Add support to use reserved memory for coresight ETR trace buffer.

Introduce a new ETR buffer mode called ETR_MODE_RESRV, which becomes available when ETR device tree node is supplied with a valid reserved memory region.

ETR_MODE_RESRV can be selected only by explicit user request.

$ echo resrv >/sys/bus/coresight/devices/tmc_etr<N>/buf_mode_preferred

Signed-off-by: Anil Kumar Reddy areddy3@marvell.com Signed-off-by: Linu Cherian lcherian@marvell.com Reviewed-by: James Clark james.clark@arm.com --- .../hwtracing/coresight/coresight-tmc-core.c | 50 ++++++++++++ .../hwtracing/coresight/coresight-tmc-etr.c | 79 +++++++++++++++++++ drivers/hwtracing/coresight/coresight-tmc.h | 25 ++++++ 3 files changed, 154 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index 3a482fd2cb22..248989833b20 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -23,6 +23,7 @@ #include <linux/spinlock.h> #include <linux/pm_runtime.h> #include <linux/of.h> +#include <linux/of_address.h> #include <linux/coresight.h> #include <linux/amba/bus.h> #include <linux/platform_device.h> @@ -398,6 +399,53 @@ static inline bool tmc_etr_has_non_secure_access(struct tmc_drvdata *drvdata)

static const struct amba_id tmc_ids[];

+static int of_tmc_get_reserved_resource_by_name(struct device *dev, + const char *name, + struct resource *res) +{ + int index, rc = -ENODEV; + struct device_node *node; + + if (!is_of_node(dev->fwnode)) + return -ENODEV; + + index = of_property_match_string(dev->of_node, "memory-region-names", + name); + if (index < 0) + return rc; + + node = of_parse_phandle(dev->of_node, "memory-region", index); + if (!node) + return rc; + + if (!of_address_to_resource(node, 0, res) && + res->start != 0 && resource_size(res) != 0) + rc = 0; + of_node_put(node); + + return rc; +} + +static void tmc_get_reserved_region(struct device *parent) +{ + struct tmc_drvdata *drvdata = dev_get_drvdata(parent); + struct resource res; + + if (of_tmc_get_reserved_resource_by_name(parent, "tracedata", &res)) + return; + + drvdata->resrv_buf.vaddr = memremap(res.start, + resource_size(&res), + MEMREMAP_WC); + if (IS_ERR_OR_NULL(drvdata->resrv_buf.vaddr)) { + dev_err(parent, "Reserved trace buffer mapping failed\n"); + return; + } + + drvdata->resrv_buf.paddr = res.start; + drvdata->resrv_buf.size = resource_size(&res); +} + /* Detect and initialise the capabilities of a TMC ETR */ static int tmc_etr_setup_caps(struct device *parent, u32 devid, struct csdev_access *access) @@ -508,6 +556,8 @@ static int __tmc_probe(struct device *dev, struct resource *res) drvdata->size = readl_relaxed(drvdata->base + TMC_RSZ) * 4; }

+ tmc_get_reserved_region(dev); + desc.dev = dev;

switch (drvdata->config_type) { diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index a48bb85d0e7f..8bca5b36334a 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -30,6 +30,7 @@ struct etr_buf_hw { bool has_iommu; bool has_etr_sg; bool has_catu; + bool has_resrv; };

/* @@ -695,6 +696,75 @@ static const struct etr_buf_operations etr_flat_buf_ops = { .get_data = tmc_etr_get_data_flat_buf, };

+/* + * tmc_etr_alloc_resrv_buf: Allocate a contiguous DMA buffer from reserved region. + */ +static int tmc_etr_alloc_resrv_buf(struct tmc_drvdata *drvdata, + struct etr_buf *etr_buf, int node, + void **pages) +{ + struct etr_flat_buf *resrv_buf; + struct device *real_dev = drvdata->csdev->dev.parent; + + /* We cannot reuse existing pages for resrv buf */ + if (pages) + return -EINVAL; + + resrv_buf = kzalloc(sizeof(*resrv_buf), GFP_KERNEL); + if (!resrv_buf) + return -ENOMEM; + + resrv_buf->daddr = dma_map_resource(real_dev, drvdata->resrv_buf.paddr, + drvdata->resrv_buf.size, + DMA_FROM_DEVICE, 0); + if (dma_mapping_error(real_dev, resrv_buf->daddr)) { + dev_err(real_dev, "failed to map source buffer address\n"); + kfree(resrv_buf); + return -ENOMEM; + } + + resrv_buf->vaddr = drvdata->resrv_buf.vaddr; + resrv_buf->size = etr_buf->size = drvdata->resrv_buf.size; + resrv_buf->dev = &drvdata->csdev->dev; + etr_buf->hwaddr = resrv_buf->daddr; + etr_buf->mode = ETR_MODE_RESRV; + etr_buf->private = resrv_buf; + return 0; +} + +static void tmc_etr_free_resrv_buf(struct etr_buf *etr_buf) +{ + struct etr_flat_buf *resrv_buf = etr_buf->private; + + if (resrv_buf && resrv_buf->daddr) { + struct device *real_dev = resrv_buf->dev->parent; + + dma_unmap_resource(real_dev, resrv_buf->daddr, + resrv_buf->size, DMA_FROM_DEVICE, 0); + } + kfree(resrv_buf); +} + +static void tmc_etr_sync_resrv_buf(struct etr_buf *etr_buf, u64 rrp, u64 rwp) +{ + /* + * Adjust the buffer to point to the beginning of the trace data + * and update the available trace data. + */ + etr_buf->offset = rrp - etr_buf->hwaddr; + if (etr_buf->full) + etr_buf->len = etr_buf->size; + else + etr_buf->len = rwp - rrp; +} + +static const struct etr_buf_operations etr_resrv_buf_ops = { + .alloc = tmc_etr_alloc_resrv_buf, + .free = tmc_etr_free_resrv_buf, + .sync = tmc_etr_sync_resrv_buf, + .get_data = tmc_etr_get_data_flat_buf, +}; + /* * tmc_etr_alloc_sg_buf: Allocate an SG buf @etr_buf. Setup the parameters * appropriately. @@ -801,6 +871,7 @@ static const struct etr_buf_operations *etr_buf_ops[] = { [ETR_MODE_FLAT] = &etr_flat_buf_ops, [ETR_MODE_ETR_SG] = &etr_sg_buf_ops, [ETR_MODE_CATU] = NULL, + [ETR_MODE_RESRV] = &etr_resrv_buf_ops };

void tmc_etr_set_catu_ops(const struct etr_buf_operations *catu) @@ -826,6 +897,7 @@ static inline int tmc_etr_mode_alloc_buf(int mode, case ETR_MODE_FLAT: case ETR_MODE_ETR_SG: case ETR_MODE_CATU: + case ETR_MODE_RESRV: if (etr_buf_ops[mode] && etr_buf_ops[mode]->alloc) rc = etr_buf_ops[mode]->alloc(drvdata, etr_buf, node, pages); @@ -844,6 +916,7 @@ static void get_etr_buf_hw(struct device *dev, struct etr_buf_hw *buf_hw) buf_hw->has_iommu = iommu_get_domain_for_dev(dev->parent); buf_hw->has_etr_sg = tmc_etr_has_cap(drvdata, TMC_ETR_SG); buf_hw->has_catu = !!tmc_etr_get_catu_device(drvdata); + buf_hw->has_resrv = tmc_has_reserved_buffer(drvdata); }

static bool etr_can_use_flat_mode(struct etr_buf_hw *buf_hw, ssize_t etr_buf_size) @@ -1831,6 +1904,7 @@ static const char *const buf_modes_str[] = { [ETR_MODE_FLAT] = "flat", [ETR_MODE_ETR_SG] = "tmc-sg", [ETR_MODE_CATU] = "catu", + [ETR_MODE_RESRV] = "resrv", [ETR_MODE_AUTO] = "auto", };

@@ -1849,6 +1923,9 @@ static ssize_t buf_modes_available_show(struct device *dev, if (buf_hw.has_catu) size += sysfs_emit_at(buf, size, "%s ", buf_modes_str[ETR_MODE_CATU]);

+ if (buf_hw.has_resrv) + size += sysfs_emit_at(buf, size, "%s ", buf_modes_str[ETR_MODE_RESRV]); + size += sysfs_emit_at(buf, size, "\n"); return size; } @@ -1876,6 +1953,8 @@ static ssize_t buf_mode_preferred_store(struct device *dev, drvdata->etr_mode = ETR_MODE_ETR_SG; else if (sysfs_streq(buf, buf_modes_str[ETR_MODE_CATU]) && buf_hw.has_catu) drvdata->etr_mode = ETR_MODE_CATU; + else if (sysfs_streq(buf, buf_modes_str[ETR_MODE_RESRV]) && buf_hw.has_resrv) + drvdata->etr_mode = ETR_MODE_RESRV; else if (sysfs_streq(buf, buf_modes_str[ETR_MODE_AUTO])) drvdata->etr_mode = ETR_MODE_AUTO; else diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index 2671926be62a..d2261eddab71 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -135,6 +135,7 @@ enum etr_mode { ETR_MODE_FLAT, /* Uses contiguous flat buffer */ ETR_MODE_ETR_SG, /* Uses in-built TMC ETR SG mechanism */ ETR_MODE_CATU, /* Use SG mechanism in CATU */ + ETR_MODE_RESRV, /* Use reserved region contiguous buffer */ ETR_MODE_AUTO, /* Use the default mechanism */ };

@@ -164,6 +165,17 @@ struct etr_buf { void *private; };

+/** + * @paddr : Start address of reserved memory region. + * @vaddr : Corresponding CPU virtual address. + * @size : Size of reserved memory region. + */ +struct tmc_resrv_buf { + phys_addr_t paddr; + void *vaddr; + size_t size; +}; + /** * struct tmc_drvdata - specifics associated to an TMC component * @pclk: APB clock if present, otherwise NULL @@ -189,6 +201,10 @@ struct etr_buf { * @idr_mutex: Access serialisation for idr. * @sysfs_buf: SYSFS buffer for ETR. * @perf_buf: PERF buffer for ETR. + * @resrv_buf: Used by ETR as hardware trace buffer and for trace data + * retention (after crash) only when ETR_MODE_RESRV buffer + * mode is enabled. Used by ETF for trace data retention + * (after crash) by default. */ struct tmc_drvdata { struct clk *pclk; @@ -214,6 +230,7 @@ struct tmc_drvdata { struct mutex idr_mutex; struct etr_buf *sysfs_buf; struct etr_buf *perf_buf; + struct tmc_resrv_buf resrv_buf; };

struct etr_buf_operations { @@ -331,6 +348,14 @@ tmc_sg_table_buf_size(struct tmc_sg_table *sg_table) return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT; }

+static inline bool tmc_has_reserved_buffer(struct tmc_drvdata *drvdata) +{ + if (drvdata->resrv_buf.vaddr && + drvdata->resrv_buf.size) + return true; + return false; +} + struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);

void tmc_etr_set_catu_ops(const struct etr_buf_operations *catu);

- Get reserved region from device tree node for metadata - Define metadata format for TMC - Add TMC ETR panic sync handler that syncs register snapshot to metadata region - Add TMC ETF panic sync handler that syncs register snapshot to metadata region and internal SRAM to reserved trace buffer region.

Signed-off-by: Linu Cherian lcherian@marvell.com Reviewed-by: James Clark james.clark@arm.com --- .../hwtracing/coresight/coresight-tmc-core.c | 14 ++++ .../hwtracing/coresight/coresight-tmc-etf.c | 80 +++++++++++++++++++ .../hwtracing/coresight/coresight-tmc-etr.c | 73 +++++++++++++++++ drivers/hwtracing/coresight/coresight-tmc.h | 66 +++++++++++++++ 4 files changed, 233 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index 248989833b20..1e3938ec12cb 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -444,6 +444,20 @@ static void tmc_get_reserved_region(struct device *parent)

drvdata->resrv_buf.paddr = res.start; drvdata->resrv_buf.size = resource_size(&res); + + if (of_tmc_get_reserved_resource_by_name(parent, "metadata", &res)) + return; + + drvdata->crash_mdata.vaddr = memremap(res.start, + resource_size(&res), + MEMREMAP_WC); + if (IS_ERR_OR_NULL(drvdata->crash_mdata.vaddr)) { + dev_err(parent, "Metadata memory mapping failed\n"); + return; + } + + drvdata->crash_mdata.paddr = res.start; + drvdata->crash_mdata.size = resource_size(&res); }

/* Detect and initialise the capabilities of a TMC ETR */ diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index d4f641cd9de6..0f9155a10ac2 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -590,6 +590,81 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, return to_read; }

+static int tmc_panic_sync_etf(struct coresight_device *csdev) +{ + u32 val; + struct tmc_crash_metadata *mdata; + struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + + mdata = (struct tmc_crash_metadata *)drvdata->crash_mdata.vaddr; + + /* Make sure we have valid reserved memory */ + if (!tmc_has_reserved_buffer(drvdata) || + !tmc_has_crash_mdata_buffer(drvdata)) + return 0; + + tmc_crashdata_set_invalid(drvdata); + + CS_UNLOCK(drvdata->base); + + /* Proceed only if ETF is enabled or configured as sink */ + val = readl(drvdata->base + TMC_CTL); + if (!(val & TMC_CTL_CAPT_EN)) + goto out; + val = readl(drvdata->base + TMC_MODE); + if (val != TMC_MODE_CIRCULAR_BUFFER) + goto out; + + val = readl(drvdata->base + TMC_FFSR); + /* Do manual flush and stop only if its not auto-stopped */ + if (!(val & TMC_FFSR_FT_STOPPED)) { + dev_dbg(&csdev->dev, + "%s: Triggering manual flush\n", __func__); + tmc_flush_and_stop(drvdata); + } else + tmc_wait_for_tmcready(drvdata); + + /* Sync registers from hardware to metadata region */ + mdata->tmc_sts = readl(drvdata->base + TMC_STS); + mdata->tmc_mode = readl(drvdata->base + TMC_MODE); + mdata->tmc_ffcr = readl(drvdata->base + TMC_FFCR); + mdata->tmc_ffsr = readl(drvdata->base + TMC_FFSR); + + /* Sync Internal SRAM to reserved trace buffer region */ + drvdata->buf = drvdata->resrv_buf.vaddr; + tmc_etb_dump_hw(drvdata); + /* Store as per RSZ register convention */ + mdata->tmc_ram_size = drvdata->len >> 2; + + /* Other fields for processing trace buffer reads */ + mdata->tmc_rrp = 0; + mdata->tmc_dba = 0; + mdata->tmc_rwp = drvdata->len; + mdata->trace_paddr = drvdata->resrv_buf.paddr; + + mdata->version = CS_CRASHDATA_VERSION; + + /* + * Make sure all previous writes are ordered, + * before we mark valid + */ + dmb(sy); + mdata->valid = true; + /* + * Below order need to maintained, since crc of metadata + * is dependent on first + */ + mdata->crc32_tdata = find_crash_tracedata_crc(drvdata, mdata); + mdata->crc32_mdata = find_crash_metadata_crc(mdata); + + tmc_disable_hw(drvdata); + + dev_dbg(&csdev->dev, "%s: success\n", __func__); +out: + CS_UNLOCK(drvdata->base); + return 0; +} + static const struct coresight_ops_sink tmc_etf_sink_ops = { .enable = tmc_enable_etf_sink, .disable = tmc_disable_etf_sink, @@ -603,6 +678,10 @@ static const struct coresight_ops_link tmc_etf_link_ops = { .disable = tmc_disable_etf_link, };

+static const struct coresight_ops_panic tmc_etf_sync_ops = { + .sync = tmc_panic_sync_etf, +}; + const struct coresight_ops tmc_etb_cs_ops = { .sink_ops = &tmc_etf_sink_ops, }; @@ -610,6 +689,7 @@ const struct coresight_ops tmc_etb_cs_ops = { const struct coresight_ops tmc_etf_cs_ops = { .sink_ops = &tmc_etf_sink_ops, .link_ops = &tmc_etf_link_ops, + .panic_ops = &tmc_etf_sync_ops, };

int tmc_read_prepare_etb(struct tmc_drvdata *drvdata) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 8bca5b36334a..fb944a68a11c 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1814,6 +1814,74 @@ static int tmc_disable_etr_sink(struct coresight_device *csdev) return 0; }

+static int tmc_panic_sync_etr(struct coresight_device *csdev) +{ + u32 val; + struct tmc_crash_metadata *mdata; + struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + + mdata = (struct tmc_crash_metadata *)drvdata->crash_mdata.vaddr; + + if (!drvdata->etr_buf) + return 0; + + /* Being in RESRV mode implies valid reserved memory as well */ + if (drvdata->etr_buf->mode != ETR_MODE_RESRV) + return 0; + + if (!tmc_has_crash_mdata_buffer(drvdata)) + return 0; + + CS_UNLOCK(drvdata->base); + + /* Proceed only if ETR is enabled */ + val = readl(drvdata->base + TMC_CTL); + if (!(val & TMC_CTL_CAPT_EN)) + goto out; + + val = readl(drvdata->base + TMC_FFSR); + /* Do manual flush and stop only if its not auto-stopped */ + if (!(val & TMC_FFSR_FT_STOPPED)) { + dev_dbg(&csdev->dev, + "%s: Triggering manual flush\n", __func__); + tmc_flush_and_stop(drvdata); + } else + tmc_wait_for_tmcready(drvdata); + + /* Sync registers from hardware to metadata region */ + mdata->tmc_ram_size = readl(drvdata->base + TMC_RSZ); + mdata->tmc_sts = readl(drvdata->base + TMC_STS); + mdata->tmc_mode = readl(drvdata->base + TMC_MODE); + mdata->tmc_ffcr = readl(drvdata->base + TMC_FFCR); + mdata->tmc_ffsr = readl(drvdata->base + TMC_FFSR); + mdata->tmc_rrp = tmc_read_rrp(drvdata); + mdata->tmc_rwp = tmc_read_rwp(drvdata); + mdata->tmc_dba = tmc_read_dba(drvdata); + mdata->trace_paddr = drvdata->resrv_buf.paddr; + mdata->version = CS_CRASHDATA_VERSION; + + /* + * Make sure all previous writes are ordered, + * before we mark valid + */ + dmb(sy); + mdata->valid = true; + /* + * Below order need to maintained, since crc of metadata + * is dependent on first + */ + mdata->crc32_tdata = find_crash_tracedata_crc(drvdata, mdata); + mdata->crc32_mdata = find_crash_metadata_crc(mdata); + + tmc_disable_hw(drvdata); + + dev_dbg(&csdev->dev, "%s: success\n", __func__); +out: + CS_UNLOCK(drvdata->base); + + return 0; +} + static const struct coresight_ops_sink tmc_etr_sink_ops = { .enable = tmc_enable_etr_sink, .disable = tmc_disable_etr_sink, @@ -1822,8 +1890,13 @@ static const struct coresight_ops_sink tmc_etr_sink_ops = { .free_buffer = tmc_free_etr_buffer, };

+static const struct coresight_ops_panic tmc_etr_sync_ops = { + .sync = tmc_panic_sync_etr, +}; + const struct coresight_ops tmc_etr_cs_ops = { .sink_ops = &tmc_etr_sink_ops, + .panic_ops = &tmc_etr_sync_ops, };

int tmc_read_prepare_etr(struct tmc_drvdata *drvdata) diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index d2261eddab71..d76e83fc840b 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -12,6 +12,7 @@ #include <linux/miscdevice.h> #include <linux/mutex.h> #include <linux/refcount.h> +#include <linux/crc32.h>

#define TMC_RSZ 0x004 #define TMC_STS 0x00c @@ -76,6 +77,9 @@ #define TMC_AXICTL_AXCACHE_OS (0xf << 2) #define TMC_AXICTL_ARCACHE_OS (0xf << 16)

+/* TMC_FFSR - 0x300 */ +#define TMC_FFSR_FT_STOPPED BIT(1) + /* TMC_FFCR - 0x304 */ #define TMC_FFCR_FLUSHMAN_BIT 6 #define TMC_FFCR_EN_FMT BIT(0) @@ -94,6 +98,9 @@

#define TMC_AUTH_NSID_MASK GENMASK(1, 0)

+/* Major version 1 Minor version 0 */ +#define CS_CRASHDATA_VERSION (1 << 16) + enum tmc_config_type { TMC_CONFIG_TYPE_ETB, TMC_CONFIG_TYPE_ETR, @@ -131,6 +138,25 @@ enum tmc_mem_intf_width { #define CORESIGHT_SOC_600_ETR_CAPS \ (TMC_ETR_SAVE_RESTORE | TMC_ETR_AXI_ARCACHE)

+/* TMC metadata region for ETR and ETF configurations */ +struct tmc_crash_metadata { + uint32_t crc32_mdata; /* crc of metadata */ + uint32_t crc32_tdata; /* crc of tracedata */ + uint32_t version; /* 31:16 Major version, 15:0 Minor version */ + uint32_t valid; /* Indicate if this ETF/ETR was enabled */ + uint32_t tmc_ram_size; /* Ram Size register */ + uint32_t tmc_sts; /* Status register */ + uint32_t tmc_mode; /* Mode register */ + uint32_t tmc_ffcr; /* Formatter and flush control register */ + uint32_t tmc_ffsr; /* Formatter and flush status register */ + uint32_t reserved32; + uint64_t tmc_rrp; /* Ram Read pointer register */ + uint64_t tmc_rwp; /* Ram Write pointer register */ + uint64_t tmc_dba; /* Data buffer address register */ + uint64_t trace_paddr; /* Phys address of trace buffer */ + uint64_t reserved64[3]; +}; + enum etr_mode { ETR_MODE_FLAT, /* Uses contiguous flat buffer */ ETR_MODE_ETR_SG, /* Uses in-built TMC ETR SG mechanism */ @@ -205,6 +231,8 @@ struct tmc_resrv_buf { * retention (after crash) only when ETR_MODE_RESRV buffer * mode is enabled. Used by ETF for trace data retention * (after crash) by default. + * @crash_mdata: Reserved memory for storing tmc crash metadata. + * Used by ETR/ETF. */ struct tmc_drvdata { struct clk *pclk; @@ -231,6 +259,7 @@ struct tmc_drvdata { struct etr_buf *sysfs_buf; struct etr_buf *perf_buf; struct tmc_resrv_buf resrv_buf; + struct tmc_resrv_buf crash_mdata; };

struct etr_buf_operations { @@ -356,6 +385,43 @@ static inline bool tmc_has_reserved_buffer(struct tmc_drvdata *drvdata) return false; }

+static inline bool tmc_has_crash_mdata_buffer(struct tmc_drvdata *drvdata) +{ + if (drvdata->crash_mdata.vaddr && + drvdata->crash_mdata.size) + return true; + return false; +} + +static inline void tmc_crashdata_set_invalid(struct tmc_drvdata *drvdata) +{ + struct tmc_crash_metadata *mdata; + + mdata = (struct tmc_crash_metadata *)drvdata->crash_mdata.vaddr; + + if (tmc_has_crash_mdata_buffer(drvdata)) + mdata->valid = false; +} + +static inline uint32_t find_crash_metadata_crc(struct tmc_crash_metadata *md) +{ + unsigned long crc_size; + + crc_size = sizeof(struct tmc_crash_metadata) - + offsetof(struct tmc_crash_metadata, crc32_tdata); + return crc32_le(0, (void *)&md->crc32_tdata, crc_size); +} + +static inline uint32_t find_crash_tracedata_crc(struct tmc_drvdata *drvdata, + struct tmc_crash_metadata *md) +{ + unsigned long crc_size; + + /* Take CRC of configured buffer size to keep it simple */ + crc_size = md->tmc_ram_size << 2; + return crc32_le(0, (void *)drvdata->resrv_buf.vaddr, crc_size); +} + struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);

void tmc_etr_set_catu_ops(const struct etr_buf_operations *catu);

Configure TMC ETR and ETF to flush and stop trace capture on FlIn event based on sysfs attribute, /sys/bus/coresight/devices/tmc_etXn/stop_on_flush.

Signed-off-by: Linu Cherian lcherian@marvell.com --- .../hwtracing/coresight/coresight-tmc-core.c | 31 +++++++++++++++++++ .../hwtracing/coresight/coresight-tmc-etf.c | 12 ++++--- .../hwtracing/coresight/coresight-tmc-etr.c | 12 ++++--- drivers/hwtracing/coresight/coresight-tmc.h | 2 ++ 4 files changed, 47 insertions(+), 10 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index 5f3789314c4d..3d3a2df4303b 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -540,9 +540,40 @@ static ssize_t buffer_size_store(struct device *dev,

static DEVICE_ATTR_RW(buffer_size);

+static ssize_t stop_on_flush_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent); + + return sprintf(buf, "%#x\n", drvdata->stop_on_flush); +} + +static ssize_t stop_on_flush_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + int ret; + u8 val; + struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent); + + ret = kstrtou8(buf, 0, &val); + if (ret) + return ret; + if (val) + drvdata->stop_on_flush = true; + else + drvdata->stop_on_flush = false; + + return size; +} + +static DEVICE_ATTR_RW(stop_on_flush); + + static struct attribute *coresight_tmc_attrs[] = { &dev_attr_trigger_cntr.attr, &dev_attr_buffer_size.attr, + &dev_attr_stop_on_flush.attr, NULL, };

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index 0f9155a10ac2..bdc3a7e9ba06 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -19,6 +19,7 @@ static int tmc_set_etf_buffer(struct coresight_device *csdev, static int __tmc_etb_enable_hw(struct tmc_drvdata *drvdata) { int rc = 0; + u32 ffcr;

CS_UNLOCK(drvdata->base);

@@ -32,10 +33,12 @@ static int __tmc_etb_enable_hw(struct tmc_drvdata *drvdata) }

writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE); - writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI | - TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT | - TMC_FFCR_TRIGON_TRIGIN, - drvdata->base + TMC_FFCR); + + ffcr = TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI | TMC_FFCR_FON_FLIN | + TMC_FFCR_FON_TRIG_EVT | TMC_FFCR_TRIGON_TRIGIN; + if (drvdata->stop_on_flush) + ffcr |= TMC_FFCR_STOP_ON_FLUSH; + writel_relaxed(ffcr, drvdata->base + TMC_FFCR);

writel_relaxed(drvdata->trigger_cntr, drvdata->base + TMC_TRG); tmc_enable_hw(drvdata); @@ -225,7 +228,6 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev) used = true; drvdata->buf = buf; } - ret = tmc_etb_enable_hw(drvdata); if (!ret) { coresight_set_mode(csdev, CS_MODE_SYSFS); diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 18752f58dfa6..e64b98c8f44c 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1060,7 +1060,7 @@ static void tmc_sync_etr_buf(struct tmc_drvdata *drvdata)

static int __tmc_etr_enable_hw(struct tmc_drvdata *drvdata) { - u32 axictl, sts; + u32 axictl, sts, ffcr; struct etr_buf *etr_buf = drvdata->etr_buf; int rc = 0;

@@ -1106,10 +1106,12 @@ static int __tmc_etr_enable_hw(struct tmc_drvdata *drvdata) writel_relaxed(sts, drvdata->base + TMC_STS); }

- writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI | - TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT | - TMC_FFCR_TRIGON_TRIGIN, - drvdata->base + TMC_FFCR); + ffcr = TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI | TMC_FFCR_FON_FLIN | + TMC_FFCR_FON_TRIG_EVT | TMC_FFCR_TRIGON_TRIGIN; + if (drvdata->stop_on_flush) + ffcr |= TMC_FFCR_STOP_ON_FLUSH; + writel_relaxed(ffcr, drvdata->base + TMC_FFCR); + writel_relaxed(drvdata->trigger_cntr, drvdata->base + TMC_TRG); tmc_enable_hw(drvdata);

diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index 2ece44e09911..589087682626 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -218,6 +218,7 @@ struct tmc_resrv_buf { * @pid: Process ID of the process that owns the session that is using * this component. For example this would be the pid of the Perf * process. + * @stop_on_flush: Stop on flush trigger user configuration. * @buf: Snapshot of the trace data for ETF/ETB. * @etr_buf: details of buffer used in TMC-ETR * @len: size of the available trace for ETF/ETB. @@ -249,6 +250,7 @@ struct tmc_drvdata { spinlock_t spinlock; pid_t pid; bool reading; + bool stop_on_flush; union { char *buf; /* TMC ETB */ struct etr_buf *etr_buf; /* TMC ETR */

Add documentation on using coresight during panic and watchdog.

Signed-off-by: Linu Cherian lcherian@marvell.com --- Changelog from v11: Convert all commands to literal code block that was missed out in v11.

Documentation/trace/coresight/panic.rst | 362 ++++++++++++++++++++++++ 1 file changed, 362 insertions(+) create mode 100644 Documentation/trace/coresight/panic.rst

diff --git a/Documentation/trace/coresight/panic.rst b/Documentation/trace/coresight/panic.rst new file mode 100644 index 000000000000..a58aa914c241 --- /dev/null +++ b/Documentation/trace/coresight/panic.rst @@ -0,0 +1,362 @@ +=================================================== +Using Coresight for Kernel panic and Watchdog reset +=================================================== + +Introduction +------------ +This documentation is about using Linux coresight trace support to +debug kernel panic and watchdog reset scenarios. + +Coresight trace during Kernel panic +----------------------------------- +From the coresight driver point of view, addressing the kernel panic +situation has four main requirements. + +a. Support for allocation of trace buffer pages from reserved memory area. + Platform can advertise this using a new device tree property added to + relevant coresight nodes. + +b. Support for stopping coresight blocks at the time of panic + +c. Saving required metadata in the specified format + +d. Support for reading trace data captured at the time of panic + +Allocation of trace buffer pages from reserved RAM +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +A new optional device tree property "memory-region" is added to the +Coresight TMC device nodes, that would give the base address and size of trace +buffer. + +Static allocation of trace buffers would ensure that both IOMMU enabled +and disabled cases are handled. Also, platforms that support persistent +RAM will allow users to read trace data in the subsequent boot without +booting the crashdump kernel. + +Note: +For ETR sink devices, this reserved region will be used for both trace +capture and trace data retrieval. +For ETF sink devices, internal SRAM would be used for trace capture, +and they would be synced to reserved region for retrieval. + + +Disabling coresight blocks at the time of panic +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +In order to avoid the situation of losing relevant trace data after a +kernel panic, it would be desirable to stop the coresight blocks at the +time of panic. + +This can be achieved by configuring the comparator, CTI and sink +devices as below:: + + Trigger on panic + Comparator --->External out --->CTI -->External In---->ETR/ETF stop + +Saving metadata at the time of kernel panic +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Coresight metadata involves all additional data that are required for a +successful trace decode in addition to the trace data. This involves +ETR/ETF/ETB register snapshot etc. + +A new optional device property "memory-region" is added to +the ETR/ETF/ETB device nodes for this. + +Reading trace data captured at the time of panic +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Trace data captured at the time of panic, can be read from rebooted kernel +or from crashdump kernel using a special device file /dev/crash_tmc_xxx. +This device file is created only when there is a valid crashdata available. + +General flow of trace capture and decode incase of kernel panic +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +1. Enable source and sink on all the cores using the sysfs interface. + ETR sinks should have trace buffers allocated from reserved memory, + by selecting "resrv" buffer mode from sysfs. + +2. Run relevant tests. + +3. On a kernel panic, all coresight blocks are disabled, necessary + metadata is synced by kernel panic handler. + + System would eventually reboot or boot a crashdump kernel. + +4. For platforms that supports crashdump kernel, raw trace data can be + dumped using the coresight sysfs interface from the crashdump kernel + itself. Persistent RAM is not a requirement in this case. + +5. For platforms that supports persistent RAM, trace data can be dumped + using the coresight sysfs interface in the subsequent Linux boot. + Crashdump kernel is not a requirement in this case. Persistent RAM + ensures that trace data is intact across reboot. + +Coresight trace during Watchdog reset +------------------------------------- +The main difference between addressing the watchdog reset and kernel panic +case are below, + +a. Saving coresight metadata need to be taken care by the + SCP(system control processor) firmware in the specified format, + instead of kernel. + +b. Reserved memory region given by firmware for trace buffer and metadata + has to be in persistent RAM. + Note: This is a requirement for watchdog reset case but optional + in kernel panic case. + +Watchdog reset can be supported only on platforms that meet the above +two requirements. + +Sample commands for testing a Kernel panic case with ETR sink +------------------------------------------------------------- + +1. Boot Linux kernel with "crash_kexec_post_notifiers" added to the kernel + bootargs. This is mandatory if the user would like to read the tracedata + from the crashdump kernel. + +2. Enable the preloaded ETM configuration:: + + #echo 1 > /sys/kernel/config/cs-syscfg/configurations/panicstop/enable + +3. Configure CTI using sysfs interface:: + + #./cti_setup.sh + + #cat cti_setup.sh + + + cd /sys/bus/coresight/devices/ + + ap_cti_config () { + #ETM trig out[0] trigger to Channel 0 + echo 0 4 > channels/trigin_attach + } + + etf_cti_config () { + #ETF Flush in trigger from Channel 0 + echo 0 1 > channels/trigout_attach + echo 1 > channels/trig_filter_enable + } + + etr_cti_config () { + #ETR Flush in from Channel 0 + echo 0 1 > channels/trigout_attach + echo 1 > channels/trig_filter_enable + } + + ctidevs=`find . -name "cti*"` + + for i in $ctidevs + do + cd $i + + connection=`find . -name "ete*"` + if [ ! -z "$connection" ] + then + echo "AP CTI config for $i" + ap_cti_config + fi + + connection=`find . -name "tmc_etf*"` + if [ ! -z "$connection" ] + then + echo "ETF CTI config for $i" + etf_cti_config + fi + + connection=`find . -name "tmc_etr*"` + if [ ! -z "$connection" ] + then + echo "ETR CTI config for $i" + etr_cti_config + fi + + cd .. + done + +Note: CTI connections are SOC specific and hence the above script is +added just for reference. + +4. Choose reserved buffer mode for ETR buffer:: + + #echo "resrv" > /sys/bus/coresight/devices/tmc_etr0/buf_mode_preferred + +5. Enable stop on flush trigger configuration:: + + #echo 1 > /sys/bus/coresight/devices/tmc_etr0/stop_on_flush + +6. Start Coresight tracing on cores 1 and 2 using sysfs interface + +7. Run some application on core 1:: + + #taskset -c 1 dd if=/dev/urandom of=/dev/null & + +8. Invoke kernel panic on core 2:: + + #echo 1 > /proc/sys/kernel/panic + #taskset -c 2 echo c > /proc/sysrq-trigger + +9. From rebooted kernel or crashdump kernel, read crashdata:: + + #dd if=/dev/crash_tmc_etr0 of=/trace/cstrace.bin + +10. Run opencsd decoder tools/scripts to generate the instruction trace. + +Sample instruction trace dump +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Core1 dump:: + + A etm4_enable_hw: ffff800008ae1dd4 + CONTEXT EL2 etm4_enable_hw: ffff800008ae1dd4 + I etm4_enable_hw: ffff800008ae1dd4: + d503201f nop + I etm4_enable_hw: ffff800008ae1dd8: + d503201f nop + I etm4_enable_hw: ffff800008ae1ddc: + d503201f nop + I etm4_enable_hw: ffff800008ae1de0: + d503201f nop + I etm4_enable_hw: ffff800008ae1de4: + d503201f nop + I etm4_enable_hw: ffff800008ae1de8: + d503233f paciasp + I etm4_enable_hw: ffff800008ae1dec: + a9be7bfd stp x29, x30, [sp, #-32]! + I etm4_enable_hw: ffff800008ae1df0: + 910003fd mov x29, sp + I etm4_enable_hw: ffff800008ae1df4: + a90153f3 stp x19, x20, [sp, #16] + I etm4_enable_hw: ffff800008ae1df8: + 2a0003f4 mov w20, w0 + I etm4_enable_hw: ffff800008ae1dfc: + 900085b3 adrp x19, ffff800009b95000 <reserved_mem+0xc48> + I etm4_enable_hw: ffff800008ae1e00: + 910f4273 add x19, x19, #0x3d0 + I etm4_enable_hw: ffff800008ae1e04: + f8747a60 ldr x0, [x19, x20, lsl #3] + E etm4_enable_hw: ffff800008ae1e08: + b4000140 cbz x0, ffff800008ae1e30 <etm4_starting_cpu+0x50> + I 149.039572921 etm4_enable_hw: ffff800008ae1e30: + a94153f3 ldp x19, x20, [sp, #16] + I 149.039572921 etm4_enable_hw: ffff800008ae1e34: + 52800000 mov w0, #0x0 // #0 + I 149.039572921 etm4_enable_hw: ffff800008ae1e38: + a8c27bfd ldp x29, x30, [sp], #32 + + ..snip + + 149.052324811 chacha_block_generic: ffff800008642d80: + 9100a3e0 add x0, + I 149.052324811 chacha_block_generic: ffff800008642d84: + b86178a2 ldr w2, [x5, x1, lsl #2] + I 149.052324811 chacha_block_generic: ffff800008642d88: + 8b010803 add x3, x0, x1, lsl #2 + I 149.052324811 chacha_block_generic: ffff800008642d8c: + b85fc063 ldur w3, [x3, #-4] + I 149.052324811 chacha_block_generic: ffff800008642d90: + 0b030042 add w2, w2, w3 + I 149.052324811 chacha_block_generic: ffff800008642d94: + b8217882 str w2, [x4, x1, lsl #2] + I 149.052324811 chacha_block_generic: ffff800008642d98: + 91000421 add x1, x1, #0x1 + I 149.052324811 chacha_block_generic: ffff800008642d9c: + f100443f cmp x1, #0x11 + + +Core 2 dump:: + + A etm4_enable_hw: ffff800008ae1dd4 + CONTEXT EL2 etm4_enable_hw: ffff800008ae1dd4 + I etm4_enable_hw: ffff800008ae1dd4: + d503201f nop + I etm4_enable_hw: ffff800008ae1dd8: + d503201f nop + I etm4_enable_hw: ffff800008ae1ddc: + d503201f nop + I etm4_enable_hw: ffff800008ae1de0: + d503201f nop + I etm4_enable_hw: ffff800008ae1de4: + d503201f nop + I etm4_enable_hw: ffff800008ae1de8: + d503233f paciasp + I etm4_enable_hw: ffff800008ae1dec: + a9be7bfd stp x29, x30, [sp, #-32]! + I etm4_enable_hw: ffff800008ae1df0: + 910003fd mov x29, sp + I etm4_enable_hw: ffff800008ae1df4: + a90153f3 stp x19, x20, [sp, #16] + I etm4_enable_hw: ffff800008ae1df8: + 2a0003f4 mov w20, w0 + I etm4_enable_hw: ffff800008ae1dfc: + 900085b3 adrp x19, ffff800009b95000 <reserved_mem+0xc48> + I etm4_enable_hw: ffff800008ae1e00: + 910f4273 add x19, x19, #0x3d0 + I etm4_enable_hw: ffff800008ae1e04: + f8747a60 ldr x0, [x19, x20, lsl #3] + E etm4_enable_hw: ffff800008ae1e08: + b4000140 cbz x0, ffff800008ae1e30 <etm4_starting_cpu+0x50> + I 149.046243445 etm4_enable_hw: ffff800008ae1e30: + a94153f3 ldp x19, x20, [sp, #16] + I 149.046243445 etm4_enable_hw: ffff800008ae1e34: + 52800000 mov w0, #0x0 // #0 + I 149.046243445 etm4_enable_hw: ffff800008ae1e38: + a8c27bfd ldp x29, x30, [sp], #32 + I 149.046243445 etm4_enable_hw: ffff800008ae1e3c: + d50323bf autiasp + E 149.046243445 etm4_enable_hw: ffff800008ae1e40: + d65f03c0 ret + A ete_sysreg_write: ffff800008adfa18 + + ..snip + + I 149.05422547 panic: ffff800008096300: + a90363f7 stp x23, x24, [sp, #48] + I 149.05422547 panic: ffff800008096304: + 6b00003f cmp w1, w0 + I 149.05422547 panic: ffff800008096308: + 3a411804 ccmn w0, #0x1, #0x4, ne // ne = any + N 149.05422547 panic: ffff80000809630c: + 540001e0 b.eq ffff800008096348 <panic+0xe0> // b.none + I 149.05422547 panic: ffff800008096310: + f90023f9 str x25, [sp, #64] + E 149.05422547 panic: ffff800008096314: + 97fe44ef bl ffff8000080276d0 <panic_smp_self_stop> + A panic: ffff80000809634c + I 149.05422547 panic: ffff80000809634c: + 910102d5 add x21, x22, #0x40 + I 149.05422547 panic: ffff800008096350: + 52800020 mov w0, #0x1 // #1 + E 149.05422547 panic: ffff800008096354: + 94166b8b bl ffff800008631180 <bust_spinlocks> + N 149.054225518 bust_spinlocks: ffff800008631180: + 340000c0 cbz w0, ffff800008631198 <bust_spinlocks+0x18> + I 149.054225518 bust_spinlocks: ffff800008631184: + f000a321 adrp x1, ffff800009a98000 <pbufs.0+0xbb8> + I 149.054225518 bust_spinlocks: ffff800008631188: + b9405c20 ldr w0, [x1, #92] + I 149.054225518 bust_spinlocks: ffff80000863118c: + 11000400 add w0, w0, #0x1 + I 149.054225518 bust_spinlocks: ffff800008631190: + b9005c20 str w0, [x1, #92] + E 149.054225518 bust_spinlocks: ffff800008631194: + d65f03c0 ret + A panic: ffff800008096358 + +Perf based testing +------------------ + +Starting perf session +~~~~~~~~~~~~~~~~~~~~~ +ETF:: + + perf record -e cs_etm/panicstop,@tmc_etf1/ -C 1 + perf record -e cs_etm/panicstop,@tmc_etf2/ -C 2 + +ETR:: + + perf record -e cs_etm/panicstop,@tmc_etr0/ -C 1,2 + +Reading trace data after panic +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Same sysfs based method explained above can be used to retrieve and +decode the trace data after the reboot on kernel panic.