On 08/07/2017 07:39 AM, Peter Maydell wrote: > For embedded systems, notably ARM, one common use of ELF > file segments is that the 'physical addresses' represent load addresses > and the 'virtual addresses' execution addresses, such that > the load addresses are packed into ROM or flash, and the > relocation and zero-initialization of data is done at runtime. > This means that the 'memsz' in the segment header represents > the runtime size of the segment, but the size that needs to > be loaded is only the 'filesz'. In particular, paddr+memsz > may overlap with the next segment to be loaded, as in this > example: > > 0x70000001 off 0x00007f68 vaddr 0x00008150 paddr 0x00008150 align 2**2 > filesz 0x00000008 memsz 0x00000008 flags r-- > LOAD off 0x000000f4 vaddr 0x00000000 paddr 0x00000000 align 2**2 > filesz 0x00000124 memsz 0x00000124 flags r-- > LOAD off 0x00000218 vaddr 0x00000400 paddr 0x00000400 align 2**3 > filesz 0x00007d58 memsz 0x00007d58 flags r-x > LOAD off 0x00007f70 vaddr 0x20000140 paddr 0x00008158 align 2**3 > filesz 0x00000a80 memsz 0x000022f8 flags rw- > LOAD off 0x000089f0 vaddr 0x20002438 paddr 0x00008bd8 align 2**0 > filesz 0x00000000 memsz 0x00004000 flags rw- > LOAD off 0x000089f0 vaddr 0x20000000 paddr 0x20000000 align 2**0 > filesz 0x00000000 memsz 0x00000140 flags rw- > > where the segment at paddr 0x8158 has a memsz of 0x2258 and > would overlap with the segment at paddr 0x8bd8 if QEMU's loader > tried to honour it. (At runtime the segments will not overlap > since their vaddrs are more widely spaced than their paddrs.) > > Currently if you try to load an ELF file like this with QEMU then > it will fail with an error "rom: requested regions overlap", > because we create a ROM image for each segment using the memsz > as the size. > > Support ELF files using this scheme, by truncating the > zero-initialized part of the segment if it would overlap another > segment. This will retain the existing loader behaviour for > all ELF files we currently accept, and also accept ELF files > which only need 'filesz' bytes to be loaded. > > Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> > --- > include/hw/elf_ops.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 48 insertions(+)
Reviewed-by: Richard Henderson <richard.hender...@linaro.org> r~
