On 22/06/2022 15:36, Adrián Larumbe wrote:
> In the event of a job timeout, debug dump information will be written into
> /sys/class/devcoredump.
>
> Inspired by etnaviv's similar feature.
>
> Signed-off-by: Adrián Larumbe <adrian.laru...@collabora.com>
Looks pretty good, a few comments below.
> ---
> drivers/gpu/drm/panfrost/Kconfig | 1 +
> drivers/gpu/drm/panfrost/Makefile | 3 +-
> drivers/gpu/drm/panfrost/panfrost_dump.c | 249 +++++++++++++++++++++++
> drivers/gpu/drm/panfrost/panfrost_dump.h | 12 ++
> drivers/gpu/drm/panfrost/panfrost_job.c | 3 +
> include/uapi/drm/panfrost_drm.h | 47 +++++
> 6 files changed, 314 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/panfrost/panfrost_dump.c
> create mode 100644 drivers/gpu/drm/panfrost/panfrost_dump.h
>
> diff --git a/drivers/gpu/drm/panfrost/Kconfig
> b/drivers/gpu/drm/panfrost/Kconfig
> index 86cdc0ce79e6..079600328be1 100644
> --- a/drivers/gpu/drm/panfrost/Kconfig
> +++ b/drivers/gpu/drm/panfrost/Kconfig
> @@ -11,6 +11,7 @@ config DRM_PANFROST
> select DRM_GEM_SHMEM_HELPER
> select PM_DEVFREQ
> select DEVFREQ_GOV_SIMPLE_ONDEMAND
> + select WANT_DEV_COREDUMP
> help
> DRM driver for ARM Mali Midgard (T6xx, T7xx, T8xx) and
> Bifrost (G3x, G5x, G7x) GPUs.
> diff --git a/drivers/gpu/drm/panfrost/Makefile
> b/drivers/gpu/drm/panfrost/Makefile
> index b71935862417..7da2b3f02ed9 100644
> --- a/drivers/gpu/drm/panfrost/Makefile
> +++ b/drivers/gpu/drm/panfrost/Makefile
> @@ -9,6 +9,7 @@ panfrost-y := \
> panfrost_gpu.o \
> panfrost_job.o \
> panfrost_mmu.o \
> - panfrost_perfcnt.o
> + panfrost_perfcnt.o \
> + panfrost_dump.o
>
> obj-$(CONFIG_DRM_PANFROST) += panfrost.o
> diff --git a/drivers/gpu/drm/panfrost/panfrost_dump.c
> b/drivers/gpu/drm/panfrost/panfrost_dump.c
> new file mode 100644
> index 000000000000..a710ed7bcefa
> --- /dev/null
> +++ b/drivers/gpu/drm/panfrost/panfrost_dump.c
> @@ -0,0 +1,249 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright 2021 Collabora ltd. */
> +
> +#include <linux/err.h>
> +#include <linux/device.h>
> +#include <linux/devcoredump.h>
> +#include <linux/moduleparam.h>
> +#include <linux/iosys-map.h>
> +#include <drm/panfrost_drm.h>
> +#include <drm/drm_device.h>
> +
> +#include "panfrost_job.h"
> +#include "panfrost_gem.h"
> +#include "panfrost_regs.h"
> +#include "panfrost_dump.h"
> +#include "panfrost_device.h"
> +
> +static bool panfrost_dump_core = true;
> +module_param_named(dump_core, panfrost_dump_core, bool, 0600);
> +
> +struct panfrost_dump_iterator {
> + void *start;
> + struct panfrost_dump_object_header *hdr;
> + void *data;
> +};
> +
> +static const unsigned short panfrost_dump_registers[] = {
> + SHADER_READY_LO,
> + SHADER_READY_HI,
> + TILER_READY_LO,
> + TILER_READY_HI,
> + L2_READY_LO,
> + L2_READY_HI,
> + JOB_INT_MASK,
> + JOB_INT_STAT,
> + JS_HEAD_LO(0),
> + JS_HEAD_HI(0),
> + JS_TAIL_LO(0),
> + JS_TAIL_HI(0),
> + JS_AFFINITY_LO(0),
> + JS_AFFINITY_HI(0),
> + JS_CONFIG(0),
> + JS_STATUS(0),
> + JS_HEAD_NEXT_LO(0),
> + JS_HEAD_NEXT_HI(0),
> + JS_AFFINITY_NEXT_LO(0),
> + JS_AFFINITY_NEXT_HI(0),
> + JS_CONFIG_NEXT(0),
> + MMU_INT_MASK,
> + MMU_INT_STAT,
> + AS_TRANSTAB_LO(0),
> + AS_TRANSTAB_HI(0),
> + AS_MEMATTR_LO(0),
> + AS_MEMATTR_HI(0),
> + AS_FAULTSTATUS(0),
> + AS_FAULTADDRESS_LO(0),
> + AS_FAULTADDRESS_HI(0),
> + AS_STATUS(0),
> +};
> +
> +static void panfrost_core_dump_header(struct panfrost_dump_iterator *iter,
> + u32 type, void *data_end)
> +{
> + struct panfrost_dump_object_header *hdr = iter->hdr;
> +
> + hdr->magic = cpu_to_le32(PANFROSTDUMP_MAGIC);
> + hdr->type = cpu_to_le32(type);
> + hdr->file_offset = cpu_to_le32(iter->data - iter->start);
> + hdr->file_size = cpu_to_le32(data_end - iter->data);
> +
> + iter->hdr++;
> + iter->data += le32_to_cpu(hdr->file_size);
> +}
> +
> +static void
> +panfrost_core_dump_registers(struct panfrost_dump_iterator *iter,
> + struct panfrost_device *pfdev,
> + u32 as_nr, int slot)
> +{
> + struct panfrost_dump_registers *dumpreg = iter->data;
> + unsigned int i;
> +
> + for (i = 0; i < ARRAY_SIZE(panfrost_dump_registers); i++, dumpreg++) {
> + unsigned int js_as_offset = 0;
> + unsigned int reg;
> +
> + if (panfrost_dump_registers[i] >= JS_HEAD_LO(0) &&
> + panfrost_dump_registers[i] <= JS_CONFIG_NEXT(0))
It would be good to use something more generic than specific registers
in case the list of registers is ever changed. We have JS_BASE already
which would work for the lower end. We seem to be missing the equivalent
MMU_BASE #define currently. The upper end is base+stride, so for JS we have:
if (panfrost_dump_registers[i] >= JS_BASE &&
panfrost_dump_registers[i] < JS_BASE + JS_SLOT_STRIDE)
> + js_as_offset = slot * JS_SLOT_STRIDE;
> + else if (panfrost_dump_registers[i] >= AS_TRANSTAB_LO(0) &&
> + panfrost_dump_registers[i] <= AS_STATUS(0))
> + js_as_offset = (as_nr << MMU_AS_SHIFT);
> +
> + reg = panfrost_dump_registers[i] + js_as_offset;
> +
> + dumpreg->reg = cpu_to_le32(reg);
> + dumpreg->value = cpu_to_le32(gpu_read(pfdev, reg));
> + }
> +
> + panfrost_core_dump_header(iter, PANFROSTDUMP_BUF_REG, dumpreg);
> +}
> +
> +void panfrost_core_dump(struct panfrost_job *job)
> +{
> + struct panfrost_device *pfdev = job->pfdev;
> + struct panfrost_dump_iterator iter;
> + struct drm_gem_object *dbo;
> + unsigned int n_obj, n_bomap_pages;
> + __le64 *bomap, *bomap_start;
> + size_t file_size;
> + u32 as_nr;
> + int slot;
> + int ret, i;
> +
> + as_nr = job->mmu->as;
> + slot = panfrost_job_get_slot(job);
> +
> + /* Only catch the first event, or when manually re-armed */
> + if (!panfrost_dump_core)
> + return;
> + panfrost_dump_core = false;
> +
> + /* At least, we dump registers and end marker */
> + n_obj = 2;
> + n_bomap_pages = 0;
> + file_size = ARRAY_SIZE(panfrost_dump_registers) *
> + sizeof(struct panfrost_dump_registers);
> +
> + /* Add in the active buffer objects */
> + for (i = 0; i < job->bo_count; i++) {
> + /*
> + * Even though the CPU could be configured to use 16K or 64K
> pages, this
> + * is a very unusual situation for most kernel setups on SoCs
> that have
> + * a Panfrost device. Also many places across the driver make
> the somewhat
> + * arbitrary assumption that Panfrost's MMU page size is the
> same as the CPU's,
> + * so let's have a sanity check to ensure that's always the case
> + */
> + WARN_ON(!IS_ALIGNED(dbo->size, PAGE_SIZE));
This warn needs to go after the assignment below - I just spent a few
minutes tracking down why I was getting a NULL pointer dereference.
Sadly my GCC doesn't seem to be able to warn about this uninitialised use :(
> +
> + dbo = job->bos[i];
> + file_size += dbo->size;
> + n_bomap_pages += dbo->size >> PAGE_SHIFT;
> + n_obj++;
> + }
> +
> + /* If we have any buffer objects, add a bomap object */
> + if (n_bomap_pages) {
> + file_size += n_bomap_pages * sizeof(*bomap);
> + n_obj++;
> + }
> +
> + /* Add the size of the headers */
> + file_size += sizeof(*iter.hdr) * n_obj;
> +
> + /*
> + * Allocate the file in vmalloc memory, it's likely to be big.
> + * The reason behind these GFP flags is that we don't want to trigger
> the
> + * OOM killer in the event that not enough memory could be found for our
> + * dump file. We also don't want the allocator to do any error
> reporting,
> + * as the right behaviour is failing gracefully if a big enough buffer
> + * could not be allocated.
> + */
> + iter.start = __vmalloc(file_size, GFP_KERNEL | __GFP_NOWARN |
> + __GFP_NORETRY);
> + if (!iter.start) {
> + dev_warn(pfdev->dev, "failed to allocate devcoredump file\n");
> + return;
> + }
> +
> + /* Point the data member after the headers */
> + iter.hdr = iter.start;
> + iter.data = &iter.hdr[n_obj];
> +
> + memset(iter.hdr, 0, iter.data - iter.start);
> +
> + /*
> + * For now, we write the job identifier in the register dump header,
> + * so that we can decode the entire dump later with pandecode
> + */
> + iter.hdr->reghdr.jc = cpu_to_le64(job->jc);
> + iter.hdr->reghdr.major = cpu_to_le32(PANFROSTDUMP_MAJOR);
> + iter.hdr->reghdr.minor = cpu_to_le32(PANFROSTDUMP_MINOR);
> + iter.hdr->reghdr.gpu_id = cpu_to_le32(pfdev->features.id);
> + iter.hdr->reghdr.nbos = cpu_to_le64(job->bo_count);
> +
> + panfrost_core_dump_registers(&iter, pfdev, as_nr, slot);
> +
> + /* Reserve space for the bomap */
> + if (job->bo_count) {
> + bomap_start = bomap = iter.data;
> + memset(bomap, 0, sizeof(*bomap) * n_bomap_pages);
> + panfrost_core_dump_header(&iter, PANFROSTDUMP_BUF_BOMAP,
> + bomap + n_bomap_pages);
> + }
> +
> + for (i = 0; i < job->bo_count; i++) {
> + struct iosys_map map;
> + struct panfrost_gem_mapping *mapping;
> + struct panfrost_gem_object *bo;
> + struct sg_page_iter page_iter;
> + void *vaddr;
> +
> + bo = to_panfrost_bo(job->bos[i]);
> + mapping = job->mappings[i];
> +
> + if (!bo->base.sgt) {
> + dev_err(pfdev->dev, "Panfrost Dump: BO has no sgt,
> cannot dump\n");
> + iter.hdr->bomap.valid = 0;
> + goto dump_header;
> + }
> +
> + ret = drm_gem_shmem_vmap(&bo->base, &map);
> + if (ret) {
> + dev_err(pfdev->dev, "Panfrost Dump: couldn't map Buffer
> Object\n");
> + iter.hdr->bomap.valid = 0;
> + goto dump_header;
> + }
> +
> + WARN_ON(!mapping->active);
> +
> + iter.hdr->bomap.data[0] = cpu_to_le32((bomap - bomap_start));
> +
> + for_each_sgtable_page(bo->base.sgt, &page_iter, 0) {
> + struct page *page = sg_page_iter_page(&page_iter);
> +
> + if (!IS_ERR(page)) {
> + *bomap++ = cpu_to_le64(page_to_phys(page));
> + } else {
> + dev_err(pfdev->dev, "Panfrost Dump: wrong
> page\n");
> + *bomap++ = ~cpu_to_le64(0);
> + }
> + }
> +
> + iter.hdr->bomap.iova = cpu_to_le64(mapping->mmnode.start <<
> PAGE_SHIFT);
> +
> + vaddr = map.vaddr;
> + memcpy(iter.data, vaddr, bo->base.base.size);
> +
> + drm_gem_shmem_vunmap(&bo->base, &map);
> +
> + iter.hdr->bomap.valid = cpu_to_le64(1);
'valid' is only 32 bit so this should be cpu_to_le32(1).
Steve
> +
> +dump_header: panfrost_core_dump_header(&iter, PANFROSTDUMP_BUF_BO, iter.data
> +
> + bo->base.base.size);
> + }
> + panfrost_core_dump_header(&iter, PANFROSTDUMP_BUF_TRAILER, iter.data);
> +
> + dev_coredumpv(pfdev->dev, iter.start, iter.data - iter.start,
> GFP_KERNEL);
> +}
> diff --git a/drivers/gpu/drm/panfrost/panfrost_dump.h
> b/drivers/gpu/drm/panfrost/panfrost_dump.h
> new file mode 100644
> index 000000000000..7d9bcefa5346
> --- /dev/null
> +++ b/drivers/gpu/drm/panfrost/panfrost_dump.h
> @@ -0,0 +1,12 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright 2021 Collabora ltd.
> + */
> +
> +#ifndef PANFROST_DUMP_H
> +#define PANFROST_DUMP_H
> +
> +struct panfrost_job;
> +void panfrost_core_dump(struct panfrost_job *job);
> +
> +#endif
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c
> b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 7c4208476fbd..dbc597ab46fb 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -20,6 +20,7 @@
> #include "panfrost_regs.h"
> #include "panfrost_gpu.h"
> #include "panfrost_mmu.h"
> +#include "panfrost_dump.h"
>
> #define JOB_TIMEOUT_MS 500
>
> @@ -727,6 +728,8 @@ static enum drm_gpu_sched_stat
> panfrost_job_timedout(struct drm_sched_job
> job_read(pfdev, JS_TAIL_LO(js)),
> sched_job);
>
> + panfrost_core_dump(job);
> +
> atomic_set(&pfdev->reset.pending, 1);
> panfrost_reset(pfdev, sched_job);
>
> diff --git a/include/uapi/drm/panfrost_drm.h b/include/uapi/drm/panfrost_drm.h
> index 9e40277d8185..eac87310b348 100644
> --- a/include/uapi/drm/panfrost_drm.h
> +++ b/include/uapi/drm/panfrost_drm.h
> @@ -224,6 +224,53 @@ struct drm_panfrost_madvise {
> __u32 retained; /* out, whether backing store still exists */
> };
>
> +/* Definitions for coredump decoding in user space */
> +#define PANFROSTDUMP_MAJOR 1
> +#define PANFROSTDUMP_MINOR 0
> +
> +#define PANFROSTDUMP_MAGIC 0x464E4150 /* PANF */
> +
> +#define PANFROSTDUMP_BUF_REG 0
> +#define PANFROSTDUMP_BUF_BOMAP (PANFROSTDUMP_BUF_REG + 1)
> +#define PANFROSTDUMP_BUF_BO (PANFROSTDUMP_BUF_BOMAP + 1)
> +#define PANFROSTDUMP_BUF_TRAILER (PANFROSTDUMP_BUF_BO + 1)
> +
> +struct panfrost_dump_object_header {
> + __le32 magic;
> + __le32 type;
> + __le32 file_size;
> + __le32 file_offset;
> +
> + union {
> + struct pan_reg_hdr {
> + __le64 jc;
> + __le32 gpu_id;
> + __le32 major;
> + __le32 minor;
> + __le64 nbos;
> + } reghdr;
> +
> + struct pan_bomap_hdr {
> + __le32 valid;
> + __le64 iova;
> + __le32 data[2];
> + } bomap;
> +
> + /*
> + * Force same size in case we want to expand the header
> + * with new fields and also keep it 512-byte aligned
> + */
> +
> + __le32 sizer[496];
> + };
> +};
> +
> +/* Registers object, an array of these */
> +struct panfrost_dump_registers {
> + __le32 reg;
> + __le32 value;
> +};
> +
> #if defined(__cplusplus)
> }
> #endif
