ELf2Hex

[John Leidel]

All, has anyone else experienced recent issues with the elf2hex built by default using the riscv-tools build?  I was originally trying to get a binary blob dumped into a Rocket test using some custom startup code (and startup addresses), but elf2hex failed to dump the hex.  I scaled back to a simple example: 

$RISCV/bin/riscv64-unknown-elf-gcc -o hello.exe hello.c

$RISCV/bin/riscv64-unknown-elf-objdump --disassemble-all --disassemble-zeroes --section=.text --section=.text.startup --section=.data hello.exe > hello.dis

The hello.dis output appears to be perfectly valid

$RISCV/bin/elf2hex 16 32768 hello.dis > hello.hex

elf2hex: ../fesvr/elfloader.cc:29: std::map<std::__cxx11::basic_string<char>, long unsigned int> load_elf(const char*, memif_t*): Assertion `IS_ELF32(*eh64) || IS_ELF64(*eh64)' failed.

The elf2hex clearly asserts, but the binary is valid: 

hello.exe:     file format elf64-littleriscv

I also runs in Spike without any issues.  

Any thoughts?

[Michael Clark]

Random question. What is the host system? Is it big endian or little endian? ppc64?

There are fewer big endian systems around these days however they do exist. I just thought I would ask as I suspect the fesvr code would fail if the host is a big endian as I can’t see any bswaps.

Unfortunately I can’t test any of the host/target loader stuff as I have a KC705 which requires an untethered rocket.

The current code looks like it should work on little endian. When did it break?

[John Leidel]

Michael, its little endian (x86_64). Strangely enough, Spike has no issues with the same binary.

-- John D. Leidel

[Michael Clark]

Hi John,

Those assertion tests should work fine on little endian.

e_ident is not even within the portion of the Ehdr struct that differs between ELF32 and ELF64. 1, 2 are the correct values for ELFCLASS32 and ELFCLASS64 and EI_CLASS is 4. it appears from the code that it should work.

#define IS_ELF32(hdr) (IS_ELF(hdr) && (hdr).e_ident[4] == 1)
#define IS_ELF64(hdr) (IS_ELF(hdr) && (hdr).e_ident[4] == 2)

The file is open and the mmap has succeeded otherwise the previous assert would have failed. i.e. stepping though the statements leading up to the failed assertion.

std::map<std::string, uint64_t> load_elf(const char* fn, memif_t* memif)
{
  int fd = open(fn, O_RDONLY);
  struct stat s;
  assert(fd != -1);
  if (fstat(fd, &s) < 0)
    abort();
  size_t size = s.st_size;

  char* buf = (char*)mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
  assert(buf != MAP_FAILED);
  close(fd);

  assert(size >= sizeof(Elf64_Ehdr));
  const Elf64_Ehdr* eh64 = (const Elf64_Ehdr*)buf;
  assert(IS_ELF32(*eh64) || IS_ELF64(*eh64));

I wonder if it is something in hello.c. Can you pastebin the file and I can test locally?

Oh, you passing the .dis file into elf2hex, not the ELF file itself? I just noticed.

Michael.

--
You received this message because you are subscribed to the Google Groups "RISC-V SW Dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sw-dev+un...@groups.riscv.org.
To post to this group, send email to sw-...@groups.riscv.org.
Visit this group at https://groups.google.com/a/groups.riscv.org/group/sw-dev/.
To view this discussion on the web visit https://groups.google.com/a/groups.riscv.org/d/msgid/sw-dev/4C20A693-A2A7-4ABF-8FB3-B6DA91372653%40gmail.com.

[John Leidel]

Michael, I arrived at the same conclusion.  My tool chain build is about a month old, so i went back and looked at trunk. The assert still exists.  

I'll setup a place where you can grab the files and test.

Cheers

John

-- John D. Leidel 

[John Leidel]

Michael (et.al.), this was entirely user error... 

elf2hex < binary, not *dis... 

The binary dumps fine now that I used it rather than the hex.  PEBKAC

[Michael Clark]

That’s good you have it working now. Same thing happens to me often.

Quite often the more obvious the issue, the harder it is to find. Human nature.

[Shraddha Devaiya]

Hi,

I ran into the same issue as @john.leidel mentioned in the beginning. Can you please suggest the solution for this error :

elf2hex: ../fesvr/elfloader.cc:36: std::map<std::__cxx11::basic_string<char>, long unsigned int> load_elf(const char*, memif_t*, reg_t*): Assertion `IS_ELF_RISCV(*eh64) || IS_ELF_EM_NONE(*eh64)' failed.

I couldn't understand from this conversation.What can I do for this?

Thanks & Regards,

Shraddha Devaiya.