diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-trbe.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-trbe.c | 1157 |
1 files changed, 1157 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c new file mode 100644 index 000000000000..176868496879 --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -0,0 +1,1157 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This driver enables Trace Buffer Extension (TRBE) as a per-cpu coresight + * sink device could then pair with an appropriate per-cpu coresight source + * device (ETE) thus generating required trace data. Trace can be enabled + * via the perf framework. + * + * The AUX buffer handling is inspired from Arm SPE PMU driver. + * + * Copyright (C) 2020 ARM Ltd. + * + * Author: Anshuman Khandual <anshuman.khandual@arm.com> + */ +#define DRVNAME "arm_trbe" + +#define pr_fmt(fmt) DRVNAME ": " fmt + +#include <asm/barrier.h> +#include "coresight-trbe.h" + +#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT)) + +/* + * A padding packet that will help the user space tools + * in skipping relevant sections in the captured trace + * data which could not be decoded. TRBE doesn't support + * formatting the trace data, unlike the legacy CoreSight + * sinks and thus we use ETE trace packets to pad the + * sections of the buffer. + */ +#define ETE_IGNORE_PACKET 0x70 + +/* + * Minimum amount of meaningful trace will contain: + * A-Sync, Trace Info, Trace On, Address, Atom. + * This is about 44bytes of ETE trace. To be on + * the safer side, we assume 64bytes is the minimum + * space required for a meaningful session, before + * we hit a "WRAP" event. + */ +#define TRBE_TRACE_MIN_BUF_SIZE 64 + +enum trbe_fault_action { + TRBE_FAULT_ACT_WRAP, + TRBE_FAULT_ACT_SPURIOUS, + TRBE_FAULT_ACT_FATAL, +}; + +struct trbe_buf { + /* + * Even though trbe_base represents vmap() + * mapped allocated buffer's start address, + * it's being as unsigned long for various + * arithmetic and comparision operations & + * also to be consistent with trbe_write & + * trbe_limit sibling pointers. + */ + unsigned long trbe_base; + unsigned long trbe_limit; + unsigned long trbe_write; + int nr_pages; + void **pages; + bool snapshot; + struct trbe_cpudata *cpudata; +}; + +struct trbe_cpudata { + bool trbe_flag; + u64 trbe_align; + int cpu; + enum cs_mode mode; + struct trbe_buf *buf; + struct trbe_drvdata *drvdata; +}; + +struct trbe_drvdata { + struct trbe_cpudata __percpu *cpudata; + struct perf_output_handle * __percpu *handle; + struct hlist_node hotplug_node; + int irq; + cpumask_t supported_cpus; + enum cpuhp_state trbe_online; + struct platform_device *pdev; +}; + +static int trbe_alloc_node(struct perf_event *event) +{ + if (event->cpu == -1) + return NUMA_NO_NODE; + return cpu_to_node(event->cpu); +} + +static void trbe_drain_buffer(void) +{ + tsb_csync(); + dsb(nsh); +} + +static void trbe_drain_and_disable_local(void) +{ + u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1); + + trbe_drain_buffer(); + + /* + * Disable the TRBE without clearing LIMITPTR which + * might be required for fetching the buffer limits. + */ + trblimitr &= ~TRBLIMITR_ENABLE; + write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1); + isb(); +} + +static void trbe_reset_local(void) +{ + trbe_drain_and_disable_local(); + write_sysreg_s(0, SYS_TRBLIMITR_EL1); + write_sysreg_s(0, SYS_TRBPTR_EL1); + write_sysreg_s(0, SYS_TRBBASER_EL1); + write_sysreg_s(0, SYS_TRBSR_EL1); +} + +static void trbe_stop_and_truncate_event(struct perf_output_handle *handle) +{ + struct trbe_buf *buf = etm_perf_sink_config(handle); + + /* + * We cannot proceed with the buffer collection and we + * do not have any data for the current session. The + * etm_perf driver expects to close out the aux_buffer + * at event_stop(). So disable the TRBE here and leave + * the update_buffer() to return a 0 size. + */ + trbe_drain_and_disable_local(); + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); + *this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL; +} + +/* + * TRBE Buffer Management + * + * The TRBE buffer spans from the base pointer till the limit pointer. When enabled, + * it starts writing trace data from the write pointer onward till the limit pointer. + * When the write pointer reaches the address just before the limit pointer, it gets + * wrapped around again to the base pointer. This is called a TRBE wrap event, which + * generates a maintenance interrupt when operated in WRAP or FILL mode. This driver + * uses FILL mode, where the TRBE stops the trace collection at wrap event. The IRQ + * handler updates the AUX buffer and re-enables the TRBE with updated WRITE and + * LIMIT pointers. + * + * Wrap around with an IRQ + * ------ < ------ < ------- < ----- < ----- + * | | + * ------ > ------ > ------- > ----- > ----- + * + * +---------------+-----------------------+ + * | | | + * +---------------+-----------------------+ + * Base Pointer Write Pointer Limit Pointer + * + * The base and limit pointers always needs to be PAGE_SIZE aligned. But the write + * pointer can be aligned to the implementation defined TRBE trace buffer alignment + * as captured in trbe_cpudata->trbe_align. + * + * + * head tail wakeup + * +---------------------------------------+----- ~ ~ ------ + * |$$$$$$$|################|$$$$$$$$$$$$$$| | + * +---------------------------------------+----- ~ ~ ------ + * Base Pointer Write Pointer Limit Pointer + * + * The perf_output_handle indices (head, tail, wakeup) are monotonically increasing + * values which tracks all the driver writes and user reads from the perf auxiliary + * buffer. Generally [head..tail] is the area where the driver can write into unless + * the wakeup is behind the tail. Enabled TRBE buffer span needs to be adjusted and + * configured depending on the perf_output_handle indices, so that the driver does + * not override into areas in the perf auxiliary buffer which is being or yet to be + * consumed from the user space. The enabled TRBE buffer area is a moving subset of + * the allocated perf auxiliary buffer. + */ +static void trbe_pad_buf(struct perf_output_handle *handle, int len) +{ + struct trbe_buf *buf = etm_perf_sink_config(handle); + u64 head = PERF_IDX2OFF(handle->head, buf); + + memset((void *)buf->trbe_base + head, ETE_IGNORE_PACKET, len); + if (!buf->snapshot) + perf_aux_output_skip(handle, len); +} + +static unsigned long trbe_snapshot_offset(struct perf_output_handle *handle) +{ + struct trbe_buf *buf = etm_perf_sink_config(handle); + + /* + * The ETE trace has alignment synchronization packets allowing + * the decoder to reset in case of an overflow or corruption. + * So we can use the entire buffer for the snapshot mode. + */ + return buf->nr_pages * PAGE_SIZE; +} + +/* + * TRBE Limit Calculation + * + * The following markers are used to illustrate various TRBE buffer situations. + * + * $$$$ - Data area, unconsumed captured trace data, not to be overridden + * #### - Free area, enabled, trace will be written + * %%%% - Free area, disabled, trace will not be written + * ==== - Free area, padded with ETE_IGNORE_PACKET, trace will be skipped + */ +static unsigned long __trbe_normal_offset(struct perf_output_handle *handle) +{ + struct trbe_buf *buf = etm_perf_sink_config(handle); + struct trbe_cpudata *cpudata = buf->cpudata; + const u64 bufsize = buf->nr_pages * PAGE_SIZE; + u64 limit = bufsize; + u64 head, tail, wakeup; + + head = PERF_IDX2OFF(handle->head, buf); + + /* + * head + * ------->| + * | + * head TRBE align tail + * +----|-------|---------------|-------+ + * |$$$$|=======|###############|$$$$$$$| + * +----|-------|---------------|-------+ + * trbe_base trbe_base + nr_pages + * + * Perf aux buffer output head position can be misaligned depending on + * various factors including user space reads. In case misaligned, head + * needs to be aligned before TRBE can be configured. Pad the alignment + * gap with ETE_IGNORE_PACKET bytes that will be ignored by user tools + * and skip this section thus advancing the head. + */ + if (!IS_ALIGNED(head, cpudata->trbe_align)) { + unsigned long delta = roundup(head, cpudata->trbe_align) - head; + + delta = min(delta, handle->size); + trbe_pad_buf(handle, delta); + head = PERF_IDX2OFF(handle->head, buf); + } + + /* + * head = tail (size = 0) + * +----|-------------------------------+ + * |$$$$|$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ | + * +----|-------------------------------+ + * trbe_base trbe_base + nr_pages + * + * Perf aux buffer does not have any space for the driver to write into. + * Just communicate trace truncation event to the user space by marking + * it with PERF_AUX_FLAG_TRUNCATED. + */ + if (!handle->size) { + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); + return 0; + } + + /* Compute the tail and wakeup indices now that we've aligned head */ + tail = PERF_IDX2OFF(handle->head + handle->size, buf); + wakeup = PERF_IDX2OFF(handle->wakeup, buf); + + /* + * Lets calculate the buffer area which TRBE could write into. There + * are three possible scenarios here. Limit needs to be aligned with + * PAGE_SIZE per the TRBE requirement. Always avoid clobbering the + * unconsumed data. + * + * 1) head < tail + * + * head tail + * +----|-----------------------|-------+ + * |$$$$|#######################|$$$$$$$| + * +----|-----------------------|-------+ + * trbe_base limit trbe_base + nr_pages + * + * TRBE could write into [head..tail] area. Unless the tail is right at + * the end of the buffer, neither an wrap around nor an IRQ is expected + * while being enabled. + * + * 2) head == tail + * + * head = tail (size > 0) + * +----|-------------------------------+ + * |%%%%|###############################| + * +----|-------------------------------+ + * trbe_base limit = trbe_base + nr_pages + * + * TRBE should just write into [head..base + nr_pages] area even though + * the entire buffer is empty. Reason being, when the trace reaches the + * end of the buffer, it will just wrap around with an IRQ giving an + * opportunity to reconfigure the buffer. + * + * 3) tail < head + * + * tail head + * +----|-----------------------|-------+ + * |%%%%|$$$$$$$$$$$$$$$$$$$$$$$|#######| + * +----|-----------------------|-------+ + * trbe_base limit = trbe_base + nr_pages + * + * TRBE should just write into [head..base + nr_pages] area even though + * the [trbe_base..tail] is also empty. Reason being, when the trace + * reaches the end of the buffer, it will just wrap around with an IRQ + * giving an opportunity to reconfigure the buffer. + */ + if (head < tail) + limit = round_down(tail, PAGE_SIZE); + + /* + * Wakeup may be arbitrarily far into the future. If it's not in the + * current generation, either we'll wrap before hitting it, or it's + * in the past and has been handled already. + * + * If there's a wakeup before we wrap, arrange to be woken up by the + * page boundary following it. Keep the tail boundary if that's lower. + * + * head wakeup tail + * +----|---------------|-------|-------+ + * |$$$$|###############|%%%%%%%|$$$$$$$| + * +----|---------------|-------|-------+ + * trbe_base limit trbe_base + nr_pages + */ + if (handle->wakeup < (handle->head + handle->size) && head <= wakeup) + limit = min(limit, round_up(wakeup, PAGE_SIZE)); + + /* + * There are two situation when this can happen i.e limit is before + * the head and hence TRBE cannot be configured. + * + * 1) head < tail (aligned down with PAGE_SIZE) and also they are both + * within the same PAGE size range. + * + * PAGE_SIZE + * |----------------------| + * + * limit head tail + * +------------|------|--------|-------+ + * |$$$$$$$$$$$$$$$$$$$|========|$$$$$$$| + * +------------|------|--------|-------+ + * trbe_base trbe_base + nr_pages + * + * 2) head < wakeup (aligned up with PAGE_SIZE) < tail and also both + * head and wakeup are within same PAGE size range. + * + * PAGE_SIZE + * |----------------------| + * + * limit head wakeup tail + * +----|------|-------|--------|-------+ + * |$$$$$$$$$$$|=======|========|$$$$$$$| + * +----|------|-------|--------|-------+ + * trbe_base trbe_base + nr_pages + */ + if (limit > head) + return limit; + + trbe_pad_buf(handle, handle->size); + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); + return 0; +} + +static unsigned long trbe_normal_offset(struct perf_output_handle *handle) +{ + struct trbe_buf *buf = perf_get_aux(handle); + u64 limit = __trbe_normal_offset(handle); + u64 head = PERF_IDX2OFF(handle->head, buf); + + /* + * If the head is too close to the limit and we don't + * have space for a meaningful run, we rather pad it + * and start fresh. + */ + if (limit && (limit - head < TRBE_TRACE_MIN_BUF_SIZE)) { + trbe_pad_buf(handle, limit - head); + limit = __trbe_normal_offset(handle); + } + return limit; +} + +static unsigned long compute_trbe_buffer_limit(struct perf_output_handle *handle) +{ + struct trbe_buf *buf = etm_perf_sink_config(handle); + unsigned long offset; + + if (buf->snapshot) + offset = trbe_snapshot_offset(handle); + else + offset = trbe_normal_offset(handle); + return buf->trbe_base + offset; +} + +static void clr_trbe_status(void) +{ + u64 trbsr = read_sysreg_s(SYS_TRBSR_EL1); + + WARN_ON(is_trbe_enabled()); + trbsr &= ~TRBSR_IRQ; + trbsr &= ~TRBSR_TRG; + trbsr &= ~TRBSR_WRAP; + trbsr &= ~(TRBSR_EC_MASK << TRBSR_EC_SHIFT); + trbsr &= ~(TRBSR_BSC_MASK << TRBSR_BSC_SHIFT); + trbsr &= ~TRBSR_STOP; + write_sysreg_s(trbsr, SYS_TRBSR_EL1); +} + +static void set_trbe_limit_pointer_enabled(unsigned long addr) +{ + u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1); + + WARN_ON(!IS_ALIGNED(addr, (1UL << TRBLIMITR_LIMIT_SHIFT))); + WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE)); + + trblimitr &= ~TRBLIMITR_NVM; + trblimitr &= ~(TRBLIMITR_FILL_MODE_MASK << TRBLIMITR_FILL_MODE_SHIFT); + trblimitr &= ~(TRBLIMITR_TRIG_MODE_MASK << TRBLIMITR_TRIG_MODE_SHIFT); + trblimitr &= ~(TRBLIMITR_LIMIT_MASK << TRBLIMITR_LIMIT_SHIFT); + + /* + * Fill trace buffer mode is used here while configuring the + * TRBE for trace capture. In this particular mode, the trace + * collection is stopped and a maintenance interrupt is raised + * when the current write pointer wraps. This pause in trace + * collection gives the software an opportunity to capture the + * trace data in the interrupt handler, before reconfiguring + * the TRBE. + */ + trblimitr |= (TRBE_FILL_MODE_FILL & TRBLIMITR_FILL_MODE_MASK) << TRBLIMITR_FILL_MODE_SHIFT; + + /* + * Trigger mode is not used here while configuring the TRBE for + * the trace capture. Hence just keep this in the ignore mode. + */ + trblimitr |= (TRBE_TRIG_MODE_IGNORE & TRBLIMITR_TRIG_MODE_MASK) << + TRBLIMITR_TRIG_MODE_SHIFT; + trblimitr |= (addr & PAGE_MASK); + + trblimitr |= TRBLIMITR_ENABLE; + write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1); + + /* Synchronize the TRBE enable event */ + isb(); +} + +static void trbe_enable_hw(struct trbe_buf *buf) +{ + WARN_ON(buf->trbe_write < buf->trbe_base); + WARN_ON(buf->trbe_write >= buf->trbe_limit); + set_trbe_disabled(); + isb(); + clr_trbe_status(); + set_trbe_base_pointer(buf->trbe_base); + set_trbe_write_pointer(buf->trbe_write); + + /* + * Synchronize all the register updates + * till now before enabling the TRBE. + */ + isb(); + set_trbe_limit_pointer_enabled(buf->trbe_limit); +} + +static enum trbe_fault_action trbe_get_fault_act(u64 trbsr) +{ + int ec = get_trbe_ec(trbsr); + int bsc = get_trbe_bsc(trbsr); + + WARN_ON(is_trbe_running(trbsr)); + if (is_trbe_trg(trbsr) || is_trbe_abort(trbsr)) + return TRBE_FAULT_ACT_FATAL; + + if ((ec == TRBE_EC_STAGE1_ABORT) || (ec == TRBE_EC_STAGE2_ABORT)) + return TRBE_FAULT_ACT_FATAL; + + if (is_trbe_wrap(trbsr) && (ec == TRBE_EC_OTHERS) && (bsc == TRBE_BSC_FILLED)) { + if (get_trbe_write_pointer() == get_trbe_base_pointer()) + return TRBE_FAULT_ACT_WRAP; + } + return TRBE_FAULT_ACT_SPURIOUS; +} + +static void *arm_trbe_alloc_buffer(struct coresight_device *csdev, + struct perf_event *event, void **pages, + int nr_pages, bool snapshot) +{ + struct trbe_buf *buf; + struct page **pglist; + int i; + + /* + * TRBE LIMIT and TRBE WRITE pointers must be page aligned. But with + * just a single page, there would not be any room left while writing + * into a partially filled TRBE buffer after the page size alignment. + * Hence restrict the minimum buffer size as two pages. + */ + if (nr_pages < 2) + return NULL; + + buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, trbe_alloc_node(event)); + if (!buf) + return ERR_PTR(-ENOMEM); + + pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL); + if (!pglist) { + kfree(buf); + return ERR_PTR(-ENOMEM); + } + + for (i = 0; i < nr_pages; i++) + pglist[i] = virt_to_page(pages[i]); + + buf->trbe_base = (unsigned long)vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL); + if (!buf->trbe_base) { + kfree(pglist); + kfree(buf); + return ERR_PTR(-ENOMEM); + } + buf->trbe_limit = buf->trbe_base + nr_pages * PAGE_SIZE; + buf->trbe_write = buf->trbe_base; + buf->snapshot = snapshot; + buf->nr_pages = nr_pages; + buf->pages = pages; + kfree(pglist); + return buf; +} + +static void arm_trbe_free_buffer(void *config) +{ + struct trbe_buf *buf = config; + + vunmap((void *)buf->trbe_base); + kfree(buf); +} + +static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev, + struct perf_output_handle *handle, + void *config) +{ + struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev); + struct trbe_buf *buf = config; + enum trbe_fault_action act; + unsigned long size, offset; + unsigned long write, base, status; + unsigned long flags; + + WARN_ON(buf->cpudata != cpudata); + WARN_ON(cpudata->cpu != smp_processor_id()); + WARN_ON(cpudata->drvdata != drvdata); + if (cpudata->mode != CS_MODE_PERF) + return 0; + + perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW); + + /* + * We are about to disable the TRBE. And this could in turn + * fill up the buffer triggering, an IRQ. This could be consumed + * by the PE asynchronously, causing a race here against + * the IRQ handler in closing out the handle. So, let us + * make sure the IRQ can't trigger while we are collecting + * the buffer. We also make sure that a WRAP event is handled + * accordingly. + */ + local_irq_save(flags); + + /* + * If the TRBE was disabled due to lack of space in the AUX buffer or a + * spurious fault, the driver leaves it disabled, truncating the buffer. + * Since the etm_perf driver expects to close out the AUX buffer, the + * driver skips it. Thus, just pass in 0 size here to indicate that the + * buffer was truncated. + */ + if (!is_trbe_enabled()) { + size = 0; + goto done; + } + /* + * perf handle structure needs to be shared with the TRBE IRQ handler for + * capturing trace data and restarting the handle. There is a probability + * of an undefined reference based crash when etm event is being stopped + * while a TRBE IRQ also getting processed. This happens due the release + * of perf handle via perf_aux_output_end() in etm_event_stop(). Stopping + * the TRBE here will ensure that no IRQ could be generated when the perf + * handle gets freed in etm_event_stop(). + */ + trbe_drain_and_disable_local(); + write = get_trbe_write_pointer(); + base = get_trbe_base_pointer(); + + /* Check if there is a pending interrupt and handle it here */ + status = read_sysreg_s(SYS_TRBSR_EL1); + if (is_trbe_irq(status)) { + + /* + * Now that we are handling the IRQ here, clear the IRQ + * from the status, to let the irq handler know that it + * is taken care of. + */ + clr_trbe_irq(); + isb(); + + act = trbe_get_fault_act(status); + /* + * If this was not due to a WRAP event, we have some + * errors and as such buffer is empty. + */ + if (act != TRBE_FAULT_ACT_WRAP) { + size = 0; + goto done; + } + + /* + * Otherwise, the buffer is full and the write pointer + * has reached base. Adjust this back to the Limit pointer + * for correct size. Also, mark the buffer truncated. + */ + write = get_trbe_limit_pointer(); + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); + } + + offset = write - base; + if (WARN_ON_ONCE(offset < PERF_IDX2OFF(handle->head, buf))) + size = 0; + else + size = offset - PERF_IDX2OFF(handle->head, buf); + +done: + local_irq_restore(flags); + + if (buf->snapshot) + handle->head += size; + return size; +} + +static int arm_trbe_enable(struct coresight_device *csdev, u32 mode, void *data) +{ + struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev); + struct perf_output_handle *handle = data; + struct trbe_buf *buf = etm_perf_sink_config(handle); + + WARN_ON(cpudata->cpu != smp_processor_id()); + WARN_ON(cpudata->drvdata != drvdata); + if (mode != CS_MODE_PERF) + return -EINVAL; + + *this_cpu_ptr(drvdata->handle) = handle; + cpudata->buf = buf; + cpudata->mode = mode; + buf->cpudata = cpudata; + buf->trbe_limit = compute_trbe_buffer_limit(handle); + buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf); + if (buf->trbe_limit == buf->trbe_base) { + trbe_stop_and_truncate_event(handle); + return 0; + } + trbe_enable_hw(buf); + return 0; +} + +static int arm_trbe_disable(struct coresight_device *csdev) +{ + struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev); + struct trbe_buf *buf = cpudata->buf; + + WARN_ON(buf->cpudata != cpudata); + WARN_ON(cpudata->cpu != smp_processor_id()); + WARN_ON(cpudata->drvdata != drvdata); + if (cpudata->mode != CS_MODE_PERF) + return -EINVAL; + + trbe_drain_and_disable_local(); + buf->cpudata = NULL; + cpudata->buf = NULL; + cpudata->mode = CS_MODE_DISABLED; + return 0; +} + +static void trbe_handle_spurious(struct perf_output_handle *handle) +{ + struct trbe_buf *buf = etm_perf_sink_config(handle); + + buf->trbe_limit = compute_trbe_buffer_limit(handle); + buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf); + if (buf->trbe_limit == buf->trbe_base) { + trbe_drain_and_disable_local(); + return; + } + trbe_enable_hw(buf); +} + +static void trbe_handle_overflow(struct perf_output_handle *handle) +{ + struct perf_event *event = handle->event; + struct trbe_buf *buf = etm_perf_sink_config(handle); + unsigned long offset, size; + struct etm_event_data *event_data; + + offset = get_trbe_limit_pointer() - get_trbe_base_pointer(); + size = offset - PERF_IDX2OFF(handle->head, buf); + if (buf->snapshot) + handle->head += size; + + /* + * Mark the buffer as truncated, as we have stopped the trace + * collection upon the WRAP event, without stopping the source. + */ + perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW | + PERF_AUX_FLAG_TRUNCATED); + perf_aux_output_end(handle, size); + event_data = perf_aux_output_begin(handle, event); + if (!event_data) { + /* + * We are unable to restart the trace collection, + * thus leave the TRBE disabled. The etm-perf driver + * is able to detect this with a disconnected handle + * (handle->event = NULL). + */ + trbe_drain_and_disable_local(); + *this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL; + return; + } + buf->trbe_limit = compute_trbe_buffer_limit(handle); + buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf); + if (buf->trbe_limit == buf->trbe_base) { + trbe_stop_and_truncate_event(handle); + return; + } + *this_cpu_ptr(buf->cpudata->drvdata->handle) = handle; + trbe_enable_hw(buf); +} + +static bool is_perf_trbe(struct perf_output_handle *handle) +{ + struct trbe_buf *buf = etm_perf_sink_config(handle); + struct trbe_cpudata *cpudata = buf->cpudata; + struct trbe_drvdata *drvdata = cpudata->drvdata; + int cpu = smp_processor_id(); + + WARN_ON(buf->trbe_base != get_trbe_base_pointer()); + WARN_ON(buf->trbe_limit != get_trbe_limit_pointer()); + + if (cpudata->mode != CS_MODE_PERF) + return false; + + if (cpudata->cpu != cpu) + return false; + + if (!cpumask_test_cpu(cpu, &drvdata->supported_cpus)) + return false; + + return true; +} + +static irqreturn_t arm_trbe_irq_handler(int irq, void *dev) +{ + struct perf_output_handle **handle_ptr = dev; + struct perf_output_handle *handle = *handle_ptr; + enum trbe_fault_action act; + u64 status; + + /* + * Ensure the trace is visible to the CPUs and + * any external aborts have been resolved. + */ + trbe_drain_and_disable_local(); + + status = read_sysreg_s(SYS_TRBSR_EL1); + /* + * If the pending IRQ was handled by update_buffer callback + * we have nothing to do here. + */ + if (!is_trbe_irq(status)) + return IRQ_NONE; + + clr_trbe_irq(); + isb(); + + if (WARN_ON_ONCE(!handle) || !perf_get_aux(handle)) + return IRQ_NONE; + + if (!is_perf_trbe(handle)) + return IRQ_NONE; + + /* + * Ensure perf callbacks have completed, which may disable + * the trace buffer in response to a TRUNCATION flag. + */ + irq_work_run(); + + act = trbe_get_fault_act(status); + switch (act) { + case TRBE_FAULT_ACT_WRAP: + trbe_handle_overflow(handle); + break; + case TRBE_FAULT_ACT_SPURIOUS: + trbe_handle_spurious(handle); + break; + case TRBE_FAULT_ACT_FATAL: + trbe_stop_and_truncate_event(handle); + break; + } + return IRQ_HANDLED; +} + +static const struct coresight_ops_sink arm_trbe_sink_ops = { + .enable = arm_trbe_enable, + .disable = arm_trbe_disable, + .alloc_buffer = arm_trbe_alloc_buffer, + .free_buffer = arm_trbe_free_buffer, + .update_buffer = arm_trbe_update_buffer, +}; + +static const struct coresight_ops arm_trbe_cs_ops = { + .sink_ops = &arm_trbe_sink_ops, +}; + +static ssize_t align_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct trbe_cpudata *cpudata = dev_get_drvdata(dev); + + return sprintf(buf, "%llx\n", cpudata->trbe_align); +} +static DEVICE_ATTR_RO(align); + +static ssize_t flag_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct trbe_cpudata *cpudata = dev_get_drvdata(dev); + + return sprintf(buf, "%d\n", cpudata->trbe_flag); +} +static DEVICE_ATTR_RO(flag); + +static struct attribute *arm_trbe_attrs[] = { + &dev_attr_align.attr, + &dev_attr_flag.attr, + NULL, +}; + +static const struct attribute_group arm_trbe_group = { + .attrs = arm_trbe_attrs, +}; + +static const struct attribute_group *arm_trbe_groups[] = { + &arm_trbe_group, + NULL, +}; + +static void arm_trbe_enable_cpu(void *info) +{ + struct trbe_drvdata *drvdata = info; + + trbe_reset_local(); + enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE); +} + +static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cpu) +{ + struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu); + struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu); + struct coresight_desc desc = { 0 }; + struct device *dev; + + if (WARN_ON(trbe_csdev)) + return; + + dev = &cpudata->drvdata->pdev->dev; + desc.name = devm_kasprintf(dev, GFP_KERNEL, "trbe%d", cpu); + if (!desc.name) + goto cpu_clear; + + desc.type = CORESIGHT_DEV_TYPE_SINK; + desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM; + desc.ops = &arm_trbe_cs_ops; + desc.pdata = dev_get_platdata(dev); + desc.groups = arm_trbe_groups; + desc.dev = dev; + trbe_csdev = coresight_register(&desc); + if (IS_ERR(trbe_csdev)) + goto cpu_clear; + + dev_set_drvdata(&trbe_csdev->dev, cpudata); + coresight_set_percpu_sink(cpu, trbe_csdev); + return; +cpu_clear: + cpumask_clear_cpu(cpu, &drvdata->supported_cpus); +} + +static void arm_trbe_probe_cpu(void *info) +{ + struct trbe_drvdata *drvdata = info; + int cpu = smp_processor_id(); + struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu); + u64 trbidr; + + if (WARN_ON(!cpudata)) + goto cpu_clear; + + if (!is_trbe_available()) { + pr_err("TRBE is not implemented on cpu %d\n", cpu); + goto cpu_clear; + } + + trbidr = read_sysreg_s(SYS_TRBIDR_EL1); + if (!is_trbe_programmable(trbidr)) { + pr_err("TRBE is owned in higher exception level on cpu %d\n", cpu); + goto cpu_clear; + } + + cpudata->trbe_align = 1ULL << get_trbe_address_align(trbidr); + if (cpudata->trbe_align > SZ_2K) { + pr_err("Unsupported alignment on cpu %d\n", cpu); + goto cpu_clear; + } + cpudata->trbe_flag = get_trbe_flag_update(trbidr); + cpudata->cpu = cpu; + cpudata->drvdata = drvdata; + return; +cpu_clear: + cpumask_clear_cpu(cpu, &drvdata->supported_cpus); +} + +static void arm_trbe_remove_coresight_cpu(void *info) +{ + int cpu = smp_processor_id(); + struct trbe_drvdata *drvdata = info; + struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu); + struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu); + + disable_percpu_irq(drvdata->irq); + trbe_reset_local(); + if (trbe_csdev) { + coresight_unregister(trbe_csdev); + cpudata->drvdata = NULL; + coresight_set_percpu_sink(cpu, NULL); + } +} + +static int arm_trbe_probe_coresight(struct trbe_drvdata *drvdata) +{ + int cpu; + + drvdata->cpudata = alloc_percpu(typeof(*drvdata->cpudata)); + if (!drvdata->cpudata) + return -ENOMEM; + + for_each_cpu(cpu, &drvdata->supported_cpus) { + smp_call_function_single(cpu, arm_trbe_probe_cpu, drvdata, 1); + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) + arm_trbe_register_coresight_cpu(drvdata, cpu); + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) + smp_call_function_single(cpu, arm_trbe_enable_cpu, drvdata, 1); + } + return 0; +} + +static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata) +{ + int cpu; + + for_each_cpu(cpu, &drvdata->supported_cpus) + smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, drvdata, 1); + free_percpu(drvdata->cpudata); + return 0; +} + +static int arm_trbe_cpu_startup(unsigned int cpu, struct hlist_node *node) +{ + struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node); + + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) { + + /* + * If this CPU was not probed for TRBE, + * initialize it now. + */ + if (!coresight_get_percpu_sink(cpu)) { + arm_trbe_probe_cpu(drvdata); + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) + arm_trbe_register_coresight_cpu(drvdata, cpu); + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) + arm_trbe_enable_cpu(drvdata); + } else { + arm_trbe_enable_cpu(drvdata); + } + } + return 0; +} + +static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node) +{ + struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node); + + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) { + disable_percpu_irq(drvdata->irq); + trbe_reset_local(); + } + return 0; +} + +static int arm_trbe_probe_cpuhp(struct trbe_drvdata *drvdata) +{ + enum cpuhp_state trbe_online; + int ret; + + trbe_online = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME, + arm_trbe_cpu_startup, arm_trbe_cpu_teardown); + if (trbe_online < 0) + return trbe_online; + + ret = cpuhp_state_add_instance(trbe_online, &drvdata->hotplug_node); + if (ret) { + cpuhp_remove_multi_state(trbe_online); + return ret; + } + drvdata->trbe_online = trbe_online; + return 0; +} + +static void arm_trbe_remove_cpuhp(struct trbe_drvdata *drvdata) +{ + cpuhp_remove_multi_state(drvdata->trbe_online); +} + +static int arm_trbe_probe_irq(struct platform_device *pdev, + struct trbe_drvdata *drvdata) +{ + int ret; + + drvdata->irq = platform_get_irq(pdev, 0); + if (drvdata->irq < 0) { + pr_err("IRQ not found for the platform device\n"); + return drvdata->irq; + } + + if (!irq_is_percpu(drvdata->irq)) { + pr_err("IRQ is not a PPI\n"); + return -EINVAL; + } + + if (irq_get_percpu_devid_partition(drvdata->irq, &drvdata->supported_cpus)) + return -EINVAL; + + drvdata->handle = alloc_percpu(struct perf_output_handle *); + if (!drvdata->handle) + return -ENOMEM; + + ret = request_percpu_irq(drvdata->irq, arm_trbe_irq_handler, DRVNAME, drvdata->handle); + if (ret) { + free_percpu(drvdata->handle); + return ret; + } + return 0; +} + +static void arm_trbe_remove_irq(struct trbe_drvdata *drvdata) +{ + free_percpu_irq(drvdata->irq, drvdata->handle); + free_percpu(drvdata->handle); +} + +static int arm_trbe_device_probe(struct platform_device *pdev) +{ + struct coresight_platform_data *pdata; + struct trbe_drvdata *drvdata; + struct device *dev = &pdev->dev; + int ret; + + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL); + if (!drvdata) + return -ENOMEM; + + pdata = coresight_get_platform_data(dev); + if (IS_ERR(pdata)) + return PTR_ERR(pdata); + + dev_set_drvdata(dev, drvdata); + dev->platform_data = pdata; + drvdata->pdev = pdev; + ret = arm_trbe_probe_irq(pdev, drvdata); + if (ret) + return ret; + + ret = arm_trbe_probe_coresight(drvdata); + if (ret) + goto probe_failed; + + ret = arm_trbe_probe_cpuhp(drvdata); + if (ret) + goto cpuhp_failed; + + return 0; +cpuhp_failed: + arm_trbe_remove_coresight(drvdata); +probe_failed: + arm_trbe_remove_irq(drvdata); + return ret; +} + +static int arm_trbe_device_remove(struct platform_device *pdev) +{ + struct trbe_drvdata *drvdata = platform_get_drvdata(pdev); + + arm_trbe_remove_cpuhp(drvdata); + arm_trbe_remove_coresight(drvdata); + arm_trbe_remove_irq(drvdata); + return 0; +} + +static const struct of_device_id arm_trbe_of_match[] = { + { .compatible = "arm,trace-buffer-extension"}, + {}, +}; +MODULE_DEVICE_TABLE(of, arm_trbe_of_match); + +static struct platform_driver arm_trbe_driver = { + .driver = { + .name = DRVNAME, + .of_match_table = of_match_ptr(arm_trbe_of_match), + .suppress_bind_attrs = true, + }, + .probe = arm_trbe_device_probe, + .remove = arm_trbe_device_remove, +}; + +static int __init arm_trbe_init(void) +{ + int ret; + + if (arm64_kernel_unmapped_at_el0()) { + pr_err("TRBE wouldn't work if kernel gets unmapped at EL0\n"); + return -EOPNOTSUPP; + } + + ret = platform_driver_register(&arm_trbe_driver); + if (!ret) + return 0; + + pr_err("Error registering %s platform driver\n", DRVNAME); + return ret; +} + +static void __exit arm_trbe_exit(void) +{ + platform_driver_unregister(&arm_trbe_driver); +} +module_init(arm_trbe_init); +module_exit(arm_trbe_exit); + +MODULE_AUTHOR("Anshuman Khandual <anshuman.khandual@arm.com>"); +MODULE_DESCRIPTION("Arm Trace Buffer Extension (TRBE) driver"); +MODULE_LICENSE("GPL v2"); |