Re: [PATCH v5 8/8] remoteproc: Adapt coredump to generate correct elf type
From: Mathieu Poirier
Date: Mon Mar 09 2020 - 16:32:29 EST
On Mon, Mar 02, 2020 at 10:39:02AM +0100, Clement Leger wrote:
> Now that remoteproc can load an elf64, coredump elf class should be
> the same as the loaded elf class. In order to do that, add a
> elf_class field to rproc with default values. If an elf is loaded
> successfully, this field will be updated with the loaded elf class.
> Then, the coredump core code has been modified to use the generic elf
> macro in order to create an elf file with correct class.
>
> Signed-off-by: Clement Leger <cleger@xxxxxxxxx>
> ---
> drivers/remoteproc/remoteproc_core.c | 67 ++++++++++++++++--------------
> drivers/remoteproc/remoteproc_elf_loader.c | 3 ++
> include/linux/remoteproc.h | 1 +
> 3 files changed, 39 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index b932a64a2be2..f923355aa3f9 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -38,6 +38,7 @@
> #include <linux/platform_device.h>
>
> #include "remoteproc_internal.h"
> +#include "remoteproc_elf_helpers.h"
>
> #define HIGH_BITS_MASK 0xFFFFFFFF00000000ULL
>
> @@ -1566,20 +1567,21 @@ EXPORT_SYMBOL(rproc_coredump_add_custom_segment);
> static void rproc_coredump(struct rproc *rproc)
> {
> struct rproc_dump_segment *segment;
> - struct elf32_phdr *phdr;
> - struct elf32_hdr *ehdr;
> + void *phdr;
> + void *ehdr;
> size_t data_size;
> size_t offset;
> void *data;
> void *ptr;
> + u8 class = rproc->elf_class;
> int phnum = 0;
>
> if (list_empty(&rproc->dump_segments))
> return;
>
> - data_size = sizeof(*ehdr);
> + data_size = elf_size_of_hdr(class);
> list_for_each_entry(segment, &rproc->dump_segments, node) {
> - data_size += sizeof(*phdr) + segment->size;
> + data_size += elf_size_of_phdr(class) + segment->size;
>
> phnum++;
> }
> @@ -1590,33 +1592,33 @@ static void rproc_coredump(struct rproc *rproc)
>
> 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;
> + 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, EM_NONE);
> + 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, 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;
> + 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 (segment->dump) {
> segment->dump(rproc, segment, data + offset);
> @@ -1632,8 +1634,8 @@ static void rproc_coredump(struct rproc *rproc)
> }
> }
>
> - offset += phdr->p_filesz;
> - phdr++;
> + offset += elf_phdr_get_p_filesz(class, phdr);
> + phdr += elf_size_of_phdr(class);
> }
>
> dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL);
> @@ -2031,6 +2033,7 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
> rproc->name = name;
> rproc->priv = &rproc[1];
> rproc->auto_boot = true;
> + rproc->elf_class = ELFCLASS32;
I would initialise this to ELFCLASSNONE to make sure that if a platform driver
overwrites rproc_elf_load_segments or doesn't provide one, we don't falsely
deduce the elf type. It goes without saying that if elf_class == ELFCLASSNONE,
a coredump is not generated.
Unless you think this is a seriously bad idea or Bjorn over rules me,
Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Thanks,
Mathieu
>
> device_initialize(&rproc->dev);
> rproc->dev.parent = dev;
> diff --git a/drivers/remoteproc/remoteproc_elf_loader.c b/drivers/remoteproc/remoteproc_elf_loader.c
> index 4869fb7d8fe4..16e2c496fd45 100644
> --- a/drivers/remoteproc/remoteproc_elf_loader.c
> +++ b/drivers/remoteproc/remoteproc_elf_loader.c
> @@ -248,6 +248,9 @@ int rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
> memset(ptr + filesz, 0, memsz - filesz);
> }
>
> + if (ret == 0)
> + rproc->elf_class = class;
> +
> return ret;
> }
> EXPORT_SYMBOL(rproc_elf_load_segments);
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index 1683d6c386a6..ed127b2d35ca 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -514,6 +514,7 @@ struct rproc {
> bool auto_boot;
> struct list_head dump_segments;
> int nb_vdev;
> + u8 elf_class;
> };
>
> /**
> --
> 2.15.0.276.g89ea799
>