@@ -89,4 +89,18 @@ config CORESIGHT_STM
logging useful software events or data coming from various entities
in the system, possibly running different OSs
+config CORESIGHT_CPU_DEBUG
+ tristate "CoreSight CPU Debug driver"
+ depends on ARM || ARM64
+ depends on DEBUG_FS
+ help
+ This driver provides support for coresight debugging module. This
+ is primarily used to dump sample-based profiling registers when
+ system triggers panic, the driver will parse context registers so
+ can quickly get to know program counter (PC), secure state,
+ exception level, etc. Before use debugging functionality, platform
+ needs to ensure the clock domain and power domain are enabled
+ properly, please refer Documentation/trace/coresight-cpu-debug.txt
+ for detailed description and the example for usage.
+
endif
@@ -16,3 +16,4 @@ obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o \
coresight-etm4x-sysfs.o
obj-$(CONFIG_CORESIGHT_QCOM_REPLICATOR) += coresight-replicator-qcom.o
obj-$(CONFIG_CORESIGHT_STM) += coresight-stm.o
+obj-$(CONFIG_CORESIGHT_CPU_DEBUG) += coresight-cpu-debug.o
new file mode 100644
@@ -0,0 +1,696 @@
+/*
+ * 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, "Knob to enable debug functionality "
+ "(default is 0, which means is disabled by default)");
+
+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);
+}
+
+static unsigned long debug_adjust_pc(struct debug_drvdata *drvdata)
+{
+ unsigned long arm_inst_offset = 0, thumb_inst_offset = 0;
+ unsigned long pc;
+
+ if (IS_ENABLED(CONFIG_64BIT))
+ return (unsigned long)drvdata->edpcsr_hi << 32 |
+ (unsigned long)drvdata->edpcsr;
+
+ 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;
+}
+
+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, "
+ "may be caused by binding wrong CPU node in the DT\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");