On 3/15/23 12:58, Palmer Dabbelt wrote: > On Tue, 28 Feb 2023 16:20:35 PST (-0800), gerg@xxxxxxxxxx wrote: >> Hi Palmer, >> >> On 1/3/23 07:52, Palmer Dabbelt wrote: >>> On Tue, 28 Feb 2023 05:51:24 PST (-0800), gerg@xxxxxxxxxx wrote: >>>> The following changes add the ability to run ELF format binaries when >>>> running RISC-V in nommu mode. That support is actually part of the >>>> ELF-FDPIC loader, so these changes are all about making that work on >>>> RISC-V. >>>> >>>> The first issue to deal with is making the ELF-FDPIC loader capable of >>>> handling 64-bit ELF files. As coded right now it only supports 32-bit >>>> ELF files. >>>> >>>> Secondly some changes are required to enable and compile the ELF-FDPIC >>>> loader on RISC-V and to pass the ELF-FDPIC mapping addresses through to >>>> user space when execing the new program. >>>> >>>> These changes have not been used to run actual ELF-FDPIC binaries. >>>> It is used to load and run normal ELF - compiled -pie format. Though the >>>> underlying changes are expected to work with full ELF-FDPIC binaries if >>>> or when that is supported on RISC-V in gcc. >>>> >>>> To avoid needing changes to the C-library (tested with uClibc-ng >>>> currently) there is a simple runtime dynamic loader (interpreter) >>>> available to do the final relocations, https://github.com/gregungerer/uldso. >>>> The nice thing about doing it this way is that the same program >>>> binary can also be loaded with the usual ELF loader in MMU linux. >>>> >>>> The motivation here is to provide an easy to use alternative to the >>>> flat format binaries normally used for RISC-V nommu based systems. >>>> >>>> Signed-off-by: Greg Ungerer <gerg@xxxxxxxxxx> >>>> --- >>>> >>>> arch/riscv/include/asm/elf.h | 11 +++++++++- >>>> arch/riscv/include/asm/mmu.h | 4 +++ >>>> arch/riscv/include/uapi/asm/ptrace.h | 5 ++++ >>>> fs/Kconfig.binfmt | 2 - >>>> fs/binfmt_elf_fdpic.c | 38 +++++++++++++++++------------------ >>>> include/linux/elf-fdpic.h | 14 +++++++++++- >>>> include/uapi/linux/elf-fdpic.h | 15 +++++++++++++ >>>> 7 files changed, 67 insertions(+), 22 deletions(-) >>> >>> Adding Damien, as IIRC he's had some hacked up userspace bits for the K210. I'm yet to get anything running, but it'd be great if we get this to a point where I can actually boot test this on QEMU (I'm just doing builds now). >> >> This is a simple script I user to generate a working QEMU example: >> >> https://raw.githubusercontent.com/gregungerer/simple-linux/master/build-riscvnommu-linux-uclibc-elf.sh >> >> It does reference some configs here https://github.com/gregungerer/simple-linux/tree/master/configs >> and this posted patchset as https://github.com/gregungerer/simple-linux/tree/master/patches (this is >> just these 2 patches combined as a single patch). >> >> >>> Given that it's the second week of the merge window and this is a bunch of new uABI it seems best to hold off until the next cycle. I poked around and don't see anything wrong, but I'll try and take a more detailed look after the merge window. >> >> Oh, yeah, no hurry. > > Maciej and Damien: I'm fine taking this, but not in any rush. I'd > rather get the uABI right if things are still in flight, but if we're > all just waiting for something to get merged first then I'm fine with > that being Linux. I did not try Gerg script with the k210. No time right now. But if it works with QEMU, should be fine. > >> >> Regards >> Greg -- Damien Le Moal Western Digital Research
