Re: [Qemu-devel] [PATCH] elf: Calculate symbol size if needed

[Blue Swirl]

On Thu, Sep 9, 2010 at 5:42 PM, Stefan Weil <address@hidden> wrote:
> Am 11.08.2010 18:21, schrieb Blue Swirl:
>>
>> On Mon, Aug 9, 2010 at 2:43 PM, Stefan Weil<address@hidden>  wrote:
>>
>>>
>>> Symbols with a size of 0 are unusable for the disassembler.
>>>
>>> Example:
>>>
>>> While running an arm linux kernel, no symbolic names are
>>> used in qemu.log when the cpu is executing an assembler function.
>>>
>>
>> That is a problem of the assembler function, it should use '.size'
>> directive like what happens when C code is compiled. And why just ARM?
>>
>>
>>>
>>> Assume that the size of such symbols is the difference to the
>>> next symbol value.
>>>
>>> Signed-off-by: Stefan Weil<address@hidden>
>>> ---
>>>  hw/elf_ops.h |    5 +++++
>>>  1 files changed, 5 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/hw/elf_ops.h b/hw/elf_ops.h
>>> index 27d1ab9..0bd7235 100644
>>> --- a/hw/elf_ops.h
>>> +++ b/hw/elf_ops.h
>>> @@ -153,6 +153,11 @@ static int glue(load_symbols, SZ)(struct elfhdr
>>> *ehdr, int fd, int must_swab,
>>>         syms = qemu_realloc(syms, nsyms * sizeof(*syms));
>>>
>>>         qsort(syms, nsyms, sizeof(*syms), glue(symcmp, SZ));
>>> +        for (i = 0; i<  nsyms - 1; i++) {
>>> +            if (syms[i].st_size == 0) {
>>> +                syms[i].st_size = syms[i + 1].st_value -
>>> syms[i].st_value;
>>> +            }
>>> +        }
>>>
>>
>> The size of the last symbol is not guesstimated, it could be assumed
>> to be _etext - syms[nsyms].st_value.
>>
>>
>>>
>>>     } else {
>>>         qemu_free(syms);
>>>         syms = NULL;
>>> --
>>> 1.7.1
>>
>
>
> The patch is still missing in qemu master.
> From the two feedbacks I did not read that anything needs to be changed.
> Was I wrong, or can it be applied?

Please fix the last symbol. Either we should fix all symbols or none,
half fixed (OK, practically all) is not so great.