Re: [PATCH v3 2/2] remoteproc: Add elf64 support in elf loader

Mathieu Poirier
2020-02-05T22:49:41Z

On Tue, Feb 04, 2020 at 06:44:12PM +0100, 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 accommodate 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>
> ---
> Documentation/remoteproc.txt | 2 +-
> drivers/remoteproc/remoteproc_elf_loader.c | 147 ++++++++++++++++++-----------
> 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, 167 insertions(+), 59 deletions(-)
> create mode 100644 drivers/remoteproc/remoteproc_elf_loader.h
>
> diff --git a/Documentation/remoteproc.txt b/Documentation/remoteproc.txt
> index 03c3d2e568b0..2be1147256e0 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 606aae166eba..21fd2b2fe5ae 100644
> --- a/drivers/remoteproc/remoteproc_elf_loader.c
> +++ b/drivers/remoteproc/remoteproc_elf_loader.c
> @@ -23,6 +23,7 @@
> #include <linux/elf.h>
>
> #include "remoteproc_internal.h"
> +#include "remoteproc_elf_loader.h"
>
> /**
> * rproc_elf_sanity_check() - Sanity Check ELF firmware image
> @@ -35,8 +36,16 @@ 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);
> @@ -50,13 +59,22 @@ int rproc_elf_sanity_check(struct rproc *rproc, const struct firmware *fw)
>
> 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;
> + }
> +
> class = ehdr->e_ident[EI_CLASS];
> - if (class != ELFCLASS32) {
> + if (class != ELFCLASS32 && class != ELFCLASS64) {
> dev_err(dev, "Unsupported class: %d\n", class);
> return -EINVAL;
> }
>
> + if (class == ELFCLASS64 && fw->size < sizeof(struct elf64_hdr)) {
> + dev_err(dev, "elf64 header is too small\n");
> + return -EINVAL;
> + }
> +
> /* We assume the firmware has the same endianness as the host */
> # ifdef __LITTLE_ENDIAN
> if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB) {
> @@ -67,26 +85,29 @@ 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);
> +
> return 0;
> }
> EXPORT_SYMBOL(rproc_elf_sanity_check);
> @@ -102,11 +123,9 @@ 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);
>
> @@ -137,37 +156,41 @@ 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;
> @@ -176,14 +199,15 @@ 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.
> @@ -200,24 +224,35 @@ 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 *
> +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;
> -
> - for (i = 0; i < ehdr->e_shnum; i++, shdr++) {
> - u32 size = shdr->sh_size;
> - u32 offset = shdr->sh_offset;
> -
> - if (strcmp(name_table + shdr->sh_name, ".resource_table"))
> + /* First, get the section header according to the elf class */
> + shdr = elf_data + elf_hdr_e_shoff(class, ehdr);
> + /* Compute name table section header entry in shdr array */
> + name_table_shdr = shdr + (shstrndx * elf_shdr_size);
> + /* Finally, compute the name table section address in elf */
> + name_table = elf_data + elf_shdr_sh_offset(class, name_table_shdr);
> +
> + 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 + name, ".resource_table"))
> continue;
>
> table = (struct resource_table *)(elf_data + offset);
> @@ -270,21 +305,21 @@ 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
> @@ -317,13 +352,17 @@ 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);
> }
> 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)
> +
> +#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 004867061721..eeb26434220e 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -55,7 +55,7 @@ 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 ee13d23b43a9..a3268d95a50e 100644
> --- a/drivers/remoteproc/st_remoteproc.c
> +++ b/drivers/remoteproc/st_remoteproc.c
> @@ -190,7 +190,7 @@ 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 f84bd5fe0211..82cebca9344c 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -382,7 +382,7 @@ 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);
> };
>
> /**
> @@ -498,7 +498,7 @@ struct rproc {
> int num_traces;
> struct list_head carveouts;
> struct list_head mappings;
> - u32 bootaddr;
> + u64 bootaddr;

That will cause problems for rproc_coredump()[1] and fixing it properly
likely means that a 32 or 64 elf should be generated based on the type of image
that was loaded. This is also true if ->p_vaddr and ->p_paddr (also in the same
function) are to be handled properly.

I'm interested in your opinion on this.

Thanks,
Mathieu

[1]. https://elixir.bootlin.com/linux/latest/source/drivers/remoteproc/remoteproc_core.c#L1600

> struct list_head rvdevs;
> struct list_head subdevs;
> struct idr notifyids;
> --
> 2.15.0.276.g89ea799
>