When booting with CONFIG_CFI_CLANG, there are numerous violations when
accessing the files under
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/gt/gt0:
$ cd /sys/devices/pci0000:00/0000:00:02.0/drm/card0/gt/gt0
$ grep . *
id:0
punit_req_freq_mhz:350
rc6_enable:1
rc6_residency_ms:214934
rps_act_freq_mhz:1300
rps_boost_freq_mhz:1300
rps_cur_freq_mhz:350
rps_max_freq_mhz:1300
rps_min_freq_mhz:350
rps_RP0_freq_mhz:1300
rps_RP1_freq_mhz:350
rps_RPn_freq_mhz:350
throttle_reason_pl1:0
throttle_reason_pl2:0
throttle_reason_pl4:0
throttle_reason_prochot:0
throttle_reason_ratl:0
throttle_reason_status:0
throttle_reason_thermal:0
throttle_reason_vr_tdc:0
throttle_reason_vr_thermalert:0
$ sudo dmesg &| grep "CFI failure at"
[ 214.595903] CFI failure at kobj_attr_show+0x19/0x30 (target: id_show+0x0/0x70 [i915]; expected type: 0xc527b809)
[ 214.596064] CFI failure at kobj_attr_show+0x19/0x30 (target: punit_req_freq_mhz_show+0x0/0x40 [i915]; expected type: 0xc527b809)
[ 214.596407] CFI failure at kobj_attr_show+0x19/0x30 (target: rc6_enable_show+0x0/0x40 [i915]; expected type: 0xc527b809)
[ 214.596528] CFI failure at kobj_attr_show+0x19/0x30 (target: rc6_residency_ms_show+0x0/0x270 [i915]; expected type: 0xc527b809)
[ 214.596682] CFI failure at kobj_attr_show+0x19/0x30 (target: act_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.596792] CFI failure at kobj_attr_show+0x19/0x30 (target: boost_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.596893] CFI failure at kobj_attr_show+0x19/0x30 (target: cur_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.596996] CFI failure at kobj_attr_show+0x19/0x30 (target: max_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.597099] CFI failure at kobj_attr_show+0x19/0x30 (target: min_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.597198] CFI failure at kobj_attr_show+0x19/0x30 (target: RP0_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.597301] CFI failure at kobj_attr_show+0x19/0x30 (target: RP1_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.597405] CFI failure at kobj_attr_show+0x19/0x30 (target: RPn_freq_mhz_show+0x0/0xe0 [i915]; expected type: 0xc527b809)
[ 214.597538] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.597701] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.597836] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.597952] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.598071] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.598177] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.598307] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.598439] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
[ 214.598542] CFI failure at kobj_attr_show+0x19/0x30 (target: throttle_reason_bool_show+0x0/0x50 [i915]; expected type: 0xc527b809)
With kCFI, indirect calls are validated against their expected type
versus actual type and failures occur when the two types do not match.
The ultimate issue is that these sysfs functions are expecting to be
called via dev_attr_show() but they may also be called via
kobj_attr_show(), as certain files are created under two different
kobjects that have two different sysfs_ops in intel_gt_sysfs_register(),
hence the warnings above. When accessing the gt_ files under
/sys/devices/pci0000:00/0000:00:02.0/drm/card0, which are using the same
sysfs functions, there are no violations, meaning the functions are
being called with the proper type.
To make everything work properly, adjust certain functions to match the
type of the ->show() and ->store() members in 'struct kobj_attribute'.
Add a macro to generate functions for that can be called via both
dev_attr_{show,store}() or kobj_attr_{show,store}() so that they can be
called through both kobject locations without violating kCFI and adjust
the attribute groups to account for this.
Link: https://github.com/ClangBuiltLinux/linux/issues/1716
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221013205909.1282545-1-nathan@kernel.org
All kmalloc'd kobjects need a kobject_put() to free memory. For example in
previous code, kobj_gt_release() never gets called. The requirement of
kobject_put() now results in a slightly different code organization.
v2: s/gtn/gt/ (Andi)
Fixes: b770bcfae9 ("drm/i915/gt: create per-tile sysfs interface")
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Acked-by: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a6f6686517c85fba61a0c45097f5bb4fe7e257fb.1653484574.git.ashutosh.dixit@intel.com
Now that we have tiles we want each of them to have its own
interface. A directory "gt/" is created under "cardN/" that will
contain as many diroctories as the tiles.
In the coming patches tile related interfaces will be added. For
now the sysfs gt structure simply has an id interface related
to the current tile count.
The directory structure will follow this scheme:
/sys/.../card0
└── gt
├── gt0
│ └── id
:
:
└─- gtN
└── id
This new set of interfaces will be a basic tool for system
managers and administrators when using i915.
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220318233938.149744-5-andi.shyti@linux.intel.com
Nathan Chancellor
Gwan-gyeong Mun
Ashutosh Dixit
Andi Shyti