irqchip: mips-gic: SYNC after enabling GIC region

A SYNC is required between enabling the GIC region and actually trying
to use it, even if the first access is a read, otherwise its possible
depending on the timing (and in my case depending on the precise
alignment of certain kernel code) to hit CM bus errors on that first
access.

Add the SYNC straight after setting the GIC base.

[paul.burton@imgtec.com:
  Changes later in this series increase our likelihood of hitting this
  by reducing the amount of code that runs between enabling the GIC &
  accessing it.]

Fixes: a7057270c2 ("irqchip: mips-gic: Add device-tree support")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.19.x-
Patchwork: https://patchwork.linux-mips.org/patch/17019/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
James Hogan 2017-08-12 21:36:09 -07:00 committed by Ralf Baechle
parent 5af2ed3669
commit 2c0e838238

View File

@ -1020,8 +1020,11 @@ static int __init gic_of_init(struct device_node *node,
gic_len = resource_size(&res);
}
if (mips_cm_present())
if (mips_cm_present()) {
write_gcr_gic_base(gic_base | CM_GCR_GIC_BASE_GICEN_MSK);
/* Ensure GIC region is enabled before trying to access it */
__sync();
}
gic_present = true;
__gic_init(gic_base, gic_len, cpu_vec, 0, node);