--- /dev/null
+From 6ccb4ac2bf8a35c694ead92f8ac5530a16e8f2c8 Mon Sep 17 00:00:00 2001
+From: Greg Kurz <groug@kaod.org>
+Date: Wed, 11 Sep 2019 17:52:18 +0200
+Subject: powerpc/xive: Fix bogus error code returned by OPAL
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Greg Kurz <groug@kaod.org>
+
+commit 6ccb4ac2bf8a35c694ead92f8ac5530a16e8f2c8 upstream.
+
+There's a bug in skiboot that causes the OPAL_XIVE_ALLOCATE_IRQ call
+to return the 32-bit value 0xffffffff when OPAL has run out of IRQs.
+Unfortunatelty, OPAL return values are signed 64-bit entities and
+errors are supposed to be negative. If that happens, the linux code
+confusingly treats 0xffffffff as a valid IRQ number and panics at some
+point.
+
+A fix was recently merged in skiboot:
+
+e97391ae2bb5 ("xive: fix return value of opal_xive_allocate_irq()")
+
+but we need a workaround anyway to support older skiboots already
+in the field.
+
+Internally convert 0xffffffff to OPAL_RESOURCE which is the usual error
+returned upon resource exhaustion.
+
+Cc: stable@vger.kernel.org # v4.12+
+Signed-off-by: Greg Kurz <groug@kaod.org>
+Reviewed-by: Cédric Le Goater <clg@kaod.org>
+Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
+Link: https://lore.kernel.org/r/156821713818.1985334.14123187368108582810.stgit@bahia.lan
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/powerpc/include/asm/opal.h | 2 +-
+ arch/powerpc/platforms/powernv/opal-call.c | 2 +-
+ arch/powerpc/sysdev/xive/native.c | 11 +++++++++++
+ 3 files changed, 13 insertions(+), 2 deletions(-)
+
+--- a/arch/powerpc/include/asm/opal.h
++++ b/arch/powerpc/include/asm/opal.h
+@@ -272,7 +272,7 @@ int64_t opal_xive_get_vp_info(uint64_t v
+ int64_t opal_xive_set_vp_info(uint64_t vp,
+ uint64_t flags,
+ uint64_t report_cl_pair);
+-int64_t opal_xive_allocate_irq(uint32_t chip_id);
++int64_t opal_xive_allocate_irq_raw(uint32_t chip_id);
+ int64_t opal_xive_free_irq(uint32_t girq);
+ int64_t opal_xive_sync(uint32_t type, uint32_t id);
+ int64_t opal_xive_dump(uint32_t type, uint32_t id);
+--- a/arch/powerpc/platforms/powernv/opal-call.c
++++ b/arch/powerpc/platforms/powernv/opal-call.c
+@@ -257,7 +257,7 @@ OPAL_CALL(opal_xive_set_queue_info, OPA
+ OPAL_CALL(opal_xive_donate_page, OPAL_XIVE_DONATE_PAGE);
+ OPAL_CALL(opal_xive_alloc_vp_block, OPAL_XIVE_ALLOCATE_VP_BLOCK);
+ OPAL_CALL(opal_xive_free_vp_block, OPAL_XIVE_FREE_VP_BLOCK);
+-OPAL_CALL(opal_xive_allocate_irq, OPAL_XIVE_ALLOCATE_IRQ);
++OPAL_CALL(opal_xive_allocate_irq_raw, OPAL_XIVE_ALLOCATE_IRQ);
+ OPAL_CALL(opal_xive_free_irq, OPAL_XIVE_FREE_IRQ);
+ OPAL_CALL(opal_xive_get_vp_info, OPAL_XIVE_GET_VP_INFO);
+ OPAL_CALL(opal_xive_set_vp_info, OPAL_XIVE_SET_VP_INFO);
+--- a/arch/powerpc/sysdev/xive/native.c
++++ b/arch/powerpc/sysdev/xive/native.c
+@@ -231,6 +231,17 @@ static bool xive_native_match(struct dev
+ return of_device_is_compatible(node, "ibm,opal-xive-vc");
+ }
+
++static s64 opal_xive_allocate_irq(u32 chip_id)
++{
++ s64 irq = opal_xive_allocate_irq_raw(chip_id);
++
++ /*
++ * Old versions of skiboot can incorrectly return 0xffffffff to
++ * indicate no space, fix it up here.
++ */
++ return irq == 0xffffffff ? OPAL_RESOURCE : irq;
++}
++
+ #ifdef CONFIG_SMP
+ static int xive_native_get_ipi(unsigned int cpu, struct xive_cpu *xc)
+ {