diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-cpu-debug.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-cpu-debug.c | 700 |
1 files changed, 700 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c new file mode 100644 index 000000000000..64a77e00eaa6 --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c @@ -0,0 +1,700 @@ +/* + * Copyright (c) 2017 Linaro Limited. All rights reserved. + * + * Author: Leo Yan <leo.yan@linaro.org> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + * + */ +#include <linux/amba/bus.h> +#include <linux/coresight.h> +#include <linux/cpu.h> +#include <linux/debugfs.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/pm_qos.h> +#include <linux/slab.h> +#include <linux/smp.h> +#include <linux/types.h> +#include <linux/uaccess.h> + +#include "coresight-priv.h" + +#define EDPCSR 0x0A0 +#define EDCIDSR 0x0A4 +#define EDVIDSR 0x0A8 +#define EDPCSR_HI 0x0AC +#define EDOSLAR 0x300 +#define EDPRCR 0x310 +#define EDPRSR 0x314 +#define EDDEVID1 0xFC4 +#define EDDEVID 0xFC8 + +#define EDPCSR_PROHIBITED 0xFFFFFFFF + +/* bits definition for EDPCSR */ +#define EDPCSR_THUMB BIT(0) +#define EDPCSR_ARM_INST_MASK GENMASK(31, 2) +#define EDPCSR_THUMB_INST_MASK GENMASK(31, 1) + +/* bits definition for EDPRCR */ +#define EDPRCR_COREPURQ BIT(3) +#define EDPRCR_CORENPDRQ BIT(0) + +/* bits definition for EDPRSR */ +#define EDPRSR_DLK BIT(6) +#define EDPRSR_PU BIT(0) + +/* bits definition for EDVIDSR */ +#define EDVIDSR_NS BIT(31) +#define EDVIDSR_E2 BIT(30) +#define EDVIDSR_E3 BIT(29) +#define EDVIDSR_HV BIT(28) +#define EDVIDSR_VMID GENMASK(7, 0) + +/* + * bits definition for EDDEVID1:PSCROffset + * + * NOTE: armv8 and armv7 have different definition for the register, + * so consolidate the bits definition as below: + * + * 0b0000 - Sample offset applies based on the instruction state, we + * rely on EDDEVID to check if EDPCSR is implemented or not + * 0b0001 - No offset applies. + * 0b0010 - No offset applies, but do not use in AArch32 mode + * + */ +#define EDDEVID1_PCSR_OFFSET_MASK GENMASK(3, 0) +#define EDDEVID1_PCSR_OFFSET_INS_SET (0x0) +#define EDDEVID1_PCSR_NO_OFFSET_DIS_AARCH32 (0x2) + +/* bits definition for EDDEVID */ +#define EDDEVID_PCSAMPLE_MODE GENMASK(3, 0) +#define EDDEVID_IMPL_EDPCSR (0x1) +#define EDDEVID_IMPL_EDPCSR_EDCIDSR (0x2) +#define EDDEVID_IMPL_FULL (0x3) + +#define DEBUG_WAIT_SLEEP 1000 +#define DEBUG_WAIT_TIMEOUT 32000 + +struct debug_drvdata { + void __iomem *base; + struct device *dev; + int cpu; + + bool edpcsr_present; + bool edcidsr_present; + bool edvidsr_present; + bool pc_has_offset; + + u32 edpcsr; + u32 edpcsr_hi; + u32 edprsr; + u32 edvidsr; + u32 edcidsr; +}; + +static DEFINE_MUTEX(debug_lock); +static DEFINE_PER_CPU(struct debug_drvdata *, debug_drvdata); +static int debug_count; +static struct dentry *debug_debugfs_dir; + +static bool debug_enable; +module_param_named(enable, debug_enable, bool, 0600); +MODULE_PARM_DESC(enable, "Control to enable coresight CPU debug functionality"); + +static void debug_os_unlock(struct debug_drvdata *drvdata) +{ + /* Unlocks the debug registers */ + writel_relaxed(0x0, drvdata->base + EDOSLAR); + + /* Make sure the registers are unlocked before accessing */ + wmb(); +} + +/* + * According to ARM DDI 0487A.k, before access external debug + * registers should firstly check the access permission; if any + * below condition has been met then cannot access debug + * registers to avoid lockup issue: + * + * - CPU power domain is powered off; + * - The OS Double Lock is locked; + * + * By checking EDPRSR can get to know if meet these conditions. + */ +static bool debug_access_permitted(struct debug_drvdata *drvdata) +{ + /* CPU is powered off */ + if (!(drvdata->edprsr & EDPRSR_PU)) + return false; + + /* The OS Double Lock is locked */ + if (drvdata->edprsr & EDPRSR_DLK) + return false; + + return true; +} + +static void debug_force_cpu_powered_up(struct debug_drvdata *drvdata) +{ + u32 edprcr; + +try_again: + + /* + * Send request to power management controller and assert + * DBGPWRUPREQ signal; if power management controller has + * sane implementation, it should enable CPU power domain + * in case CPU is in low power state. + */ + edprcr = readl_relaxed(drvdata->base + EDPRCR); + edprcr |= EDPRCR_COREPURQ; + writel_relaxed(edprcr, drvdata->base + EDPRCR); + + /* Wait for CPU to be powered up (timeout~=32ms) */ + if (readx_poll_timeout_atomic(readl_relaxed, drvdata->base + EDPRSR, + drvdata->edprsr, (drvdata->edprsr & EDPRSR_PU), + DEBUG_WAIT_SLEEP, DEBUG_WAIT_TIMEOUT)) { + /* + * Unfortunately the CPU cannot be powered up, so return + * back and later has no permission to access other + * registers. For this case, should disable CPU low power + * states to ensure CPU power domain is enabled! + */ + dev_err(drvdata->dev, "%s: power up request for CPU%d failed\n", + __func__, drvdata->cpu); + return; + } + + /* + * At this point the CPU is powered up, so set the no powerdown + * request bit so we don't lose power and emulate power down. + */ + edprcr = readl_relaxed(drvdata->base + EDPRCR); + edprcr |= EDPRCR_COREPURQ | EDPRCR_CORENPDRQ; + writel_relaxed(edprcr, drvdata->base + EDPRCR); + + drvdata->edprsr = readl_relaxed(drvdata->base + EDPRSR); + + /* The core power domain got switched off on use, try again */ + if (unlikely(!(drvdata->edprsr & EDPRSR_PU))) + goto try_again; +} + +static void debug_read_regs(struct debug_drvdata *drvdata) +{ + u32 save_edprcr; + + CS_UNLOCK(drvdata->base); + + /* Unlock os lock */ + debug_os_unlock(drvdata); + + /* Save EDPRCR register */ + save_edprcr = readl_relaxed(drvdata->base + EDPRCR); + + /* + * Ensure CPU power domain is enabled to let registers + * are accessiable. + */ + debug_force_cpu_powered_up(drvdata); + + if (!debug_access_permitted(drvdata)) + goto out; + + drvdata->edpcsr = readl_relaxed(drvdata->base + EDPCSR); + + /* + * As described in ARM DDI 0487A.k, if the processing + * element (PE) is in debug state, or sample-based + * profiling is prohibited, EDPCSR reads as 0xFFFFFFFF; + * EDCIDSR, EDVIDSR and EDPCSR_HI registers also become + * UNKNOWN state. So directly bail out for this case. + */ + if (drvdata->edpcsr == EDPCSR_PROHIBITED) + goto out; + + /* + * A read of the EDPCSR normally has the side-effect of + * indirectly writing to EDCIDSR, EDVIDSR and EDPCSR_HI; + * at this point it's safe to read value from them. + */ + if (IS_ENABLED(CONFIG_64BIT)) + drvdata->edpcsr_hi = readl_relaxed(drvdata->base + EDPCSR_HI); + + if (drvdata->edcidsr_present) + drvdata->edcidsr = readl_relaxed(drvdata->base + EDCIDSR); + + if (drvdata->edvidsr_present) + drvdata->edvidsr = readl_relaxed(drvdata->base + EDVIDSR); + +out: + /* Restore EDPRCR register */ + writel_relaxed(save_edprcr, drvdata->base + EDPRCR); + + CS_LOCK(drvdata->base); +} + +#ifdef CONFIG_64BIT +static unsigned long debug_adjust_pc(struct debug_drvdata *drvdata) +{ + return (unsigned long)drvdata->edpcsr_hi << 32 | + (unsigned long)drvdata->edpcsr; +} +#else +static unsigned long debug_adjust_pc(struct debug_drvdata *drvdata) +{ + unsigned long arm_inst_offset = 0, thumb_inst_offset = 0; + unsigned long pc; + + pc = (unsigned long)drvdata->edpcsr; + + if (drvdata->pc_has_offset) { + arm_inst_offset = 8; + thumb_inst_offset = 4; + } + + /* Handle thumb instruction */ + if (pc & EDPCSR_THUMB) { + pc = (pc & EDPCSR_THUMB_INST_MASK) - thumb_inst_offset; + return pc; + } + + /* + * Handle arm instruction offset, if the arm instruction + * is not 4 byte alignment then it's possible the case + * for implementation defined; keep original value for this + * case and print info for notice. + */ + if (pc & BIT(1)) + dev_emerg(drvdata->dev, + "Instruction offset is implementation defined\n"); + else + pc = (pc & EDPCSR_ARM_INST_MASK) - arm_inst_offset; + + return pc; +} +#endif + +static void debug_dump_regs(struct debug_drvdata *drvdata) +{ + struct device *dev = drvdata->dev; + unsigned long pc; + + dev_emerg(dev, " EDPRSR: %08x (Power:%s DLK:%s)\n", + drvdata->edprsr, + drvdata->edprsr & EDPRSR_PU ? "On" : "Off", + drvdata->edprsr & EDPRSR_DLK ? "Lock" : "Unlock"); + + if (!debug_access_permitted(drvdata)) { + dev_emerg(dev, "No permission to access debug registers!\n"); + return; + } + + if (drvdata->edpcsr == EDPCSR_PROHIBITED) { + dev_emerg(dev, "CPU is in Debug state or profiling is prohibited!\n"); + return; + } + + pc = debug_adjust_pc(drvdata); + dev_emerg(dev, " EDPCSR: [<%p>] %pS\n", (void *)pc, (void *)pc); + + if (drvdata->edcidsr_present) + dev_emerg(dev, " EDCIDSR: %08x\n", drvdata->edcidsr); + + if (drvdata->edvidsr_present) + dev_emerg(dev, " EDVIDSR: %08x (State:%s Mode:%s Width:%dbits VMID:%x)\n", + drvdata->edvidsr, + drvdata->edvidsr & EDVIDSR_NS ? + "Non-secure" : "Secure", + drvdata->edvidsr & EDVIDSR_E3 ? "EL3" : + (drvdata->edvidsr & EDVIDSR_E2 ? + "EL2" : "EL1/0"), + drvdata->edvidsr & EDVIDSR_HV ? 64 : 32, + drvdata->edvidsr & (u32)EDVIDSR_VMID); +} + +static void debug_init_arch_data(void *info) +{ + struct debug_drvdata *drvdata = info; + u32 mode, pcsr_offset; + u32 eddevid, eddevid1; + + CS_UNLOCK(drvdata->base); + + /* Read device info */ + eddevid = readl_relaxed(drvdata->base + EDDEVID); + eddevid1 = readl_relaxed(drvdata->base + EDDEVID1); + + CS_LOCK(drvdata->base); + + /* Parse implementation feature */ + mode = eddevid & EDDEVID_PCSAMPLE_MODE; + pcsr_offset = eddevid1 & EDDEVID1_PCSR_OFFSET_MASK; + + drvdata->edpcsr_present = false; + drvdata->edcidsr_present = false; + drvdata->edvidsr_present = false; + drvdata->pc_has_offset = false; + + switch (mode) { + case EDDEVID_IMPL_FULL: + drvdata->edvidsr_present = true; + /* Fall through */ + case EDDEVID_IMPL_EDPCSR_EDCIDSR: + drvdata->edcidsr_present = true; + /* Fall through */ + case EDDEVID_IMPL_EDPCSR: + /* + * In ARM DDI 0487A.k, the EDDEVID1.PCSROffset is used to + * define if has the offset for PC sampling value; if read + * back EDDEVID1.PCSROffset == 0x2, then this means the debug + * module does not sample the instruction set state when + * armv8 CPU in AArch32 state. + */ + drvdata->edpcsr_present = + ((IS_ENABLED(CONFIG_64BIT) && pcsr_offset != 0) || + (pcsr_offset != EDDEVID1_PCSR_NO_OFFSET_DIS_AARCH32)); + + drvdata->pc_has_offset = + (pcsr_offset == EDDEVID1_PCSR_OFFSET_INS_SET); + break; + default: + break; + } +} + +/* + * Dump out information on panic. + */ +static int debug_notifier_call(struct notifier_block *self, + unsigned long v, void *p) +{ + int cpu; + struct debug_drvdata *drvdata; + + mutex_lock(&debug_lock); + + /* Bail out if the functionality is disabled */ + if (!debug_enable) + goto skip_dump; + + pr_emerg("ARM external debug module:\n"); + + for_each_possible_cpu(cpu) { + drvdata = per_cpu(debug_drvdata, cpu); + if (!drvdata) + continue; + + dev_emerg(drvdata->dev, "CPU[%d]:\n", drvdata->cpu); + + debug_read_regs(drvdata); + debug_dump_regs(drvdata); + } + +skip_dump: + mutex_unlock(&debug_lock); + return 0; +} + +static struct notifier_block debug_notifier = { + .notifier_call = debug_notifier_call, +}; + +static int debug_enable_func(void) +{ + struct debug_drvdata *drvdata; + int cpu, ret = 0; + cpumask_t mask; + + /* + * Use cpumask to track which debug power domains have + * been powered on and use it to handle failure case. + */ + cpumask_clear(&mask); + + for_each_possible_cpu(cpu) { + drvdata = per_cpu(debug_drvdata, cpu); + if (!drvdata) + continue; + + ret = pm_runtime_get_sync(drvdata->dev); + if (ret < 0) + goto err; + else + cpumask_set_cpu(cpu, &mask); + } + + return 0; + +err: + /* + * If pm_runtime_get_sync() has failed, need rollback on + * all the other CPUs that have been enabled before that. + */ + for_each_cpu(cpu, &mask) { + drvdata = per_cpu(debug_drvdata, cpu); + pm_runtime_put_noidle(drvdata->dev); + } + + return ret; +} + +static int debug_disable_func(void) +{ + struct debug_drvdata *drvdata; + int cpu, ret, err = 0; + + /* + * Disable debug power domains, records the error and keep + * circling through all other CPUs when an error has been + * encountered. + */ + for_each_possible_cpu(cpu) { + drvdata = per_cpu(debug_drvdata, cpu); + if (!drvdata) + continue; + + ret = pm_runtime_put(drvdata->dev); + if (ret < 0) + err = ret; + } + + return err; +} + +static ssize_t debug_func_knob_write(struct file *f, + const char __user *buf, size_t count, loff_t *ppos) +{ + u8 val; + int ret; + + ret = kstrtou8_from_user(buf, count, 2, &val); + if (ret) + return ret; + + mutex_lock(&debug_lock); + + if (val == debug_enable) + goto out; + + if (val) + ret = debug_enable_func(); + else + ret = debug_disable_func(); + + if (ret) { + pr_err("%s: unable to %s debug function: %d\n", + __func__, val ? "enable" : "disable", ret); + goto err; + } + + debug_enable = val; +out: + ret = count; +err: + mutex_unlock(&debug_lock); + return ret; +} + +static ssize_t debug_func_knob_read(struct file *f, + char __user *ubuf, size_t count, loff_t *ppos) +{ + ssize_t ret; + char buf[3]; + + mutex_lock(&debug_lock); + snprintf(buf, sizeof(buf), "%d\n", debug_enable); + mutex_unlock(&debug_lock); + + ret = simple_read_from_buffer(ubuf, count, ppos, buf, sizeof(buf)); + return ret; +} + +static const struct file_operations debug_func_knob_fops = { + .open = simple_open, + .read = debug_func_knob_read, + .write = debug_func_knob_write, +}; + +static int debug_func_init(void) +{ + struct dentry *file; + int ret; + + /* Create debugfs node */ + debug_debugfs_dir = debugfs_create_dir("coresight_cpu_debug", NULL); + if (!debug_debugfs_dir) { + pr_err("%s: unable to create debugfs directory\n", __func__); + return -ENOMEM; + } + + file = debugfs_create_file("enable", 0644, debug_debugfs_dir, NULL, + &debug_func_knob_fops); + if (!file) { + pr_err("%s: unable to create enable knob file\n", __func__); + ret = -ENOMEM; + goto err; + } + + /* Register function to be called for panic */ + ret = atomic_notifier_chain_register(&panic_notifier_list, + &debug_notifier); + if (ret) { + pr_err("%s: unable to register notifier: %d\n", + __func__, ret); + goto err; + } + + return 0; + +err: + debugfs_remove_recursive(debug_debugfs_dir); + return ret; +} + +static void debug_func_exit(void) +{ + atomic_notifier_chain_unregister(&panic_notifier_list, + &debug_notifier); + debugfs_remove_recursive(debug_debugfs_dir); +} + +static int debug_probe(struct amba_device *adev, const struct amba_id *id) +{ + void __iomem *base; + struct device *dev = &adev->dev; + struct debug_drvdata *drvdata; + struct resource *res = &adev->res; + struct device_node *np = adev->dev.of_node; + int ret; + + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL); + if (!drvdata) + return -ENOMEM; + + drvdata->cpu = np ? of_coresight_get_cpu(np) : 0; + if (per_cpu(debug_drvdata, drvdata->cpu)) { + dev_err(dev, "CPU%d drvdata has already been initialized\n", + drvdata->cpu); + return -EBUSY; + } + + drvdata->dev = &adev->dev; + amba_set_drvdata(adev, drvdata); + + /* Validity for the resource is already checked by the AMBA core */ + base = devm_ioremap_resource(dev, res); + if (IS_ERR(base)) + return PTR_ERR(base); + + drvdata->base = base; + + get_online_cpus(); + per_cpu(debug_drvdata, drvdata->cpu) = drvdata; + ret = smp_call_function_single(drvdata->cpu, debug_init_arch_data, + drvdata, 1); + put_online_cpus(); + + if (ret) { + dev_err(dev, "CPU%d debug arch init failed\n", drvdata->cpu); + goto err; + } + + if (!drvdata->edpcsr_present) { + dev_err(dev, "CPU%d sample-based profiling isn't implemented\n", + drvdata->cpu); + ret = -ENXIO; + goto err; + } + + if (!debug_count++) { + ret = debug_func_init(); + if (ret) + goto err_func_init; + } + + mutex_lock(&debug_lock); + /* Turn off debug power domain if debugging is disabled */ + if (!debug_enable) + pm_runtime_put(dev); + mutex_unlock(&debug_lock); + + dev_info(dev, "Coresight debug-CPU%d initialized\n", drvdata->cpu); + return 0; + +err_func_init: + debug_count--; +err: + per_cpu(debug_drvdata, drvdata->cpu) = NULL; + return ret; +} + +static int debug_remove(struct amba_device *adev) +{ + struct device *dev = &adev->dev; + struct debug_drvdata *drvdata = amba_get_drvdata(adev); + + per_cpu(debug_drvdata, drvdata->cpu) = NULL; + + mutex_lock(&debug_lock); + /* Turn off debug power domain before rmmod the module */ + if (debug_enable) + pm_runtime_put(dev); + mutex_unlock(&debug_lock); + + if (!--debug_count) + debug_func_exit(); + + return 0; +} + +static struct amba_id debug_ids[] = { + { /* Debug for Cortex-A53 */ + .id = 0x000bbd03, + .mask = 0x000fffff, + }, + { /* Debug for Cortex-A57 */ + .id = 0x000bbd07, + .mask = 0x000fffff, + }, + { /* Debug for Cortex-A72 */ + .id = 0x000bbd08, + .mask = 0x000fffff, + }, + { 0, 0 }, +}; + +static struct amba_driver debug_driver = { + .drv = { + .name = "coresight-cpu-debug", + .suppress_bind_attrs = true, + }, + .probe = debug_probe, + .remove = debug_remove, + .id_table = debug_ids, +}; + +module_amba_driver(debug_driver); + +MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>"); +MODULE_DESCRIPTION("ARM Coresight CPU Debug Driver"); +MODULE_LICENSE("GPL"); |