alpha: irq: run all handlers with interrupts disabled

Linux has expected that interrupt handlers are executed with local
interrupts disabled for a while now, so ensure that this is the case on
Alpha even for non-device interrupts such as IPIs.

Without this patch, secondary boot results in the following backtrace:

  warning: at kernel/softirq.c:139 __local_bh_enable+0xb8/0xd0()
  trace:
    __local_bh_enable+0xb8/0xd0
    irq_enter+0x74/0xa0
    scheduler_ipi+0x50/0x100
    handle_ipi+0x84/0x260
    do_entint+0x1ac/0x2e0
    irq_exit+0x60/0xa0
    handle_irq+0x98/0x100
    do_entint+0x2c8/0x2e0
    ret_from_sys_call+0x0/0x10
    load_balance+0x3e4/0x870
    cpu_idle+0x24/0x80
    rcu_eqs_enter_common.isra.38+0x0/0x120
    cpu_idle+0x40/0x80
    rest_init+0xc0/0xe0
    _stext+0x1c/0x20

A similar dump occurs if you try to reboot using magic-sysrq.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 8 insertions, 8 deletions

diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c
index 2872accd2215..7b2be251c30f 100644
--- a/arch/alpha/kernel/irq.c
+++ b/arch/alpha/kernel/irq.c
@@ -117,13 +117,6 @@ handle_irq(int irq)
                 return;
         }
 
-        /*
-         * From here we must proceed with IPL_MAX. Note that we do not
-         * explicitly enable interrupts afterwards - some MILO PALcode
-         * (namely LX164 one) seems to have severe problems with RTI
-         * at IPL 0.
-         */
-        local_irq_disable();
         irq_enter();
         generic_handle_irq_desc(irq, desc);
         irq_exit();
diff --git a/arch/alpha/kernel/irq_alpha.c b/arch/alpha/kernel/irq_alpha.c
index 772ddfdb71a8..1216dfb4fcc5 100644
--- a/arch/alpha/kernel/irq_alpha.c
+++ b/arch/alpha/kernel/irq_alpha.c
@@ -45,6 +45,14 @@ do_entInt(unsigned long type, unsigned long vector,
           unsigned long la_ptr, struct pt_regs *regs)
 {
         struct pt_regs *old_regs;
+
+        /*
+         * Disable interrupts during IRQ handling.
+         * Note that there is no matching local_irq_enable() due to
+         * severe problems with RTI at IPL0 and some MILO PALcode
+         * (namely LX164).
+         */
+        local_irq_disable();
         switch (type) {
         case 0:
 #ifdef CONFIG_SMP
@@ -62,7 +70,6 @@ do_entInt(unsigned long type, unsigned long vector,
           {
                 long cpu;
 
-                local_irq_disable();
                 smp_percpu_timer_interrupt(regs);
                 cpu = smp_processor_id();
                 if (cpu != boot_cpuid) {