                /*
@@ -1500,10 +1499,10 @@ void program_check_exception(struct pt_regs *regs)
                if (!(regs->msr & MSR_PR) &&  /* not user-mode */
                    report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {
                        regs->nip += 4;
-                       goto bail;
+                       return;
                }
                _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
-               goto bail;
+               return;
        }
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        if (reason & REASON_TM) {
@@ -1524,7 +1523,7 @@ void program_check_exception(struct pt_regs *regs)
                 */
                if (user_mode(regs)) {
                        _exception(SIGILL, regs, ILL_ILLOPN, regs->nip);
-                       goto bail;
+                       return;
                } else {
                        printk(KERN_EMERG "Unexpected TM Bad Thing exception "
                               "at %lx (msr 0x%lx) tm_scratch=%llx\n",
@@ -1557,7 +1556,7 @@ void program_check_exception(struct pt_regs *regs)
         * pattern to occurrences etc. -dgibson 31/Mar/2003
         */
        if (!emulate_math(regs))
-               goto bail;
+               return;
 
        /* Try to emulate it if we should. */
        if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
@@ -1565,10 +1564,10 @@ void program_check_exception(struct pt_regs *regs)
                case 0:
                        regs->nip += 4;
                        emulate_single_step(regs);
-                       goto bail;
+                       return;
                case -EFAULT:
                        _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
-                       goto bail;
+                       return;
                }
        }
 
@@ -1578,7 +1577,14 @@ sigill:
        else
                _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 
-bail:
+}
+
+void program_check_exception(struct pt_regs *regs)
+{
+       enum ctx_state prev_state = exception_enter();
+
+       do_program_check(regs);
+
        exception_exit(prev_state);
 }
 NOKPROBE_SYMBOL(program_check_exception);
@@ -1589,8 +1595,12 @@ NOKPROBE_SYMBOL(program_check_exception);
  */
 void emulation_assist_interrupt(struct pt_regs *regs)
 {
+       enum ctx_state prev_state = exception_enter();
+
        regs->msr |= REASON_ILLEGAL;
-       program_check_exception(regs);
+       do_program_check(regs);
+
+       exception_exit(prev_state);
 }
 NOKPROBE_SYMBOL(emulation_assist_interrupt);