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

Clément Leger
2020-02-06T08:37:59Z

Hi Mathieu,

----- On 5 Feb, 2020, at 23:49, Mathieu Poirier mathieu.poirier@linaro.org wrote:

> 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.

Indeed, you are right !

I'm "afraid" I will have to fix that !
Most sane thing to do is to dump an elf with the input elf class.
I will make a V4 with a patch for that.

Thanks,

Clément

>
> 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