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
Now tiles have their own sysfs interfaces under the gt/
directory. Because RC6 is a property that can be configured on a
tile basis, then each tile should have its own interface
The new sysfs structure will have a similar layout for the 4 tile
case:
/sys/.../card0
├── gt
│ ├── gt0
│ │ ├── id
│ │ ├── rc6_enable
│ │ ├── rc6_residency_ms
. . .
. . .
. .
│ └── gtN
│ ├── id
│ ├── rc6_enable
│ ├── rc6_residency_ms
│ .
│ .
│
└── power/ -+
├── rc6_enable | Original interface
├── rc6_residency_ms +-> kept as existing ABI;
. | it multiplexes over
. | the GTs
-+
The existing interfaces have been kept in their original location
to preserve the existing ABI. They act on all the GTs: when
reading they provide the average value from all the GTs.
This patch is not really adding exposing new interfaces (new
ABI) other than adapting the existing one to more tiles. In any
case 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>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@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/20220318233938.149744-6-andi.shyti@linux.intel.com
