user/sven/linux.git/include/linux/cpufreq.h, branch v4.9.140

cpufreq: fix overflow in cpufreq_table_find_index_dl()

2016-10-20T14:35:50Z

'best' is always less or equals to 'pos', so `best - pos' returns a negative value which is then getting casted to `unsigned int' and passed to __cpufreq_driver_target()->acpi_cpufreq_target() for policy->freq_table selection. This results in BUG: unable to handle kernel paging request at ffff881019b469f8 IP: [] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] PGD 267f067 PUD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 6 PID: 70 Comm: kworker/6:1 Not tainted 4.9.0-rc1-next-20161017-dbg-dirty Workqueue: events dbs_work_handler task: ffff88041b808000 task.stack: ffff88041b810000 RIP: 0010:[] [] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] RSP: 0018:ffff88041b813c60 EFLAGS: 00010282 RAX: ffff880419b46a00 RBX: ffff88041b848400 RCX: ffff880419b20f80 RDX: 00000000001dff38 RSI: 00000000ffffffff RDI: ffff88041b848400 RBP: ffff88041b813cb0 R08: 0000000000000006 R09: 0000000000000040 R10: ffffffff8207f9e0 R11: ffffffff8173595b R12: 0000000000000000 R13: ffff88041f1dff38 R14: 0000000000262900 R15: 0000000bfffffff4 FS: 0000000000000000(0000) GS:ffff88041f000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff881019b469f8 CR3: 000000041a2d3000 CR4: 00000000001406e0 Stack: ffff88041b813cb0 ffffffff813347f9 ffff88041b813ca0 ffffffff81334663 ffff88041f1d4bc0 ffff88041b848400 0000000000000000 0000000000000000 0000000000262900 0000000000000000 ffff88041b813d00 ffffffff813355dc Call Trace: [] ? cpufreq_freq_transition_begin+0xf1/0xfc [] ? get_cpu_idle_time+0x97/0xa6 [] __cpufreq_driver_target+0x3b6/0x44e [] cs_dbs_timer+0x11a/0x135 [] dbs_work_handler+0x39/0x62 [] process_one_work+0x280/0x4a5 [] worker_thread+0x24f/0x397 [] ? rescuer_thread+0x30b/0x30b [] ? nl80211_get_key+0x29/0x36a [] kthread+0xfc/0x104 [] ? put_lock_stats.isra.9+0xe/0x20 [] ? kthread_create_on_node+0x3f/0x3f [] ret_from_fork+0x22/0x30 Code: 56 4d 6b ff 0c 41 55 41 54 53 48 83 ec 28 48 8b 15 ad 1e 00 00 44 8b 41 08 48 8b 87 c8 00 00 00 49 89 d5 4e 03 2c c5 80 b2 78 81 <46> 8b 74 38 04 45 3b 75 00 75 11 31 c0 83 39 00 0f 84 1c 01 00 RIP [] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] RSP CR2: ffff881019b469f8 ---[ end trace 16d9fc7a17897d37 ]--- [ rjw: In some cases this bug may also cause incorrect frequencies to be selected by cpufreq governors. ] Fixes: 899bb6642f2a (cpufreq: skip invalid entries when searching the frequency) Link: http://marc.info/?l=linux-kernel&m=147672030714331&w=2 Reported-and-tested-by: Sedat Dilek Reported-and-tested-by: Jörg Otte Signed-off-by: Sergey Senozhatsky Acked-by: Viresh Kumar Cc: 4.8+ # 4.8+ Signed-off-by: Rafael J. Wysocki

cpufreq: skip invalid entries when searching the frequency

2016-10-12T19:01:18Z

Skip invalid entries when searching the frequency. This fixes cpufreq at least on loongson2 MIPS board. Fixes: da0c6dc00c69 (cpufreq: Handle sorted frequency tables more efficiently) Signed-off-by: Aaro Koskinen Signed-off-by: Viresh Kumar Cc: 4.8+ # 4.8+ Signed-off-by: Rafael J. Wysocki

cpufreq: add cpufreq_driver_resolve_freq()

2016-07-21T12:46:08Z

Cpufreq governors may need to know what a particular target frequency maps to in the driver without necessarily wanting to set the frequency. Support this operation via a new cpufreq API, cpufreq_driver_resolve_freq(). This API returns the lowest driver frequency equal or greater than the target frequency (CPUFREQ_RELATION_L), subject to any policy (min/max) or driver limitations. The mapping is also cached in the policy so that a subsequent fast_switch operation can avoid repeating the same lookup. The API will call a new cpufreq driver callback, resolve_freq(), if it has been registered by the driver. Otherwise the frequency is resolved via cpufreq_frequency_table_target(). Rather than require ->target() style drivers to provide a resolve_freq() callback it is left to the caller to ensure that the driver implements this callback if necessary to use cpufreq_driver_resolve_freq(). Suggested-by: Rafael J. Wysocki Signed-off-by: Steve Muckle Signed-off-by: Rafael J. Wysocki

cpufreq: Handle sorted frequency tables more efficiently

2016-07-06T22:13:20Z

cpufreq drivers aren't required to provide a sorted frequency table today, and even the ones which provide a sorted table aren't handled efficiently by cpufreq core. This patch adds infrastructure to verify if the freq-table provided by the drivers is sorted or not, and use efficient helpers if they are sorted. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Return index from cpufreq_frequency_table_target()

2016-06-08T22:58:06Z

This routine can't fail unless the frequency table is invalid and doesn't contain any valid entries. Make it return the index and WARN() in case it is used for an invalid table. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Drop freq-table param to cpufreq_frequency_table_target()

2016-06-08T22:58:06Z

The policy already has this pointer set, use it instead. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Remove cpufreq_frequency_get_table()

2016-06-08T22:58:05Z

Most of the callers of cpufreq_frequency_get_table() already have the pointer to a valid 'policy' structure and they don't really need to go through the per-cpu variable first and then a check to validate the frequency, in order to find the freq-table for the policy. Directly use the policy->freq_table field instead for them. Only one user of that API is left after above changes, cpu_cooling.c and it accesses the freq_table in a racy way as the policy can get freed in between. Fix it by using cpufreq_cpu_get() properly. Since there are no more users of cpufreq_frequency_get_table() left, get rid of it. Signed-off-by: Viresh Kumar Acked-by: Javi Merino (cpu_cooling.c) Signed-off-by: Rafael J. Wysocki

cpufreq: stats: Make the stats code non-modular

2016-06-02T21:24:41Z

The modularity of cpufreq_stats is quite problematic. First off, the usage of policy notifiers for the initialization and cleanup in the cpufreq_stats module is inherently racy with respect to CPU offline/online and the initialization and cleanup of the cpufreq driver. Second, fast frequency switching (used by the schedutil governor) cannot be enabled if any transition notifiers are registered, so if the cpufreq_stats module (that registers a transition notifier for updating transition statistics) is loaded, the schedutil governor cannot use fast frequency switching. On the other hand, allowing cpufreq_stats to be built as a module doesn't really add much value. Arguably, there's not much reason for that code to be modular at all. For the above reasons, make the cpufreq stats code non-modular, modify the core to invoke functions provided by that code directly and drop the notifiers from it. Make the stats sysfs attributes appear empty if fast frequency switching is enabled as the statistics will not be updated in that case anyway (and returning -EBUSY from those attributes breaks powertop). While at it, clean up Kconfig help for the CPU_FREQ_STAT and CPU_FREQ_STAT_DETAILS options. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar

cpufreq: Drop the 'initialized' field from struct cpufreq_governor

2016-06-02T21:24:39Z

The 'initialized' field in struct cpufreq_governor is only used by the conservative governor (as a usage counter) and the way that happens is far from straightforward and arguably incorrect. Namely, the value of 'initialized' is checked by cpufreq_dbs_governor_init() and cpufreq_dbs_governor_exit() and the results of those checks are passed (as the second argument) to the ->init() and ->exit() callbacks in struct dbs_governor. Those callbacks are only implemented by the ondemand and conservative governors and ondemand doesn't use their second argument at all. In turn, the conservative governor uses it to decide whether or not to either register or unregister a transition notifier. That whole mechanism is not only unnecessarily convoluted, but also racy, because the 'initialized' field of struct cpufreq_governor is updated in cpufreq_init_governor() and cpufreq_exit_governor() under policy->rwsem which doesn't help if one of these functions is run twice in parallel for different policies (which isn't impossible in principle), for example. Instead of it, add a proper usage counter to the conservative governor and update it from cs_init() and cs_exit() which is guaranteed to be non-racy, as those functions are only called under gov_dbs_data_mutex which is global. With that in place, drop the 'initialized' field from struct cpufreq_governor as it is not used any more. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar

cpufreq: governor: Create cpufreq_policy_apply_limits()

2016-06-02T21:24:39Z

Create a new helper to avoid code duplication across governors. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki