Re: [PATCH v2] remoteproc: Add elf64 support in elf loader

["Clément Leger" <cleger@kalray.eu>]

Ok, here is the example to be more clear:

Content of elfxx_loader.h:

int elf##ELF_TYPE##_load(...) {
	struct elf##ELF_TYPE##_shdr *shdr = data;
	...
}

Then in elf_loader.c file:

#define ELF_TYPE 32
#include "elfxx_loader.h"
#undef ELF_TYPE
#define ELF_TYPE 64
#include "elfxx_loader.h"

int elf_load(...) {
	if (class == elf64)
		elf64_load(...);
	else
		elf32_load(...);
}

This is used for syscall_table.c in arch for instance.
A macro must be defined and then the ehader is included and
"generates" code.

#undef __SYSCALL
#define __SYSCALL(nr, call)	[nr] = (call),

void *sys_call_table[__NR_syscalls] = {
	[0 ... __NR_syscalls - 1] = sys_ni_syscall,
#include <asm/unistd.h>
};

Hope this shed some light on my suggestion.

Clément

----- On 28 Jan, 2020, at 18:14, Mathieu Poirier mathieu.poirier@linaro.org wrote:

> On Mon, 27 Jan 2020 at 01:33, Clément Leger <cleger@kalray.eu> wrote:
>>
>> Hi Mathieu,
>>
>> Thanks for your thorough review. While thinking about it,there is at least
>> another option which would consist in splitting all elf specific functions into
>> a separate .h file and then include it in a .c to "instantiate" the functions
>> with correct types. For instance, it would look like this:
>>
>> #define ELF_TYPE 32
>> #include "elf_functions.h"
>> #undef ELF_TYPE
>> #define ELF_TYPE 64
>> #include "elf_functions.h"
>>
>> pros: More readable and type-checking ok
>> cons: A bit hackish
>>
>> I would say this might be a better optino than my current patch.
>> However, I'm not sure this kind of thing of well accepted in the kernel.
> 
> I won't claim to fully understand your suggestion above, but if it is
> suspicious enough to look hackish to you than it will probably look
> hackish to other people.  Nonetheless there might be a case for
> exception if the approach yields clear advantages.  Can you point me
> to an example somewhere in the kernel code where something similar
> would have been done?
> 
>>
>> Clément
>>
>> ----- On 24 Jan, 2020, at 22:58, Mathieu Poirier mathieu.poirier@linaro.org
>> wrote:
>>
>> > On Fri, Jan 24, 2020 at 09:24:16AM +0100, Clément Leger wrote:
>> >> Hi Mathieu,
>> >>
>> >> ----- On 24 Jan, 2020, at 01:53, Mathieu Poirier mathieu.poirier@linaro.org
>> >> wrote:
>> >>
>> >> > Hi Clement,
>> >> >
>> >> > On Fri, Oct 04, 2019 at 08:42:20PM +0200, Clement Leger wrote:
>> >> >> elf32 and elf64 mainly differ by their types. In order to avoid
>> >> >> copy/pasting the whole loader code, generate static inline functions
>> >> >> which will access values according to the elf class. It allows to keep a
>> >> >> common loader basis.
>> >> >> In order to accomodate both elf types sizes, the maximum size for a
>> >> >> elf header member is chosen using the maximum value of both elf class.
>> >> >>
>> >> >> Signed-off-by: Clement Leger <cleger@kalray.eu>
>> >> >> Tested-by: Arnaud POULIQUEN <arnaud.pouliquen@st.com>
>> >> >> ---
>> >> >> Changes in v2:
>> >> >>  - Add ELF64 support in documentation
>> >> >>
>> >> >
>> >> > First and foremost please address the complaints from checkpatch.
>> >>
>> >> I fixed one typo in accommodate. The other checkpatch complaint is
>> >> about missing parenthesis for macros with complex values which is
>> >> unfortunately not possible since I'm generating inline functions.
>> >>
>> >> Did you have any other one ?
>> >>
>> >> >
>> >> >> ---
>> >> >>  Documentation/remoteproc.txt               |   2 +-
>> >> >>  drivers/remoteproc/remoteproc_elf_loader.c | 135 ++++++++++++++++++-----------
>> >> >>  drivers/remoteproc/remoteproc_elf_loader.h |  69 +++++++++++++++
>> >> >>  drivers/remoteproc/remoteproc_internal.h   |   2 +-
>> >> >>  drivers/remoteproc/st_remoteproc.c         |   2 +-
>> >> >>  include/linux/remoteproc.h                 |   4 +-
>> >> >>  6 files changed, 157 insertions(+), 57 deletions(-)
>> >> >>  create mode 100644 drivers/remoteproc/remoteproc_elf_loader.h
>> >> >>
>> >> >> diff --git a/Documentation/remoteproc.txt b/Documentation/remoteproc.txt
>> >> >> index 77fb03acdbb4..bf4f0c41ec4e 100644
>> >> >> --- a/Documentation/remoteproc.txt
>> >> >> +++ b/Documentation/remoteproc.txt
>> >> >> @@ -230,7 +230,7 @@ in the used rings.
>> >> >>  Binary Firmware Structure
>> >> >>  =========================
>> >> >>
>> >> >> -At this point remoteproc only supports ELF32 firmware binaries. However,
>> >> >> +At this point remoteproc supports ELF32 and ELF64 firmware binaries. However,
>> >> >>  it is quite expected that other platforms/devices which we'd want to
>> >> >>  support with this framework will be based on different binary formats.
>> >> >>
>> >> >> diff --git a/drivers/remoteproc/remoteproc_elf_loader.c
>> >> >> b/drivers/remoteproc/remoteproc_elf_loader.c
>> >> >> index b17d72ec8603..6a2d31d6092c 100644
>> >> >> --- a/drivers/remoteproc/remoteproc_elf_loader.c
>> >> >> +++ b/drivers/remoteproc/remoteproc_elf_loader.c
>> >> >> @@ -31,6 +31,7 @@
>> >> >>  #include <linux/elf.h>
>> >> >>
>> >> >>  #include "remoteproc_internal.h"
>> >> >> +#include "remoteproc_elf_loader.h"
>> >> >>
>> >> >>  /**
>> >> >>   * rproc_elf_sanity_check() - Sanity Check ELF firmware image
>> >> >> @@ -43,8 +44,16 @@ int rproc_elf_sanity_check(struct rproc *rproc, const struct
>> >> >> firmware *fw)
>> >> >>  {
>> >> >>   const char *name = rproc->firmware;
>> >> >>   struct device *dev = &rproc->dev;
>> >> >> + /*
>> >> >> +  * Elf files are beginning with the same structure. Thus, to simplify
>> >> >> +  * header parsing, we can use the elf32_hdr one for both elf64 and
>> >> >> +  * elf32.
>> >> >> +  */
>> >> >>   struct elf32_hdr *ehdr;
>> >> >> + u32 elf_shdr_size;
>> >> >> + u64 phoff, shoff;
>> >> >>   char class;
>> >> >> + u16 phnum;
>> >> >>
>> >> >>   if (!fw) {
>> >> >>           dev_err(dev, "failed to load %s\n", name);
>> >> >> @@ -58,9 +67,13 @@ int rproc_elf_sanity_check(struct rproc *rproc, const struct
>> >> >> firmware *fw)
>> >> >
>> >> > In the current code [1] fw->size is compared against the size of an elf32_hdr.
>> >> > If support for elf64 is added that code needs to be modified to check for the
>> >> > right header size using fw_elf_get_class().
>> >>
>> >> Actually, the elf32 header is smaller than the elf64 one so this check is
>> >> there to ensure that we have at least a minimal elf header (elf32).
>> >> And since the class is derived from the header, you better have to check the
>> >> header size before accessing it.
>> >>
>> >> To be more clear, I could compare it to min(sizeof(struct elf32_hdr),
>> >> sizeof(struct elf64_hdr)) or add a comment at least stating that since
>> >> elf header contains the same fields for identification, we can use the
>> >> elf32 one.
>> >>
>> >> >
>> >> > [1]
>> >> > https://elixir.bootlin.com/linux/v5.5-rc6/source/drivers/remoteproc/remoteproc_elf_loader.c#L46
>> >> >
>> >> >>
>> >> >>   ehdr = (struct elf32_hdr *)fw->data;
>> >> >>
>> >> >> - /* We only support ELF32 at this point */
>> >> >> + if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG)) {
>> >> >> +         dev_err(dev, "Image is corrupted (bad magic)\n");
>> >> >> +         return -EINVAL;
>> >> >> + }
>> >> >> +
>> >> >
>> >> > Is there a reason to move this check up where?  If not please bring it back to
>> >> > its original location, that is below:
>> >> >
>> >> > "if (fw->size < ehdr->e_shoff + sizeof(structelf32_shdr))"
>> >> >
>> >>
>> >> This is because the new check for size uses elf_shdr_size which is derived from
>> >> the class. And since the class is extracted from the elf header, we need to
>> >> check
>> >> the header to be correct first.
>> >>
>> >> >>   class = ehdr->e_ident[EI_CLASS];
>> >> >> - if (class != ELFCLASS32) {
>> >> >> + if (class != ELFCLASS32 && class != ELFCLASS64) {
>> >> >>           dev_err(dev, "Unsupported class: %d\n", class);
>> >> >>           return -EINVAL;
>> >> >>   }
>> >> >> @@ -75,26 +88,29 @@ int rproc_elf_sanity_check(struct rproc *rproc, const struct
>> >> >> firmware *fw)
>> >> >>           return -EINVAL;
>> >> >>   }
>> >> >>
>> >> >> - if (fw->size < ehdr->e_shoff + sizeof(struct elf32_shdr)) {
>> >> >> -         dev_err(dev, "Image is too small\n");
>> >> >> -         return -EINVAL;
>> >> >> - }
>> >> >> + phoff = elf_hdr_e_phoff(class, fw->data);
>> >> >> + shoff = elf_hdr_e_shoff(class, fw->data);
>> >> >> + phnum =  elf_hdr_e_phnum(class, fw->data);
>> >> >> + elf_shdr_size = elf_size_of_shdr(class);
>> >> >>
>> >> >> - if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG)) {
>> >> >> -         dev_err(dev, "Image is corrupted (bad magic)\n");
>> >> >> + if (fw->size < shoff + elf_shdr_size) {
>> >> >> +         dev_err(dev, "Image is too small\n");
>> >> >>           return -EINVAL;
>> >> >>   }
>> >> >>
>> >> >> - if (ehdr->e_phnum == 0) {
>> >> >> + if (phnum == 0) {
>> >> >>           dev_err(dev, "No loadable segments\n");
>> >> >>           return -EINVAL;
>> >> >>   }
>> >> >>
>> >> >> - if (ehdr->e_phoff > fw->size) {
>> >> >> + if (phoff > fw->size) {
>> >> >>           dev_err(dev, "Firmware size is too small\n");
>> >> >>           return -EINVAL;
>> >> >>   }
>> >> >>
>> >> >> + dev_dbg(dev, "Firmware is an elf%d file\n",
>> >> >> +         class == ELFCLASS32 ? 32 : 64);
>> >> >> +
>> >> >
>> >> > Yes, this is useful.
>> >> >
>> >> >>   return 0;
>> >> >>  }
>> >> >>  EXPORT_SYMBOL(rproc_elf_sanity_check);
>> >> >> @@ -110,11 +126,9 @@ EXPORT_SYMBOL(rproc_elf_sanity_check);
>> >> >>   * Note that the boot address is not a configurable property of all remote
>> >> >>   * processors. Some will always boot at a specific hard-coded address.
>> >> >>   */
>> >> >> -u32 rproc_elf_get_boot_addr(struct rproc *rproc, const struct firmware *fw)
>> >> >> +u64 rproc_elf_get_boot_addr(struct rproc *rproc, const struct firmware *fw)
>> >> >>  {
>> >> >> - struct elf32_hdr *ehdr  = (struct elf32_hdr *)fw->data;
>> >> >> -
>> >> >> - return ehdr->e_entry;
>> >> >> + return elf_hdr_e_entry(fw_elf_get_class(fw), fw->data);
>> >> >>  }
>> >> >>  EXPORT_SYMBOL(rproc_elf_get_boot_addr);
>> >> >>
>> >> >> @@ -145,37 +159,41 @@ EXPORT_SYMBOL(rproc_elf_get_boot_addr);
>> >> >>  int rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
>> >> >>  {
>> >> >>   struct device *dev = &rproc->dev;
>> >> >> - struct elf32_hdr *ehdr;
>> >> >> - struct elf32_phdr *phdr;
>> >> >> + const void *ehdr, *phdr;
>> >> >>   int i, ret = 0;
>> >> >> + u16 phnum;
>> >> >>   const u8 *elf_data = fw->data;
>> >> >> + u8 class = fw_elf_get_class(fw);
>> >> >> + u32 elf_phdr_size = elf_size_of_phdr(class);
>> >> >>
>> >> >> - ehdr = (struct elf32_hdr *)elf_data;
>> >> >> - phdr = (struct elf32_phdr *)(elf_data + ehdr->e_phoff);
>> >> >> + ehdr = elf_data;
>> >> >> + phnum = elf_hdr_e_phnum(class, ehdr);
>> >> >> + phdr = elf_data + elf_hdr_e_phoff(class, ehdr);
>> >> >>
>> >> >>   /* go through the available ELF segments */
>> >> >> - for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
>> >> >> -         u32 da = phdr->p_paddr;
>> >> >> -         u32 memsz = phdr->p_memsz;
>> >> >> -         u32 filesz = phdr->p_filesz;
>> >> >> -         u32 offset = phdr->p_offset;
>> >> >> + for (i = 0; i < phnum; i++, phdr += elf_phdr_size) {
>> >> >> +         u64 da = elf_phdr_p_paddr(class, phdr);
>> >> >> +         u64 memsz = elf_phdr_p_memsz(class, phdr);
>> >> >> +         u64 filesz = elf_phdr_p_filesz(class, phdr);
>> >> >> +         u64 offset = elf_phdr_p_offset(class, phdr);
>> >> >> +         u32 type = elf_phdr_p_type(class, phdr);
>> >> >>           void *ptr;
>> >> >>
>> >> >> -         if (phdr->p_type != PT_LOAD)
>> >> >> +         if (type != PT_LOAD)
>> >> >>                   continue;
>> >> >>
>> >> >> -         dev_dbg(dev, "phdr: type %d da 0x%x memsz 0x%x filesz 0x%x\n",
>> >> >> -                 phdr->p_type, da, memsz, filesz);
>> >> >> +         dev_dbg(dev, "phdr: type %d da 0x%llx memsz 0x%llx filesz 0x%llx\n",
>> >> >> +                 type, da, memsz, filesz);
>> >> >>
>> >> >>           if (filesz > memsz) {
>> >> >> -                 dev_err(dev, "bad phdr filesz 0x%x memsz 0x%x\n",
>> >> >> +                 dev_err(dev, "bad phdr filesz 0x%llx memsz 0x%llx\n",
>> >> >>                           filesz, memsz);
>> >> >>                   ret = -EINVAL;
>> >> >>                   break;
>> >> >>           }
>> >> >>
>> >> >>           if (offset + filesz > fw->size) {
>> >> >> -                 dev_err(dev, "truncated fw: need 0x%x avail 0x%zx\n",
>> >> >> +                 dev_err(dev, "truncated fw: need 0x%llx avail 0x%zx\n",
>> >> >>                           offset + filesz, fw->size);
>> >> >>                   ret = -EINVAL;
>> >> >>                   break;
>> >> >> @@ -184,14 +202,15 @@ int rproc_elf_load_segments(struct rproc *rproc, const
>> >> >> struct firmware *fw)
>> >> >>           /* grab the kernel address for this device address */
>> >> >>           ptr = rproc_da_to_va(rproc, da, memsz);
>> >> >>           if (!ptr) {
>> >> >> -                 dev_err(dev, "bad phdr da 0x%x mem 0x%x\n", da, memsz);
>> >> >> +                 dev_err(dev, "bad phdr da 0x%llx mem 0x%llx\n", da,
>> >> >> +                         memsz);
>> >> >>                   ret = -EINVAL;
>> >> >>                   break;
>> >> >>           }
>> >> >>
>> >> >>           /* put the segment where the remote processor expects it */
>> >> >> -         if (phdr->p_filesz)
>> >> >> -                 memcpy(ptr, elf_data + phdr->p_offset, filesz);
>> >> >> +         if (filesz)
>> >> >> +                 memcpy(ptr, elf_data + offset, filesz);
>> >> >>
>> >> >>           /*
>> >> >>            * Zero out remaining memory for this segment.
>> >> >> @@ -208,24 +227,32 @@ int rproc_elf_load_segments(struct rproc *rproc, const
>> >> >> struct firmware *fw)
>> >> >>  }
>> >> >>  EXPORT_SYMBOL(rproc_elf_load_segments);
>> >> >>
>> >> >> -static struct elf32_shdr *
>> >> >> -find_table(struct device *dev, struct elf32_hdr *ehdr, size_t fw_size)
>> >> >> +static const void *
>> >> >
>> >> > Not sure I understand the "const" - was the compiler complaining?
>> >>
>> >> It's actually caused by the fact I used a const void* shdr in the caller.
>> >> I will check if this is mandatory.
>> >>
>> >> >
>> >> >> +find_table(struct device *dev, const struct firmware *fw)
>> >> >>  {
>> >> >> - struct elf32_shdr *shdr;
>> >> >> + const void *shdr, *name_table_shdr;
>> >> >>   int i;
>> >> >>   const char *name_table;
>> >> >>   struct resource_table *table = NULL;
>> >> >> - const u8 *elf_data = (void *)ehdr;
>> >> >> + const u8 *elf_data = (void *)fw->data;
>> >> >> + u8 class = fw_elf_get_class(fw);
>> >> >> + size_t fw_size = fw->size;
>> >> >> + const void *ehdr = elf_data;
>> >> >> + u16 shnum = elf_hdr_e_shnum(class, ehdr);
>> >> >> + u32 elf_shdr_size = elf_size_of_shdr(class);
>> >> >> + u16 shstrndx = elf_hdr_e_shstrndx(class, ehdr);
>> >> >>
>> >> >>   /* look for the resource table and handle it */
>> >> >> - shdr = (struct elf32_shdr *)(elf_data + ehdr->e_shoff);
>> >> >> - name_table = elf_data + shdr[ehdr->e_shstrndx].sh_offset;
>> >> >> + shdr = elf_data + elf_hdr_e_shoff(class, ehdr);
>> >> >> + name_table_shdr = shdr + (shstrndx * elf_shdr_size);
>> >> >> + name_table = elf_data + elf_shdr_sh_offset(class, name_table_shdr);
>> >> >
>> >> > It took me a while but I figured out what is happening here.  To save me (and
>> >> > other people) from going through the same mental process every time I look at
>> >> > this code, please add a comment for each of the above 3 lines.
>> >>
>> >> Indeed.
>> >>
>> >> >
>> >> >>
>> >> >> - for (i = 0; i < ehdr->e_shnum; i++, shdr++) {
>> >> >> -         u32 size = shdr->sh_size;
>> >> >> -         u32 offset = shdr->sh_offset;
>> >> >> + for (i = 0; i < shnum; i++, shdr += elf_shdr_size) {
>> >> >> +         u64 size = elf_shdr_sh_size(class, shdr);
>> >> >> +         u64 offset = elf_shdr_sh_offset(class, shdr);
>> >> >> +         u32 name = elf_shdr_sh_name(class, shdr);
>> >> >>
>> >> >> -         if (strcmp(name_table + shdr->sh_name, ".resource_table"))
>> >> >> +         if (strcmp(name_table + name, ".resource_table"))
>> >> >>                   continue;
>> >> >>
>> >> >>           table = (struct resource_table *)(elf_data + offset);
>> >> >> @@ -279,21 +306,21 @@ find_table(struct device *dev, struct elf32_hdr *ehdr,
>> >> >> size_t fw_size)
>> >> >>   */
>> >> >>  int rproc_elf_load_rsc_table(struct rproc *rproc, const struct firmware *fw)
>> >> >>  {
>> >> >> - struct elf32_hdr *ehdr;
>> >> >> - struct elf32_shdr *shdr;
>> >> >> + const void *shdr;
>> >> >>   struct device *dev = &rproc->dev;
>> >> >>   struct resource_table *table = NULL;
>> >> >>   const u8 *elf_data = fw->data;
>> >> >>   size_t tablesz;
>> >> >> + u8 class = fw_elf_get_class(fw);
>> >> >> + u64 sh_offset;
>> >> >>
>> >> >> - ehdr = (struct elf32_hdr *)elf_data;
>> >> >> -
>> >> >> - shdr = find_table(dev, ehdr, fw->size);
>> >> >> + shdr = find_table(dev, fw);
>> >> >>   if (!shdr)
>> >> >>           return -EINVAL;
>> >> >>
>> >> >> - table = (struct resource_table *)(elf_data + shdr->sh_offset);
>> >> >> - tablesz = shdr->sh_size;
>> >> >> + sh_offset = elf_shdr_sh_offset(class, shdr);
>> >> >> + table = (struct resource_table *)(elf_data + sh_offset);
>> >> >> + tablesz = elf_shdr_sh_size(class, shdr);
>> >> >>
>> >> >>   /*
>> >> >>    * Create a copy of the resource table. When a virtio device starts
>> >> >> @@ -326,13 +353,17 @@ EXPORT_SYMBOL(rproc_elf_load_rsc_table);
>> >> >>  struct resource_table *rproc_elf_find_loaded_rsc_table(struct rproc *rproc,
>> >> >>                                                  const struct firmware *fw)
>> >> >>  {
>> >> >> - struct elf32_hdr *ehdr = (struct elf32_hdr *)fw->data;
>> >> >> - struct elf32_shdr *shdr;
>> >> >> + const void *shdr;
>> >> >> + u64 sh_addr, sh_size;
>> >> >> + u8 class = fw_elf_get_class(fw);
>> >> >>
>> >> >> - shdr = find_table(&rproc->dev, ehdr, fw->size);
>> >> >> + shdr = find_table(&rproc->dev, fw);
>> >> >>   if (!shdr)
>> >> >>           return NULL;
>> >> >>
>> >> >> - return rproc_da_to_va(rproc, shdr->sh_addr, shdr->sh_size);
>> >> >> + sh_addr = elf_shdr_sh_addr(class, shdr);
>> >> >> + sh_size = elf_shdr_sh_size(class, shdr);
>> >> >> +
>> >> >> + return rproc_da_to_va(rproc, sh_addr, sh_size);
>> >> >
>> >> > The prototype for the above is as follow:
>> >> >
>> >> > void *rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>> >> >
>> >> > But sh_size is a u64, which will cause problem that are hard to debug.  I think
>> >> > it is better to move 'len' to an 8 byte type along with the refactoring of the
>> >> > existing code that is implied.  I suggest to split this work in a preparatory
>> >> > patch (that will still be part of this set).
>> >>
>> >> Nice catch ! I will do that.
>> >>
>> >> >
>> >> >>  }
>> >> >>  EXPORT_SYMBOL(rproc_elf_find_loaded_rsc_table);
>> >> >> diff --git a/drivers/remoteproc/remoteproc_elf_loader.h
>> >> >> b/drivers/remoteproc/remoteproc_elf_loader.h
>> >> >> new file mode 100644
>> >> >> index 000000000000..fac3565734f9
>> >> >> --- /dev/null
>> >> >> +++ b/drivers/remoteproc/remoteproc_elf_loader.h
>> >> >> @@ -0,0 +1,69 @@
>> >> >> +/* SPDX-License-Identifier: GPL-2.0 */
>> >> >> +/*
>> >> >> + * Remote processor elf loader defines
>> >> >> + *
>> >> >> + * Copyright (C) 2019 Kalray, Inc.
>> >> >> + */
>> >> >> +
>> >> >> +#ifndef REMOTEPROC_ELF_LOADER_H
>> >> >> +#define REMOTEPROC_ELF_LOADER_H
>> >> >> +
>> >> >> +#include <linux/elf.h>
>> >> >> +#include <linux/types.h>
>> >> >> +
>> >> >> +/**
>> >> >> + * fw_elf_get_class - Get elf class
>> >> >> + * @fw: the ELF firmware image
>> >> >> + *
>> >> >> + * Note that we use and elf32_hdr to access the class since the start of the
>> >> >> + * struct is the same for both elf class
>> >> >> + *
>> >> >> + * Return: elf class of the firmware
>> >> >> + */
>> >> >> +static inline u8 fw_elf_get_class(const struct firmware *fw)
>> >> >> +{
>> >> >> + struct elf32_hdr *ehdr = (struct elf32_hdr *)fw->data;
>> >> >> +
>> >> >> + return ehdr->e_ident[EI_CLASS];
>> >> >> +}
>> >> >> +
>> >> >> +#define ELF_GET_FIELD(__s, __field, __type) \
>> >> >> +static inline __type elf_##__s##_##__field(u8 class, const void *arg) \
>> >> >> +{ \
>> >> >> + if (class == ELFCLASS32) \
>> >> >> +         return (__type) ((const struct elf32_##__s *) arg)->__field; \
>> >> >> + else \
>> >> >> +         return (__type) ((const struct elf64_##__s *) arg)->__field; \
>> >> >> +}
>> >> >> +
>> >> >> +ELF_GET_FIELD(hdr, e_entry, u64)
>> >> >> +ELF_GET_FIELD(hdr, e_phnum, u16)
>> >> >> +ELF_GET_FIELD(hdr, e_shnum, u16)
>> >> >> +ELF_GET_FIELD(hdr, e_phoff, u64)
>> >> >> +ELF_GET_FIELD(hdr, e_shoff, u64)
>> >> >> +ELF_GET_FIELD(hdr, e_shstrndx, u16)
>> >> >> +
>> >> >> +ELF_GET_FIELD(phdr, p_paddr, u64)
>> >> >> +ELF_GET_FIELD(phdr, p_filesz, u64)
>> >> >> +ELF_GET_FIELD(phdr, p_memsz, u64)
>> >> >> +ELF_GET_FIELD(phdr, p_type, u32)
>> >> >> +ELF_GET_FIELD(phdr, p_offset, u64)
>> >> >> +
>> >> >> +ELF_GET_FIELD(shdr, sh_size, u64)
>> >> >> +ELF_GET_FIELD(shdr, sh_offset, u64)
>> >> >> +ELF_GET_FIELD(shdr, sh_name, u32)
>> >> >> +ELF_GET_FIELD(shdr, sh_addr, u64)
>> >> >
>> >> > I like how you did this.
>> >> >
>> >> >> +
>> >> >> +#define ELF_STRUCT_SIZE(__s) \
>> >> >> +static inline unsigned long elf_size_of_##__s(u8 class) \
>> >> >> +{ \
>> >> >> + if (class == ELFCLASS32)\
>> >> >> +         return sizeof(struct elf32_##__s); \
>> >> >> + else \
>> >> >> +         return sizeof(struct elf64_##__s); \
>> >> >> +}
>> >> >> +
>> >> >> +ELF_STRUCT_SIZE(shdr)
>> >> >> +ELF_STRUCT_SIZE(phdr)
>> >> >> +
>> >> >> +#endif /* REMOTEPROC_ELF_LOADER_H */
>> >> >> diff --git a/drivers/remoteproc/remoteproc_internal.h
>> >> >> b/drivers/remoteproc/remoteproc_internal.h
>> >> >> index 45ff76a06c72..4ef745e3a1bc 100644
>> >> >> --- a/drivers/remoteproc/remoteproc_internal.h
>> >> >> +++ b/drivers/remoteproc/remoteproc_internal.h
>> >> >> @@ -63,7 +63,7 @@ phys_addr_t rproc_va_to_pa(void *cpu_addr);
>> >> >>  int rproc_trigger_recovery(struct rproc *rproc);
>> >> >>
>> >> >>  int rproc_elf_sanity_check(struct rproc *rproc, const struct firmware *fw);
>> >> >> -u32 rproc_elf_get_boot_addr(struct rproc *rproc, const struct firmware *fw);
>> >> >> +u64 rproc_elf_get_boot_addr(struct rproc *rproc, const struct firmware *fw);
>> >> >>  int rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw);
>> >> >>  int rproc_elf_load_rsc_table(struct rproc *rproc, const struct firmware *fw);
>> >> >>  struct resource_table *rproc_elf_find_loaded_rsc_table(struct rproc *rproc,
>> >> >> diff --git a/drivers/remoteproc/st_remoteproc.c
>> >> >> b/drivers/remoteproc/st_remoteproc.c
>> >> >> index 51049d17b1e5..e23abd8a96b0 100644
>> >> >> --- a/drivers/remoteproc/st_remoteproc.c
>> >> >> +++ b/drivers/remoteproc/st_remoteproc.c
>> >> >> @@ -193,7 +193,7 @@ static int st_rproc_start(struct rproc *rproc)
>> >> >>           }
>> >> >>   }
>> >> >>
>> >> >> - dev_info(&rproc->dev, "Started from 0x%x\n", rproc->bootaddr);
>> >> >> + dev_info(&rproc->dev, "Started from 0x%llx\n", rproc->bootaddr);
>> >> >>
>> >> >>   return 0;
>> >> >>
>> >> >> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>> >> >> index 04d04709f2bd..512de9a2590c 100644
>> >> >> --- a/include/linux/remoteproc.h
>> >> >> +++ b/include/linux/remoteproc.h
>> >> >> @@ -362,7 +362,7 @@ struct rproc_ops {
>> >> >>                           struct rproc *rproc, const struct firmware *fw);
>> >> >>   int (*load)(struct rproc *rproc, const struct firmware *fw);
>> >> >>   int (*sanity_check)(struct rproc *rproc, const struct firmware *fw);
>> >> >> - u32 (*get_boot_addr)(struct rproc *rproc, const struct firmware *fw);
>> >> >> + u64 (*get_boot_addr)(struct rproc *rproc, const struct firmware *fw);
>> >> >>  };
>> >> >>
>> >> >>  /**
>> >> >> @@ -478,7 +478,7 @@ struct rproc {
>> >> >>   int num_traces;
>> >> >>   struct list_head carveouts;
>> >> >>   struct list_head mappings;
>> >> >> - u32 bootaddr;
>> >> >> + u64 bootaddr;
>> >> >>   struct list_head rvdevs;
>> >> >>   struct list_head subdevs;
>> >> >>   struct idr notifyids;
>> >> >
>> >> > Please hold off before doing another respin of this patch.  While doing
>> >> > something completely different I noticed TI also did some work in this area.
>> >> > I'd like to take some time to look at their implementation and see if they carry
>> >> > features that haven't been included here.  I intend to do this tomorrow.
>> >>
>> >> Ok,
>> >>
>> >> Thanks for your review,
>> >
>> > As promised I looked at what Suman had done on his side [1] to support 64-bit
>> > ELF
>> > files. His approach to offer the same functionality but for 64 bit in a new file
>> > is quick, simple and flexible.  On the flip side it introduces code duplication,
>> > something that is seriously frowned upon upstream.
>> >
>> > I did some soul searching in the kernel code and found very little in terms of
>> > implementation that deals with both 32 and 64 bit ELF format.  The most
>> > convincing approach was set forth by the MIPS guys [2].  They too have decided
>> > to support both types in the same functions, but I don't see us adding an if()
>> > statement (and the code duplication that comes with it) every time we need to
>> > deal with file types.
>> >
>> > Given the above I'm in favour of moving forward with your approach.  One could
>> > rightly argue the macros make the code harder to read but given the
>> > alternatives, it seems to be the best solution.
>> >
>> > Mathieu
>> >
>> > [1]. https://bit.ly/2Rpmb4E
>> > [2]. https://elixir.bootlin.com/linux/v5.5-rc6/source/arch/mips/kernel/elf.c#L75
>> >>
>> >> Clément
>> >>
>> >> >
>> >> > Thanks,
>> >> > Mathieu
>> >> >
>> >> >> --
> > > > >> 2.15.0.276.g89ea799