Hi,
I got some question about the AT directive in linker script. I have
post this question to binutils{at}sourceware.org with no reply.
Hopefully someone can help me out.
After some searching and asking, I finally know that the AT directive
tell the linker about LMA of a section.
For example there is some linker script like this:
SECTIONS
{
. = 0X80100000;
.text : AT(0x100000) {
*(.text .stub .text.* .gnu.linkonce.t.*)
}
... blah blah ...
}
Now 0x8010000 is a VMA, and 0x100000 is a LMA.
My question is, is LMA the same as the physical address in a ELF
program header ? A typical ELF declaration would be something like
this:
typedef struct
{
Elf32_Word p_type; /* Segment type */
Elf32_Off p_offset; /* Segment file offset */
Elf32_Addr p_vaddr; /* Segment virtual address */
Elf32_Addr p_paddr; /* Segment physical address */
Elf32_Word p_filesz; /* Segment size in file */
Elf32_Word p_memsz; /* Segment size in memory */
Elf32_Word p_flags; /* Segment flags */
Elf32_Word p_align; /* Segment alignment */
} Elf32_Phdr;
Is LMA just **p_paddr** in the program header?
My understanding is, when the linker link all the object files
together and then output a executable file of ELF format, those LMA
declare in the linker script would be the **p_paddr** in the
executable file, so the loader can correspondingly put that program on
the physical address as declared by **p_paddr**. Is that correct?
Please correct me if you may. I'm reading some low level code and is
not really familiar with those low level stuff.
Thanks in advance!
Ruan.
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