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>

diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c
index 2872accd22156b7ee134f70c84376a7dff48a4c8..7b2be251c30fb92981d4aef8cf4f8951bed24728 100644 (file)
--- 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 772ddfdb71a8e67af8f20e38ff7f8def9af3b943..1216dfb4fcc58a0e812be9c80df6cd8495ec28b2 100644 (file)
--- 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) {