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ad055fb8e0
linux/drivers/gpu/drm
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Tvrtko Ursulin ad055fb8e0 drm/i915/pmu: Work around compiler warnings on some kernel configs 
Arnd Bergman reports:
"""
The conditional spinlock confuses gcc into thinking the 'flags' value
might contain uninitialized data:

drivers/gpu/drm/i915/i915_pmu.c: In function '__i915_pmu_event_read':
arch/x86/include/asm/paravirt_types.h:573:3: error: 'flags' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The code is correct, but it's easy to see how the compiler gets confused
here. This avoids the problem by pulling the lock outside of the function
into its only caller.
"""

On deeper look it seems this is caused by paravirt spinlocks
implementation when CONFIG_PARAVIRT_DEBUG is set, which by being
complicated, manages to convince gcc locked parameter can be changed
externally (impossible).

Work around it by removing the conditional locking parameters altogether.
(It was never the most elegant code anyway.)

Slight penalty we now pay is an additional irqsave spin lock/unlock cycle
on the event enable path. But since enable is not a fast path, that is
preferrable to the alternative solution which was doing MMIO under irqsave
spinlock.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 1fe699e301 ("drm/i915/pmu: Fix sleep under atomic in RC6 readout")
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180314080535.17490-1-tvrtko.ursulin@linux.intel.com
2018-03-14 17:40:06 +00:00
..
amd Merge tag 'drm-intel-next-2018-02-21' of git://anongit.freedesktop.org/drm/drm-intel into drm-next 2018-03-01 14:07:22 +10:00
arc drm/arcpgu: remove drm_encoder_slave 2018-01-30 18:05:25 +01:00
arm drm/arm/mali-dp: Use drm_mode_get_hv_timing() to populate plane clip rectangle 2018-01-23 17:41:36 +02:00
armada Merge branch 'drm-armada-devel-4.15' of git://git.armlinux.org.uk/~rmk/linux-arm into drm-next 2018-01-05 09:51:43 +10:00
ast drm/ast: Load lut in crtc_commit 2018-02-01 11:35:46 +10:00
atmel-hlcdc drm/atmel-hlcdc: Use the alpha format field in drm_format_info 2018-01-29 12:08:37 +01:00
bochs drm/bochs: make structure bochs_bo_driver static 2018-02-19 10:43:44 +01:00
bridge drm/bridge/synopsys: dw-hdmi: don't clobber drvdata 2018-02-16 09:33:07 +01:00
cirrus drm/ttm: use an operation ctx for ttm_tt_populate in ttm_bo_driver (v2) 2017-12-28 09:48:19 -05:00
etnaviv drm/etnaviv: use memset32 to init pagetable 2018-01-02 17:36:53 +01:00
exynos drm/atmel-exynos: Use the alpha format field in drm_format_info 2018-01-29 12:08:42 +01:00
fsl-dcu drm/fsl-dcu: Use drm_mode_config_helper_suspend/resume() 2017-12-05 13:46:41 +01:00
gma500 pci-v4.16-changes 2018-02-06 09:59:40 -08:00
hisilicon drm/ttm: use an operation ctx for ttm_tt_populate in ttm_bo_driver (v2) 2017-12-28 09:48:19 -05:00
i2c drm/i2c: tda998x: Remove duplicate NULL check 2018-01-18 16:24:38 +02:00
i810
i915 drm/i915/pmu: Work around compiler warnings on some kernel configs 2018-03-14 17:40:06 +00:00
imx drm/bridge/synopsys: dw-hdmi: don't clobber drvdata 2018-02-16 09:33:07 +01:00
lib License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mediatek drm/mediatek: Use drm_mode_get_hv_timing() to populate plane clip rectangle 2018-01-23 17:41:45 +02:00
meson drm/bridge/synopsys: dw-hdmi: don't clobber drvdata 2018-02-16 09:33:07 +01:00
mga
mgag200 drm/mgag200: fix a test in mga_vga_mode_valid() 2018-01-30 18:05:25 +01:00
msm drm-misc-next for 4.17: 2018-02-16 09:29:27 +10:00
mxsfb drm/mxsfb: Use drm_gem_fb_create() and drm_gem_fb_prepare_fb() 2017-10-01 17:02:20 +02:00
nouveau drm-misc-next for 4.17: 2018-02-16 09:29:27 +10:00
omapdrm drm/omapdrm: Use of_find_backlight helper 2018-02-20 11:07:22 -05:00
panel drm/panel: Use of_find_backlight helper 2018-02-20 11:07:22 -05:00
pl111 drm/pl111: Support multiple endpoints on the CLCD 2018-02-07 09:08:51 +01:00
qxl drm/ttm: use an operation ctx for ttm_tt_populate in ttm_bo_driver (v2) 2017-12-28 09:48:19 -05:00
r128 r128: don't open-code memdup_user() 2017-12-27 19:00:09 -05:00
radeon Merge tag 'drm-intel-next-2018-02-21' of git://anongit.freedesktop.org/drm/drm-intel into drm-next 2018-03-01 14:07:22 +10:00
rcar-du drm-misc-next for 4.17: 2018-02-23 11:12:52 +10:00
rockchip drm/rockchip: Respect page offset for PRIME mmap calls 2018-02-18 11:16:55 +01:00
savage
scheduler drm: Fix trailing semicolon 2018-02-19 14:19:04 -05:00
selftests Merge tag 'drm-misc-next-2017-11-30' of git://anongit.freedesktop.org/drm/drm-misc into drm-next 2017-12-04 05:42:49 +10:00
shmobile main drm pull request for v4.15 2017-11-15 20:42:10 -08:00
sis
sti drm/sti: Use drm_fb_cma_fbdev_init/fini() 2017-12-08 14:47:41 +01:00
stm drm/stm: ltdc: remove non-alpha color formats on layer 2 for older hw 2018-02-08 10:23:32 +01:00
sun4i Merge airlied/drm-next into drm-misc-next 2018-02-16 15:47:43 -05:00
tdfx
tegra Merge tag 'drm-intel-next-2018-02-21' of git://anongit.freedesktop.org/drm/drm-intel into drm-next 2018-03-01 14:07:22 +10:00
tilcdc drm/tilcdc: tilcdc_panel: Rename device from "panel" to "tilcdc-panel" 2018-02-28 11:48:25 +02:00
tinydrm drm/tinydrm: Call devres version of of_find_backlight 2018-02-20 11:07:22 -05:00
ttm drm/ttm: add ttm_tt_populate wrapper 2018-02-19 14:19:52 -05:00
tve200 drm/tve200: Use drm_fb_cma_fbdev_init/fini() 2017-12-08 14:47:42 +01:00
udl Merge tag 'drm-misc-next-2017-10-20' of git://anongit.freedesktop.org/drm/drm-misc into drm-next 2017-10-24 16:51:05 +10:00
vc4 drm-misc-next for 4.17: 2018-02-16 09:29:27 +10:00
vgem treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
via Merge tag 'drm-misc-next-2017-11-30' of git://anongit.freedesktop.org/drm/drm-misc into drm-next 2017-12-04 05:42:49 +10:00
virtio drm/virtio: Don't return invalid caps on timeout 2018-02-01 17:45:41 +01:00
vmwgfx drm-misc-next for 4.17: 2018-02-16 09:29:27 +10:00
zte drm/zte: Use drm_mode_get_hv_timing() to populate plane clip rectangle 2018-01-23 17:59:14 +02:00
ati_pcigart.c
drm_agpsupport.c
drm_atomic_helper.c drm/atomic: Fix memleak on ERESTARTSYS during non-blocking commits 2018-01-30 11:27:26 +01:00
drm_atomic.c Add HDCP support to i915 drm driver. 2018-02-16 09:36:04 +10:00
drm_auth.c drm: Check for lessee in DROP_MASTER ioctl 2018-01-31 09:27:51 +01:00
drm_blend.c drm/docs: Align layout of optional plane blending properties 2018-02-20 12:10:46 +01:00
drm_bridge.c
drm_bufs.c
drm_cache.c
drm_color_mgmt.c drm: Pass struct drm_file * to __drm_mode_object_find [v2] 2017-10-12 10:03:04 +10:00
drm_connector.c drm/docs: Document "scaling mode" property better 2018-02-20 12:10:46 +01:00
drm_context.c
drm_crtc_helper_internal.h
drm_crtc_helper.c drm: Replace kzalloc with kcalloc 2017-10-13 15:49:03 -04:00
drm_crtc_internal.h drm: rework delayed connector cleanup in connector_iter 2017-12-13 22:59:00 +01:00
drm_crtc.c drm/modes: Provide global mode_valid hook 2018-01-29 21:51:51 +02:00
drm_debugfs_crc.c drm/crc: Add support for polling on the data fd. 2018-02-05 13:22:44 +01:00
drm_debugfs.c drm/debugfs: Fix framebuffer debugfs file init 2017-11-14 11:08:17 +02:00
drm_dma.c
drm_dp_aux_dev.c Pass mode to wait_on_atomic_t() action funcs and provide default actions 2017-11-13 15:38:16 +00:00
drm_dp_dual_mode_helper.c drm: Add retries for lspcon mode detection 2017-10-13 12:13:54 +03:00
drm_dp_helper.c drm/dp: Add HBR3 support in existing DRM DP helpers 2018-01-26 13:36:53 +02:00
drm_dp_mst_topology.c drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem 2018-02-19 12:58:20 +01:00
drm_drv.c Merge airlied/drm-next into drm-misc-next 2017-11-21 14:17:56 +01:00
drm_dumb_buffers.c
drm_edid_load.c
drm_edid.c drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem 2018-02-19 13:01:20 +01:00
drm_encoder_slave.c
drm_encoder.c drm: Warn if plane/crtc/encoder/connector index exceeds our 32bit bitmasks 2018-01-29 18:46:53 +02:00
drm_fb_cma_helper.c drm/cma-helper: Add drm_fb_cma_fbdev_init/fini() 2017-12-08 14:27:47 +01:00
drm_fb_helper.c drm/framebuffer: Print task that allocated the fb in debug info. 2017-12-20 15:30:17 +01:00
drm_file.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
drm_flip_work.c
drm_fourcc.c drm/fourcc: Add a alpha field to drm_format_info 2018-01-29 12:07:47 +01:00
drm_framebuffer.c drm/framebuffer: Print task that allocated the fb in debug info. 2017-12-20 15:30:17 +01:00
drm_gem_cma_helper.c drm: gem_cma_helper.c: Allow importing of contiguous scatterlists with nents > 1 2017-11-15 18:14:46 +01:00
drm_gem_framebuffer_helper.c drm/gem-fb-helper: drm_gem_fbdev_fb_create() make funcs optional 2017-12-08 14:26:00 +01:00
drm_gem.c drm: Use idr_init_base(1) when using id==0 for invalid 2018-02-19 12:21:24 +00:00
drm_global.c
drm_hashtab.c
drm_info.c
drm_internal.h Merge airlied/drm-next into drm-misc-next 2017-11-21 14:17:56 +01:00
drm_ioc32.c
drm_ioctl.c drm: Print the pid when debug logging an ioctl error. 2018-02-10 22:23:10 +00:00
drm_irq.c
drm_kms_helper_common.c
drm_lease.c drm: Fix kerneldoc warnings for drm_lease 2018-02-19 10:49:59 +01:00
drm_legacy.h
drm_lock.c
drm_memory.c drm: add func to get max iomem address v2 2018-02-13 11:57:59 -05:00
drm_mipi_dsi.c drm/dsi: Fix improper use of mipi_dsi_device_transfer() return value 2018-01-16 17:10:14 -05:00
drm_mm.c Linux 4.15-rc4 2017-12-19 21:37:24 +10:00
drm_mode_config.c Linux 4.15-rc4 2017-12-19 21:37:24 +10:00
drm_mode_object.c drm/mode_object: fix documentation for object lookups. 2017-11-10 13:50:47 +10:00
drm_modes.c drm/doc: Polish for drm_mode_parse_command_line_for_connector 2018-02-20 12:10:46 +01:00
drm_modeset_helper.c drm/modeset-helper: Add simple modeset suspend/resume helpers 2017-11-30 18:18:08 +01:00
drm_modeset_lock.c drm: Require __GFP_NOFAIL for the legacy drm_modeset_lock_all 2017-10-31 17:36:46 +01:00
drm_of.c drm/drm_of: Move drm_of_panel_bridge_remove_function into header. 2017-10-13 16:59:36 +02:00
drm_panel_orientation_quirks.c drm: fix tainted kernel caused by drm_panel_orientation_quirks.c 2017-12-23 20:06:45 +01:00
drm_panel.c
drm_pci.c drm/core: clean up references to drm_dev_unref() 2017-09-27 10:53:12 +02:00
drm_plane_helper.c drm: Move drm_plane_helper_check_state() into drm_atomic_helper.c 2017-11-20 21:14:22 +02:00
drm_plane.c Merge tag 'drm-intel-next-2018-02-21' of git://anongit.freedesktop.org/drm/drm-intel into drm-next 2018-03-01 14:07:22 +10:00
drm_prime.c drm: add kernel doc for exported gem dmabuf_ops 2018-01-19 11:14:59 -05:00
drm_print.c drm/printer: Add drm_vprintf() 2017-11-23 12:31:49 +02:00
drm_probe_helper.c drm/modes: Provide global mode_valid hook 2018-01-29 21:51:51 +02:00
drm_property.c drm: Pass struct drm_file * to __drm_mode_object_find [v2] 2017-10-12 10:03:04 +10:00
drm_rect.c
drm_scatter.c
drm_scdc_helper.c Merge tag 'drm-misc-next-2017-09-20' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-09-28 05:46:15 +10:00
drm_simple_kms_helper.c drm: simple_kms_helper: Add mode_valid() callback support 2018-02-20 08:42:17 +01:00
drm_syncobj.c drm: Use idr_init_base(1) when using id==0 for invalid 2018-02-19 12:21:24 +00:00
drm_sysfs.c
drm_trace_points.c
drm_trace.h main drm pull request for v4.15 2017-11-15 20:42:10 -08:00
drm_vblank.c drm/doc: Fix documentation for _vblank_restore(). 2018-02-21 19:29:06 +01:00
drm_vm.c
drm_vma_manager.c drm/drm_vma_manager.c: Remove useless goto statement 2017-11-02 10:44:08 +01:00
Kconfig Fixes for 4.16: 2018-01-25 11:42:25 +10:00
Makefile drm: fix gpu scheduler link order 2018-01-24 15:49:04 -05:00