On 2016年07月16日 02:42, Dave Hylands wrote: > > On Thu, Jul 14, 2016 at 1:45 AM, Yubin Ruan <ablacktshirt@xxxxxxxxx > <mailto:ablacktshirt@xxxxxxxxx>> wrote: > > On Wed, Jul 13, 2016 at 7:33 PM, Yubin Ruan > <ablacktshirt@xxxxxxxxx <mailto:ablacktshirt@xxxxxxxxx> > <mailto:ablacktshirt@xxxxxxxxx <mailto:ablacktshirt@xxxxxxxxx>>> > wrote: > > Hi, > I got some question about the AT directive in linker > script. I have > post this question to binutils{at}sourceware.org > <http://sourceware.org> > <http://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? > > ...snip... > > Thank you for replying. I think I understand what you mean. > But I still want the answer to my question, that is, is LMA just > **p_paddr** in the program header? > > > I'm pretty sure that's the case. There are actually 2 sets of headers. > You can use: > > objdump -p foo.elf > > to view the "private" headers which shows you the p_vaddr and p_paddr > fields. > > And you can use > > objdump -h foo.elf > > to view the section headers. > > Here's some example output for a typical embedded program: > > 2216 >objdump -p firmware.elf > > firmware.elf: file format elf32-little > > Program Header: > LOAD off 0x00008000 vaddr 0x08000000 paddr 0x08000000 align 2**15 > filesz 0x0000288c memsz 0x0000288c flags r-x > LOAD off 0x00010000 vaddr 0x08020000 paddr 0x08020000 align 2**15 > filesz 0x00040470 memsz 0x00040470 flags r-x > LOAD off 0x00058000 vaddr 0x20000000 paddr 0x08060470 align 2**15 > filesz 0x00000108 memsz 0x000064f0 flags rw- > LOAD off 0x0005e4f0 vaddr 0x200064f0 paddr 0x08060578 align 2**15 > filesz 0x00000000 memsz 0x00004000 flags rw- > LOAD off 0x0005a4f0 vaddr 0x2000a4f0 paddr 0x08060578 align 2**15 > filesz 0x00000000 memsz 0x00000800 flags rw- > > 2217 >objdump -h firmware.elf > > firmware.elf: file format elf32-little > > Sections: > Idx Name Size VMA LMA File off Algn > 0 .isr_vector 0000288c 08000000 08000000 00008000 2**2 > CONTENTS, ALLOC, LOAD, READONLY, CODE > 1 .text 00040470 08020000 08020000 00010000 2**2 > CONTENTS, ALLOC, LOAD, READONLY, CODE > 2 .data 00000108 20000000 08060470 00058000 2**2 > CONTENTS, ALLOC, LOAD, DATA > 3 .bss 000063e8 20000108 08060578 00058108 2**2 > ALLOC > 4 .heap 00004000 200064f0 08060578 0005e4f0 2**0 > ALLOC > 5 .stack 00000800 2000a4f0 08060578 0005a4f0 2**0 > ALLOC > 6 .ARM.attributes 00000037 00000000 00000000 00058108 2**0 > CONTENTS, READONLY > 7 .comment 000000e0 00000000 00000000 0005813f 2**0 > CONTENTS, READONLY > > -- > Dave Hylands > Shuswap, BC, Canada > http://www.davehylands.com Thanks :-) Your reply really eliminate my doubts. Regards, Ruan. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
