The hierarchical parts of MSM pinctrl/GPIO is only used when the device tree has a "wakeup-parent" as a phandle, but the .irq_eoi is anyway assigned leading to semantic problems on elder Qualcomm chipsets.

When the drivers/mfd/qcom-pm8xxx.c driver calls chained_irq_exit() that call will in turn call chip->irq_eoi() which is set to irq_chip_eoi_parent() by default on a hierachical IRQ chip, and the parent is pinctrl-msm.c so that will in turn unconditionally call irq_chip_eoi_parent() again, but its parent is invalid so we get the following crash:

Unnable to handle kernel NULL pointer dereference at virtual address 00000010 pgd = (ptrval) [00000010] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM (...) PC is at irq_chip_eoi_parent+0x4/0x10 LR is at pm8xxx_irq_handler+0x1b4/0x2d8

If we solve this crash by avoiding to call up to irq_chip_eoi_parent(), the machine will hang and get reset by the watchdog, because of semantic issues, probably inside irq_chip.

As a solution, just assign the .irq_eoi conditionally if we are actually using a wakeup parent.

Cc: David Heidelberg david@ixit.cz Cc: Bjorn Andersson bjorn.andersson@linaro.org Cc: Lina Iyer ilina@codeaurora.org Cc: Marc Zyngier maz@kernel.org Cc: Stephen Boyd swboyd@chromium.org Cc: stable@vger.kernel.org Fixes: e35a6ae0eb3a ("pinctrl/msm: Setup GPIO chip in hierarchy") Link: https://lore.kernel.org/r/20200306121221.1231296-1-linus.walleij@linaro.org Link: https://lore.kernel.org/r/20200309125207.571840-1-linus.walleij@linaro.org Tested-by: David Heidelberg david@ixit.cz Signed-off-by: Linus Walleij linus.walleij@linaro.org --- ChangeLog v3->v4: - Fix the patch subject too, doh. ChangeLog v2->v3: - Keep .irq_disable() around, just make the assignment of .irq_eoi() conditional. ChangeLog v1->v2: - Noticed that the previous solution doesn't actually work, the machine hangs and reboots intead (even if it got rid of the most obvious crash). Make a more thorough solution that completely avoids using these callbacks if we don't have a parent. - v1 was called "Guard irq_eoi()" --- drivers/pinctrl/qcom/pinctrl-msm.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c index 9a8daa256a32..1a948c3f54b7 100644 --- a/drivers/pinctrl/qcom/pinctrl-msm.c +++ b/drivers/pinctrl/qcom/pinctrl-msm.c @@ -1104,7 +1104,6 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl) pctrl->irq_chip.irq_mask = msm_gpio_irq_mask; pctrl->irq_chip.irq_unmask = msm_gpio_irq_unmask; pctrl->irq_chip.irq_ack = msm_gpio_irq_ack; - pctrl->irq_chip.irq_eoi = irq_chip_eoi_parent; pctrl->irq_chip.irq_set_type = msm_gpio_irq_set_type; pctrl->irq_chip.irq_set_wake = msm_gpio_irq_set_wake; pctrl->irq_chip.irq_request_resources = msm_gpio_irq_reqres; @@ -1118,7 +1117,7 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl) if (!chip->irq.parent_domain) return -EPROBE_DEFER; chip->irq.child_to_parent_hwirq = msm_gpio_wakeirq; - + pctrl->irq_chip.irq_eoi = irq_chip_eoi_parent; /* * Let's skip handling the GPIOs, if the parent irqchip * is handling the direct connect IRQ of the GPIO.