Re: [PATCH 1/3] remoteproc: Make coredump functionality configurable

Mathieu Poirier
2020-04-23T18:07:19Z

Hi Rishabh,

On Thu, Apr 16, 2020 at 11:38:30AM -0700, Rishabh Bhatnagar wrote:
> Add a new file implementing coredump specific functionality.
> This would enable clients to have the option to implement custom
> dump functionality. The default coredump functionality remains same
> as rproc_coredump function.

Next time please add a cover letter that mentions the baseline your work applies
on and version your patches.

>
> Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
> ---
> drivers/remoteproc/Makefile | 1 +
> drivers/remoteproc/remoteproc_core.c | 83 -----------------------
> drivers/remoteproc/remoteproc_coredump.c | 111 +++++++++++++++++++++++++++++++
> drivers/remoteproc/remoteproc_internal.h | 10 +++
> 4 files changed, 122 insertions(+), 83 deletions(-)
> create mode 100644 drivers/remoteproc/remoteproc_coredump.c
>
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index e30a1b1..f1d1264 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -9,6 +9,7 @@ remoteproc-y += remoteproc_debugfs.o
> remoteproc-y += remoteproc_sysfs.o
> remoteproc-y += remoteproc_virtio.o
> remoteproc-y += remoteproc_elf_loader.o
> +remoteproc-y += remoteproc_coredump.o
> obj-$(CONFIG_IMX_REMOTEPROC) += imx_rproc.o
> obj-$(CONFIG_MTK_SCP) += mtk_scp.o mtk_scp_ipi.o
> obj-$(CONFIG_OMAP_REMOTEPROC) += omap_remoteproc.o
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 097f33e..c0e9e5d 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1555,89 +1555,6 @@ int rproc_coredump_add_custom_segment(struct rproc *rproc,
> EXPORT_SYMBOL(rproc_coredump_add_custom_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;
> -
> - if (segment->dump) {
> - segment->dump(rproc, segment, data + offset);
> - } else {
> - 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
> *
> diff --git a/drivers/remoteproc/remoteproc_coredump.c b/drivers/remoteproc/remoteproc_coredump.c
> new file mode 100644
> index 0000000..9de0467
> --- /dev/null
> +++ b/drivers/remoteproc/remoteproc_coredump.c
> @@ -0,0 +1,111 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Coredump functionality for Remoteproc framework.
> + *
> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/devcoredump.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/remoteproc.h>
> +#include "remoteproc_internal.h"
> +
> +static void create_elf_header(void *data, int phnum, struct rproc *rproc)
> +{
> + struct elf32_phdr *phdr;
> + struct elf32_hdr *ehdr;
> + struct rproc_dump_segment *segment;
> + int offset;
> +
> + 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;
> +
> + offset += phdr->p_filesz;
> + phdr++;
> + }
> +}
> +
> +/**
> + * rproc_default_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.
> + */
> +void rproc_default_coredump(struct rproc *rproc)
> +{
> + struct rproc_dump_segment *segment;
> + struct elf32_phdr *phdr;
> + struct elf32_hdr *ehdr;
> + size_t data_size;
> + void *data, *ptr;
> + int offset, 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;
> + create_elf_header(data, phnum, rproc);

Please leave function rproc_default_coredump() the same way it originally was
for this patch. Modifications can be done in later patches.

> +
> + phdr = data + ehdr->e_phoff;
> + offset = ehdr->e_phoff + sizeof(*phdr) * ehdr->e_phnum;
> + list_for_each_entry(segment, &rproc->dump_segments, node) {
> + if (segment->dump) {
> + segment->dump(rproc, segment, data + offset);
> + } else {
> + 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);
> + }
> + }
> + phdr++;

Here @offset is not updated and as such will trample the previous value with
each iteration. To be honest I would rather keep the initialisation of @phdr in
this loop, that way it is done only once.

Thanks,
Mathieu

> + }
> +
> + dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL);
> +}
> +EXPORT_SYMBOL(rproc_default_coredump);
> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> index 493ef92..28b6af2 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -47,6 +47,9 @@ struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
> int rproc_init_sysfs(void);
> void rproc_exit_sysfs(void);
>
> +/* from remoteproc_coredump.c */
> +void rproc_default_coredump(struct rproc *rproc);
> +
> void rproc_free_vring(struct rproc_vring *rvring);
> int rproc_alloc_vring(struct rproc_vdev *rvdev, int i);
>
> @@ -119,4 +122,11 @@ struct resource_table *rproc_find_loaded_rsc_table(struct rproc *rproc,
> return NULL;
> }
>
> +static inline
> +void rproc_coredump(struct rproc *rproc)
> +{
> + return rproc_default_coredump(rproc);
> +
> +}
> +
> #endif /* REMOTEPROC_INTERNAL_H */
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project