linux/drivers/remoteproc/remoteproc_coredump.c
Rishabh Bhatnagar c97319881c remoteproc: Add inline coredump functionality
The current coredump implementation uses vmalloc area to copy
all the segments. But this might put strain on low memory targets
as the firmware size sometimes is in tens of MBs. The situation
becomes worse if there are multiple remote processors undergoing
recovery at the same time. This patch adds inline coredump
functionality that avoids extra memory usage. This requires
recovery to be halted until data is read by userspace and free
function is called.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Tested-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/1594938035-7327-5-git-send-email-rishabhb@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-07-21 14:03:57 -07:00

326 lines
8.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Coredump functionality for Remoteproc framework.
*
* Copyright (c) 2020, The Linux Foundation. All rights reserved.
*/
#include <linux/completion.h>
#include <linux/devcoredump.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/remoteproc.h>
#include "remoteproc_internal.h"
#include "remoteproc_elf_helpers.h"
struct rproc_coredump_state {
struct rproc *rproc;
void *header;
struct completion dump_done;
};
/**
* rproc_coredump_cleanup() - clean up dump_segments list
* @rproc: the remote processor handle
*/
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_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_add_custom_segment() - add custom coredump segment
* @rproc: handle of a remote processor
* @da: device address
* @size: size of segment
* @dumpfn: custom dump function called for each segment during coredump
* @priv: private data
*
* Add device memory to the list of segments to be included in the coredump
* and associate the segment with the given custom dump function and private
* data.
*
* Return: 0 on success, negative errno on error.
*/
int rproc_coredump_add_custom_segment(struct rproc *rproc,
dma_addr_t da, size_t size,
void (*dumpfn)(struct rproc *rproc,
struct rproc_dump_segment *segment,
void *dest, size_t offset,
size_t size),
void *priv)
{
struct rproc_dump_segment *segment;
segment = kzalloc(sizeof(*segment), GFP_KERNEL);
if (!segment)
return -ENOMEM;
segment->da = da;
segment->size = size;
segment->priv = priv;
segment->dump = dumpfn;
list_add_tail(&segment->node, &rproc->dump_segments);
return 0;
}
EXPORT_SYMBOL(rproc_coredump_add_custom_segment);
/**
* rproc_coredump_set_elf_info() - set coredump elf information
* @rproc: handle of a remote processor
* @class: elf class for coredump elf file
* @machine: elf machine for coredump elf file
*
* Set elf information which will be used for coredump elf file.
*
* Return: 0 on success, negative errno on error.
*/
int rproc_coredump_set_elf_info(struct rproc *rproc, u8 class, u16 machine)
{
if (class != ELFCLASS64 && class != ELFCLASS32)
return -EINVAL;
rproc->elf_class = class;
rproc->elf_machine = machine;
return 0;
}
EXPORT_SYMBOL(rproc_coredump_set_elf_info);
static void rproc_coredump_free(void *data)
{
struct rproc_coredump_state *dump_state = data;
vfree(dump_state->header);
complete(&dump_state->dump_done);
}
static void *rproc_coredump_find_segment(loff_t user_offset,
struct list_head *segments,
size_t *data_left)
{
struct rproc_dump_segment *segment;
list_for_each_entry(segment, segments, node) {
if (user_offset < segment->size) {
*data_left = segment->size - user_offset;
return segment;
}
user_offset -= segment->size;
}
*data_left = 0;
return NULL;
}
static void rproc_copy_segment(struct rproc *rproc, void *dest,
struct rproc_dump_segment *segment,
size_t offset, size_t size)
{
void *ptr;
if (segment->dump) {
segment->dump(rproc, segment, dest, offset, size);
} else {
ptr = rproc_da_to_va(rproc, segment->da + offset, size);
if (!ptr) {
dev_err(&rproc->dev,
"invalid copy request for segment %pad with offset %zu and size %zu)\n",
&segment->da, offset, size);
memset(dest, 0xff, size);
} else {
memcpy(dest, ptr, size);
}
}
}
static ssize_t rproc_coredump_read(char *buffer, loff_t offset, size_t count,
void *data, size_t header_sz)
{
size_t seg_data, bytes_left = count;
ssize_t copy_sz;
struct rproc_dump_segment *seg;
struct rproc_coredump_state *dump_state = data;
struct rproc *rproc = dump_state->rproc;
void *elfcore = dump_state->header;
/* Copy the vmalloc'ed header first. */
if (offset < header_sz) {
copy_sz = memory_read_from_buffer(buffer, count, &offset,
elfcore, header_sz);
return copy_sz;
}
/*
* Find out the segment memory chunk to be copied based on offset.
* Keep copying data until count bytes are read.
*/
while (bytes_left) {
seg = rproc_coredump_find_segment(offset - header_sz,
&rproc->dump_segments,
&seg_data);
/* EOF check */
if (!seg) {
dev_info(&rproc->dev, "Ramdump done, %lld bytes read",
offset);
break;
}
copy_sz = min_t(size_t, bytes_left, seg_data);
rproc_copy_segment(rproc, buffer, seg, seg->size - seg_data,
copy_sz);
offset += copy_sz;
buffer += copy_sz;
bytes_left -= copy_sz;
}
return count - bytes_left;
}
/**
* 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. Based on the
* coredump configuration this function will directly copy the segments
* from device memory to userspace or copy segments from device memory to
* a separate buffer, which can then be read by userspace.
* The first approach avoids using extra vmalloc memory. But it will stall
* recovery flow until dump is read by userspace.
*/
void rproc_coredump(struct rproc *rproc)
{
struct rproc_dump_segment *segment;
void *phdr;
void *ehdr;
size_t data_size;
size_t offset;
void *data;
u8 class = rproc->elf_class;
int phnum = 0;
struct rproc_coredump_state dump_state;
enum rproc_dump_mechanism dump_conf = rproc->dump_conf;
if (list_empty(&rproc->dump_segments) ||
dump_conf == RPROC_COREDUMP_DISABLED)
return;
if (class == ELFCLASSNONE) {
dev_err(&rproc->dev, "Elf class is not set\n");
return;
}
data_size = elf_size_of_hdr(class);
list_for_each_entry(segment, &rproc->dump_segments, node) {
/*
* For default configuration buffer includes headers & segments.
* For inline dump buffer just includes headers as segments are
* directly read from device memory.
*/
data_size += elf_size_of_phdr(class);
if (dump_conf == RPROC_COREDUMP_DEFAULT)
data_size += segment->size;
phnum++;
}
data = vmalloc(data_size);
if (!data)
return;
ehdr = data;
memset(ehdr, 0, elf_size_of_hdr(class));
/* e_ident field is common for both elf32 and elf64 */
elf_hdr_init_ident(ehdr, class);
elf_hdr_set_e_type(class, ehdr, ET_CORE);
elf_hdr_set_e_machine(class, ehdr, rproc->elf_machine);
elf_hdr_set_e_version(class, ehdr, EV_CURRENT);
elf_hdr_set_e_entry(class, ehdr, rproc->bootaddr);
elf_hdr_set_e_phoff(class, ehdr, elf_size_of_hdr(class));
elf_hdr_set_e_ehsize(class, ehdr, elf_size_of_hdr(class));
elf_hdr_set_e_phentsize(class, ehdr, elf_size_of_phdr(class));
elf_hdr_set_e_phnum(class, ehdr, phnum);
phdr = data + elf_hdr_get_e_phoff(class, ehdr);
offset = elf_hdr_get_e_phoff(class, ehdr);
offset += elf_size_of_phdr(class) * elf_hdr_get_e_phnum(class, ehdr);
list_for_each_entry(segment, &rproc->dump_segments, node) {
memset(phdr, 0, elf_size_of_phdr(class));
elf_phdr_set_p_type(class, phdr, PT_LOAD);
elf_phdr_set_p_offset(class, phdr, offset);
elf_phdr_set_p_vaddr(class, phdr, segment->da);
elf_phdr_set_p_paddr(class, phdr, segment->da);
elf_phdr_set_p_filesz(class, phdr, segment->size);
elf_phdr_set_p_memsz(class, phdr, segment->size);
elf_phdr_set_p_flags(class, phdr, PF_R | PF_W | PF_X);
elf_phdr_set_p_align(class, phdr, 0);
if (dump_conf == RPROC_COREDUMP_DEFAULT)
rproc_copy_segment(rproc, data + offset, segment, 0,
segment->size);
offset += elf_phdr_get_p_filesz(class, phdr);
phdr += elf_size_of_phdr(class);
}
if (dump_conf == RPROC_COREDUMP_DEFAULT) {
dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL);
return;
}
/* Initialize the dump state struct to be used by rproc_coredump_read */
dump_state.rproc = rproc;
dump_state.header = data;
init_completion(&dump_state.dump_done);
dev_coredumpm(&rproc->dev, NULL, &dump_state, data_size, GFP_KERNEL,
rproc_coredump_read, rproc_coredump_free);
/*
* Wait until the dump is read and free is called. Data is freed
* by devcoredump framework automatically after 5 minutes.
*/
wait_for_completion(&dump_state.dump_done);
}