From: John Harrison <John.C.Harrison(a)Intel.com>
Direction from hardware is that ring buffers should never be mapped
via the BAR on systems with LLC. There are too many caching pitfalls
due to the way BAR accesses are routed. So it is safest to just not
use it.
Signed-off-by: John Harrison <John.C.Harrison(a)Intel.com>
Fixes: 9d80841ea4c9 ("drm/i915: Allow ringbuffers to be bound anywhere")
Cc: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen(a)linux.intel.com>
Cc: Jani Nikula <jani.nikula(a)linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin(a)linux.intel.com>
Cc: intel-gfx(a)lists.freedesktop.org
Cc: <stable(a)vger.kernel.org> # v4.9+
---
drivers/gpu/drm/i915/gt/intel_ring.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_ring.c b/drivers/gpu/drm/i915/gt/intel_ring.c
index fb1d2595392ed..fb99143be98e7 100644
--- a/drivers/gpu/drm/i915/gt/intel_ring.c
+++ b/drivers/gpu/drm/i915/gt/intel_ring.c
@@ -53,7 +53,7 @@ int intel_ring_pin(struct intel_ring *ring, struct i915_gem_ww_ctx *ww)
if (unlikely(ret))
goto err_unpin;
- if (i915_vma_is_map_and_fenceable(vma)) {
+ if (i915_vma_is_map_and_fenceable(vma) && !HAS_LLC(vma->vm->i915)) {
addr = (void __force *)i915_vma_pin_iomap(vma);
} else {
int type = i915_coherent_map_type(vma->vm->i915, vma->obj, false);
@@ -98,7 +98,7 @@ void intel_ring_unpin(struct intel_ring *ring)
return;
i915_vma_unset_ggtt_write(vma);
- if (i915_vma_is_map_and_fenceable(vma))
+ if (i915_vma_is_map_and_fenceable(vma) && !HAS_LLC(vma->vm->i915))
i915_vma_unpin_iomap(vma);
else
i915_gem_object_unpin_map(vma->obj);
--
2.39.1
BugLink: https://bugs.launchpad.net/bugs/2007581
GPIO chip irq members are exposed before they could be completely
initialized and this leads to race conditions.
One such issue was observed for the gc->irq.domain variable which
was accessed through the I2C interface in gpiochip_to_irq() before
it could be initialized by gpiochip_add_irqchip(). This resulted in
Kernel NULL pointer dereference.
Following are the logs for reference :-
kernel: Call Trace:
kernel: gpiod_to_irq+0x53/0x70
kernel: acpi_dev_gpio_irq_get_by+0x113/0x1f0
kernel: i2c_acpi_get_irq+0xc0/0xd0
kernel: i2c_device_probe+0x28a/0x2a0
kernel: really_probe+0xf2/0x460
kernel: RIP: 0010:gpiochip_to_irq+0x47/0xc0
To avoid such scenarios, restrict usage of GPIO chip irq members before
they are completely initialized.
Signed-off-by: Shreeya Patel <shreeya.patel(a)collabora.com>
Cc: stable(a)vger.kernel.org
Reviewed-by: Andy Shevchenko <andy.shevchenko(a)gmail.com>
Reviewed-by: Linus Walleij <linus.walleij(a)linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl(a)bgdev.pl>
(backported from commit 5467801f1fcbdc46bc7298a84dbf3ca1ff2a7320)
Signed-off-by: Asmaa Mnebhi <asmaa(a)nvidia.com>
---
drivers/gpio/gpiolib.c | 19 +++++++++++++++++++
include/linux/gpio/driver.h | 9 +++++++++
2 files changed, 28 insertions(+)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index abdf448b11a3..e4d47e00c392 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2146,6 +2146,16 @@ static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
{
struct irq_domain *domain = chip->irq.domain;
+#ifdef CONFIG_GPIOLIB_IRQCHIP
+ /*
+ * Avoid race condition with other code, which tries to lookup
+ * an IRQ before the irqchip has been properly registered,
+ * i.e. while gpiochip is still being brought up.
+ */
+ if (!chip->irq.initialized)
+ return -EPROBE_DEFER;
+#endif
+
if (!gpiochip_irqchip_irq_valid(chip, offset))
return -ENXIO;
@@ -2321,6 +2331,15 @@ static int gpiochip_add_irqchip(struct gpio_chip *gpiochip,
acpi_gpiochip_request_interrupts(gpiochip);
+ /*
+ * Using barrier() here to prevent compiler from reordering
+ * gc->irq.initialized before initialization of above
+ * GPIO chip irq members.
+ */
+ barrier();
+
+ gpiochip->irq.initialized = true;
+
return 0;
}
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 5dd9c982e2cb..15418caf76fc 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -201,6 +201,15 @@ struct gpio_irq_chip {
*/
bool threaded;
+ /**
+ * @initialized:
+ *
+ * Flag to track GPIO chip irq member's initialization.
+ * This flag will make sure GPIO chip irq members are not used
+ * before they are initialized.
+ */
+ bool initialized;
+
/**
* @init_hw: optional routine to initialize hardware before
* an IRQ chip will be added. This is quite useful when
--
2.30.1