arm64: Unmask asynchronous aborts when in kernel mode

The asynchronous aborts are generally fatal for the kernel but they can
be masked via the pstate A bit. If a system error happens while in
kernel mode, it won't be visible until returning to user space. This
patch enables this kind of abort early to help identifying the cause.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
index aa11943..b2fcfbc 100644 (file)
--- a/arch/arm64/include/asm/irqflags.h
+++ b/arch/arm64/include/asm/irqflags.h
@@ -56,6 +56,9 @@ static inline void arch_local_irq_disable(void)
 #define local_fiq_enable()     asm("msr        daifclr, #1" : : : "memory")
 #define local_fiq_disable()    asm("msr        daifset, #1" : : : "memory")
 
+#define local_async_enable()   asm("msr        daifclr, #4" : : : "memory")
+#define local_async_disable()  asm("msr        daifset, #4" : : : "memory")
+
 /*
  * Save the current interrupt enable state.
  */

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 0bc5e4c..bd9bbd0 100644 (file)
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -205,6 +205,11 @@ u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };
 
 void __init setup_arch(char **cmdline_p)
 {
+       /*
+        * Unmask asynchronous aborts early to catch possible system errors.
+        */
+       local_async_enable();
+
        setup_processor();
 
        setup_machine_fdt(__fdt_pointer);

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index a5aeefa..a0c2ca6 100644 (file)
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -160,6 +160,7 @@ asmlinkage void secondary_start_kernel(void)
 
        local_irq_enable();
        local_fiq_enable();
+       local_async_enable();
 
        /*
         * OK, it's off to the idle thread for us