On Mon, Sep 19, 2022 at 09:24:01AM -0700, Ashutosh Dixit wrote: > Register GT0_PERF_LIMIT_REASONS (0x1381a8) is available only for > Gen11+. Therefore ensure perf_limit_reasons sysfs/debugfs files are created > only for Gen11+. Otherwise on Gen < 5 accessing these files results in the > following oops: > > <1> [88.829420] BUG: unable to handle page fault for address: ffffc90000bb81a8 > <1> [88.829438] #PF: supervisor read access in kernel mode > <1> [88.829447] #PF: error_code(0x0000) - not-present page > > Bspec: 20008 > Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6863 > Fixes: fe5979665f64 ("drm/i915/debugfs: Add perf_limit_reasons in debugfs") > Fixes: fa68bff7cf27 ("drm/i915/gt: Add sysfs throttle frequency interfaces") > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > --- > drivers/gpu/drm/i915/gt/intel_gt.c | 4 ++++ > drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c | 10 +++++++++- > drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c | 15 +++++++++++---- > 3 files changed, 24 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c > index 5ddae95d4886..b367cfff48d5 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt.c > @@ -233,6 +233,10 @@ static void gen6_clear_engine_error_register(struct intel_engine_cs *engine) > > i915_reg_t intel_gt_perf_limit_reasons_reg(struct intel_gt *gt) > { > + /* GT0_PERF_LIMIT_REASONS is available only for Gen11+ */ > + if (GRAPHICS_VER(gt->i915) < 11) > + return INVALID_MMIO_REG; > + > return gt->type == GT_MEDIA ? > MTL_MEDIA_PERF_LIMIT_REASONS : GT0_PERF_LIMIT_REASONS; > } > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c > index 68310881a793..10f680dbd7b6 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c > @@ -682,6 +682,14 @@ static int perf_limit_reasons_clear(void *data, u64 val) > > return 0; > } > + > +static bool perf_limit_reasons_eval(void *data) > +{ > + struct intel_gt *gt = data; > + > + return i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt)); > +} > + > DEFINE_SIMPLE_ATTRIBUTE(perf_limit_reasons_fops, perf_limit_reasons_get, > perf_limit_reasons_clear, "%llu\n"); > > @@ -694,7 +702,7 @@ void intel_gt_pm_debugfs_register(struct intel_gt *gt, struct dentry *root) > { "forcewake_user", &forcewake_user_fops, NULL}, > { "llc", &llc_fops, llc_eval }, > { "rps_boost", &rps_boost_fops, rps_eval }, > - { "perf_limit_reasons", &perf_limit_reasons_fops, NULL }, > + { "perf_limit_reasons", &perf_limit_reasons_fops, perf_limit_reasons_eval }, > }; > > intel_gt_debugfs_register_files(root, files, ARRAY_SIZE(files), gt); > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c > index 54deae45d81f..904160952369 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c > @@ -545,8 +545,7 @@ static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_ratl, RATL_MASK); > static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_thermalert, VR_THERMALERT_MASK); > static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_tdc, VR_TDC_MASK); > > -static const struct attribute *freq_attrs[] = { > - &dev_attr_punit_req_freq_mhz.attr, > +static const struct attribute *throttle_reason_attrs[] = { > &attr_throttle_reason_status.attr, > &attr_throttle_reason_pl1.attr, > &attr_throttle_reason_pl2.attr, > @@ -791,12 +790,20 @@ void intel_gt_sysfs_pm_init(struct intel_gt *gt, struct kobject *kobj) > if (!is_object_gt(kobj)) > return; > > - ret = sysfs_create_files(kobj, freq_attrs); > + ret = sysfs_create_file(kobj, &dev_attr_punit_req_freq_mhz.attr); > if (ret) > drm_warn(>->i915->drm, > - "failed to create gt%u throttle sysfs files (%pe)", > + "failed to create gt%u punit_req_freq_mhz sysfs (%pe)", > gt->info.id, ERR_PTR(ret)); > > + if (i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt))) { > + ret = sysfs_create_files(kobj, throttle_reason_attrs); > + if (ret) > + drm_warn(>->i915->drm, > + "failed to create gt%u throttle sysfs files (%pe)", > + gt->info.id, ERR_PTR(ret)); > + } > + > if (HAS_MEDIA_RATIO_MODE(gt->i915) && intel_uc_uses_guc_slpc(>->uc)) { > ret = sysfs_create_files(kobj, media_perf_power_attrs); > if (ret) > -- > 2.34.1 >
