Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 11 Jun 2019 10:25:46 +0200 | Subject | Re: [PATCH 07/15] binfmt_flat: use __be32 for the on-disk format |
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Hi Christoph,
On Mon, Jun 10, 2019 at 11:21 PM Christoph Hellwig <hch@lst.de> wrote: > So far binfmt_flat has onl been supported on 32-bit platforms, so the > variable size of the fields didn't matter. But the upcoming RISC-V > nommu port supports 64-bit CPUs, and we now have a conflict between > the elf2flt creation tool that always uses 32-bit fields and the kernel > that uses (unsigned) long field. Switch to the userspace view as the > rest of the binfmt_flat format is completely architecture neutral, > and binfmt_flat isn't the right binary format for huge executables to > start with. > > While we're at it also ensure these fields are using __be types as > they big endian and are byteswapped when loaded. > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> --- a/include/linux/flat.h > +++ b/include/linux/flat.h
> @@ -67,19 +67,19 @@ struct flat_hdr { > #define OLD_FLAT_RELOC_TYPE_BSS 2 > > typedef union { > - unsigned long value; > + u32 value; > struct { > # if defined(mc68000) && !defined(CONFIG_COLDFIRE) > - signed long offset : 30; > - unsigned long type : 2; > + s32 offset : 30; > + u32 type : 2; > # define OLD_FLAT_FLAG_RAM 0x1 /* load program entirely into RAM */ > # elif defined(__BIG_ENDIAN_BITFIELD) > - unsigned long type : 2; > - signed long offset : 30; > + u32 type : 2; > + s32 offset : 30; > # define OLD_FLAT_FLAG_RAM 0x1 /* load program entirely into RAM */ > # elif defined(__LITTLE_ENDIAN_BITFIELD) > - signed long offset : 30; > - unsigned long type : 2; > + s32 offset : 30; > + u32 type : 2; > # define OLD_FLAT_FLAG_RAM 0x1 /* load program entirely into RAM */
The definitions of OLD_FLAT_FLAG_RAM are identical, so could be factored out. However, they appear to be unused.
> # else > # error "Unknown bitfield order for flat files."
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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