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

["Clément Leger" <cleger@kalray.eu>]

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.

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