remoteproc: Add remote processor coredump support

As the remoteproc framework restarts the remote processor after a fatal
event, it's useful to be able to acquire a coredump of the remote
processor's state, for post mortem debugging.

This patch introduces a mechanism for extracting the memory contents
after the remote has stopped and before the restart sequence has begun
in the recovery path. The remoteproc framework builds the core dump in
memory and use devcoredump to expose this to user space.

Signed-off-by: Sarangdhar Joshi <spjoshi@codeaurora.org>
[bjorn: Use vmalloc instead of composing the ELF on the fly]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
index b609e1d3654ba65f13d480ce71834fb5b507773b..3e4bca77188de9e01c8f5140d06c1d2adc080d6f 100644 (file)
--- a/drivers/remoteproc/Kconfig
+++ b/drivers/remoteproc/Kconfig
@@ -6,6 +6,7 @@ config REMOTEPROC
        select CRC32
        select FW_LOADER
        select VIRTIO
+       select WANT_DEV_COREDUMP
        help
          Support for remote processors (such as DSP coprocessors). These
          are mainly used on embedded systems.

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 4170dfbd93bdba5e9fa6a57e5c68ec9d95a9a274..5af7547b9d8d8ff4f637cd9cf069dcb5ffb21a27 100644 (file)
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -33,6 +33,7 @@
 #include <linux/firmware.h>
 #include <linux/string.h>
 #include <linux/debugfs.h>
+#include <linux/devcoredump.h>
 #include <linux/remoteproc.h>
 #include <linux/iommu.h>
 #include <linux/idr.h>
@@ -801,6 +802,20 @@ static void rproc_remove_subdevices(struct rproc *rproc)
                subdev->remove(subdev);
 }
 
+/**
+ * rproc_coredump_cleanup() - clean up dump_segments list
+ * @rproc: the remote processor handle
+ */
+static void rproc_coredump_cleanup(struct rproc *rproc)
+{
+       struct rproc_dump_segment *entry, *tmp;
+
+       list_for_each_entry_safe(entry, tmp, &rproc->dump_segments, node) {
+               list_del(&entry->node);
+               kfree(entry);
+       }
+}
+
 /**
  * rproc_resource_cleanup() - clean up and free all acquired resources
  * @rproc: rproc handle
@@ -848,6 +863,8 @@ static void rproc_resource_cleanup(struct rproc *rproc)
        /* clean up remote vdev entries */
        list_for_each_entry_safe(rvdev, rvtmp, &rproc->rvdevs, node)
                kref_put(&rvdev->refcount, rproc_vdev_release);
+
+       rproc_coredump_cleanup(rproc);
 }
 
 static int rproc_start(struct rproc *rproc, const struct firmware *fw)
@@ -1017,6 +1034,113 @@ static int rproc_stop(struct rproc *rproc)
        return 0;
 }
 
+/**
+ * rproc_coredump_add_segment() - add segment of device memory to coredump
+ * @rproc:     handle of a remote processor
+ * @da:                device address
+ * @size:      size of segment
+ *
+ * Add device memory to the list of segments to be included in a coredump for
+ * the remoteproc.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int rproc_coredump_add_segment(struct rproc *rproc, dma_addr_t da, size_t size)
+{
+       struct rproc_dump_segment *segment;
+
+       segment = kzalloc(sizeof(*segment), GFP_KERNEL);
+       if (!segment)
+               return -ENOMEM;
+
+       segment->da = da;
+       segment->size = size;
+
+       list_add_tail(&segment->node, &rproc->dump_segments);
+
+       return 0;
+}
+EXPORT_SYMBOL(rproc_coredump_add_segment);
+
+/**
+ * rproc_coredump() - perform coredump
+ * @rproc:     rproc handle
+ *
+ * This function will generate an ELF header for the registered segments
+ * and create a devcoredump device associated with rproc.
+ */
+static void rproc_coredump(struct rproc *rproc)
+{
+       struct rproc_dump_segment *segment;
+       struct elf32_phdr *phdr;
+       struct elf32_hdr *ehdr;
+       size_t data_size;
+       size_t offset;
+       void *data;
+       void *ptr;
+       int phnum = 0;
+
+       if (list_empty(&rproc->dump_segments))
+               return;
+
+       data_size = sizeof(*ehdr);
+       list_for_each_entry(segment, &rproc->dump_segments, node) {
+               data_size += sizeof(*phdr) + segment->size;
+
+               phnum++;
+       }
+
+       data = vmalloc(data_size);
+       if (!data)
+               return;
+
+       ehdr = data;
+
+       memset(ehdr, 0, sizeof(*ehdr));
+       memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
+       ehdr->e_ident[EI_CLASS] = ELFCLASS32;
+       ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
+       ehdr->e_ident[EI_VERSION] = EV_CURRENT;
+       ehdr->e_ident[EI_OSABI] = ELFOSABI_NONE;
+       ehdr->e_type = ET_CORE;
+       ehdr->e_machine = EM_NONE;
+       ehdr->e_version = EV_CURRENT;
+       ehdr->e_entry = rproc->bootaddr;
+       ehdr->e_phoff = sizeof(*ehdr);
+       ehdr->e_ehsize = sizeof(*ehdr);
+       ehdr->e_phentsize = sizeof(*phdr);
+       ehdr->e_phnum = phnum;
+
+       phdr = data + ehdr->e_phoff;
+       offset = ehdr->e_phoff + sizeof(*phdr) * ehdr->e_phnum;
+       list_for_each_entry(segment, &rproc->dump_segments, node) {
+               memset(phdr, 0, sizeof(*phdr));
+               phdr->p_type = PT_LOAD;
+               phdr->p_offset = offset;
+               phdr->p_vaddr = segment->da;
+               phdr->p_paddr = segment->da;
+               phdr->p_filesz = segment->size;
+               phdr->p_memsz = segment->size;
+               phdr->p_flags = PF_R | PF_W | PF_X;
+               phdr->p_align = 0;
+
+               ptr = rproc_da_to_va(rproc, segment->da, segment->size);
+               if (!ptr) {
+                       dev_err(&rproc->dev,
+                               "invalid coredump segment (%pad, %zu)\n",
+                               &segment->da, segment->size);
+                       memset(data + offset, 0xff, segment->size);
+               } else {
+                       memcpy(data + offset, ptr, segment->size);
+               }
+
+               offset += phdr->p_filesz;
+               phdr++;
+       }
+
+       dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL);
+}
+
 /**
  * rproc_trigger_recovery() - recover a remoteproc
  * @rproc: the remote processor
@@ -1043,6 +1167,9 @@ int rproc_trigger_recovery(struct rproc *rproc)
        if (ret)
                goto unlock_mutex;
 
+       /* generate coredump */
+       rproc_coredump(rproc);
+
        /* load firmware */
        ret = request_firmware(&firmware_p, rproc->firmware, dev);
        if (ret < 0) {
@@ -1443,6 +1570,7 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
        INIT_LIST_HEAD(&rproc->traces);
        INIT_LIST_HEAD(&rproc->rvdevs);
        INIT_LIST_HEAD(&rproc->subdevs);
+       INIT_LIST_HEAD(&rproc->dump_segments);
 
        INIT_WORK(&rproc->crash_handler, rproc_crash_handler_work);
 

diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index 728d421fffe983ff877b5ba279d21d7b3857352a..b60c3a31b75db3c6c501ac3f7af359fc718af6f7 100644 (file)
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -394,6 +394,21 @@ enum rproc_crash_type {
        RPROC_FATAL_ERROR,
 };
 
+/**
+ * struct rproc_dump_segment - segment info from ELF header
+ * @node:      list node related to the rproc segment list
+ * @da:                device address of the segment
+ * @size:      size of the segment
+ */
+struct rproc_dump_segment {
+       struct list_head node;
+
+       dma_addr_t da;
+       size_t size;
+
+       loff_t offset;
+};
+
 /**
  * struct rproc - represents a physical remote processor device
  * @node: list node of this rproc object
@@ -424,6 +439,7 @@ enum rproc_crash_type {
  * @cached_table: copy of the resource table
  * @table_sz: size of @cached_table
  * @has_iommu: flag to indicate if remote processor is behind an MMU
+ * @dump_segments: list of segments in the firmware
  */
 struct rproc {
        struct list_head node;
@@ -455,6 +471,7 @@ struct rproc {
        size_t table_sz;
        bool has_iommu;
        bool auto_boot;
+       struct list_head dump_segments;
 };
 
 /**
@@ -534,6 +551,7 @@ void rproc_free(struct rproc *rproc);
 int rproc_boot(struct rproc *rproc);
 void rproc_shutdown(struct rproc *rproc);
 void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type);
+int rproc_coredump_add_segment(struct rproc *rproc, dma_addr_t da, size_t size);
 
 static inline struct rproc_vdev *vdev_to_rvdev(struct virtio_device *vdev)
 {