From 955ef4833574636819cd269cfbae12f79cbde63a Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 16 May 2013 05:09:58 +0000 Subject: cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT With the rwsem lock around __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT), we get circular dependency when we call sysfs_remove_group(). ====================================================== [ INFO: possible circular locking dependency detected ] 3.9.0-rc7+ #15 Not tainted ------------------------------------------------------- cat/2387 is trying to acquire lock: (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}, at: [] lock_policy_rwsem_read+0x25/0x34 but task is already holding lock: (s_active#41){++++.+}, at: [] sysfs_read_file+0x4f/0xcc which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (s_active#41){++++.+}: [] lock_acquire+0x61/0xbc [] sysfs_addrm_finish+0xc1/0x128 [] sysfs_hash_and_remove+0x35/0x64 [] remove_files.isra.0+0x1b/0x24 [] sysfs_remove_group+0x2d/0xa8 [] cpufreq_governor_interactive+0x13b/0x35c [] __cpufreq_governor+0x2b/0x8c [] __cpufreq_set_policy+0xa9/0xf8 [] store_scaling_governor+0x61/0x100 [] store+0x39/0x60 [] sysfs_write_file+0xed/0x114 [] vfs_write+0x65/0xd8 [] sys_write+0x2f/0x50 [] ret_fast_syscall+0x1/0x52 -> #0 (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}: [] __lock_acquire+0xef3/0x13dc [] lock_acquire+0x61/0xbc [] down_read+0x25/0x30 [] lock_policy_rwsem_read+0x25/0x34 [] show+0x21/0x58 [] sysfs_read_file+0x67/0xcc [] vfs_read+0x63/0xd8 [] sys_read+0x2f/0x50 [] ret_fast_syscall+0x1/0x52 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(s_active#41); lock(&per_cpu(cpu_policy_rwsem, cpu)); lock(s_active#41); lock(&per_cpu(cpu_policy_rwsem, cpu)); *** DEADLOCK *** 2 locks held by cat/2387: #0: (&buffer->mutex){+.+.+.}, at: [] sysfs_read_file+0x25/0xcc #1: (s_active#41){++++.+}, at: [] sysfs_read_file+0x4f/0xcc stack backtrace: [] (unwind_backtrace+0x1/0x9c) from [] (print_circular_bug+0x19d/0x1e8) [] (print_circular_bug+0x19d/0x1e8) from [] (__lock_acquire+0xef3/0x13dc) [] (__lock_acquire+0xef3/0x13dc) from [] (lock_acquire+0x61/0xbc) [] (lock_acquire+0x61/0xbc) from [] (down_read+0x25/0x30) [] (down_read+0x25/0x30) from [] (lock_policy_rwsem_read+0x25/0x34) [] (lock_policy_rwsem_read+0x25/0x34) from [] (show+0x21/0x58) [] (show+0x21/0x58) from [] (sysfs_read_file+0x67/0xcc) [] (sysfs_read_file+0x67/0xcc) from [] (vfs_read+0x63/0xd8) [] (vfs_read+0x63/0xd8) from [] (sys_read+0x2f/0x50) [] (sys_read+0x2f/0x50) from [] (ret_fast_syscall+0x1/0x52) This lock isn't required while calling __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT). Remove it. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 4b8c7f297d74..2d53f47d1747 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1729,18 +1729,23 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data, /* end old governor */ if (data->governor) { __cpufreq_governor(data, CPUFREQ_GOV_STOP); + unlock_policy_rwsem_write(policy->cpu); __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT); + lock_policy_rwsem_write(policy->cpu); } /* start new governor */ data->governor = policy->governor; if (!__cpufreq_governor(data, CPUFREQ_GOV_POLICY_INIT)) { - if (!__cpufreq_governor(data, CPUFREQ_GOV_START)) + if (!__cpufreq_governor(data, CPUFREQ_GOV_START)) { failed = 0; - else + } else { + unlock_policy_rwsem_write(policy->cpu); __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT); + lock_policy_rwsem_write(policy->cpu); + } } if (failed) { -- cgit v1.2.3 From c96d53d600643ee0adfd1cb90814bd9510e62b71 Mon Sep 17 00:00:00 2001 From: Dirk Brandewie Date: Fri, 17 May 2013 16:10:24 +0000 Subject: cpufreq / intel_pstate: Add additional supported CPU ID Add CPU ID for Ivybrigde processor. Signed-off-by: Dirk Brandewie Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 9c36ace92a39..07f2840ad805 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -521,6 +521,7 @@ static void intel_pstate_timer_func(unsigned long __data) static const struct x86_cpu_id intel_pstate_cpu_ids[] = { ICPU(0x2a, default_policy), ICPU(0x2d, default_policy), + ICPU(0x3a, default_policy), {} }; MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids); -- cgit v1.2.3 From b5f14720a6421aab841d9f03f0129cfbe7db5133 Mon Sep 17 00:00:00 2001 From: RafaƂ Bilski Date: Sun, 19 May 2013 19:27:55 +0000 Subject: cpufreq / e_powersaver: Fix linker error when ACPI processor is a module on i386: CONFIG_ACPI_PROCESSOR=m CONFIG_X86_E_POWERSAVER=y drivers/built-in.o: In function `eps_cpu_init.part.8': e_powersaver.c:(.text.unlikely+0x2243): undefined reference to `acpi_processor_register_performance' e_powersaver.c:(.text.unlikely+0x22a2): undefined reference to `acpi_processor_unregister_performance' e_powersaver.c:(.text.unlikely+0x246b): undefined reference to `acpi_processor_get_bios_limit' X86_E_POWERSAVER should also depend on ACPI_PROCESSOR. Signed-off-by: Rafal Bilski Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/Kconfig.x86 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86 index 2b8a8c374548..6bd63d63d356 100644 --- a/drivers/cpufreq/Kconfig.x86 +++ b/drivers/cpufreq/Kconfig.x86 @@ -272,7 +272,7 @@ config X86_LONGHAUL config X86_E_POWERSAVER tristate "VIA C7 Enhanced PowerSaver (DANGEROUS)" select CPU_FREQ_TABLE - depends on X86_32 + depends on X86_32 && ACPI_PROCESSOR help This adds the CPUFreq driver for VIA C7 processors. However, this driver does not have any safeguards to prevent operating the CPU out of spec -- cgit v1.2.3 From 92a9b5c291c72aa9899021699458f0b6e328b940 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Fri, 17 May 2013 11:25:11 +0000 Subject: cpufreq: arm_big_little_dt: Register driver only if DT has valid data If arm_big_little_dt driver is enabled, then it will always try to register with big LITTLE cpufreq core driver. In case DT doesn't have relevant data for cpu nodes, i.e. operating points aren't present, then we should exit early and shouldn't register with big LITTLE cpufreq core driver. Otherwise we will fail continuously from the driver->init() routine. This patch fixes this issue. Reported-and-tested-by: Jon Medhurst Reviewed-by: Jon Medhurst Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/arm_big_little_dt.c | 73 +++++++++++++++++++++---------------- 1 file changed, 42 insertions(+), 31 deletions(-) diff --git a/drivers/cpufreq/arm_big_little_dt.c b/drivers/cpufreq/arm_big_little_dt.c index 173ed059d95f..27e2f45ccdd5 100644 --- a/drivers/cpufreq/arm_big_little_dt.c +++ b/drivers/cpufreq/arm_big_little_dt.c @@ -19,6 +19,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include #include #include @@ -29,60 +30,63 @@ #include #include "arm_big_little.h" -static int dt_init_opp_table(struct device *cpu_dev) +/* get cpu node with valid operating-points */ +static struct device_node *get_cpu_node_with_valid_op(int cpu) { - struct device_node *np, *parent; - int count = 0, ret; + struct device_node *np = NULL, *parent; + int count = 0; parent = of_find_node_by_path("/cpus"); if (!parent) { pr_err("failed to find OF /cpus\n"); - return -ENOENT; + return NULL; } for_each_child_of_node(parent, np) { - if (count++ != cpu_dev->id) + if (count++ != cpu) continue; if (!of_get_property(np, "operating-points", NULL)) { - ret = -ENODATA; - } else { - cpu_dev->of_node = np; - ret = of_init_opp_table(cpu_dev); + of_node_put(np); + np = NULL; } - of_node_put(np); - of_node_put(parent); - return ret; + break; } - return -ENODEV; + of_node_put(parent); + return np; +} + +static int dt_init_opp_table(struct device *cpu_dev) +{ + struct device_node *np; + int ret; + + np = get_cpu_node_with_valid_op(cpu_dev->id); + if (!np) + return -ENODATA; + + cpu_dev->of_node = np; + ret = of_init_opp_table(cpu_dev); + of_node_put(np); + + return ret; } static int dt_get_transition_latency(struct device *cpu_dev) { - struct device_node *np, *parent; + struct device_node *np; u32 transition_latency = CPUFREQ_ETERNAL; - int count = 0; - parent = of_find_node_by_path("/cpus"); - if (!parent) { - pr_info("Failed to find OF /cpus. Use CPUFREQ_ETERNAL transition latency\n"); + np = get_cpu_node_with_valid_op(cpu_dev->id); + if (!np) return CPUFREQ_ETERNAL; - } - - for_each_child_of_node(parent, np) { - if (count++ != cpu_dev->id) - continue; - - of_property_read_u32(np, "clock-latency", &transition_latency); - of_node_put(np); - of_node_put(parent); - return transition_latency; - } + of_property_read_u32(np, "clock-latency", &transition_latency); + of_node_put(np); - pr_info("clock-latency isn't found, use CPUFREQ_ETERNAL transition latency\n"); - return CPUFREQ_ETERNAL; + pr_debug("%s: clock-latency: %d\n", __func__, transition_latency); + return transition_latency; } static struct cpufreq_arm_bL_ops dt_bL_ops = { @@ -93,6 +97,13 @@ static struct cpufreq_arm_bL_ops dt_bL_ops = { static int generic_bL_init(void) { + struct device_node *np; + + np = get_cpu_node_with_valid_op(0); + if (!np) + return -ENODEV; + + of_node_put(np); return bL_cpufreq_register(&dt_bL_ops); } module_init(generic_bL_init); -- cgit v1.2.3 From 9076eaca60b3796b3b97d1914c4924c4bc39f066 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 20 May 2013 09:57:17 +0530 Subject: cpufreq: arm_big_little_dt: Instantiate as platform_driver As multiplatform build is being adopted by more and more ARM platforms, initcall function should be used very carefully. For example, when both arm_big_little_dt and cpufreq-cpu0 drivers are compiled in, arm_big_little_dt driver may try to register even if we had platform device for cpufreq-cpu0 registered. To eliminate this undesired the effect, the patch changes arm_big_little_dt driver to have it instantiated as a platform_driver. Then it will only run on platforms that create the platform_device "arm-bL-cpufreq-dt". Reported-and-tested-by: Rob Herring Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/arm_big_little_dt.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/cpufreq/arm_big_little_dt.c b/drivers/cpufreq/arm_big_little_dt.c index 27e2f45ccdd5..fd9e3ea6a480 100644 --- a/drivers/cpufreq/arm_big_little_dt.c +++ b/drivers/cpufreq/arm_big_little_dt.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include "arm_big_little.h" @@ -95,7 +96,7 @@ static struct cpufreq_arm_bL_ops dt_bL_ops = { .init_opp_table = dt_init_opp_table, }; -static int generic_bL_init(void) +static int generic_bL_probe(struct platform_device *pdev) { struct device_node *np; @@ -106,13 +107,22 @@ static int generic_bL_init(void) of_node_put(np); return bL_cpufreq_register(&dt_bL_ops); } -module_init(generic_bL_init); -static void generic_bL_exit(void) +static int generic_bL_remove(struct platform_device *pdev) { - return bL_cpufreq_unregister(&dt_bL_ops); + bL_cpufreq_unregister(&dt_bL_ops); + return 0; } -module_exit(generic_bL_exit); + +static struct platform_driver generic_bL_platdrv = { + .driver = { + .name = "arm-bL-cpufreq-dt", + .owner = THIS_MODULE, + }, + .probe = generic_bL_probe, + .remove = generic_bL_remove, +}; +module_platform_driver(generic_bL_platdrv); MODULE_AUTHOR("Viresh Kumar "); MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT"); -- cgit v1.2.3