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

Clément Leger
2020-02-06T15:05:51Z

Hi Mathieu,

----- On 6 Feb, 2020, at 09:37, Clément Leger cleger@kalray.eu wrote:

> 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.
>

Actually, this does not seems directly related to elf loading.
The coredump mecanism dumps segment that have been registered
using rproc_coredump_add_*_segment and this is not done directly
by the elf loader.
I'm not 100% sure but the coredump elf format is not tied to
any machine (EM_NONE) and as a special type (ET_CORE) so the elf
type is probably not relevant adn elf64 would be generic.
If some coredump user could speak for that part, that would be
nice !

If needed, then we could add a rproc_coredump_set_format() function
to specify various parameters (machine, elf type, lsb/msb, etc).

Let me know what you think about it.

Clément

> 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